Turbine Operation Manual 600 MW Dongfang

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Table of Content Part I Turbine Mainframe Operation .............................................................................. - 2 - Chapter I Overview and Specifications of Unit Equipment ............................................ - 2 - 1. Overview of Steam Turbine and Auxiliaries ............................................................... - 2 - 2. Main Design Specifications of the Unit ...................................................................... - 7 -

2.1 Main Design Specifications of the Steam Turbine ............................................ - 7 - 2.2 Index of Steam and Water Quality.................................................................. - 11 -

Chapter II Protection, Control and Test of the Unit ...................................................... - 12 - 1. General Rules of Interlock Protection Test .............................................................. - 12 -

1.1 Purpose and Division of Interlock Protection.................................................. - 12 - 1.2 Test Method of Interlock Protection................................................................ - 13 - 1.3 Verification for Interlock Protection Test Results ............................................ - 13 -

2. Interlock Protection of Mainframe............................................................................ - 13 - 2.1 Main Thermal Protection of Steam Turbine .................................................... - 13 -

3. Thermal Interlock Protection of Auxiliaries .............................................................. - 25 - 4. Unit Control and Regulation Devices ...................................................................... - 49 -

4.1 Sequence Control System (SCS)................................................................... - 49 - 4.2 Analogue Control System (MCS) ................................................................... - 49 - 4.3 Turbine Digital Electro-hydraulic Control System (DEH) ................................ - 60 -

5. Main Test of the Unit ............................................................................................... - 69 - 5.1 Static Test of the Control System ................................................................... - 69 - 5.2 Manual Trip Test............................................................................................. - 70 - 5.3 Trip Protection Test of Turbine Emergency Trip System (ETS) ...................... - 71 - 5.4 Turbine Main Trip Solenoid Valve Test ........................................................... - 72 - 5.5 Power-load Unbalance Relay (PLU) Loop Test.............................................. - 73 - 5.6 Eccentric Ring Oil Spray Test of Emergency Governor .................................. - 73 - 5.7 Emergency Governor Minimum Oil Spray Action Speed Test......................... - 74 - 5.8 Turbine Mechanical Over-speed Test............................................................. - 75 - 5.9 Electric Over-speed Test of Steam Turbine .................................................... - 77 - 5.10 Valves Activity Test....................................................................................... - 79 - 5.11 MSV and CV Leak Test ................................................................................ - 79 - 5.12 Mainframe Low Lube Oil Pressure Interlock Protection Test........................ - 79 - 5.13 Vacuum Leakage Test.................................................................................. - 80 - 5.14 Extraction Check Valve Activity Test............................................................. - 81 - 5.15 Load Rejection Test...................................................................................... - 81 -

Chapter III Start-up and Outage of the Unit and Operating Maintenance Thereof....... - 84 - 1 Start-up of the Unit ................................................................................................... - 84 -

1.1 Start-up Specifications and Requirements ..................................................... - 84 - 1.2 Start-up Prohibition Conditions of the Unit ..................................................... - 85 - 1.3 Start-up State Classification of the Unit .......................................................... - 86 - 1.4 Inspection before the Steam Turbine Start-up ................................................ - 87 - 1.5 Operation of Auxiliaries and Systems before the Unit Start-up....................... - 88 - 1.6 Unit Start-up Parameters and Mode Selection Principal ................................ - 90 - 1.7 Cold Start-up of the Unit................................................................................. - 91 - 1.8 Warm and Hot Start-up of Unit ..................................................................... - 103 - 1.9 Extreme Hot Start-up of Unit ........................................................................ - 105 -

2. Normal Operation and Maintenance of Unit .......................................................... - 106 - 2.1 Routine Maintenance and Requirements ..................................................... - 106 - 2.2 Operational Parameters of Unit.................................................................... - 107 - 2.3 Adjustment and Maintenance for Normal Operational Parameters of Unit ... - 109 -

3. Normal Shutdown of Unit ...................................................................................... - 112 - 3.1 Preparations before Shutdown..................................................................... - 112 - 3.2 Shutdown with Variable Parameter .............................................................. - 113 - 3.3 Operations after Generator Disconnection................................................... - 115 - 3.4 Cautions for Unit Shutdown ......................................................................... - 116 -

Chapter Ⅳ Accident Management of Unit ............................................................... - 118 - 1. General Principles................................................................................................. - 118 -

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2. Regulations on the Handling of Unit Accidents ..................................................... - 120 - 2.1 Emergency Outage Conditions of Unit ......................................................... - 120 - 2.2 Fault Shutdown Conditions of Unit............................................................... - 124 - 2.3 Comprehensive Accident Management of Unit ............................................ - 126 -

3. Abnormal Operation and Accident Management of Steam Turbine ...................... - 133 - 3.1 Condenser Vacuum Drop............................................................................. - 133 - 3.2 Steam Turbine Water Attack......................................................................... - 135 - 3.3 Abnormal Vibration of Steam Turbine........................................................... - 137 - 3.4 Increased Axial Displacement ...................................................................... - 139 - 3.5 Damaged or Broken Blade........................................................................... - 140 - 3.6 Lubricating Oil System Failure ..................................................................... - 141 - 3.7 EH Oil System Failure.................................................................................. - 144 - 3.8 Feed Pump Failure ...................................................................................... - 145 - 3.9 Deaerator Failure ......................................................................................... - 149 - 3.10 Heater Failure ............................................................................................ - 152 - 3.11 Generator Sealing Oil System Failure ........................................................ - 153 - 3.12 Generator Hydrogen Cooling System Failure ............................................ - 155 - 3.13 Generator Stator Cooling Water System Failure ........................................ - 157 -

Part II Auxiliary System Operation............................................................................. - 159 - Chapter Ⅰ General Rules on Start-up (in operation) and Shutdown (out of service) of Auxiliaries and systems............................................................................................. - 159 - 1. General Operating Rules of Auxiliaries ................................................................. - 159 - 2 General Outage Rules of Auxiliaries ...................................................................... - 162 - Chapter II Auxiliaries and Systems............................................................................ - 163 - 1. Lubricating Oil System .......................................................................................... - 163 - 2. EH Oil System....................................................................................................... - 167 - 3. Unit Bypass System .............................................................................................. - 171 - 4. Gland Sealing System........................................................................................... - 173 - 5. Vacuum System .................................................................................................... - 179 - 6. Circulating Water System...................................................................................... - 183 - 7 Open Circulating Cooling Water System................................................................ - 185 - 8. Condensate System.............................................................................................. - 186 - 9. Regeneration and extraction Steam System ......................................................... - 190 - 10. Feed pump System............................................................................................. - 202 - 11. Auxiliary Steam System....................................................................................... - 211 - 12. Generator Sealing Oil System............................................................................. - 214 - 13. Generator Hydrogen Cooling System ................................................................. - 217 -

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Part I Turbine Mainframe Operation

Chapter I Overview and Specifications of Unit Equipment 1. Overview of Steam Turbine and Auxiliaries

The N600-16.7/538/538/-3 steam turbine used in this project is a subcritical, single

reheat, condensing, tandem, three-cylinder four-exhaust, impulse steam turbine

produced and designed by Dongfang Steam Turbine Works. The main and reheat

steam of it is configured to unit system in form of two-one-two. Its high pressure (HP)

cylinder contains one single-governing stage and eight-pressure stage; the

intermediate pressure (IP) cylinder has five-pressure stage; the high and intermediate

pressure (HIP) flow passages are designed to two-layer countercurrent with a

common casing; and the low pressure (LP) is two-layer double-flow LP cylinder with

2*2*7 pressure stages. Through four pieces of admission pipe that are vertically and

symmetrically arranged at the middle of the HIP outer casing, the main steam enters

into the steam turbine, and then to the boiler reheater after experiencing HP 9-stage

work. Similarly, the reheat steam enters into the IP part of the steam turbine in the

same way as the main steam, and then enters into two LP two-pass cylinders

separately through a piece of reducing connector after IP five-stage work; at last it is

exhausted into a double-back pressure condenser through the bi-directionally

arranged exhaust pipe of the two cylinders after the 7-stage work.

The steam turbine is equipped with two HP main stop valves that are used for

contacting the sealing surface well so as to prevent steam leak at the status of wide

open. There are steam strainers inside the valves for purpose of preventing foreign

substances from flowing into the flow passage. The unit is provided with four main

steam control valves for regulating steam volume entering the steam turbine. They

are equipped with a balance chamber for preventing from vibrating and arranged into

a shared valve casing in the form of straight line. The valve casing is independent of

the steam turbine proper. The IP main steam valves and control valves are union

valves with a common valve seat, wherein the former two are sleeve valves and the

later four are spherical valves. Both of them are able to move independently during

the total stroke, and opened, closed by hydraulic pressure and spring separately. The

unit is also provided with two IP union valves each of which has a steam strainer for

preventing foreign substances from entering the flow passage. Under normal

condition, the IP main stop valves and control valves are widely open. The main stop

valves, control valves and union valves are equipped with on-off testers solely used

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after overhaul and the remote test can be performed in operation of them on the

condition that the load is not subject to large fluctuation.

The structure of HIP cylinder with common casing and double-shell is used. It

consists of four parts, including an integrated HIP outer casing divided into upper and

low half casings from the split, a HP inner casing divided into upper and lower half

casings, an IP inner casing divided into upper and lower half casings and an IP outer

casing. Two LP cylinders are symmetrical double split flow structure with the function

of middle steam admission and divided into upper and lower parts from the split. The

LP cylinders are designed to three-layer with the first layer served as inner casing for

accommodating the elements of the flow passage, the second one as a heat

insulating layer and the third one as an outer casing for exhausting steam and

supporting the elements in the inner casing. The LP cylinder is connected with the

condenser by a stainless steel elastic expansion joint.

The shaft system of the unit is composed of a steam turbine HP rotor and IP rotor, LP

rotor A and B and a generator rotor. Each of them is connected by a solid coupling.

The steam turbine rotors without center holes are totally integral rotor.

The steam turbine is supported by six pieces of bearing blocks; the HIP rotors are

supported by two titling-pad bearings with #1 and #2 numbers of bearing block; two

LP rotors are supported by two elliptical bearing with #3, #4, #5 and #6 numbers of

bearing block, horizontal split and spherical types, and automatic alignment and

regulation functions. A thrust bearing with the capability of withstanding much high

axial thrust load, whereas resulting in little loss on any loads is structured to bevel

dual thrust disc and located in a middle bearing housing beside the #2 bearing block.

The expansion dead points of the HIP cylinder locates near the center line of the #2

bearing block, the LP cylinder A and B, respectively. A transverse pin at the dead

point restricts the axial displacement of the cylinder, and longitudinal pins in front and

back of the front bearing housing and the longitudinal center line of the two low

pressure cylinders guide the cylinders to expand freely along the axial direction and

restrict the deviation laterally.

An automatic-meshing turning gear of the steam turbine consisting of a motor and

gear train is equipped between the steam turbine and the generator. Its revolution is

1.5r/min and it is able to automatically operate and trip.

To avoid water and steam from returning back the steam turbine, the drainage and

exhaust steam systems of the steam turbine are designed to able to exhaust

condensate in all of devices, pipelines and valves and steam in the HIP cylinder and

HIP gland sealing system discharged at the time of unit trip. Their pneumatic drain

valves are able to be automatically and widely opened at the time of lacking

compressed air resource. To prevent steam from arriving at the intermediate and low

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pressure parts to do work through the steam sealing gland located between the high

and intermediate pressure parts at the time of load rejection, an emergency discharge

valve is set at the place of the steam sealing gland. In case that the IP control valve is

closed, it automatically opens and reliefs most of leaked steam into the condenser. In

order to avoid overheat at the HP steam exhaust part resulting from windage loss in

case that the unit is started by the IP cylinder or high and low pressure bypass on low

load, a vent valve (VV) is equipped on the exhaust pipeline of the HP cylinder to

connect with the condenser. There are no drain points on the high and intermediate

pressure cylinders, and so water can be drained solely through the drain point on an

extraction steam pipe. Water of the LP cylinder is drained to a condenser hot well

level and water of the HP main steam pipes and valves is drained to a drain flash tank

of the condenser. The unit is provided with two sets of rectangular drain flash tank

located at lateral outer walls of the HP condenser and the LP condenser, respectively,

and a spray de-superheating device that is used for spraying water while the unit is in

operation.

The regenerative system of the steam turbine has 8-stage non-regulatory extraction

for three sets of HP heater, one deaerator and four sets of LP heater, respectively.

Water of the HP and LP heaters reflows to the deaerator and the condenser,

respectively by means of cascaded drain. Drain water can flow into the condenser

directly in case of accident or low load. Steam source of the steam turbine for feed

water pump is from four-stage extraction under normal conditions; in case of startup

of the unit and low load, it is automatically switched to reheat steam. Its exhaust

steam is discharged into a main condenser. Besides, for regenerative extraction

steam and steam of the steam turbine of the feed water pump, four-stage extraction

of the steam turbine is able to provide auxiliary steam for others. To meet the demand

of connecting the steam exhaust pipe and the drain pipe, the #7 and #8 LP heaters

are designed to compound heaters with a common shell and horizontally configured

at throat part of the condenser with part of which out of the shell.

The condensate system employs an IP condensate polishing system each of which is

provided with a vertical condensate pump with 2*100% volume and one of which is

served as standby. Condensate after boosting pressure enters into the deaerator

through a polishing unit, a gland heater and four LP heaters.

The gland sealing system of the steam turbine is a self-sealing system, i.e. in normal

operation of the unit, steam leakage from the shaft-end steam gland of the HIP

cylinder, and the steam leakage from HIP main stop valve and valve stems of the

control valves after being sprayed and de-superheated is provided for the LP

shaft-end steam gland. The redundant steam flows to the LP heater or condenser

through an overflow station. During startup or operation of unit on low load, the

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auxiliary steam station is used for providing steam for the steam gland. The unit is

provided with one set of gland heater with 100% volume and two sets of gland

extraction fan with 100% volume. The gland cooler and the steam turbine of the feed

water pump shares the gland steam. During startup and operation of the unit with low

load, gland steam is fresh or auxiliary steam and pressure of the gland main pipe is

maintained by a gland steam supply valve and an overflow valve. During operation of

the unit with 25%-60% of load, its gland steam is provided by the gland cooler; while

the load is over 60%, the unit is self-sealed and the gland steam supply valve is

closed. The set value of the gland pressure is maintained by the overflow valve and

the redundant steam is discharged into #8 A LP heater through the overflow valve.

The redundant steam is discharged into the condenser through a conversion valve in

case of #8 A LP heater failures.

The emergency governing system is the actuating mechanism of the HP fire-resistant

oil DEH, which works on instruction reception from the DEH and completion of

latching, meets the requirements of combined startup of high and intermediate

pressure cylinders, startup of the IP cylinder and activity test of the valves, and has

the functions of over-speed limitation, fast reliable steam admission interruption and

over-speed protection. The system comprises a LP governing system and a HP

fire-resistant oil system. The LP governing system is composed of an emergency

governor, an emergency governor device and its link lever, a manual stop mechanism,

a reset test valve block, a mechanical shutdown electromagnet and an oil guide ring,

etc. Main functions of it comprise latch, interruption, oil spray and speed hoisting. The

HP fire-resistant oil system consists of a hydraulic servo system, a HP trip system and

a fire-resistant oil supply system. The hydraulic servo system, consisting of a valve

control stage and a servomotor, is used for controlling opening of the valves and

completing fast shutdown of them. This unit is provided with four sets of servomotor

for HP control valves, two for HP main stop valves, IP main stop valves and IP control

valves, respectively. All of said servomotors, with unilateral oil feed, are started up by

fire-resistant oil pressure and closed by spring force of the control stage, so as to

guarantee all of them can be shut down in case of pressure oil loss. The oil supply

system, mainly consisting of two sets of pressure-compensated variable plunger

pump, a regenerative device, an accumulator, oil filtering components, etc., is used

for supplying HP working oil for every actuating mechanisms of the emergency

governing system.

The lubricating oil system is served as main oil pump-oil turbine system driven by the

major axis of the steam turbine. In addition to all bearings of the turbine generators, it

supplies oil for the hydrogen sealing system of the generators, the lubricating device

of the turning gear and the jacking oil pump as well. It comprises a packaged oil

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container, a main oil pump (MOP), an AC auxiliary oil pump (TOP), a DC emergency

oil pump (EOP), a boiler oil pump (BOP), a jacking oil device, an oil purification and

regeneration device, six sets of electric heater, two sets of oil cooler with 100%

volume, a change-over valve, a flume extractor, etc. The strainers in the lubricating oil

system are able to be replaced to clean. In view from the head, the lubricating oil

system locates on the right.

For the purpose of successfully putting the turning gear into operation, the jacking oil

system is applied to providing HP oil for every bearing at the time of startup and

shutdown of the unit. Therefore, two sets of jacking oil pump, with the advantages of

high efficiency, low heat value and noise, reliable performance and no leakage under

continuous HP operation, and high volumetric efficiency, etc., are applied in the

system.

The unit employs a HLP two-stage series-wound pneumatic bypass system, in which

the capacity of high pressure bypass is 60%BMCR. This system is able to make the

unit optimally start and shut down, realize two operating modes in accordance with

the operating conditions, startup and stop curves of the steam turbine, shorten the

starting time of the unit in cooperation of setting up a steam temperature of the steam

turbine suitable for the boiler’s. In case that the unit load is variable, the system can

be applied to regulating it so as to improve the stability of the boiler in operation.

The feed water system is configured to unit system, with two sets of 50% BMCR

turbo-feed pump and one set of 50% BMCR electro-driven variable-speed feed water

pump for one set of unit. The turbo-feed pump is put into normal operation and the

electro-driven variable-speed feed water pump is served as standby or startup. The

turbo-feed pump is provided with HP and LP steam sources and configured at the

operating floor of the steam turbine, and its steam is exhausted into the condenser of

the turbine mainframe. The feed water system also provides attemperating water for

overheat and reheat attemperators, and the bypass system.

The unit adopts a distributed control system (DCS) that has the functions of

monitoring the DEH, MEH operator stations and other control systems (data

communication interface) and meeting the requirements of various operating

conditions. The DEH produced by Dongfang Electric Automatic Control Cooperation

Limited for controlling the rotating speed and load of the steam turbine is employed in

the turbine governing system.

Startup mode of the unit: IP cylinder startup, combined startup of the HP, IP cylinders,

whereas IP cylinder startup in priority. The combined startup mode is solely used in

case that the bypass system is cut off due to failure.

Operating mode of the unit: constant pressure, and constant pressure-to-sliding

pressure-to-constant pressure

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Load character: with the main functions of bearing base load, and peak load

regulation function

Arrangement of the unit: the turbine generating set is indoors longitudinal sequential

arrangement. The lubricating oil system is configured on the right in view from the

head to the generating set.

Cooling mode of the unit: unit system with counter-flow circulating water system

2. Main Design Specifications of the Unit

2.1 Main Design Specifications of the Steam Turbine

2.1.1 Steam Turbine Proper Specifications

S/N Item Unit Data

Unit specifications

1 Unit model Sub-critical,

single reheat,

three-cylinder

four-exhaust,

tandem and

condensing

2 Steam turbine model N600-16.7/538/5

38-3

3 TMCR output MW 600

4 VWO output MW 640.647

5 HP heater and omni-segmentation

output

MW 600

6 TMCR main steam pressure MPa(a) 16.7

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S/N Item Unit Data

7 TMCR main steam temperature ℃ 538

8 TMCR HP cylinder exhaust steam

pressure

Mpa(a) 3.849

9 TMCR inlet pressure of reheat steam Mpa(a) 3.464

10 TMCR inlet temperature of reheat steam ℃ 538

11 TMCR main steam throttle flow t/h 1876

12 Maximum throttle flow of main steam t/h 2028

13 TMCR throttle flow of reheat steam t/h 1596.377

14 TMCR exhaust steam pressure Mpa(a) 0.01013

15 Steam distribution mode Composite

(nozzle/throttle)

16 Design temp of cooling water ℃ Open

32.4/closed 38

17 TMCR feed temperature ℃ 277.2

18 Rated speed R/Min 3000

19 TMCR heat consumption kJ/kW.

h

kcal/kW

8130/1942

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S/N Item Unit Data

20 Regenerative heat grade of feed water 3+1+4 (high

pressure plus

de-oxidation plus

low pressure)

21 Length of low pressure last stage blade mm 851

22 Total internal efficiency of steam turbine %

High pressure cylinder efficiency %

Intermediate pressure cylinder

efficiency

%

Low pressure cylinder efficiency %

23 Series of flow passage

High pressure cylinder Grade 9

Intermediate pressure cylinder Grade 5

Low pressure cylinder Grade 2*2*7

24 Critical speed

25 Shafting torsion frequency Hz

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S/N Item Unit Data

26 Dimensions (Length, width and height) m 27.82*10.68*6.29

2.1.2 Operational parameter

Item Unit Data

Full vacuum idle time min 6Idle time without vacuum min 3Max. load in case of main switch disconnection and over-speed trip

kW

640647

Rotating speed of over-speed trip r.p.m 3330～3360(mechanical)3300（electronic）

Max. operational back pressure KPa(a) 18.6 Alarm back pressure of steam turbine KPa(a) 19.7 Turbine trip back pressure KPa(a) 25.3 Max. allowable operational exhaust temp ℃ 12Alarm exhaust temp ℃ 8Exhaust temp of manual shutdown ℃ 12Spray flow of LP cylinder t/h 4Allowable min. continuous rating M 9Allowable runtime under min. continuous rating min No limit

Max. back pressure at allowable min. continuous rating

MPa(a) 0.0186

Max. main steam pressure at allowable min. continuous rating

MPa(a) 16.67

Max. main steam temp at allowable min. continuous rating ℃ 53Vibration limit value of shaft relative to double amplitude of vibration at rated revolution

μm Not greater than 34

Vibration limit value of shaft block relative to double amplitudof vibration at over-critical revolution

μm Not greater than 80

Load limit at the time of stopping one set of LP heater MW

600

Revolution of turning gear r.p.m 1.5 Max. cylinder temp at turning gear shutdown ℃ 15

0

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Max. rotor temp at turning gear shutdown ℃ 150

Requirements for other short-term abnormal condition -

2.1.3 Combined critical speed of every rotor in shaft system

First critical speed (r/min) Second critical speed (r/min)

Name Shafting design

value Tandem design

value Shafting design

value Tandem design value

HIP rotor 17222 1621 Greater than 4000 Greater than 4000

LP rotor A 1839 1723 3521 Greater than 4000

LP rotor B 1903 1750 Greater than 4000 Greater than 4000

Generator rotor

984 1070 Greater than 3400 3338

2.1.4 Allowable load variation rate of the unit

100％～50％MCR Not less than 5％/min.

50％～30％MCR Not less than 3％/min.

Less than 30％MCR Not less than 2％/min.

2.2 Index of Steam and Water Quality

Item Unit Index Remarks

Electrical

conductivity μs/cm ≤0.3

After hydrogen ion

exchange at 25℃

Sodium μg/kg ≤10

Steam

Silicon dioxide μg/kg ≤20

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Iron μg/kg ≤20

Copper μg/kg ≤5

Hardness μmol/L ≈0

Less than or equal to

5.0 when boiler

startup

Silicon dioxide Qualified Less than or equal to

80 boiler startup

Dissolved oxygen μg/L ≤7


30 when boiler

startup

Iron μg/L ≤20


75 when boiler

startup

Copper μg/L ≤5

Hydrazine μg/L 10～50

pH 9.0-9.5

Oil mg/L ≤0.3

Feed water

Electrical

conductivity μs/cm ≤0.3

After hydrogen ion

exchange at 25℃

Hardness μmol/L 0

Electrical

conductivity of

hydrogen

μS/cm ≤0.3

Dissolved oxygen μg/L ≤30

Condensate

Sodium μg/L ≤10

Chapter II Protection, Control and Test of the Unit

1. General Rules of Interlock Protection Test

1.1 Purpose and Division of Interlock Protection

1.1.1 Test purposes: check thermal interlock protection circuit action for correctness,

including the action of primary single circuit and interlock protection.

1.1.2 Division of test

1.1.2.1 Inspection associated with thermal device, and thermal technicians in responsible

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of forcing, stimulating and resetting of thermal single

1.1.3.2 Field apparatus inspection associated with the test, and operators in responsible

of the operation of the electric switches and OPR

1.2 Test Method of Interlock Protection

1.2.1 Single imitation

1.2.2 Transmission test

1.3 Verification for Interlock Protection Test Results

1.3.1 Hard wired circuit test

1.3.2 Interlock protection test

1.3.2.1 Mainframe protection test (see thermal protection of the mainframe)

1.3.2.2 Auxiliary protection test

2. Interlock Protection of Mainframe

2.1 Main Thermal Protection of Steam Turbine

2.1.1 Turbine DEH and ETS trip protection

ETS over-speed protection

TST over-speed protection

DEH over-speed protection

High metal temperature (left and right) protection for inner walls of the HP cylinder

exhaust

1. Send an alarm signal of high metal temperature in case that the metal

temperature of the HP cylinder’s exhaust is greater than or equal to 420 degrees

centigrade.

2. Shut down by the action of protection in case that the metal temperature of the

HP cylinder’s exhaust is greater than or equal to 432 degrees centigrade.

High metal temperature (back and right) protection for LP cylinder exhaust

3. Send an alarm signal of high metal temperature in case that the metal

temperature of the LP cylinder‘s exhaust is greater than or equal to 80 degrees

centigrade.

4. Shut down by the action of protection in case that the metal temperature of the

LP cylinder’s exhaust is greater than or equal to 107 degrees centigrade.

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Low vacuum protection of condenser: Shut down by the action of protection in

case of low vacuum of condenser.

Low lube oil pressure protection:

5. Send an alarm signal of low lube oil pressure in case that the lube oil pressure is

less than 0.115MPa;

6. Shut down by the action of protection in case that the lube oil pressure is less

than 0.069MPa;

Shut down by the action of projection in case of low EH oil pressure (one of two

logic) (1, 3 and/or 2, 4).

Large vibration protection of bearings

Send an alarm signal of large vibration in case that the vibration of any bearing is

greater than or equal to 125um; Shut down by the action of protection in case that

the vibration is greater than or equal to 250um.

1. Send an alarm signal of large axial displacement in case that the axial

displacement of the steam turbine is less than negative 1.05mm or greater than

positive 0.6mm.

2. Shut down by the action of protection in case that the axial displacement of the

steam turbine is less than negative 1.65mm or greater than positive 1.2 mm.

Differential expansion protection of HIP cylinders

1. Send alarm signal of large differential expansion in case that the differential

expansion is less than negative 5.3mm or greater than positive 10.3mm;

2. Shut down by the action of protection in case that the differential expansion is

less than negative 6.6mm or greater than positive 11.6mm.

Differential expansion protection of LP cylinder

1. Send alarm signal of large differential expansion in case that the differential

expansion is less than negative 4.6mm or greater than positive 19.8mm;

2. Shut down by the action of protection in case that the differential expansion is

less than negative 8mm or greater than positive 30mm.

DEH electricity loss protection

Generator protection

Malfunction of a trip protection button on the console

Trip by the action of protection in case that temperature of any bearing shell of

#1-#8 journal bearings is high (5 seconds delay) (alarm when temperature of #1-#6

bearing shells reaches 110 degrees centigrade and trip when reaching 115

degrees centigrade; meanwhile, alarm and trip temperatures of the #7 and #8

bearing shells are 110 and 115 degrees centigrade, respectively);

Trip by the action of protection in case that the temperatures of #1-#8 working

thrust pads are high (time delay 5s) (alarm and trip temperatures of them are 85

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and 110 degrees centigrade, respectively);

Trip by the action of protection in case that the temperatures of #1-#8 locating

thrust pads are high (time delay 5s) (alarm and trip temperatures of them are 85

and 110 degrees centigrade, respectively);

Shut down by the action of protection in case that the steam temperature of the

main stop valve at the inlet is LL (low, low);

Shut down by the action of protection in case that cooling water inlet flow of the

generator stator is LL;

Shut down by the action of protection in case that inlet cooling water pressure of

the generator stator is LL;

Shut down by the action of protection in case that outlet cooling water temperature

of the generator stator is HH (high, high).

2.1.2 Over-speed protection

2.1.2.1 Over-speed protection control system (OPC): the momentary speed of the steam

turbine will reach maximum in case that the trip signal of the generator main switch does

not send out due to control single lag and residual steam at the time of load rejection of

the unit. In order to prevent the unit from tripping for a rotating speed capable of causing

tripping, the HIP control valve must be closed fast and immediately to prevent speed rise

when the rotating speed reaches 103% of the rated.

2.1.2.2 When the rotating speed of the steam turbine reaches 110%-111% of the rated

speed, the eccentric ring mechanical emergency governor drives the mechanical trip

valve into action to drain the oil in the emergency trip system (ETS), to close the high

pressure main stop valve and the high pressure control valve and to open the vent valve.

And then the steam turbine is stopped after closing the intermediate pressure main stop

and control valves, the extraction check valves and exhaust check valve of the HP

cylinder at all levels and opening the dump valve.

2.1.2.3 Electric over-speed protection: immediately close the HIP MSV and CV to stop

feeding steam while the rotating speed of the unit reaches 111% of the rated speed;

meanwhile, the DEH sends out a stop signal.

2.1.3 Manual shutdown

2.1.3.1 Manual field tripper: it is set at the front box of the steam turbine. While operating,

the tripper is first drawn out after counter-clockwise rotating 90°, and then the HP MSV

and HP CV, IP MSV and IP CV, the exhaust check valve of the HP cylinder and check

valves at all level are closed and the vent valve is opened after the safety oil is drained by

the action of the mechanical trip valve.

- 16 -

2.1.3.2 Manual remote tripper: it is of double-button and equipped on the control desk of

the central control room. Pressing the buttons will bring the mechanical solenoid and the

main trip solenoid A and B into action to close HP MSV and HP CV, IP MSV and IP CV, the

exhaust check valve of the HP cylinder and check valves at all level and open the vent

valve.

2.1.4 Protection system for preventing water induction

Principal for classification of water induction-preventing control

Divide the turbine steam source piping, steam turbine proper and drain valves of

every extraction piping into HP, IP, LP drain valves;

Exclude every extraction check valves for the reason that the said valves are totally

used for preventing water into steam turbine;

Open and close the said three valves in accordance with the load level, they are

divided into 10%, 20% and 30% MCR;

Set one operating button for three of them;

The said three drain valves include the drain valves of 1-6 segments extraction

pipeline.

LBA41AA560VC

Pneumatic drain valve of the main steam pipe LBA41AA560VC Open conditions of interlock

Load less than or equal to 10%

Steam turbine trip

Generator trip Closure conditions of interlock

Load greater than 10%

Low-low condenser vacuum (similarly to the said drain valves) (with the use of an

analogue value less than 50kpa)

Pneumatic drain valves of main steam pipe on the left and right sides

LBA21AA560VC/ LBA31AA560VC Open conditions of interlock


Steam turbine trip


Load greater than 10%

Low-low condenser vacuum (similarly to the said drain valves) (with the use of a

analogue value less than 50kpa)

Pneumatic drain valves of main steam pipe on the left and right sides

- 17 -

LBA21AA560VC/ LBA31AA560VC Closure conditions of interlock


Steam turbine trip


Steam turbine more than 20%

Low-low condenser vacuum

Pneumatic drain valves of upper and lower valve blocks of right and left main

steam valves MAL70AA560VO/ MAL30AA560VO/ MAL60AA560VO/

MAL40AA560VO Closure conditions of interlock


Steam turbine trip


Steam turbine greater than 10%


Pneumatic drain valves of right and left RSV 1/2 MAL10AA560VO/

MAL20AA560VO Closure conditions of interlock


Steam turbine trip




Pneumatic drain valve for outlet of the HP control valve MAL50AA560VO Closure conditions of interlock


Steam turbine trip




Over-speed protection control system action (OPCACT for short)

Steam turbine trip

Generator trip

- 18 -

Following valves will automatically open in case that the load is less than 10% of

the rated.

Steam turbine trip

Generator trip


Drain valve of the left main steam pipe

Drain valve of the right main steam pipe

Drain valve of HP steam conduit

Drain valve for the left upper valve block of the HP MSV

Drain valve for the left lower valve block of the HP MSV

Drain valve for the right upper valve block of the HP MSV

Drain valve for the right lower valve block of the HP MSV

Drain valve for the left exhaust pipe of the HP cylinder

Drain valve for the right exhaust pipe of the HP cylinder

Drain valve for the exhaust manifold of the HP cylinder

Outlet drain valve for the 1st extraction electric valve

Inlet drain valve for the 1st extraction electric valve

Outlet drain valve for the 2nd extraction electric valve

Inlet drain valve for the 2nd extraction electric valve

Drain valve of HP bypass pipe

Following valves will automatically close in case that the load is greater than 10%:


Drain valve of the left main steam pipe

Drain valve of the right main steam pipe

Drain valve of HP steam conduit

Drain valve for the left upper valve block of the HP MSV

Drain valve for the left lower valve block of the HP MSV

Drain valve for the right upper valve block of the HP MSV

Drain valve for the right lower valve block of the HP MSV




Outlet drain valve for the 1st extraction electric valve

Inlet drain valve for the 1st extraction electric valve

Outlet drain valve for the 2nd extraction electric valve

Inlet drain valve for the 2nd extraction electric valve

Drain valve of HP bypass pipe

- 19 -

Following valves will automatically open in case that the load is less than 20%:

Steam turbine trip

Generator trip


Drain valve of left reheat steam pipe

Drain valve of right reheat steam pipe

Drain valve of left IP union valve

Drain valve of right IP union valve

Inlet drain valve of 3ird extraction electric valve

Outlet drain valve of 3ird extraction electric valve

Inlet drain valve of 4th extraction electric valve

Outlet drain valve of 4th extraction electric valve



Drain valve of left reheat steam pipe

Drain valve of right reheat steam pipe

Drain valve of left IP union valve

Drain valve of right IP union valve

Inlet drain valve of 3ird extraction electric valve

Outlet drain valve of 3ird extraction electric valve



Following valves will automatically open in case that the load is less than 30%:

Steam turbine trip

Generator trip













High-high water level in the drain pot triggers the drain valve to open, whereas to

- 20 -

close.



close.



close.

Drain valve for the exhaust pipe at the inlet A of the LP bypass valve


close.

Drain valve for the exhaust pipe at the inlet B of the LP bypass valve


close.

Drain valve for the exhaust pipe at the outlet A of the LP bypass valve


close.

Drain valve for the exhaust pipe at the outlet B of the LP bypass valve


close.

Steam turbine trip or generator asynchronous protection or OPC action will close

the left exhaust check valve of the HP cylinder.

Steam turbine trip or generator asynchronous protection or OPC action will close

the right exhaust check valve of the HP cylinder.

2.1.5 Interlock protection for lubricating oil system of mainframe

2.1.5.1 The turbine AC auxiliary pump is self-driven in case of meeting one of following

conditions:

1) Low outlet pressure of the main oil pump

2) The period before turbine rotating speed down to 2900r/min

3) Low lube oil

4) Steam turbine trip

2.1.5.2 The manual shutdown of the turbine AC auxiliary pump is available in case of

meeting one of following conditions:

1) Zero rotating speed of steam turbine

2) Stable and constant rotating speed of the steam turbine up to 3000r/min and normal

lube oil pressure

2.1.5.3 The mainframe startup pump (MSP) is self-driven in case of meeting one of

- 21 -

following conditions: 1）Turbine rotating speed less than or equal to 2850 r/min

2）Low inlet pressure of the main oil pump (MOP) (less than Mpa)

3）Steam turbine trip.

2.1.5.4 The manual shutdown of the mainframe startup pump (MSP) is available in case of


1) Stable and constant rotating speed of the steam turbine up to 3000r/min

2) Zero rotating speed of steam turbine.

2.1.5.5 The DC emergency oil pump (EOP) is self-driven in case of meeting one of

following conditions:

1) Non-zero rotating speed of the steam turbine and low-low lube oil pressure of the

mainframe (less than Mpa)

2) Standby AC lube oil pump startup with the AC lube oil pump trip 3）Low inlet pressure of the MOP and TOP.

2.1.5.6 The manual shutdown of the DC emergency oil pump (EOP) is available in case of


1) Zero rotating speed of steam turbine

2) Normal lube oil pressure (0.137Mpa- 0.176Mpa).

2.1.5.7 The startup of the mainframe jacking oil pump is allowable under the following

condition:

1) Inlet pressure of the jacking oil pump more than 0.03Mpa

2.1.5.8 The mainframe jacking oil pump is allowable for shutdown in case of meeting one

of following conditions:

1) The AC auxiliary oil pump out of service

2) The turbine rotating speed is greater than or equal to 2000r/min (tentative speed)

3) Allowable for one standby in two sets of jacking oil pump

2.1.5.9 The jacking oil pump is self-driven in case of meeting one of following conditions: 1）When the rotating speed of the steam turbine MAA00CS002 is less than 2000, a

specified standby pump will bring into action; if the standby delays 10s, the other one

will be put into operation; 2）When the rotating speed of the steam turbine MAA00CS002 is less than 2000, the

working pump is in operation and the outlet manifold pressure of the jacking oil pump is

low, the standby jacking oil pump is put into operation; 3）When the rotating speed of the steam turbine MAA00CS002 is less than 2000 and

the working pump trips, the standby jacking oil pump is brought into action.

2.1.5.10 the jacking oil pump automatically stops in case of meeting one of following

conditions:

1) Rotating speed of the steam turbine is greater than or equal to 2000r/min (tentative

- 22 -

speed); 2）60s delay time of the steam turbine at zero rotating speed

2.1.5.11 the electric heater of the lube oil box is self-driven in case of meeting one of


1) Lube oil temperature in the main oil tank less than 32℃ 2）Surface temperature of the electric heater of the main oil tank less than 100℃

2.1.5.12 the electric heater of the main lube oil automatically stops in case of meeting one

of following conditions:

1) High lube oil temperature in the main oil tank greater than 37℃

2) High surface temperature of the electric heater of the main oil tank greater than

150℃

2.1.6 Interlock protection for EH oil system of the mainframe

2.1.6.1 The EH oil pump is allowable for starting in case of full meeting following

conditions:

1) Main EH oil pump allowable for being operated

2) Normal oil level of the EH oil tank 3）20 Oil temperature of the EH oil tank higher than 20℃ ℃

2.1.6.2 The standby EH oil pump will automatically start in case of meeting one of


1) One set in operation and pressure of the EH oil manifold less than or equal to Mpa

2) Motor trip of a EH oil process pump

2.1.6.3 The EH oil pump will automatically stop in case of meeting one of following

conditions: 1）Excessively low oil level of the EH oil tank (less than negative 200mm)

2）Breaker trip of the EH oil pump or overload protection of the motor in action

2.1.6.4 The electric heater of the EH oil tank will automatically start in case of full meeting

following conditions: 1）Normal oil level of the oil tank

2）#1 and #2 circulating pumps of the oil tank in operation

3）The breaker of the heater at on-position

4）Oil temperature less than or equal to 20℃

2.1.6.5 The electric heater of the EH oil tank will automatically stop in case of meeting one

of following conditions: 1）The oil temperature greater than or equal to 35℃

2）The breaker of the heater tripped

3）Excessively low oil level

4）Both the #1 circulating pump and #2 circulating pump of the oil tank out of service

- 23 -

2.1.7 Turning gear interlocks protection of the mainframe

2.1.7.1 The turning gear will automatically start in case of full meeting following conditions:

1) The interlock switch of its motor at AUTO position

2) Lube oil pressure of the bearing greater than 0.103MPa

3) Jacking oil pressure of every bearing greater than or equal to 3.43MPa

4) A manual turning interlock switch in standby

5) Both of the MSV in fully closed state

6) Zero rotating speed of the steam turbine and 30s delay time

2.1.7.2 The turning gear will automatically trip in case of meeting one of following

conditions:

1) Jacking oil pressure of any bearing less than 2.7Mpa

2) Lube oil pressure less than or equal to ≤0.07Mpa

3) Overload protection for the turning motor in action

2.1.8 Control and interlock protection of HP and LP bypass system

2.1.8.1 Control mode of the HP and LP bypass system

Decentralized control system (DCS) control modes of the HP bypass system: minimum

opening, boost, fixed pressure and follow modes

DCS control modes of the LP bypass system: minimum opening, fixed pressure and

track modes

2.1.8.2 Bypass attemperating water control

1) The control modes include AUTO and MAN; in the AUTO mode, the outlet temperature

of the bypass valve is able to be automatically regulated by setting the inlet temperature

of the HP bypass valve; in another case, the outlet temperature is maintained through

manually controlling the opening of an attemperating water valve by the operator.

Meanwhile, automatic control mode of the HP bypass pressure into operation is to bring

the HP bypass attemperating water control mode automatically into operation.

2) The control modes of the LP bypass attemperating water include AUTO and MAN; in

the AUTO mode, the outlet temperature of it is automatically controlled at 160 ; in ℃

another case, the outlet temperature is maintained through manually controlling the

opening of an attemperating water valve by the operator. Meanwhile, the automatic

control mode of the LP or HP bypass pressure into operation is to bring the LP bypass

attemperating water control mode automatically into operation.

2.1.8.3 Interlock protection of bypass 1）HP bypass pressure reducing valve

Allowable fast-opening conditions:

Pressure to be regulated to greater than or equal to 30% prior to triggering

- 24 -

the fast-opening action

In HP cylinder control before triggering the fast-opening action

Bypass in operation

No fast-closing condition (the fast-closing in prior to the fast-closing)

Trigger conditions of fast-opening

A changeover switch has already put into operation. The HP cylinder control

is put into operation and the steam turbine trips.

Fast-closing conditions:

5s duration at an outlet temperature of the HP bypass valve higher than

380℃

0% opening 2）HP bypass spray valve (set temperature ranging from 250 to 330 )℃ ℃

Fast-opening condition: The fast-opening of the HP bypass pressure valve

is available.

Fast-closing condition: The fast-closing of the HP bypass pressure valve is

available.

Less than 2.5% opening of the HP bypass pressure control valve (PCV) is to

jointly close the LP bypass PCV after 5s delay time. 3）HP bypass spray isolation valve

1. The spray isolation valve is triggered to open in case that the opening of the HP

bypass valve is greater than or equal to 2.5%;

2. The spray isolation valve is triggered to close after 15s delay in case that the

opening of the HP bypass valve is less than 2.5%. 4）LP bypass pressure reducing valve

Fast-closing conditions include， but not limit to, the following:

1. Low condenser vacuum

2. High condenser temperature

3. Low spray pressure of the LP bypass spray valve

4. High outlet steam temperature of the LP bypass spray valve

Fast-closing opening: 0

Fast-opening conditions (the fast-closing in prior to the fast-opening) include, but not

limit to, the following:

1. Reheater pressure more than 4.4Mpa

2. Fast-opening of the HP bypass valve is available.

Opening: The LP bypass pressure valve is put into control mode as it is pre-opened to

80% and in automatic operation. 5）LP bypass spray valve

Fast-closing condition: Fast-closing of the LP bypass pressure reducing valve is

- 25 -

available.

Fast-closing opening: 0

Fast-opening condition: Fast-Opening of the LP bypass pressure reducing valve is

available.

Opening: The LP bypass pressure valve is put into control mode as it is pre-opened to

80% and in automatic operation. 6）LP bypass spray isolation valve

1. The spray isolation valve is jointly opened as the opening of the LP bypass valve is

greater than or equal to 2%;

2. The spray isolation valve is jointly closed as the opening of the LP bypass valve is

less than 2%;

2.1.9 Turbine supervisory instrument (TSI)

2.1.9.1 Rotating speed supervision (revolution indicator and electric over-speed protection

2.1.9.2 Vibration supervision on the #1-#8 bearing shells

2.1.9.3 Vibration supervision on X and Y directions of the #1-#8 bearings

2.1.9.4 Supervision on axial displacement

2.1.9.5 Differential expansion supervision on the HIP and LP cylinders

2.1.9.6 Eccentricity monitoring 2.1.9.7 ；Supervision on right and left heat expansion of the HIP cylinder

2.1.9.8 Precision transient tachometer (tachometer equipped at the head of a motor)

3. Thermal Interlock Protection of Auxiliaries

3.1 Thermal Interlock and Protection of Turbine Auxiliaries

3.1.1 Interlock protection of turbo-feed pump

3.1.1.1 The A/B booster pumps are allowable for starting in each of following conditions:

Water level of the deaerator in normal condition (LAA10CL501L NOT) (based on

the analogue value)

The electric valves of the A/B booster pumps at the inlets to be opened in place

LAA30CZ130ZO

The electric valve of the A turbo-feed pump at the outlet to be closed in place

LAC10CZ130ZC

The re-circulating electric valves of the A/B turbo-feed pumps to be opened in

place

The minimum flow control valves of the A/B turbo-feed pumps to be opened in

- 26 -

place

Radial bearing temperature of the driving ends of the A/B turbo-feed pumps’

booster pumps LAA01CT381

Radial bearing temperature of the free ends of the A/B turbo-feed pumps’ booster

pumps LAA01CT383

Radial bearing temperature of the motor driving ends of the A/B turbo-feed

pumps’ booster pumps LAA01CT403

Radial bearing temperature of the motor free ends of the A/B turbo-feed pumps’

booster pumps LAA01CT401

The stator phase winding temperature of the motors of the A/B turbo-feed pumps’

booster pumps are ultra-limit.

No tripping condition

No motor protection for the A/B turbo-feed pumps’ booster pumps (no contact

point)

Normal inlet pressure of the feed pump (more than 1.4MPa)

3.1.1.2 The A/B booster pumps trip by interlock in any one of following conditions:

Low-low water level of the deaerator LBD04CL203

The minimum flow control valves and the re-circulating electric valves of the A/B

turbo-feed pumps have already closed in place. The inlet minimum flow is less

than 270T/H and delay time is 15s when any one of the valves is closed.

The inlet electric valves of the A/B booster pumps to be closed in place after 3s

delay in operation

The radial bearing temperature of the driving ends LAA01CT381 and the free

ends LAA01CT383 of the A/B booster pumps more than 100 during 3s delay ℃

The bearing temperature of the motor driving ends LAA01CT403 and non-driving

ends LAA01CT401 of the A/B booster pumps more than 90 during 3s delay℃

Stator phase winding temperature of the motors of the A/B booster pumps more

than 130 d℃ uring 3s delay

3.1.1.3 The A/B booster pumps are allowable for starting in each of following conditions:

Normal water level of the deaerator higher than 1950mm (median of three)

The re-circulating electric valves of the A/B turbo-feed pumps to be opened in

place

The minimum flow control valves of the A/B turbo-feed pumps to be opened in

place

The motors of the A/B turbo-feed pumps’ booster pumps in operation

LAA01AP001ZS

The booster pumps in operation and the normal inlet pressure of the feed pump

(more than 1.4MPa)

- 27 -

The radial bearing temperature of the driving ends of the A/B turbo-feed pumps

less than 75℃

The radial bearing temperature of the free ends less than 75℃

Inside temperature of the thrust bearings less than 80℃

Outside temperature of the thrust bearings less than 80℃

The thrust bearing temperature of the steam turbine for the A/B turbo-feed

pumps less than 105℃

The electric exhaust butterfly valve of the steam turbine of the A/B turbo-feed

pumps to be opened in place

No tripping condition

Normal lube oil pressure of the steam turbine for the A turbo-feed pump (more

than 0.08MPa)

The temperature difference of the upper and lower barrels of the pumps in

normal condition (the temperature difference of the upper and lower parts not

exceeding 30 )℃

Exhaust pressure not exceeding 1-value

3.1.1.4 The interlocks of the A/B turbo-feed pumps will trip in any one of following

conditions:

Low-low water level of the deaerator

Motors trip of the A/B turbo-feed pumps’ booster pumps

The minimum flow control valves and the re-circulating electric valves of the A/B

turbo-feed pumps have already closed in place. The inlet minimum flow is less

than 270T/H and delay time is 15s when any one of the valves is closed. The radial bearing temperature of the driving ends of the A/B booster pumps

more than 100 (90) during 3s delay℃

The bearing temperature of the free ends of the A/B booster pumps more than

100 (90) during 3s delay℃

Inside temperature of the thrust bearings less than 100(110) during 3s d℃ elay

Outside temperature of the thrust bearings more than 100(110) during 3s ℃

delay The thrust bearing temperature of the steam turbine for the A/B turbo-feed

pumps more than 120(110)℃ during 3s delay

The inlet pressure of the A/B turbo-feed pumps less than 1.0MPa during 10s

delay

Alarm in case that the front bearings of the steam turbine for the A/B turbo-feed

pumps horizontally and vertically vibrate or any one of the bearings vibrate.

The exhaust electric butterfly valve of the steam turbine for the A/B turbo-feed

pumps in closed state

- 28 -

Water temperature different at the inlet and outlet more than

3.1.1.5 Trip protection conditions of the steam turbine for the feed pump (METS)

1) Over-speed of the steam turbine for the feed pump (greater than or equal to

5972 r/min, two of three)

2) Low safety oil pressure (less than 6.0MPa, two of three)

3) Large axial displacement (positive 0.9mm, negative 0.9mm)

4) Large bearing vibration (greater than or equal to 0.15mm)

5) Low exhaust vacuum (negative 47.7kPa, one of two)

6) Lube oil pressure lower than 3-value (less than 0.08MPa, one of two)

7) Any one of the return oil temperature of the front bearing, the thrust bearing and

the back bearings of the steam turbine for the feed pump greater than or equal to

75℃

8) MEH required to trip

9) Trip single of the turbo-feed pump

10) Manual shutdown

3.1.1.6 Alarm single of the turbo-feed pumps

1) High radial bearing temperature of the free ends of the booster pumps (greater

than or equal to 95 )℃

2) The thrust bearing temperature of the free ends of the booster pumps greater

than or equal to 95 ℃

3) High radial bearing temperature of the driving ends of the booster pumps

(greater than or equal to 95 )℃

4) The motor bearing temperature of the driving ends of the booster pumps

greater than or equal to 90 ℃

5) High motor bearing temperature of the non-driving ends of the booster pumps

(greater than or equal to 90 )℃

6) High motor coil temperature of the booster pumps (greater than or equal to 120

)℃

7) High thrust bearings temperature (insides A and B, or outsides A and B) of the

turbo-feed pumps (greater than 85 )℃

8) High radial bearing temperature of the turbo-feed pumps (the driving ends or

the free ends) (greater than 100 )℃

9) Low lube oil pressure (1-value less than 0.15MPa; 2-value less than 0.12MPa;

3-value less than 0.08MPa)

10) Outlet flow less than a given value (less than 270m3/h)

11) Low inlet pressure of the turbo-feed pump (less than 1.4MPa)

12) Low sealing water differential pressure of the turbo-feed pumps (1-value less

than 0.035MPa and 2-value less than 0.015MPa)

- 29 -

13) Large temperature difference of the upper and lower barrels of the turbo-feed

pumps (more than 30 )℃

14) Over-speed of the steam turbine for the feed pump (greater than or equal to

5972 r/min)

15) Low safety oil pressure (less than 6.0MPa)

16) Large axial displacement (positive 0.8mm, negative 0.8mm)

17) Large bearing vibration (greater than or equal to 0.1mm)

18) Low exhaust vacuum (negative 67.7kPa)

19) Any one of the return oil temperature of the front bearing, the thrust bearing

and the back bearings of the steam turbine for the feed pump greater than or

equal to 65℃

20) Any one of the front and back bearings and the thrust bearings temperature of

the steam turbine for the feed pump greater than or equal to 75℃

21) High filter differential pressure of the fire-resistant oil manifold (greater than or

equal to 0.35MPa) 22）High or low lube oil level of the oil tank (positive 150mm, negative 150mm)

23）High differential pressure of the lube oil filter (greater than or equal to 0.1MPa)

24）Bearing eccentricity of the steam turbine for the feed pump greater than or

equal to 0.13mm

3.1.1.7 Minimum flow re-circulating valve and control valve of the turbo-feed pump 1) Open interlock: outlet flow of the turbo-feed pump less than 270m3/h or the

turbo-feed pump out of service

2) Closed interlock: the outlet flow more than m3/h

3.1.1.8 Outlet electric valve of the turbo-feed pump

1) Open interlock: the turbo-feed pump starts after delay time

2) Closed interlock: the turbo-feed pump out of service (impulse) or rotating speed of

the steam turbine for the feed pump less than 500

3.1.1.9HP main stop valve and drain valve (A/B) of the steam turbine for feed pump 1) Open interlock

a) Load of the unit less than a given value (15%)

b) Steam turbine trip

c) The corresponding steam turbine for the feed pump trip 2) Closed interlock: the valves will automatically close after the said conditions are

reset.

3.1.1.10 Electric vacuum exhaust butterfly valve of steam turbine for feed pump 1) Open interlock: corresponding steam turbine for feed pump trip

2) Closed interlock: corresponding steam turbine for feed pump trip

3.1.1.11Startup of AC main oil pumps (A/B) interlock of the steam turbine for the feed

- 30 -

pump

1) Outage of the process oil pump triggers the standby to start up;

2) The standby pump is jointly started in case of low-low lube oil pressure of the steam

turbine for the feed pump (less than or equal to 0.12Mpa).

3.1.1.12 One of the following startup conditions should be met in need for the DC

emergency oil pump’s interlock of the steam turbine for the feed pump, comprising:

1) Both of the AC oil pumps of the steam turbine for the feed pump trips due to failure.

2) The lube oil pressure of the steam turbine for the feed pump is low-low (less than or

equal to 0.105Mpa).

Note: The DC emergency oil pump of the steam turbine for the feed pump must be

manually stopped.

3.1.1.14 Startup and outage of lube oil tank's heater of the steam turbine for the feed

pump

1) Interlock startup: Low oil temperature of the lube oil tank (less than 25 )℃

2) Interlock stop: High oil temperature of the lube oil tank (more than 30 ) and high ℃

surface temperature of the heater (more than 140 )℃

3.1.2 Interlock protection of motor-driven feed pump

3.1.2.1 Startup conditions of the motor-driven feed pump (all the conditions are required to

meet):

No reverse alarm of the motor-driven feed pump happened LAA03CS102RT

Inlet electric valve of the booster pump of the motor-driven feed pump to be

opened already LAA10CZ130ZO

The minimum flow control valve of the motor-driven feed pump to be opened already LAE30ZZ001 (greater than 95％)

）Lube oil pressure of the motor-driven feed pump in normal condition (not less

than LAC03CP215L and set to NOT)(greater than or equal to 0.15MPa)

Water level of the deaerator’s water tank in normal condition (greater than

1950mm and median of three)

Minimum location of a scoop tube LAC03ZZ001(less than 5%)

Outlet electric valve of the motor-driven feed pump to be closed in place

LAC30CZ130ZC

Differential pressure of the inlet strainer of the motor-driven pump in normal

condition

Radial bearing temperature of inlet LAA03CT382 and outlet LAA03CT381 sides

of the booster pump for the motor-driven feed pump less than 75℃

Thrust bearing temperature LAA03CT383 less than 75℃

Radial bearing temperature LAC03CT412 less than 80℃

- 31 -

Radial bearing temperature LAC03CT411 at hydraulic coupling end less than

80℃

Radial bearing temperature LAC03CT401 at the inlet side less than 75℃

Radial bearing temperature LAC03CT403 at the outlet side less than 75℃

Thrust bearings' temperature 1/2 of the motor-driven feed pump (LAC03CT405

and LAC03CT406) less than 75℃

Inlet oil temperature LAC03CT391 of the lube oil cooler of the hydraulic coupler

less than 75℃

Outlet oil temperature LAC03CT391 of the lube oil cooler of the hydraulic coupler

less than 55℃

A/B/C phase windings’ temperature of the motor’s 1/2/3 stators of the

motor-driven feed pump less than 120℃

Inlet temperature LAC03CT394 and outlet temperature LAC03CT393 of the

working oil cooler of the hydraulic coupler less than 110 and 75 , respectively℃ ℃

Radial #1 bearing temperature 1/2/3/4/5/6/7/8/9/10 of the coupler less than 85℃

3.1.2.2 Trip conditions of the motor-driven feed pump (one of these conditions is required

to meet):

1) Low-low water level of the deaerator LBD04CL203

Low-low lube oil pressure of the motor-driven feed pump

LAC03CP212LL/LAC03CP213LL/LAC03CP214LL (less than or equal to

0.08MPa)

The inlet electric valve LAA10CZ130ZC of the booster pump is closed when the

motor-driven feed pump is in operation.

High-high differential pressure of the inlet strainer (greater than 0.06MPa)

As the motor-driven feed pump is in operation, any one of the minimum flow

control valves is closed and the inlet flow is less than 164T/H with 10s delay.

Radial bearing temperature of inlet LAC03CT401/outlet LAC03CT403 sides of

the motor-driven feed pump greater than 100℃ 1/2 thrust bearings’（LAC03CT405 and LAC03CT406 ）temperature of the

motor-driven feed pump greater than 100℃

Inlet LAC03CT394/outlet LAC03CT393 oil temperature of the working oil cooler

of the hydraulic coupler greater than 130/70℃

Inlet LAC03CT391/outlet LAC03CT392 oil temperature of the working oil cooler

of the hydraulic coupler greater than 80/65℃

Radial bearing LAC03CT412 temperature at the booster pump end of the

motor-driven pump greater than 90℃

Radial bearing LAC03CT411 temperature at hydraulic coupler end of the motor

greater than 90℃

- 32 -

Radial #1 bearing temperature 1/2/3/4/5/6/7/8/9/10 of the coupler greater than

90 ℃

As the pump LAC03AP001ZS is in operation, the inlet pressure LAC03CP001 is

less than 0.8(1.25MPa) and delays 10s.

Inlet and outlet water differential pressure greater than

3.1.2.3 Standby mode

1) Automatically operational conditions of the standby pump: a）Start the auxiliary oil pump;

b）Open the outlet electric valve of the motor-driven feed pump;

c）Open the minimum flow re-circulating valve of the motor-driven feed pump (greater

than 95％).

2) Effective conditions of the standby pump: a）The inlet valve of the booster pump has opened already;

b）The outlet valve of the motor-driven feed pump has opened already;

c）The minimum flow re-circulating valve of the motor-driven feed pump has opened

already; d）The startup condition of the feed pump is met;

e）The feed pump is in outage state.

3) The standby pump in operation by interlock: Outage of any motor-driven feed pumps

will trigger the standby to operate under the standby mode.

4) Exit from the standby mode a）Manually cut off the standby pump;

b）Start the standby pump by the interlock; Exit the standby mode after 30s;

c）Bring integrated protection of the feed pump in action

3.1.2.4 Startup/outage of an auxiliary oil pump interlock of the motor-driven feed pump 1）The auxiliary oil pump is started up by the interlock as the motor-driven feed pump is

put into standby. 2）The motor-driven feed pump in operation: In case of low lube oil pressure (less than

or equal to 0.15MPa), the auxiliary oil pump is started up by the interlock; whereas high

lube oil pressure (greater than or equal to 0.3Mpa) will trigger the auxiliary oil pump to

stop. 3）Outage of the motor-driven feed pump starts the auxiliary oil pump by the interlock,

and then it is jointly stopped after 5m. 3.1.2.5 Inlet electric valve of the booster pump

1) Closure-allowable condition: the motor-driven feed pump out of service and the inlet

electric valve to be closed in place LAC30CZ130ZC

2) Open interlock: when the motor-driven feed pump is put into standby, the interlock is

opened.

- 33 -

3.1.2.6 Outlet electric valve of the motor-driven feed pump

1) Closed interlock: the motor-driven feed pump trip

2) Open interlock: the motor-driven feed pump in operation or standby

3.1.2.7 Minimum flow re-circulating control valve of the motor-driven feed pump 1) Open interlock: outlet flow of it less than 200m3/h

2) Closed interlock: outlet flow of it greater than 400m3/h

3.1.2.8 Alarm conditions of the motor-driven feed pump 1) Outlet flow of it less than 200m3/h or greater than 400m3/h

2) Low lube oil pressure (less than or equal to 0.15MPa) 3）Low inlet pressure (less than or equal to 1.4MPa and 30s delay)

4）High inlet oil temperature of the lube oil cooler of the hydraulic coupler (1-value

greater than 65 and 2℃ -value greater than 70 )℃ 5）High outlet oil temperature of the lube oil cooler of the hydraulic coupler (1-value

greater than 55 and 2℃ -value greater than 60 )℃ 6）Inlet oil temperature of the working oil cooler of the hydraulic coupler (scoop pipe

orifice oil) (1-value greater than 110 and 2℃ -value greater than 130 )℃ 7）Outlet oil temperature of the working oil cooler of the hydraulic coupler (1-value

greater than 75 and 2℃ -value greater than 85 )℃

8) High radial bearing temperature of the hydraulic coupler (1-value greater than 90 ℃

and 2-value greater than 95 )℃

9) High stator winding temperature of the motor (greater than 120 )℃

10) High radial bearing temperature of the driving end of the motor-driven feed pump

(1-value greater than 75 and 2℃ -value greater than 90 )℃

11) High radial bearing temperature of the free end of the motor-driven feed pump

(1-value greater than 75 and 2℃ -value greater than 90 )℃ 12）High thrust bearing temperature (inside and outside) of the motor-driven feed pump

(1-value greater than 80 and 2℃ -value greater than 95 )℃ 13）High radial bearing temperature of the driving end of the booster pump (1-value


14) High radial bearing temperature of the free end of the booster pump (1-value

greater than 75 and 2℃ -value greater than 90 )℃ 15）High thrust bearing temperature (inside and outside) of the booster pump (1-value


16) High end bearing temperature of the motor coupling of the motor-driven feed pump

(1-value greater than 75 and 2℃ -value greater than 80 )℃

17) High end bearing temperature of the motor booster pump of the motor-driven feed

pump (1-value greater than 70 and 2℃ -value greater than 80 )℃

18) High differential pressure of the inlet strainer of the motor-driven feed pump (greater

- 34 -

than 0.06MPa) 19）High differential pressure of the inlet strainer of the booster pump (greater than

0.06MPa) 20）High differential pressure of the lube oil strainer (greater than 0.06MPa)

21) Pump reversal

3.1.3 Control and interlock protection of HP heater and extraction system

3.1.3.1 Stop and startup sequences of HP heater function sub-group 1) Allowable sequence-control startup condition: Water level of the HP heater in

normal condition

2) Startup sequence:

Open the HP heater outlet valves LAC60CZ131ZO, LAC50CZ131ZO and

LAC40CZ131Z;

Open the HP heater inlet valves LAC60CZ130ZO, LAC50CZ130ZO and

LAC40CZ130ZO;

Close the bypass valves LAC61CZ130ZC, LAC51CZ130ZC and LAC41CZ130ZC;

Open the drain valves at the outlets of the first/second/third extraction check valves

and the drain valves at the inlets of the first/second/third extraction electric valves;

Open the third extraction electric valve LBD30CZ130ZO;

Open the second extraction electric valve LBD20CZ130ZO

Open the first extraction electric valve LBD10CZ130ZO

Open the first/second/third extraction check valves BD10CZ430ZO, LBD20CZ430ZO

and LBD30CZ430ZO.

3) Stop sequence:

Close the first/second/third extraction check valves LBD10CZ430ZC,

LBD20CZ430ZC and LBD30CZ430ZC

Close the first extraction electric valve LBD10CZ130ZC;

Close the second extraction electric valve LBD20CZ130ZC;

Close the third extraction electric valve LBD30CZ130ZC

Open the drain valves at the outlets of the first/second/third extraction check

valves and the inlets of the electric valves;

Open the bypass valves LAC61CZ130ZO, LAC51CZ130ZO and LAC41CZ130ZO;

Close the HP heater inlet electric valves LAC60CZ130ZC, LAC50CZ130ZC and

LAC40CZ130ZC

Close the HP heater outlet electric valves LAC60CZ131ZC, LAC50CZ131ZC and

LAC40CZ131ZC.

3.1.3.2 HP heaters disconnection (#1, #2 and #3 HP heaters disconnection)

1) The HP heaters disconnection occurs under any one of following conditions:

- 35 -

Steam turbine trip

Generator trip

H-H-H water level

Manual disconnection of the HP heaters

OPC in operation

2) Activities after HP heaters disconnection:

Close the first/second/third extraction check valves;

Close the first/second/third extraction eletric valves;

Open the drain valves at the inlet of the first/second/third extraction check valves

and outlets of the eletric valves;

Open the bypass valves of the #1, #2 and #3 HP heaters and close the inlet and

outlet valves of the #1, #2 and #3 HP heaters;

Open the emergency drain valves of the #1, #2 and #3 HP heaters;

The first/second/third extraction check valves

Allowable open conditions:

The outlet electric valve of the HP heaters to be opened in place LAC60CZ131ZO as well

as the inlet electric valve LAC60CZ130ZO

High water level not greater than 2-value (less than )

Interlock closure conditions:

HP heaters disconnection

OPC in operation U1007SOE:OPCACT.CIN

Steam turbine trip

Generator trip

The inlet LAC60CZ130ZC or outlet LAC60CZ131ZC electric valves of the HP heaters in

closed condition

Open conditions of the interlock:

The first extraction electric valve


The outlet electric valve LAC60CZ130ZO and the inlet electric valve LAC60CZ131ZO of

the #1 HP heaters to be closed in place

No first extraction electric valve failure LBD10CZ130ZF

Allowable closure conditions:



Steam turbine trip

Generator trip

The inlet electric valve LAC60CZ130ZC and the outlet electric valve LAC60CZ131ZC of

the #1 HP heaters to be closed

- 36 -

OPC in operation

Pneumatic drain valves of steam pipes at inlet and outlet of the first extraction electric

valve

Open conditions of the interlock


Steam turbine load less than 10%

The first extraction electric valve LBD10CZ130ZC and check valve LBD10CZ430ZC in

closure condition

Upper and lower walls temperature difference of the first extraction steam pipe up to 42℃

OPC in operation


30s delay in case that said interlock conditions are not existed;

The interlock is closed after 5m delay when the steam turbine load is greater than 10%.

Pneumatic drain valve of the steam turbine of the first extraction check valve inlet




The first extraction electric valve LBD10CZ130ZC or check valve LBD10CZ430ZC in

closure condition

The upper and lower walls temperature difference of the first extraction steam pipe up to

42℃

OPC in operation


30s delay in case that said closure conditions are not existed

The interlock is closed after 5m delay when the steam turbine load is greater than 10%.

Logic control sequence of the second and third extraction electric valve, the pneumatic

drain valve of the steam pipe of the electric valve inlet and outlet, the pneumatic drain

valve of the steam pipe of the check valve inlet is similar to the first extraction valves.

#1, #2 and #3 HP heaters inlet electric valves


#1, #2 and #3 HP heaters outlet electric valves to be opened in place

NO HP heaters electric valve failure

Water level of the HP heaters in normal condition


3s delay when the #1, #2 and #3 HP heaters outlet valves are changed over on-position


The HP heaters in operation and the bypass valve to be closed

- 37 -

#1, #2 and #3 HP heaters outlet electric valves

Allowable open condition: Water level of the HP heaters in normal condition

Allowable closure condition: #1, #2 and #3 HP heaters inlet electric valves in closure

condition



The HP heaters in operation (the bypass valve to be closed) or the inlet valves to be

closed

#1, #2 and #3 HP heaters electric bypass valves

Allowable open condition: No failure

Allowable closure condition: #1, #2 and #3 HP heaters inlet and outlet electric valves

in open state

Open conditions of the interlock


3s delay when the #1, #2 and #3 HP heaters inlet and outlet valves are changed over

on-position

#1 HP heaters emergency drain valve

HP heaters emergency disconnection or H-H water level is to open the valve by

the interlock.

1# HP heaters normal drain valve

High water level of the #2 HP heater is to close the normal drain valve by the

interlock.



the interlock.

#2 HP heaters normal drain valve

High water level of the #3 HP heater is to close the normal drain valve by the

interlock.



the interlock.

#3 HP heaters normal drain valve

H-H water level of the deaerator is to close the normal drain valve by the

interlock.

- 38 -

The third extraction check valve has opened already; the third extraction electric valve is

allowed to open.

The second extraction check valve has opened already; the second extraction electric

valve is allowed to open.

The first extraction check valve has opened already; the first extraction electric valve is

allowed to open.

3.1.3.1 #1, #2 and #3 HP heaters interlock protection 1）Water level protection of the HP heaters

a) Open corresponding pneumatic emergency drain control valves in case that water

level of any HP heater reaches high I value (greater than or equal to positive 38mm);

close it when the water level is normal.

b) In case that water level of any HP heater reaches high II value (greater than or

equal to positive 76mm) （1）Close the pneumatic normal drain control valve of upper-stage heater;

（2）Open the emergency pneumatic drain control valve of upper-stage heater.

c) In case that water level of any HP heater reaches high III value (greater than or

equal to positive 120mm)

(1) Disconnect the HP heater 2）HP heater disconnection

a) HP heater disconnection conditions (one condition is required to meet) （1）Steam turbine trip

（2）Generator trip

（3）Water level of any HP heater up to high 3-value

（4）OPC in operation

b) Linked objects and sequences of HP heaters disconnection （1）Close the #1, #2 and #3 HP heaters extraction electric valves;

（2）Close the #1, #2 and #3 HP heaters extraction check valves;

（3）Close the #1, #2 and #3 HP heaters normal drain valves;

（4）Open #1, #2 and #3 HP heaters drain valves of the extraction electric valve inlet

and the extraction pneumatic check valve outlet; （5）Close the HP heaters inlet three-way valves;

（6）Close the #1 HP heater outlet valve.

3）Low water level of the HP heater (less than or equal to negative 30mm) will interlock

following devices:

a) Alarm;

b) Automatically electrify the HP heater emergency drain solenoid valve.

3.1.3.2 #5 and #6 LP heaters interlock protection (normal water level is 0mm) 1）LP heater water level protection

- 39 -

a) Open corresponding pneumatic emergency drain control valves in case that water

level of any LP heater reaches high I value (greater than or equal to 40mm); close it

when the water level is normal.

b) In case that water level of any LP heater reaches high II value (greater than or

equal to 80mm) （1）Close the pneumatic normal drain control valve of upper-stage heater;

（2）Open the emergency pneumatic drain control valve of upper-stage heater. c) In case that water level of any LP heater reaches high III value (greater than or

equal to 120mm)

2）LP heater disconnection

a）LP heater disconnection conditions (one condition is required to meet)

（1）Steam turbine trip


（3）Water level of any HP heater up to high 3-value


b）Linked objects and sequences of LP heaters disconnection

(1) Close the LP heater extraction electric valve of this stage;

(2) Close the LP heater extraction check valve of this stage;

(3) Open the drain valve of the LP heater extraction electric valve inlet and close it

after 5m delay;

(4) Open the drain valve of the LP heater extraction electric valve outlet and close it

after 5m delay;

(5) Open the corresponding LP heater water side bypass valve and close the inlet

and outlet valves (close the corresponding outlet electric drain valve in case of the #5

LP heater disconnection);

(6) Fully open the emergency pneumatic drain control valve of this stage;

(7) Fully close the pneumatic normal drain control valve of this stage;

(8) Fully open the emergency pneumatic drain control valve of upper stage;

(9) Fully close the pneumatic normal drain control valve of upper stage. 3）Low water level (less than or equal to negative 40mm) of the #5 and #6 LP heaters

will interlock the following device.

(1) Electrify the corresponding LP heater emergency pneumatic drain control valve.

3.1.3.3 #7(A/B) and #8(A/B) LP heaters interlock protection 1）LP heater water level protection

a）Open the corresponding #7(A/B) and #8(A/B) LP heater emergency pneumatic

drain control valves in case that water level of any LP heaters is up to high I value

(greater than or equal to 50mm) or water level of the condenser is high 2-value

(greater than or equal to 550mm); close the corresponding LP heater emergency

- 40 -

pneumatic drain control valves in case that the water level of the LP heaters of this

stage is normal. b）High II values water level of any LP heater (greater than or equal to 90mm)

（1）Close the pneumatic normal drain control valve of upper-stage heater;

（2）Open the pneumatic normal drain control valve of upper-stage heater.

c）High III value water level of any LP heater (greater than or equal to 130mm): LP

heater disconnection 2）LP heater disconnection

a）LP heater disconnection conditions (one of those conditions is required to meet)

（1）Steam turbine trip


（3）High 3-value water level of any LP heater


b）Linked objects and sequences of LP heater disconnection

(1) Fully open the emergency pneumatic drain control valve of this stage LP heater;

(2) Fully close the pneumatic normal drain control valve of this stage LP heater;

(3) Fully open the emergency pneumatic drain control valve of upper-stage LP

heater;

(4) Fully close the pneumatic normal drain control valve of upper-stage LP heater;

(5) Open the corresponding #7 and #8 LP heaters water-side bypass valves; （6）Close the #7(A/B) and #8(A/B) LP heaters inlet valves;

（7）Close the #7(A/B) and #8(A/B) LP heaters outlet valves.

3.1.4 The fourth extraction control and interlock protection of deaerator water level

3.1.4.1 Startup and stop sequences of the fourth extraction functional sub-group 1）Startup sequences:

Close the electric drain valve of the deaerator;

Open the steam pipe pneumatic drain valve of the fourth extraction A check valve

inlet and the fourth extraction B check valve outlet;

Open the fourth extraction A/B check valves;

Open the fourth extraction electric valve 1 after the deaerator water level (less

than ) is normal;

Open the fourth extraction to deaerator steam supply electric valve 2(including

pre-heating) and the fourth extraction steam pressure reaches a set value (greater

than 0.15MPa);

Close the steam pipe pneumatic drain valves of the fourth extraction A check valve

inlet and the fourth extraction B check valve after 600s delay. 2）Stop sequences:

- 41 -

Close the fourth extraction electric valve;

Operate to the deaerator fourth extraction electric valve;

Close the fourth extraction A/B check valves;

Open the steam pipe pneumatic valve of the fourth extraction A check valve inlet

and the fourth extraction B check valve outlet.

3.1.4.2 The fourth extraction A/B check valves Interlock closure conditions:

Steam turbine trip

Generator trip

H-H-H water level of the deaerator LBD04CL201

OPC in operation U1007SOE: OPCACT

Deaerator pressure greater than 1.3MPa

Deaerator pressure less than 0.15MPa and the pressure control valves from the

auxiliary steam to the deaerator to be opened already

3.1.4.3 To the deaerator fourth extraction electric valve 1）Allowable open condition: No failure occurred at the segment to the fourth extraction

electric valve

2）Interlock closure conditions:

Steam turbine trip

Generator trip


OPC in operation

The fourth extraction main electrical valve in closure condition LBD40CZ330Z




3.1.4.3 The fourth extraction electric valve 1）Allowable open conditions:

Steam turbine trip

No fourth extraction electric valve failure 2）Allowable closure condition

3）Interlock closure conditions

Steam turbine trip

Generator trip


OPC in operation



- 42 -


3.1.4.4 The fourth extraction A/B check valves inlet and outlet steam pipe drain valve Open conditions of the interlock

Steam turbine trip

Generator trip


The fourth extraction main electric valve or A/B check valves in closure condition

The top and bottom temperature difference of the fourth extraction steam pipe in

exceed of 50℃

H-H-H water level of the deaerator

OPC in operation Interlock closure condition

15s delay in case that the said conditions are not existed

3.1.4.5 The fourth extraction steam supply electric valve (to an auxiliary steam header) Allowable open condition: No failure of the fourth extraction steam supply electric valve


Steam turbine trip

Generator trip

The fourth extraction main electric valve LBD40CZ330ZC in closure condition

OPC in operation

3.1.4.6 Deaerator overflow

The overflow is linked to open in case of H-H water level of the deaerator, whereas

it is closed.

3.1.4.7 The deaerator overflow valve drains water to the electric valve of the Intermittent

blow-down flash tank.

Opening of the overflow valve and high water level of the condenser hot well links

the electric valve to open;

Closure of the overflow valve jointly closes the electric valve.

3.1.4.8 The deaerator overflow valve drains water to the drain flash tank’s electric valve of

the condenser.

Opening of the overflow valve and non-high water level of the condenser hot well

links the electric valve to open;

Closure of the overflow valve jointly closes the electric valve.

3.1.4.9 Deaerator electric drain valve

Allowable open condition: No failure occurred at the electric drain valve

Open condition of the interlock: high 3-value of the deaerator water level (LBD04CL201）

Interlock closure condition: Normal water level less than 1950MM

- 43 -

3.1.4.10 the fourth extraction steam to electric valve of A/B steam turbine for feed water

pump Allowable open condition: No failure


Steam turbine trip

Generator trip

The steam turbine for feed water pump in outage (FROM MEH）

The steam turbine for feed water pump trip (FROM MEH）

OPC in operation

Deaerator vent valve

High deaerator pressure links the vent valve to open (greater than or equal to

1.0Mpa);

Non-high pressure links the vent valve to close (less than 1.0Mpa).

3.1.5 Interlock protection of condensate system

Sequence-control functional group of A/B condensate pump

Startup sequences of A/B condensate pump sub-group: Open the re-circulating valve 1LCG10CZ060ZO;

Close the outlet valve LCA21CZ130ZC of the A/B condensate pump;

Open the inlet electric valve LCA11CZ400ZO of the A/B condensate pump;

Start the A/B condensate pump LCE01AP001ZS;

Open the outlet valves LCA21CZ130ZO of the A/B condensate pumps;

Release the minimum flow valve.

Stop sequences of A/B condensate pump sub-group Open the minimum flow valve;

Close the A/B condensate pump outlet valve LCA21CZ130ZC;

Stop the A/B condensate pump;

Release the minimum flow valve

A/B condensate pump

Allowable startup conditions:

Condenser water level in normal conditions (10MAG01CL101 condensers A/B

water level greater than 600mm )

Inlet electric valves of the A/B condensate pumps to be opened in place

LCA11CZ400ZO

100% opening of the outlet electric valve of the standby condensate pump in

operation or the outlet electric valves of the A/B condensate pumps to be closed in

place LCA21CZ130ZC

Motor lower bearing temperature of the A condensate pump LCE01CT405 less

- 44 -

than 70℃

Motor thrust bearing temperature of the A condensate pump LCE01CT401 less

than 70℃

Motor stator winding temperature of the A/B condensate pumps less than 110℃

A/B condensate pumps thrust bearing temperature LCE01CT412 and

LCE01CT413 less than 75℃

No trip condition

Interlock startup conditions:

The interlock is started as the standby condensate pump is put into operation and

the process pump trips.

The interlock is started at 3s delay as the standby condensate pump and the

process pump are put into operation, and the condensate pump outlet manifold

pressure is low (less than 2.7).

Interlock trip conditions:

Low-low condenser water level (condensers A/B water level lower than 280mm)

and 20s delay

The A condensate pump motor lower bearing temperature LCE01CT405 greater

than 80℃

The A condensate motor thrust bearing temperature LCE01CT401 greater than

80 ℃

The A/B condensate pumps thrust bearing temperature LCE01CT412 and

LCE01CT413 greater than 80℃

When the condensate pump is in operation, the inlet electric valve is closed in

place LCA11CZ400ZO.

When the condensate pump is in operation, the outlet electric valve is closed in

place after 30s delay LCA21CZ130ZC.

Sum of condensate flow and re-circulating flow less than 380t/h

Large vibration

Standby condensate pump self-start conditions:

1) Standby interlock in operation

a) Open the condensate pump outlet electric valve.

2) Standby effective conditions:

a) The condensate pump inlet valve to be opened already

b) The condensate pump outlet valve to be opened already

c) The condensate pump startup condition to be met (except that the minimum flow

re-circulating control valve is opened to the maximum position)

d) The condensate pump at outage state

3) Exit the standby mode

- 45 -

a) Manually cut off the standby mode;

b) Start the standby condensate pump by the interlock and exit the standby mode

after 30s in operation;

c) The integrated protection of the condensate pump is in operation.

A/B condensate pumps’ inlet electric valves

Allowable open condition: No failure occurred at the inlet electric valves

Allowable closure conditions:

This condensate pump is out of service;

This condensate pump is not allowed to stop in operation.

Open condition of the interlock

The standby condensate pump has put into operation.

A/B condensate pumps’ outlet electric valves

Allowable open and closure condition: No failure occurred at the inlet electric valves of

the A/B condensate pumps

Open condition of the interlock: This standby condensate pump has put into operation

or the condensate pump LCE01AP001ZS is in operation at 5s delay time.

Interlock closure condition: This condensate pump LCE01AP001ZS is in operation

Minimum flow re-circulating valve of the condensate pump (long instruction)

Allowable open condition: No fault signal


a) Low flow 350T/H

b) Interlock startup in case of high 2-value water level

Interlock closure condition: High condensate flow

Deaerator water level-control electric bypass valve

Allowable open condition: No fault signal

Open condition of the interlock: this valve is opened by the interlock at 10s delay

time in case that the condensate pump in operation and the deaerator water level

is low.

Interlock closure condition: This valve is closed by the protection of the interlock in

case of high water level.

Deaerator water level main control valve

This valve is closed by the interlock in case of high water level.

Make-up water control valve of the condensate hot well (electric bypass valve)

Allowable open condition: Fault signal

The valve is closed by the interlock in case of high hot well water level, but not

high release.

The valve is opened in case of low water level.

- 46 -

Attemperating water control valve inlet electric valve of condenser drain flash tank I

Open the attemperating water control valve in case of high exhaust temperature of

the drain flash tank I (greater than or equal to 60 );℃

Close the attemperating water control valve in case of low exhaust temperature of

the drain flash tank I.

Low bypass tertiary attemperator (HP condenser) spray control valve inlet electric valve

Opening the LP bypass valve will link the tertiary attemperating water control valve

to open.

Closing the LP bypass valve will link the tertiary attemperating water control valve

to close.

Attemperating water control valve inlet electric valve of condenser drain flash tank II

Open the attemperating water control valve in case of high exhaust

temperature of the drain flash tank II (greater than or equal to 60 );℃

Close the attemperating water control valve in case of low exhaust temperature

(less than or equal to 50 )of the drain fla℃ sh tank II.

Low bypass tertiary attemperator (LP condenser) spray control valve inlet electric valve

Opening the LP bypass valve will link the tertiary attemperating water control valve

to open.

Closing the LP bypass valve will link the tertiary attemperating water control valve to

close.

Temperature and pressure reducer control valve bypass electric valve from condensate

to sealing steam of the steam turbine

3.1.6 Condenser and vacuum system

A/B vacuum pumps Allowable startup conditions:

Inlet pressure of the A/B vacuum pumps LFA01CP201N/LFA02CP201N in

normal condition

Inlet valves of the A/B water-ring vacuum pumps LFA21CZ100ZC/

LFA22CZ100ZC to be closed in place Interlock startup conditions:

Prepare the standby vacuum pump into operation; in case that any one of the

main vacuum pumps trips, the standby pump is jointly started.

The interlock in operation and low condenser vacuum.

Inlet valves of A/B water-ring vacuum pumps Allowable open and closure conditions:

Interlock closure condition: The corresponding pump trip LFA01AP001ZD

- 47 -

Open condition of the interlock: The corresponding vacuum pump startup

LFA01AP001ZS and allowable opening of the vacuum pump inlet valve LFA01CP202

A condenser electric vacuum break valve Allowable open conditions:

Steam turbine trip

No electric vacuum break valve failure

B condenser electric vacuum break valve Allowable open conditions:

Steam turbine trip

No electric vacuum break valve failure

A/B vacuum pump make-up solenoid valve The make-up solenoid valve of the steam-water separator automatically opens in

case of the vacuum or standby pump in operation and low water level of the

separator.

The make-up water valve automatically closes at 10s delay in case of high water

level of the vacuum pump.

3.1.7 Gland sealing and auxiliary steam systems of the steam turbine

A/B gland extraction fan Allowable startup condition


Prepare the standby gland extraction fan into operation; the standby gland

extraction fan is jointly started in case that the gland extraction fan in operation

trips.

Gland pressure greater than or equal to 5KPa

Gland steam temperature pneumatic control valve inlet electric valve

Allowable open condition: No fault of the gland steam temperature pneumatic control

valve inlet electric valve MAW20AA230ZF

Bypass valve of gland LP steam source pressure control valve

Allowable open condition: No fault of the gland LP steam source pressure control valve

bypass valve MAW10AA233ZF

Bypass valve of gland overflow station control valve Allowable open condition: No fault of the bypass valve of gland overflow station

control valve

Emergency electric drain valve of gland cooler

High water level of the gland cooler links the valve to open;

The valve is closed in case that the water level of the gland cooler is normal.

- 48 -

Open conditions of the gland overflow control valve interlock

High pressure of the gland steam supply manifold (greater than 0.18MPa)

Interlock closure condition of the gland overflow control valve

Low pressure of the gland steam supply manifold (less than or equal to 0.118MPa)

Open condition of the gland overflow electric valves A/B interlock

The gland overflow control valve to be open already

Interlock open conditions of main gland steam pressure control valve

Low pressure of the gland steam supply manifold (less than 0.13 MPa)

Interlock closure condition of main gland steam, auxiliary gland steam and cooling gland

steam pressure control valve

High gland steam manifold pressure (greater than 0.18MPa)

3.1.8 Interlock protection of generator sealing oil system

A/B main sealing oil pumps motor Allowable startup conditions

No fault

Oil level of vacuum oil tank in normal condition

At remote Open conditions of the interlock

Prepare the standby and then put it into operation in case of low manifold pressure of

the sealing oil pump outlet MKW10CP201

Prepare the standby and then put it into operation after main oil pump trip

Trigger the sealing oil main pumps (A/B) to stop in case of low oil level in the sealing oil

vacuum oil tank.

Emergency stealing oil pump motor Allowable startup conditions:

No fault

At remote Interlock startup conditions:

Prepare the standby and then trigger it into operation after 6s delay in case of low

manifold pressure of the sealing oil pump outlet MKW10CP201 and two sets of the

sealing oil pump in operation;

Put it in standby in case of low oil level of the sealing oil vacuum oil tank

MKW10CL002L;

Put it in standby after 3s delay in case that both of the A/B oil pumps trip.

Sealing oil re-circulating oil pump motor Allowable startup condition: No fault


- 49 -

Combined interlock startup of the A/B main sealing oil pumps motor

MKW10AP001ZS/MKW10AP002ZS

Emergency sealing oil pump MKW10AP003ZS

Sealing oil vacuum pump motor Allowable startup condition: No fault

Interlock stop condition: High oil level of the sealing oil vacuum oil tank

MKW10CL002H

4. Unit Control and Regulation Devices

4.1 Sequence Control System (SCS)

4.1.1 Sequence Control System (SCS) of Turbine Motor

4.1.1.1 Turbine turning gear sequence control

4.1.1.2 Fire-resistant oil sequence control of turbine lube oil

4.1.1.3 Turbine vacuum sequence control

4.1.1.4 LP heater sequence control

4.1.1.5 HP heater sequence control

4.1.1.6 Motor-driven feed pump sequence control

4.1.1.7 Turbo-driven feed pump sequence control

4.1.1.8 Generator water-cooled sequence control

4.1.1.9 Generator hydrogen-cooled sequence control

4.1.1.10 Generator sealing oil sequence control

4.2 Analogue Control System (MCS)

4.2.1 The turbine-boiler coordinated control system, through serving the boiler and turbine

generating set as an integer to control and enabling the functions of automatic

regulation, logic control and interlock protection to organically combine, is formed into an

integrated control system with multiple control functions that are able to meet the control

requirements of various operating modes and conditions.

4.2.1.1 Unit control modes: There are totally four modes for the turbine-boiler coordinated

control system

1) Coordinated control mode (CCSMODE): main control modes of the steam turbine

and the boiler are totally put into operation;

2) The main control mode of the steam turbine is manual; the boiler is automatic and the

boil main control mode is used for regulating main steam pressure; 3) Turbine follow mode（TFMODE）: The main control mode of the steam turbine is

- 50 -

automatic; the main control mode of the boiler is manual and the former one is used for

regulating the main steam pressure;

4) Base mode (BASE): main control modes of the steam turbine and the boiler are

manual.

4.2.1.2 Unit target load formation

1) Automatic generation control: in case that the unit is in stable operation and the

coordinated control mode (CCSMODE) had put into operation, manually send out a

UNIT REMO ALLOWABLE command; send a “AGC (automatic generation control) in

operation signal” to the distributed control system (DCS) after the system control room

makes a judgment that the AGC can be put into operation; then receive an ADS

(automatic dispatching system) by the operator and trigger the UNIT REMO/LOCAL HANDOVER COMMAND；in case that the unit needs to an independent operation, the

operator sends a command to cut off the ADS signal that triggers the UNIT

REMO/LOCAL HANDOVER COMMAND at the same time and dispatches returning the

AGC CUT-OFF signal.

Unit load circuit is of two modes that are manual and automatic modes. As the circuit is

automatic, the unit is in AGC mode and the unit target load receives the ADS command;

otherwise, the target load could be set by the operator (coordinated control mode) or through tracking the actual unit load （non-coordinated control mode）. The main control

mode of the unit needs to be set to trace status in case of RUNBACK, RUNUP and

RUNDOWN. 2）Allowable operating conditions of AGC

a) Effective ADS signal

b) The unit in coordinate operating mode

c) No RUNBACK

d) ADS command under limit

3) High-low limit: maximum and minimum limits of the unit target load are manually set

by the operator.

4) Variable load rate limit

The load rate is changed by a rate limit module and its limit value is set at an operator

station by the operation. Besides, the direction blocking functions merely by increasing

and reducing the blocking through setting the corresponding directional rate limit to zero.

Blocking command increase and reduction conditions comprise

a) Increased feed water control blocking

b) Increased fuel blocking

c) Increase main steam pressure blocking

d) Increased air flow control blocking

e) Increased induced air flow control blocking

- 51 -

f) Increased primary air control blocking

5) Load forward and maintenance

When the operator inputs a new target load at turbine-boiler coordinated control

mode, the reset target load is effective after pressing the FORWARD/MAINTENANCE

button; when the load set value reaches the target load, load automatically maintains. In

case of AGC mode, RUNBACK, RUNUP and RUNDOWN, the load automatically sets

to FORWARD and the target load is automatically effective. 6）Frequency correction

The frequency correction circuit is used for inherent frequency modulation for grid

frequency. The frequency correction is conducted by superimposing the corresponding

unit load adjusted value that is obtained by calculating the deviation of the grid

frequency through some dead bands on the target load. The circuit automatically

disconnects under following conditions:

a) Not at the coordinated control mode

b) Invalid frequency deviation signal

c) Unit under RUNBACK, RUNUP and RUNDOWN conditions

4.2.1.3 RUNBACK control

4.2.1.3 RUNBACK control RB（Run Back）means that the unit on load is greater than the sustainable load

of current auxiliaries when essential auxiliaries of the unit are fault. At this time,

RB is required to quickly conduct to reduce the load acceptable to current

auxiliaries. The unit target load equal to the RB target value under the RB

condition. In case that the unit target load is up to the RB target value, namely

the unit allowable maximum output, the RB is completed. The AGC is cut off and

the unit is changed from the coordinated control mode the turbine following

boiler mode and it also can be manually reset.

1) RB adjustment: at the coordinated control mode, the RB is caused by following

auxiliaries’ faults, comprising:

a) Forced draft fan

b) Induced draft fan

c) Primary air fan

d) Coal pulverizer (two-layer and three-layer)

e) Feed water pump 2）RB occurrence conditions: in case that the unit load is greater than the allowable

maximum output of one of the forced draft fan, the induced draft fan and the primary

air fan, the allowable maximum output of one of the feed water pumps under the

situation that one set of feed water pump trips and the standby is not started in 5s and

the allowable maximum output of the coal pulverizer in operation under the situation

- 52 -

that one trips. The coal pulverizer-caused RB is different from the other one, the coal

pulverizer-caused RB is classified as RB#2 and the other one is RB#1.

The RB is completed when the actual unit load is less than the allowable maximum

load of the unit or the RB also can be manually reset.

3）RUNBACK target value circuit formation

When the RB happens, the target load automatically changes to the allowable

maximum output of the device that causes this RB and then the RB rate takes

effective.

4.2.1.4 Main steam pressure circuit setting

In constant pressure operation, keep the main steam admission pressure invariable

and change the unit power by regulating opening of the turbine control valve;

In sliding pressure operation, the control valve is full opened or closes to full open

and the unit power is changed by altering the steam admission pressure, namely

the steam admission pressure is maintained by the boiler and the pressure is the

function of the unit power that is changed with the power variation.

The adoption of the sliding pressure operation is to change the thermal stress and

deformation of the unit in condition-variable operation, so as to shorten the start

and stop time of the unit, reduce throttling loss and power consumption of the feed

water pump and improve the unit efficiency. The throttling loss refers to the loss of

steam flowed through the control valve.

The operating mode of the unit is classified as the constant and sliding pressure, with

different main steam pressure set value under different operating mode.

4.2.1.5 Boiler main control

1) Boiler main control M/A: the boiler command used for presetting the total fuel quantity

value synchronously functions to the main fuel control and air flow control circuits. In

case that the boiler main control is not automatic, it outputs a trace command for current

total fuel quantity. 2）Boiler main control and manual control switching conditions:

a) Bad actual power measuring point quality (take effect merely under the

coordinated control mode)

b) Bad main steam pressure measuring point quality

c) Bad governing stage pressure measuring point quality

d) Bad steam drum pressure measuring point quality

e) Big deviation between the main steam pressure and the set value

f) Furnace draft under manual control

g) All fuel under manual control

h) Out fire MFT

i) UNBACK

- 53 -

4.2.1.6 Turbine main control

1) Turbine follow control mode (TF): the boiler main control is manual. The main

steam pressure is changed by regulating opening of the turbine control valve.

2) Coordinated control mode: both the boiler and the turbine main control modes in

operation are called as turbine-boiler coordinated control mode.

3) Turbine main control M/A: Turbine main control and manual control switching

conditions:

a) Bad actual power measuring point quality

b) Bad main steam pressure measuring point quality

c) Unallowable DEH remote control

d) DEH out of remote control

4.2.1.7 Allowable cut-off conditions of DEH remote control 1）Manual cut-off

2）Bad load reference measuring point quality

3）Large deviation between the turbine main control output and the load reference value

4）Large deviation between the load command and the actual power

5）Large deviation between the main steam pressure set value and the measuring value

Allowable DEH remote control can be sent out by a DEH remote control request button in

case that the aforesaid conditions are totally met.

4.2.2 Steam drum water level control

4.2.2.1 As the unit starts on low load, a set of motor-driven pump is put into operation and

the water level of the steam drum is controlled by a feed water bypass control valve. A

main feed water valve is opened as the opening of the bypass valve is above 75% and the

main steam reaches the required flow. After the main feed water valve is full opened, the

water level of the steam drum is controlled by governing the rotating speed of the

motor-driven pump. With the load rise, the turbo-feed water pump starts. It first operates in

parallel with the motor-driven pump, and then gradually replaces the motor-driven pump to

bear the load.

4.2.2.2 Single impulse control is used when the unit load is less than 25%; otherwise

three-element control is applied. Water level of the steam drum is controlled by governing

the rotating speed of the turbo-feed water pump and the motor-driven pump is used to

standby after the unit load is greater than 25%.

4.2.2.3 Feed pump regulation

1) Manual switching conditions of the motor-driven feed pump

a) Invalid steam drum water level signal

b) Big deviation between the set valve of the steam drum water level and the

measuring value

- 54 -

c) Big deviation between the scoop pipe control command of the feed pump and the

feedback

d) Bad scoop pipe position feedback quality

e) Feed pump out of service

f) The turbo-feed water pump in automatic operation

2) Manual switching conditions of the turbo-feed water pump control

a) Invalid steam drum water level signal

b) Big deviation between the set valve of the steam drum water level and the

measuring value

c) Invalid feed water flow signal

d) Poor main steam flow signal quality e) Big deviation of MEH（microcomputer electro-hydraulic）control command and

feedback

f) The steam turbine for feed water pump trip

g) MEH control

h) The motor-driven feed pump in automatic operation 3）Lockout load increase, reduction and rundown

After the output commands of the feed water pump in operation are totally out of

tolerance, the lockout load increases. Further deterioration and the water level of the

steam drum lower than the set value, rundown occurs. In case that the output

commands of the feed pump in operation totally exceed the lower limit, the lockout

load reduces.

4.2.3 Feed pump minimum flow control

4.2.3.1 In order to prevent cavitation, the re-circulating valve of the feed pump is used for

controlling the inlet flow of the feed pump not lower than the allowable minimum flow.

4.2.3.2 Full open the re-circulating valve in case of the inlet flow of the feed pump less

than the alarm value

4.2.3.2 Manual switching conditions:

1) Big deviation of the valve command and the position feedback

2) Poor quality of the valve position feedback

3) Invalid inlet flow signal of the feed pump

4.2.4 Deaerator pressure control

4.2.4.1 Control of deaerator pressure control valve

- 55 -

At the initial startup of the unit, the deaerator is in constant pressure operation

maintained by its pressure control valve and its steam supply is from the auxiliary steam

system.

2) While the deaerator steam supply is replaced with the fourth extraction steam supply

with the load rise, it is put into sliding pressure operation and its control valve is

gradually full closed.

3) When the unit trips in normal operation with the pressure drop rate in exceed of the set rate (0.05MPa/min）, the pressure control valve could be gradually opened to

prevent from flash evaporation resulting from excessively fast pressure drop rate.

4) Full-closed pressure control valve for H-H deaerator pressure

5) Manual switching conditions:

a) Invalid deaerator pressure signal

b) Big deviation of the valve command and position feedback

c) Poor quality of the valve position feedback

4.2.5 Deaerator water level control

4.2.5.1 Opening regulation of the water control valves A (main control valve) and B

(bypass control valve) is to control the deaerator water level. 4.2.5.2 The single impulse control is applied at the time of initial startup and low load stage

of the unit and the three-element control is used in normal load operation of the unit. The

feed water flow is used as a feed-forward signal under three-element control and the

condensate flow is served as a process value of a three-element secondary controller.

4.2.5.3 The bypass valve is used as the output of the secondary control is within 30%;

otherwise the main control valve is applied.

4.2.5.4 The bypass and main control valves are forced to be closed while the water level

of the deaerator is high 2-value.

4.2.5.5 Manual switching conditions

1) Invalid deaerator water level signal

2) Big deviation of the deaerator water level and set value

3) Big deviation of the control valve command and the position feedback

4) Poor quality of the control valve position feedback

4.2.6 Deaerator water level control

4.2.6.1 A make-up water control valve on the make-up water pipe of the condenser is used

for controlling the water level of it.

4.2.6.2 Manual conditions:

1) Invalid condenser water level signal

- 56 -

2) Big deviation of the set value and the measuring value



4.2.7 Deaerator flash tank temperature control

4.2.7.1 Inside temperature of the flash tank in normal operation is regulated by the control

valve. The bypass electric valve is opened to spray in case of the control valve fault or

excessive inside temperature.

4.2.8 Condensate recirculation flow control

4.2.8.1 The condensate recirculation flow is controlled by regulating the condensate

recirculation flow control valve.

4.2.8.2 Manual switching conditions:

1) Invalid condensate recirculation flow signal




4.2.9 #1 HP heater water level control

4.2.9.1 The #1 HP heater water level in normal condition is controlled by regulating the

opening of the #1 HP heater water level control valve (regulate the #1 HP heater drain

water to flow into the #2 HP heater drain water well). When the #1 HP heater water level is

excessively high, it can be controlled by regulating the opening of the #1 HP heater

emergency drain valve (make the #1 HP heater drain water flow into the drain flash tank).

When the circuit is manually controlled, the water level is set to actual trace value. After it

is automatic, the water level can be set by the operator. The set value of the controller of

the #1 HP heater emergency drain valve is higher than forward-bias of the normal water

level set value.

4.2.9.2 Full open the emergency drain valve in case of H-H #1 HP heater water level

4.2.9.3 Manual switching conditions of the water level control valve of the #1 HP heater

1) Invalid water level signal




4.2.9.4 Manual switching conditions of the water level emergency drain valve of the #1 HP

- 57 -

heater

1) Invalid water level signal






water to flow into the #3 HP heater drain water well). When the #2 HP heater water level is

excessively high, it can be controlled by regulating the opening of the #2 HP heater

emergency drain valve (make the #2 HP heater drain water flow into the drain flash tank).


4.2.10.3 Manual switching conditions of the water level control valve of the #2 HP heater 1）Invalid water level signal

2）Big deviation of the set value and the measuring value

3）Big deviation of the control valve command and the position feedback

4）Poor quality of the control valve position feedback

4.2.10.4 Manual switching conditions of the water level emergency drain valve of the #2

HP heater 1）Invalid water level signal






water to flow into the deaerator). When the #3 HP heater water level is excessively high, it

can be controlled by regulating the opening of the #3 HP heater emergency drain valve

(make the #3 HP heater drain water flow into the drain flash tank).


4.2.11.3 Manual switching conditions of the water level control valve of the #3 HP heater 1）Invalid water level signal




4.2.11.4 Manual switching conditions of the water level emergency drain valve of the #3

HP heater

- 58 -

1）Invalid water level signal



4.2.12 #5 LP heater water level control

4.2.12.1 The #5 LP heater water level in normal condition is controlled by regulating the

opening of the #5 LP heater water level control valve (regulate the #5 LP heater drain

water to flow into the #6 LP heater). When the #5 LP heater water level is excessively high,

it can be controlled by regulating the opening of the #5 LP heater emergency drain valve

(make the #5 LP heater drain water flow into the condensate tank).

4.2.12.2 Full open the emergency drain valve in case of H-H #5 LP heater water level

4.2.12.3 Manual switching conditions of the water level control valve of the #5 LP heater 1）Invalid water level signal




4.2.12.4 Manual switching conditions of the #5 LP heater emergency drain valve 1）Invalid water level signal



4.2.13 #6 LP heater water level control

4.2.13.1 The #6 LP heater water level in normal condition is controlled by regulating the

opening of the #6 LP heater water level control valve (regulate the #6 LP heater drain

water to flow into the #7 LP heater). When the #6 LP heater water level is excessively high,

it can be controlled by regulating the opening of the #6 LP heater emergency drain valve

(make the #6 LP heater drain water flow into the condensate tank).

4.2.13.2 Full open the emergency drain valve in case of H-H #6 LP heater water level

4.2.13.3 Manual switching conditions of the water level control valve of the #6 LP heater 1）Invalid water level signal




4.2.13.4 Manual switching conditions of the #6 LP heater emergency drain valve 1）Invalid water level signal



- 59 -

4.2.14 #7 A/B LP heaters water level control

4.2.14.1 The #7 A/B LP heaters water level in normal condition is controlled by regulating

the opening of the #7 A/B LP heaters water level control valve (regulate the #7 A/B LP

heaters drain water to flow into the #8 A/B LP heaters). When the #7 A/B LP heaters water

level is excessively high, it can be controlled by regulating the opening of the #7 A/B LP

heaters emergency drain valve (make the #7 A/B LP heaters drain water flow into the

condensate tank).

4.2.14.2 Full open the emergency drain valve in case of H-H #7 A/B LP heaters water

level

4.2.14.3 Manual switching conditions of the water level control valve of the #7 A/B LP

heaters 1）Invalid water level signal




4.2.14.4 Manual switching conditions of the #7 A/B LP heaters emergency drain valve 1）Invalid water level signal



4.2.15 #8 A/B LP heaters water level control

4.2.15.1 The #8 A/B LP heaters water level in normal condition is controlled by regulating

the opening of the #8 A/B LP heaters water level control valve (regulate the #8 A/B LP

heaters drain water to the condensate tank flow). When the #8 A/B LP heaters water level

is excessively high, it can be controlled by regulating the opening of the #8 A/B LP heaters

emergency drain valve (make the #8 A/B LP heaters drain water flow into the condensate

tank ).

4.2.15.2 Full open the emergency drain valve in case of H-H #8 A/B LP heaters water

level

4.2.15.3 Manual switching conditions of the water level control valve of the #8 A/B LP

heaters 1）Invalid water level signal




4.2.15.4 Manual switching conditions of the #8 A/B LP heaters emergency drain valve 1）Invalid water level signal

- 60 -



4.3 Turbine Digital Electro-hydraulic Control System (DEH)

4.3.1 Brief introduction of the DEH control system 4.3.1.1 The turbine control system, with two main functions of turbine rotating speed and

load control, employs a digital electro-hydraulic control system of the Dongfang Electric

Automatic Control Cooperation Limited consisting of a pure electric governing system and

a HP fire-resistant oil hydraulic servo system.

4.3.1.2 The HP and IP steam admission parts are totally provided with four HP control

valves (CV), two IP control valves (ICV), two HP main stop valves (MSV) and two IP main

stop valves (RSV). Six of the said ten valves are able to continuously control with the DEH

microcomputer interface through servo valves; wherein one HP main stop valve (on right)

employs a servo valve as a electro-hydraulic interface as well for the purpose of

pre-warming. The other one HP main stop valve and two IP main stop valves realize

two-position switch control with the DEH interface through a solenoid valve.

4.3.1.3 Pre-warming is conducted prior to steam admission under turning state when the

IP cylinder is used for starting. The pre-warming is completed by leading auxiliary steam

or re-cooled steam from the inlet of the HP cylinder exhaust check valve through a

pre-warming valve. After the primary outlet inwall temperature of the HP cylinder reaches

150 , close the cylinder to preserve heat. Then pre℃ -warm the HP main stop

valves-casing and control valves-casing through opening the HP right main stop valve to

some certain with the DEH.

4.3.2 DEH main functions

4.3.2.1 Turbine latched

The conditions of all admission valves in full closing and turbine tripped already must

be met before latching the steam turbine. After said conditions are all met, the turbine

latched can be completed after the DEH outputs a boost command and the HP safety

oil is in place.

4.3.2.2 Control prior to startup

1) Automatic thermal state judgment

For the steam turbine and rotors, the startup procedure of the steam turbine is a

heating process. In order to reduce the thermal stress during startup, different

startup curves could be applied to different initial temperatures.

The unit thermal states division accords with the HP inner casing wall temperature

T at the governing stage of the steam turbine when HP starting.

- 61 -

Cold state T<320℃

Warm state 320 ≤T<420℃ ℃

Hot state 420 ≤T<445℃ ℃

Extreme hot state 445 ≤T℃

The unit thermal states division automatically accords with the reheater inner

casing wall temperature T when IP starting.

Cold state T<305℃

Warm state 305 ≤T<420℃ ℃

Hot state 420 ≤T<490℃ ℃

Extreme hot state 490 ≤T℃

2) HP control valve casing pre-warming

Pre-warming the HP control valve casing could be selected prior to the turbine

rolling. When the pre-warming of the HP control valve casing is in operation,

slightly open the right HP main stop valve could pre-warm four HP control valves at

the same time.

3) Selection of startup modes

Startup modes of the steam turbine include IP cylinder startup and HIP cylinder

combined startup.

DEH default mode is the IP cylinder startup. The HIP cylinder combined startup mode is

merely used in case that the bypass system is failure or non-automatic.

4.3.2.3 Rotating speed control

The DEH is speed closed-loop non-corresponding control before the synchronization of

the steam turbine generator. Its set point is the set rotating speed. After the difference

between the set rotating speed and the actual rotating speed is calculated by a PID

controller through controlling the servomotor’s opening with the servo system, the

actuate rotating speed can vary with the set rotating speed. The flow commands are

derived from the calculation of the rotating speed controller. The opening commands of

the control valves and IP control valves are generated by the flow curves distribution.

While the IP control valves approximate to full open at the mode of HP cylinder startup,

the rotating speed of the IP control valves is governed by the HP control valves. In case

that a HEAT SOAK operating mode and IP cylinder startup mode are selected and the

unit rotating speed is less than 400r, the CV are slightly opened to pre-warm the HP

cylinder. When the rotating speed is greater than 400r, the control valves’ opening is

invariable and the ICV are opened. If the HEAT SOAL operating mode is not selected,

the HP control valves are not opened with only the IP control valves in open state.

After a target rotating speed is set, the given rotating speed automatically approaches

to the target rotating speed with a set acceleration rate. When given rotating speed

- 62 -

reaches the critical speed zone, its acceleration rate automatically alters to

300r/min/min (if the operator sets a acceleration rate greater than 300r/min/min, this

one is served as the benchmark). During speed rising, the steam turbine is necessary

for medium-high speed warming, so as to reduce thermal stress.

1) Target rotating speed: the operator can set the target rotating speed by the button on

the OIS. The rotating speed includes three shifts, namely 200, 1500 and 3000. Besides

the operator, the DEH can automatically set the target value under following conditions:

The target rotating speed is current speed while the steam turbine latches.

The target rotating speed is 3000r/min while the oil switch is disconnected.

The target rotating speed is zero in case that the steam turbine has tripped already.

The target rotating speed is to be changed to 3060r/min or 3300r/min when it exceeds

the upper limit.

The target rotating speed is set in accordance with the thermal stress control in

self-startup mode.

If the target rotating speed is set within the critical speed zone by error, alter it to the

lower limit.

Current combined critical set speed is set as follows (it can be modified according to

actual conditions): 910r/min～1113 r/min The first stage: 910r/min～1113 r/min

1541r/min～1946 r/min The second stage: 1541r/min～1946 r/min

2) Acceleration rate: the operator can set the acceleration rate within 0r/min/min～

500r/min/min. Under the condition that the operator has not set, the acceleration rates

at cold startup and warm startup are 100r/min/min and 150r/min/min, respectively, hot

startup and extreme hot startup are 300r/min/min. Under the self-driving mode, it is

selected by the ATR software. Within the combined critical speed, it is 300r/min/min.

After the selection of the target rotating speed and the acceleration rate, the unit begins

to raise speed. If certain rotating speed needs to be maintained in the process of speed

rising, press the HOLD button; in case that it reaches the critical speed zone, the button

HOLD is ineffective, and so the unit automatically rolls through the zone. 3) Friction check（FRIC CHK）: When the actual rotating speed reaches 200r/min, press

a FRIC CHK button by the DEH to close all valves. When the rotating speed of the

steam turbine gradually drops, check the friction. After the friction check is completed,

set the corresponding acceleration rate and target rotating speed to raise the unit speed

again. 4）Warm-up: The warm-up speed of the steam turbine is usually set to 1500r/min and

3000r/min, and so the target value is usually 1500r/min and 3000r/min. After reaching

the target rotating speed, it can be automatically stopped to warm up. If it needs to stop

rising in the process of speed-raising, operate as follows:

- 63 -

The operator sends a HOLD command while it is not at the ATR mode.

In the critical speed zone, the HOLD command is invalid, target speed modification is

the only way. 5）3000r/min constant rotating speed: While the rotating speed of the steam turbine is

stabilized above 3000 minus or plus 2r/min, the check prior to the synchronization for

each system is conducted. For checking reliability and regulation correctively of an

automatic synchronization system, the generator is conducted a false synchronization

test. During the test, an isolating switch of the generator grid side disconnects to send a

false synchronization test signal. Similar to the condition in normal operation, the

synchronization system alters the motor frequency and voltage with the DEH and the

generator excitation system. While meeting the synchronous condition, the oil switch is

connected. For the reason that the isolating switch is disconnected, the generator is

actually not synchronous. Therefore, the DEH-received false synchronization test signal

when the oil switch is connected is not regarded as generator synchronization during

the test, so as to avoid speed rise resulting from synchronization and initial load. 6）Automatic synchronization: Before the unit synchronization, the steam turbine

rotating speed is automatically governed according to synchronization increase and

reduction signals of a synchronization device while the DEH receives the

“synchronization in operation” signal from the device. The oil switch can be connected

on the premise of meeting all synchronous conditions.

4.3.2.4 Before the unit synchronization, the steam turbine rotating speed is

automatically governed according to synchronization increase and reduction signals

of a synchronization device while the DEH receives the “synchronization in operation”

signal from the device. The oil switch can be connected on the premise of meeting all

synchronous conditions. To avoid the occurrence of reverse-power, the DEH

immediately increases the given value to enable the motor on 5% initial load.

4.3.2.5 Loading

1) For the inherent frequency modulation, the governing system of the SHE is provided

with rotating speed feedback after the generator synchronization. While testing or

operating on a base load, load control or main steam pressure control functions also can

be taken effect. While the load control functions, both the target value and the set value

are expressed in the form of MW. While the main steam pressure control functions, they

are expressed in the form of MPa. In case that the said two functions are unavailable, they

are expressed by the percentage of the total flow under rated pressure.

After the target value is set, the set value automatically approaches to the target value

with a set load rate, and then the generator load gradually increases. In the process of

loading, pre-warming is required for the steam turbine to reduce thermal stress. 2）Target value: Besides the operator, the DEH also can automatically set the target

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value under following conditions:

While the load control function is just put into operation, the target value is current

load (MW).

As the main steam pressure control function is put into operation, the target value is

current main steam pressure (MPa).

While the generator is just synchronized, the target value is initial load set value (%).

The target value is valve total flow command (%) at the manual state.

While the said functions are stopped, the target value is valve total flow command

(%).

The target value equals to zero at the time of trip.

The target value (%) is set by the CCS as the CCS is in operation.

In case of excessive target value, it is 115% of the upper limit or 640MW. 3）Load rate: The load rate scope set by the operation is within 0MW/min～100MW/min.

Under the self-driving mode, the load rate is obtained according to the ATR. If the target

value is expressed in form of percentage, the load rate is correspondingly expressed in

percentage. 4）Warm-up: The steam turbine in the process of load is required to warm up for the

reasons of thermal stress, differential expansion and so on. If temporary stopping is

needed, operate as follow:

The operator sends a HOLD command when the steam turbine is not at the CCS.

Otherwise, the operator sends a HOLD command after exiting the CCS mode. 5）Constant pressure-sliding pressure-constant pressure loading: After the HP bypass

valves are full closed, feed fuel to the boiler and maintain the HP control valves at 90%

of the rated value. With the increase of the steam parameter, the load gradually

increases. During sliding pressure loading, both the load control and the main steam

control functions are not put into operation. If it is necessary for warming up, a

combustion control system could be used for maintaining flaming so as to keep the load

invariable; otherwise, the said two functions must be put into operation. At this time, the

invariable load must be maintained by the function of throttling of the control valve.

4.3.2.6 Load control mode 1）Main steam pressure control (TPC): the main steam pressure controller is a PI

regulator that is used for outputting a calculated control commands for the control valves

and the ICV by comparing the set valve with the main steam pressure. In case that the

coordinated control and steam pressure control under the turbine follow mode are

required for the DEH system, the DEH system must be provided with a main steam

pressure control circuit. Controlling the opening of the control valves according to the

deviation of the main stop valve inlet main steam pressure and the set value is able to

keep the inlet pressure invariable in constant pressure operation and the unit power can

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be altered by controlling the opening of the control valves. The unit power variation in

sliding pressure operation is realized by altering the inlet pressure when the turbine

control valves are nearly full open or full open. That is the inlet pressure is maintained by

the boiler. And the pressure is the function of the unit power and changes with the

variation of the unit power.

Operating conditions of the main steam pressure control:

The control system in automatic mode

Unavailable CCS control function

The main steam pressure signal in normal condition

Unavailable TPC

Unavailable inherent frequency modulation

Unavailable load limit

Disable conditions of the main steam pressure control function

The main steam pressure control function to be stopped by the operator

The main steam pressure signal failure

The control system in manual operation

Available TPC

Available inherent frequency modulation

Available load limit

Oil switch to be disconnected

Turbine trip

The main steam pressure control and load control functions can not be put into

operation at the same time. When the main steam pressure control functions, the set

point is expressed in the form of MPa. While adopting the PID no-corresponding control,

the actual main steam pressure equals to the set value at stable state. 2）Load control: The main steam pressure controller is a PI regulator that is used for

outputting a calculated control commands for the control valves and the ICV by

comparing the set valve with the main steam pressure. The operating conditions of the

load control, comprising:

The control system in automatic mode

Unavailable CCS control function

Normal power signal

Unavailable load limit

Unavailable TPC


Disable conditions of the load control

The load control function to be stopped by the operator

Power signal failure

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At the time of reaching the sliding pressure point

Available TPC




Load less than 30MW or greater than 600MW

Turbine trip

The main steam pressure control and load control functions can not be put into

operation at the same time. When the load control functions, the set point is expressed

in the form of MW. While adopting the PID no-corresponding control, the actual load

equals to the set value at the stable state. 3）Inherent frequency modulation: In order to guarantee the stability of the grid and the

electricity supply quality, the inherent frequency modulation usually could be put into

operation when the turbine generating set is in synchronous operation. When the unit

rotating speed is within the dead zone, the frequency regulation is set to zero and the

inherent frequency modulation is unavailable. Otherwise, the inherent frequency

modulation is available and the frequency regulation set value is varied with the rotating

speed based on a regulation. The regulation is adjustable within 3%-6%, primarily 5%. The dead zone is adjustable within 0r/min～30r/min and set to 4.5r/min. The dead zone

range: 3000r/min minus or plus dead zone value. The operating conditions of the inherent

frequency modulation:

The control system in automatic operation and no rotating speed circuit failure

After the load is firstly greater than 10% of the rated load 4）CCS control: in case that the CCS control is put into operation, the valves general

commands of the steam turbine are controlled by the boiler control system, the DEH target

load is set by the CCS set signal and the inherent frequency modulation dead zone is

changed to 30r/min. The operating conditions of the CCS control function comprise:

The control system in automatic operation already

The unit to be synchronized already

The CCS request signal to be received already and its command signal in normal

condition

Unavailable TPC


Disable conditions of the CCS control function

Available TPC



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No CCS request signal or CCS command signal failure

Oil switch to be disconnected 5）Main steam pressure limit (TPC): in case that the boiler system is unable to maintain

the main steam pressure for some failures, turning down the opening of the control valves

to reduce the steam flow can be used for putting back the main steam pressure. The

operating conditions of the main steam pressure limit:

The steam turbine to be synchronized already

The main steam pressure signal in normal condition

The control system in automatic operation

Disable conditions of the main steam pressure control


The main steam pressure signal failure

The control system changed into manual mode If the main steam pressure is less than the set limit value during the period of the

main steam pressure limit function in operation, the main steam pressure limit

functions. In operation, the set point reduces with 1%/s change rate based on the

change rate of the early period. The target value and the set point equal to the

total valves position reference value and they reduce with the reference value. If

the main steam pressure rises above the limit value, stop the set point. If the main

steam pressure keeps invariable, stop reducing the actual load while it drops to a

given value.

While the main steam pressure limit is in operation, the load control and main

steam control functions are automatically unavailable and the CCS control

function is out of service as well. 6）High load limit: in case that the steam turbine generating set is inclined to operate on

a load not high during a period, the operator is able to set a high load limit value within a

scope ranging from 570MW to 640MW, so as to keep the actual load less than the value

corresponding to the limit value all the time. 7）Low load limit: in case that the steam turbine generating set is inclined to operate on a

load not very low during a period, the operator is able to set a low load limit value within a

scope ranging from 0MW to 60MW, so as to keep the actual load greater than the value

corresponding to the limit value all the time. 8）Valve-position limit: in case that the steam turbine generating set is inclined to

operate with a small valves opening for some reasons during a period, the operator is

able to set a valve position limit value within the range from 0% to 120%. The DEH total

valve position set value is a much small value between the load reference value and the

limit value. In order to prevent the valve position from jumping, the valve position limit

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value is limited by the change rate, namely 1%/s.

4.3.2.7 Over-speed limit

1) Load rejection: when the unit rejects load greater than or equal to 15% and less than

or equal to 40% of the rated load, a DEH acceleration relay acts to fast close the IP

control valve and the target and set rotating speeds are changed to 3000r/min at the

same time. After a time, the servo valve recoveries control for the IP control valve. At

last the turbine rotating speed is stabilized at 3000r/min, so as to avoid fast

synchronization after removing the accident. When the unit rejects load greater than or

equal to 40% of the rated load, a DEH power-load unbalance relay acts to fast close the

HP control valve and the IP control valve and to enable the target and set rotating

speeds to be changed to 3000r/min. After a time, the servo valve recoveries control for

the HP control valve. At last the turbine rotating speed is stabilized at 3000r/min, so as

to avoid fast synchronization after removing the accident.

2) Acceleration control (ACC): when the turbine rotating speed is greater than

3060r/min and acceleration is greater than 49r/min/s, an acceleration control circuit acts

to fast close the IP control valve and restrict the maximum momentary speed of the

steam turbine.

3) Power-load unbalance (PLU): Unbalance of the steam turbine power (with the use of

reheat steam pressure characterization) and the steam turbine load (with the use of

generator load characterization) will lead to steam turbine over-speed. When the

deviation of the reheat steam pressure and the generator load exceeds the set value,

the power-load unbalance relay acts to fast close the HP and IP control valves so as to

restrict the turbine maximum momentary speed.

4) 103% over-speed (OPC): Under the condition that an over-speed test key switch is at

normal position, once the rotating speed in excess of 103%, an over-speed limit

solenoid valve quickly acts to close the HP and IP control valves and the servomotors

are totally in outage. When the rotating speed is less than 103% of the rated speed, the

solenoid valve loses electricity and the servo valves recoveries control for the control

valves.

4.3.2.8 Over-speed protection

For safety and reliability, the system is equipped with multiple over-speed

protection, including DEH electric over-speed protection 110%, emergency trip

eccentric ring mechanical over-speed protection 110%-111%, operator manual

stop and trip signal from the ETS (emergency trip system).

4.3.2.9 Online test: it comprises emergency governor eccentric ring oil spray test,

DEH electric over-speed test, mechanical over-speed test, valve mobility test,

main trip solenoid valve test and valve tightness test.

4.3.2.10 Switch-over between the DEH automatic/manual modes: the turbine

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control modes include the manual and automatic modes. If there are some faults

occurred for the automatic mode, the steam turbine will automatically switch to

the manual mode.

Exit the automatic mode under following conditions:

Turbine manual button to be operated

The valve leak test

The rotating speed is less than 2980r/min at the time of synchronizing.

Automatic mode is allowable for operating in case that there are not above said

conditions happed and the valve position limit does not act.

4.3.2.11 Changeover between the DEH automatic/manual modes

1) The turbine control includes the automatic and manual control modes.

2) If there is part of failure for the automatic control mode, replace it with the manual

control mode. Exit the automatic control mode under following conditions:

a) Turbine manual button to be operated

b) The valve leak test

c) The rotating speed is less than 2980r/min at the time of synchronizing.

Automatic mode is allowable for operating in case that there are not above said

conditions happed and the valve position limit does not act.

5. Main Test of the Unit

5.1 Static Test of the Control System

5.1.1 Testing conditions: 5.1.1.1 After overhaul and minor overhaul of the steam turbine；

5.1.1.2 after overhaul of the control system；

5.1.2 Test purposes: check flexibility of the control system and corresponding relation of

the control signal and the valve stroke characteristic and check whether the valve stroke

characteristic meets the requirement.

5.1.3 Test requirement

5.1.3.1 The test could be made after the boiler relieves all pressure and water stored up in

the main and reheat steam pipes exhausts.

5.1.3.2 Thermal technician is in main charge of the test in the cooperation of the operator.

5.1.3.3 The static state action of the control system must be reliable and flexible. The

corresponding relation of the control signal and the valve stroke must meet the

requirement.

5.1.4 Test procedures:

5.1.4.1 Check that the DEH control system has put into operation and it is in normal

operation;

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5.1.4.2 Check the outage stage of the bypass system and make sure the HP and LP

bypass relief valves are closed;

5.1.4.3 Put the lube oil system and the EH oil system into operation and make sure they

are normal;

5.1.4.4 Output a mandatory tripped protection signal by the thermal technician and make

sure the DEH has no alarm signal sent out;

5.1.4.5 Press a LATCH button on the DEH AUTO CONTROL screen, check the safety oil

of the mainframe and make sure it is in place, make sure the RSVL and RSVR IP main

stop valves are full open, and then click RUN.

5.1.4.6 Set the manual valve positions on the DEH MANUAL CONTROL screen, set the opening of the HP and IP control valves to 10％,30％,50％,80％ and 100％, respectively,

check and make sure the opening displayed on the CRT accords with the actual opening,

and the operation of every valve is flexible without jam;

5.1.4.7 Manually trip after the completion of the test;

5.1.4.8 Contact the thermal technician and restore the released signals.

5.2 Manual Trip Test

5.2.1 Testing conditions:

5.2.1.1 before cold startup of the unit;

5.2.1.2 after overhaul of the governing and control system;

5.2.2 Test purposes: check the flexibility of the emergency governor and emergency trip

lever, the reliability of action of the emergency governor.

5.2.3 Causes:

5.2.3.1 The test before starting could be made after the boiler relieves all pressure and

water stored up in the main and reheat steam pipes exhausts;

5.2.3.2 Remote and local trip operations must be performed separately in this test under

normal action condition.

5.2.4 Procedures:

5.2.4.1 Check the DEH, i.e. make sure it is normally put into operation and is in normal

operation;

5.2.4.2 Check the bypass system, the HP and LP bypass valves, i.e. make sure the

bypass system is in outage and the valves are closed.

5.2.4.3 Put the lubricating oil system and the EH oil system into operation and check for

their normality;

5.2.4.4 Unblock the closed trip signals by the thermal technician and make sure the

signals disappear;

5.2.4.5 Open the HP and IP main stop valves and the control valves in case of the steam

turbine latches;

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5.2.4.6 Press the emergency shutdown button and put the local manual trip handle to the

trip position once separately in the central control room; make sure the HP and IP main

stop valves and the HP and IP control valves fast close (It must be ensured that the

closing time of the main stop valve and the control valves meets the required standards at

the time of the initial startup after the unit installation or startup after the overhaul of the

control system);

5.2.4.7 Restore the signals after the completion of the test.

5.3 Trip Protection Test of Turbine Emergency Trip System (ETS)


5.3.1.1 After overhaul and minor repair of the unit;

5.3.1.2 After the overhaul of some parts of the protection system or the modification of the

protection set value;

5.3.1.3 Cold startup of the unit

5.3.2 Purposes: check the ETS trip circuits and make sure they are normal; check the

protection action for correction, so as to improve the operating safety of the unit.

5.3.3 Requirements

5.3.3.1 The test could be made after the boiler relieves all pressure and water stored up in

the main and reheat steam pipes exhausts;

5.3.3.2 Thermal technician is in main charge of the test in the cooperation of the operator.

5.3.4 Procedures

5.3.4.1 Check the DEH, i.e. make sure it is normally put into operation and is in normal

operation;

5.3.4.2 Check the bypass system, the HP and LP bypass valves, i.e. make sure the

bypass system is in outage and the valves are closed.

5.3.4.3 Put the lubricating oil system and the EH oil system into operation and check for

their normality;

5.3.4.4 Unblock the closed trip signals by the thermal technician and make sure the

signals disappear;

5.3.4.5 Press a LATCH button on the DEH AUTO CONTROL screen; open the HP and IP

main stop valves and the control valves;

5.3.4.6 Make a test one by one for following trip signals and make sure the steam turbine

trips by the thermal technician:

1) Low mainframe lube oil pressure (less than or equal to 69kPa)

2) Low EH oil pressure (less than or equal to 7.8MPa)

3) High A or B exhaust temperature of the LP cylinder (greater than or equal to 107 )℃

4) HP cylinder exhaust (inner wall) metal temperature greater than or equal to 432℃

5) LP cylinder exhaust metal temperature greater than or equal to 107℃

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6) Low condensers A/B vacuum (greater than kPa)

7) Low-low main stop valve inlet steam temperature and shut-down under the action of

the protection

8) 3s delay in case that any one of the journal bearings vibrates up to 0.250mm and any

one of the rest bearings vibrates up to 0.125mm; 0.08mm vibration of the bearing caps

9) #1-#6 bearings metal temperature of the generating set greater than or equal to

115 and #7℃ -#9 bearings metal temperature greater than or equal to 115 with 2s ℃

delay

10) HIP pressure differential expansion greater than or equal to 11.6mm or less than or

equal to -6.6mm; LP differential expansion greater than or equal to 30mm less than or

equal to -8mm

11) Mainframe axial displacement greater than or equal to 1.2mm or less than or equal

to -1.65mm

12) Turbine supervisory instrument action greater than 3300r/min

13) Low-low generator stator cooling water inflow rate 14）Low-low generator stator cooling water inflow pressure

15）High generator stator outlet cooling water

16) DEH major failure

17) Generator trip

18) Main fuel trip (MFT) of the boiler

19) Manual shut-down

5.3.4.7 Restore all signals after the completion of the test

5.4 Turbine Main Trip Solenoid Valve Test


5.4.1.1 Initial startup of the unit or after the overhaul and minor repair of the unit;

5.4.1.2 after the overhaul of the emergency governing system;

5.4.1.3 Make the test weekly in normal operation.

5.4.2 Purposes: Check whether its control circuit and action are normal and flexible, so as

to ensure the unit can fast trip the steam turbine under the action of the ETS protection.

5.4.3 Test methods

5.4.3.1 Make sure that the testing conditions are met, indicating lamps associated with the

test indicate correctly and the main trip solenoid valves 5YV, 6YV, 7YV and 8YV are live

on the DEH SOLENOIDS TEST screen;

5.4.3.2 Press the 5YV TEST key on the SOLENOIDS TEST screen; check whether the

5YV turns red for electricity loss; locally listen to the solenoid valves and make sure they

are acting; check whether the PS4 turns red. The color of the PS4 disappears after the

completion of the test. Green means that the test is successful and red means failure of

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the test.

5.4.3.3 Select NORMAL in TEST/NORMAL of the 5YV TEST dialog box; when the colors

of the 5YV and PS4 get ring, it means that the test is completed.

5.4.3.4 Do not allow to continue to test in case of 5YV test failure.

5.4.3.5 Perform the 7YV, 6YV and 8YV tests according to above said methods and

procedures.

5.4.3.6 Make sure all lamps are off after the completion of the test.

5.4.3.7 Cautions:

1) First perform the 5YV and 7YV trip solenoid valves test and then the 6YV and 8YV;

2) Strictly forbid alternately performing the 5YV, 7YV, 6YV and 8YV tests;

3) Perform the 6YV and 8YV tests after confirming the 5YV and 7YV tests are qualified;

4) The thermal technical and relevant operator must be present at the time of test;

5) The person specialized for operation and monitoring is required.

6) The testing conditions must be met in first.

5.4.3.7 All signals must be restored after the completion of the test prior to the startup of

the unit.

5.5 Power-load Unbalance Relay (PLU) Loop Test

5.6 Eccentric Ring Oil Spray Test of Emergency Governor


5.6.1.1 before the unit over-speed test;

5.6.1.2 after the overhaul of the emergency governing system;

5.6.1.3 Purposes: move about the eccentric ring to ensure that it is not locked and it can trip the steam turbine when the unit speed exceeds 110%～111% of the

rated speed.

5.6.3 Oil-spray test methods:

5.6.3.1 Check the steam turbine, i.e. make sure it is in stable operation at 3000r/min;

5.6.2.2 Make sure that the indicating lamps associated with the test on the DEH indicate

correctly;

5.6.2.3 Make sure that the DEH is in automatic mode;

5.6.2.4 Click the SPRAY OIL TEST in the SPRAY OIL TEST screen, the TEST indicating

lamp is on;

5.6.2.5 Check whether the insolating solenoid valve 4YV acts and then check the oil spray

solenoid valve 2YV; in case that the oil sprays into the emergency governor, the eccentric

ring knocks out and the ZS2 sends out signal;

5.6.2.6 And then the 2YV loses electricity. The 1YV automatically connects several

minutes later. After latching, the 4YV loses electricity again. The turbine mechanical trip

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system resets, the unit is in normal operation and the test is completed.

5.7 Emergency Governor Minimum Oil Spray Action Speed Test

5.7.1 Testing conditions

5.7.1.1 at the initial startup of the unit or after the overhaul and minor repair of the unit;

5.7.1.2 after the emergency governor parts to be checked

5.7.2 Purposes: Check whether the action speed of the emergency governor eccentric

ring is qualified at the time of oil injection speed rise, so as to make sure the operating

safety of the unit. (Notes: the actual over-speed trip action speed of the emergency

governor is corresponding to the minimum oil spray action speed. For the 3000r/min rated

sped of the steam turbine, in case that the minimum oil spray action speed is greater than

2880r/min, the speed should be governed less than 2700r/min at outage before

synchronizing.

5.7.3 Methods

5.7.3.1 Raise the turbine speed to 2700r/min at cold startup state, and then hold it;

5.7.2.2 Confirm that all indicating lamps on the DEH indicate correctly;

5.7.2.3 Put the SPRAY OIL TEST to the ON position on the SPARY OIL TEST screen;

when the ZS4 (4YV LOCKOUT) indicating lamp on the DIGITAL SIGNAL screen is on,

locally check whether the insolating valve of the emergency trip test is at the insolating

position.

5.7.2.4 Modify the target rotating speed of the unit to 3000r/min; stop speed rise

maintenance and then keep on accelerating; when the LATCHED in the TURBINE

LATCHED dialog box on the AUTO CONTROL is altered to TRIPPED, the emergency

governor eccentric ring acts, and then record the action speed at this time.

5.7.2.5 If the steam turbine trips at the rotating speed less than or equal to 2700r/min or

greater than 2880r/min, shut down to overhaul and regulate the emergency governor.

5.7.2.6 Put the SPRAY OIL TEST on the SPARY OIL TES screen to OFF position. When

the ZS4 (4YV LOCKOUT) indicating lamp on the DIGITAL SIGNAL screen is off and the

ZS5 (4YVRESETED) is on, locally check the insolating valve and reset it. When the

TRIPPED in the TURBINE LATCHED dialog box on the AUTO CONTROL screen is

altered into LATCHED, the emergency governor resets.

5.7.2.7 After the said procedures are completed, the turbine mechanical trip system resets

and the unit is in normal operation.

5.7.2.8 It must be confirmed that the insolating valve 4YV is closed and reverent signals

indicate correctly in test; otherwise, the unit is to trip.

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5.8 Turbine Mechanical Over-speed Test

5.8.1 Testing conditions

5.8.1.1 Initial startup after the steam turbine assembly

5.8.1.2 after the overhaul of the unit;

5.8.1.3 after reassembly of the emergency governor;

5.8.1.4 After overhauling the set valve in the front box that affects on the action speed of

the emergency governor;

5.8.1.5 Before making the load rejection test

5.8.2 Purposes: Check the eccentric ring for flexibility and the action speed for correction,

so as to ensure the safe operation.


5.8.3.1 The over-sped test must be in charge of the general engineer and under the

direction of associated technicians.

5.8.3.2 The test must be performed and monitored by special person.

5.8.3.3 The test must be made after the tests of the HIP main stop valves and control

valves, centralized manual trip shut-down, local manual trip and emergency governor oil

spray, leakage and turbine supervisory instruments are completed and qualified.

5.8.3.4 The over-speed test during the cold startup of the unit should be made under the

condition that the unit operates for 3-4h with the load greater than or equal to 150MW.

5.8.3.5 The test must be performed when the unit has operated for 2s after the unit oil

spray test; otherwise it is to affect the action speed of the emergency governor. If the

regular oil-spray test had performed and the emergency governor did not disassembled or

regulated, merely the over-speed test is required and it is unnecessary for making the oil

spray test.

5.8.3.6 During the test, the local manual trip handle and the centralized emergency

shut-down trip button must be in charge of special person. They must communicate well

and a speed indicator must be provided at the front box.

5.8.3.7 During the test, it must closely monitor the rotating speed, vibration, axial

displacement, LP cylinder exhaust temperature and so on, and put associated recorders

and printers into operation to continuously type the said parameters.

5.8.3.8 The main and reheat steam pressure must meet the requirement of the

corresponding startup curves, and the main and reheat steam temperature should be

stable and matched with the turbine metal temperature. The main steam pressure should be ranged from 5MPa to 6MPa; the main steam temperature should be above 350℃～

400 ; the IP cylinder admission pressure should be maintained at 0.1MPa℃ ～0.2MPa

through the HLP bypass; The reheat temperature should be ranged from 300 to 350 . ℃ ℃

The condenser vacuum and exhaust temperature must be normal; otherwise, a cooling

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water spray device must be put into operation.

5.8.3.9 Modify the DEH and the TSI protection action value to 3330 r/min;


5.8.4.1 Load down according to normal stop procedure;

5.8.4.2 Start the TOP and MSP and make sure they are in normal operation;

5.8.4.3 The HLP bypass at the follow mode;

5.8.4.4 Latch again to keep the rotating speed at 3000r/min after the remote and local

manual trip tests is separately performed and qualified;

5.8.4.5 Confirm that the indicating lamps on the DEH associated with the tests indicate

correctly;

5.8.4.6 Check whether the testing conditions on the DEH CONTROL screen are met;

5.8.4.7 Press the MECH OSP TEST button to put it at the ON position after accessing the

OVERSPEED TEST screen;

5.8.4.8 Set the target rotating speed at 3340 r/min;

5.8.4.9 Press a GO button to begin rising speed; beginning from the speed of 3000 r/min

at the rate of 300r/min/min, the speed accelerates to 108% of the rated speed, namely

3240 r/min; and then its rate is changed to 100r/min/min and it slowly raises to the

eccentric ring action speed. The DEH records the trip rotating speed and displays it on the

OIS screen. If the unit does not act as its speed is up to 3330r/min, it means that the

mechanical trip is failed and the electric over-speed protection functions. Check whether

the HIP main stop valves, control valves, every extraction check valves, HP cylinder

exhaust check valves are fast closed, and the emergency dump valve (BDV) is opened;

record current action speed.

5.8.4.10 in case that the electric over-speed protection does not function as the speed of

the steam turbine rises to its action value, manually stop immediately.

5.8.4.11 the emergency governor over-speed test should be made twice under the same

situation and difference of the action speed during twice tests should not exceed 18r/min.

5.8.4.12 The MECH OSP TEST button automatically switches to the OFF position after

the completion of the test.

5.8.4.13 reset the electric over-speed protection set value to 3300 r/min after the

completion of the test.

5.8.4.14 the test must be completed in 30min.

5.8.5 Cautions:

5.8.5.1 Dwell time at the high speed zone with the speed of 3200r/min should not exceed

1min.

5.8.5.2 in case that the emergency governor does not act when the speed is up to 3330

r/min, immediately trip. The test should be continuous after finding out the causes and

taking the right measures.

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5.8.5.3 The unit is prepared for stopping after a long-term operation. In case that its

operating condition is unclear, it strictly forbids making the over-speed test.

5.8.5.4 Prohibit performing the over-speed test prior to the overhaul;

5.8.5.5 Prohibit performing the test at the rated parameter or approximate to the rated

parameter;

5.8.5.6 Prohibit performing the test under following conditions: jammed emergency

governing system, control valves, main stop valves, extraction check valves; unqualified

tightness of the control valves, main stop valves and the extraction check valves; the unit

bearing vibration out of limits and the unit in abnormal operation.

5.8.5.7 The bearing oil inlet temperature should be maintained within normal range during

the test.

5.9 Electric Over-speed Test of Steam Turbine


5.9.1.1 Initial startup after the steam turbine assembly

5.9.1.2 after the overhaul of the unit;

5.9.1.3 after reassembly of the emergency governor;

5.9.1.4 After overhauling the set valve in the front box that affects on the action speed of

the emergency governor;

5.9.1.5 Before making the load rejection test

5.9.2 Purposes: Check whether the electric over-speed protection is normal and the action

speed is qualified, so as to ensure the safe operation.

5.9.3 Testing conditions: 5.9.3.1 The over-sped test must be in charge of the general engineer and under the

direction of associated technicians.

5.9.3.2 The test must be made after the tests of the HIP main stop valves and control

valves, centralized manual emergency trip shut-down, local manual trip and valves

leakage are completed and qualified.

5.9.3.3 The over-speed test during the cold startup of the unit should be made under the

condition that the unit operates for 3-4h with the load of 150MW.

5.9.3.4 Enough testing personnel, testers and tools are required to prepare prior to the

test.

5.9.3.5 During the test, the remote and local manual trip handles must be in charge of

special personnel. A speed indicator should be provided at the front box. The centralized

and local communication facilities are in good condition.

5.9.3.6 During the test, it must closely monitor the rotating speed, vibration, axial

displacement, LP cylinder exhaust temperature and so on.

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5.9.3.7 Before the test, put associated recorders and printers into operation to

continuously type the said parameters.

5.9.3.8 The main and reheat steam pressure must meet the requirement of the

corresponding startup curves, and the main and reheat steam temperature should be

stable and matched with the turbine metal temperature. The main steam pressure should be ranged from 5MPa to 6MPa; the main steam temperature should be above 350℃～

400 ; the IP cylinder admission pressure should be maintained at 0.1MPa℃ ～0.2MPa

through the HLP bypass; The reheat temperature should be ranged from 300 to 350 . ℃ ℃

The condenser vacuum and exhaust temperature must be normal; otherwise, a cooling

water spray device must be put into operation.


5.9.4.1 OPC protection test 1）The OPC key test is performed before the unit startup.

2）Methods:

a. Check the EH oil system, i.e. make sure it has put into operation and electrified;

b. Click the LATCH button on the DEH AUTO CONTROL screen; make sure the

mainframe safety oil is in place, the RSVL, RSVR IP main stop valves are full opened;

check the MSVL and MSVR and make sure they are full open after clicking the RUN

button;

c. Manually open the HP and IP control valves;

d. Switch the OPC changeover switch to the “TEST” position on the DEH manual

operating panel;

e. Check the HP and IP control valves i.e. make sure they are closed;

f. Switching the OPC changeover switch to the "NORMAL” position, making sure the

HP and IP control valves are opened, the test is completed. 3）OPC dynamic test

a. The unit rolls to 3000 r/min.

b. Check the OPC key switch i.e. makes sure it is at the NORMAL position;

c. Set the target rotating speed as 3091 r/min, acceleration rate 50 r/min/min and then

accelerate;

d. The rotating speed displayed on the screen is greater than or equal to 103% when

the rotating speed is up to 3090 r/min.

e. Check that the HP and IP control valves, the HP and IP drain valves and the HP

cylinder exhaust check valve are closed, the HP cylinder exhaust vent valve and the

LP cylinder exhaust spray valve are opened; the rotating speed begins to slow down.

f. When the rotating speed slows down below 3000r/min, check the HP and IP control

valves i.e. make sure they are gradually opening and maintain the rotating speed at

3000r/min.

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5.9.4.2 Electric over-speed protection test

1) Load down according to normal stop procedure;

2) Start the TOP and MSP and make sure they are in normal operation;

3) The HLP bypass at the follow mode;

4) Generator disconnection and the rotating speed to be maintained at 3000r/min;

5) Latch again to keep the rotating speed at 3000r/min after the remote and local

manual trip tests is separately performed and qualified;

6) Confirm that the indicating lamps on the DEH associated with the tests indicate

correctly;

7) Press the ELEC OSP TEST button to put it at the ON position after accessing the

OSP TEST screen;

8) Modify the rotating speed as 3310r/min;

9) Send out GO command through the OIS;

10) Beginning from the speed of 3000 r/min at the rate of 300r/min/min, the speed

accelerates to 108% of the rated speed; and then its rate is changed to 100r/min/min

and it slowly rises to the eccentric ring action speed till 3300r/min to trip (or manual trip).

The DEH records the trip rotating speed and displays it on the OIS screen.

11) The ELEC OSP TEST button automatically switched to the OFF position after the

completion of the test.

5.10 Valves Activity Test

5.11 MSV and CV Leak Test

5.12 Mainframe Low Lube Oil Pressure Interlock Protection Test


5.12.1.1 before the initial startup after the unit reassembly or the overhaul and minor

repair;

5.12.1.2 The lube oil of the mainframe or its control system to be overhauled;

5.12.1.3 Once a week in normal operation

5.12.2 Purposes: regularly check the standby state of the AC and DC lube oil pumps, so

as to ensure they are in good condition and improve the safety of the unit in operation and

accident.


5.12.3.1 The test prior to the unit startup can be realized by starting the pumps in the

corporation of the thermal technician.

5.12.3.2 In normal case, the test should be made in stable operation of the unit.

5.12.4 Procedures:

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5.12.4.1 Check the mainframe lubricating oil system i.e. makes sure it is in normal

operation;

5.12.4.2 Slowly open the test valve of the AC auxiliary oil pump;

5.12.4.3 Check the AC auxiliary oil pump, i.e. make sure its startup, current and oil

pressure are normal;

5.12.4.4 Close the test valve;

5.12.4.5 Remotely stop the AC auxiliary oil pump;

5.12.4.6 Check the mainframe lubricating oil system i.e. make sure it is normal; if the

pressure of the system drops, immediately start the AC oil pump and report to associated

leaders;

5.12.4.7 Make the low oil pressure startup test for the corresponding oil pumps with the

test valves of the DC emergency oil pump and the startup oil pump;

5.12.4.8 Confirm that every test valve is at the anticlockwise bottom after the completion

of the test;

5.12.4.9 Check the lubricating oil system, i.e. make sure it is in normal operation.

5.13 Vacuum Leakage Test


5.13.1.1 The test is applicable to the restarted unit after reassembly or overhaul.

5.13.1.2 In normal operation, the test is made once a month.

5.13.2 Purposes: Check whether the vacuum leakage is met the requirement, so as to

process it immediately and improve the economical efficiency.

5.13.3 Necessary conditions for the test:

5.13.3.1 The condenser pressure is normal and stable;

5.13.3.2 The load of the unit is stabilized at 80% of the rated load as performing the test;

5.13.3.3 The unit load and its operating parameters are stable during the test;

5.13.3.4 Before the test, the mainframe vacuum should be greater than negative 92KPa;

otherwise, find out the causes and remove them;

5.13.3.5 The water circulating pump must be in MCR operation during testing.

5.13.4 Test methods:

5.13.4.1 Record the unit load, condenser vacuum and the LP cylinder exhaust

temperature before the test;

5.13.4.2 Close the vacuum pump inlet manual insolating valve in operation at the HP and

LP side of the condenser or full stop the vacuum process pump (Note: the stopped

vacuum pump inlet pneumatic valve should be closed by interlock);

5.13.4.3 After the valve shut-down, continuously record the HP and LP condenser vacuum

for 5min at once per minute and then seek its average value;

5.13.4.4 Open the vacuum process pump outlet manual isolating valve (or start the

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vacuum process pump);

5.13.4.5 Obtain the condition of the vacuum drop in every minute with the vacuum

drop-out value in later 5min;

5.13.4.6 The test must be stopped in time and the vacuum system must be put into

operation again in case that the condenser vacuum during the test drops to the alarm

value or the exhaust temperature rises to 50 .℃

5.13.4.7 Standards of the condenser vacuum leakage test : excellent: 0.13KPa/min（1mmHg/min）; good: 0.27KPa/min（2mmHg/min）; qualified: 0.4 KPa/min（3mmHg/min）

5.14 Extraction Check Valve Activity Test

5.15 Load Rejection Test

5.15.1 Purposes:

5.15.1.1 Measure the dynamic maximum momentary speed of the control system after the

load rejection of the unit that should be less than the action value of the over-speed

protection device.

5.15.1.2 The transition process of the rotating speed after the load rejection attenuates

and the unit is in idle operation at the rotating speed of 3000r/min after oscillating several

times.

5.15.1.3 Measure the dynamic process of the key link in the control system at the time of

load rejection;

5.15.1.4 Check the mainframe and associated facilitates for their adoptive capability to

the load rejection and mutual time relation, so as to provide data for improving the

dynamic quality of the unit and analyzing the performances of the facilities.


5.15.2.1 Establish a commanding agency for the test with clear assignment of

responsibilities and duties and appoint a commander in chief for the unified command of

the test;

5.15.2.2 Have a testing schedule that is approved by the department in charge and set

jointly by every party;

5.15.2.3 Every professional participant in the test must be provided with reliable

communication facility;

5.15.2.4 The testers must be full, reliably and soundly equipped.

5.15.2.5 The workers in charge of the operation should be well trained and has a clear

assignment for the responsibility and duty.

5.15.2.6 Completed and qualified tests

⑴ Every valve activity test of the steam turbine

⑵ Normally auto-switch between the two EH main oil pumps with 10.7-11.7MPa oil

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pressure, 32℃-54 oil temperature and normal oil level; 8.0MPa HP accumulator ℃

nitrogen-filled pressure

⑶ The action set value of the emergency governor accounting for 110%-111% of the

rated rotating speed meets the requirement.

⑷ The electric over-speed protection set value accounting for 110% of the rated

rotating speed meets the requirement.

⑸ The completion of totally closing time measurement of every main stop valve and

control valve at the time of latching meets the requirement.

⑹ The leakage test for every main stop valve and control valve meets the

requirement.

⑺ The no-load test and on-load test are qualified; the system and mainframe,

auxiliary of the steam turbine are normally and flexibility operated without defect. Every

supervisory instrument indicates correctly.

⑻ The fire-resistant oil and turbine oil quality of the emergency governing system are

fully qualified.

⑼ The turbine extraction regenerative system, steam bypass system and extraction

check valve are in normal operation and the protection interlock is reliable.

⑽ The local manual trip and remote control trip devices are flexible and reliable.

⑾ The unit bypass system is normal.

⑿ The temperately equipped devices such as the load rejection button (convenient for

the program control of the oscillograph, generator main oil switch and busbar switch

and so on) are ready and qualified.

⒀ The indicators, recorders and instruments for the test are complete and in good

condition.

5.15.2.7 Cautions:

⑴ Operate the activity tester for preventing from jamming in the system prior to the

test to avoid the failure to operate on command;

⑵ Check the testing instruments and meters before the test to ensure they are

complete and sound;

⑶ Release these interlocks that hinders from testing before the test;

⑷ Regulate the operating conditions before the test to guarantee it is operating at the

rated parameter, vacuum and load, and full record the parameters including the rotating

speed, pressure, displacement (stroke) and so on after it is stabilized;

⑸ Ensure fluent communication for the commanding system;

⑹ The command in chief orders to reject load based on the reports from the person in

charge of every project.

⑺ The oscillograph must be started in about 1s before the load rejection.

⑻ Closely monitor the conditions of the unit maximum momentary speed; Immediately

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trip while the rotating speed is up to 3330r/min;

⑼ Closely monitor the conditions of every main stop valve, control valve and

extraction check valve; Take right measure in time in case of normal condition;

⑽ Closely monitor the conditions of the unit bearings to ensure safe operation;

⑾ The parameters including the rotating speed, pressure and displacement (stroke)

and so on recorded during the test must contain the maximum and minimum values.

⑿ Full record the rotating speed, pressure and displacement (stroke) once after the

rotating speed is stabilized;

⒀ Restore the unit to operate in normal condition and every interlocks after the

completion of the test;

⒁ Sort the waveforms and hand-written records and compile the test reports in time.

5.15.2.8 Safety precautions

⑴ Test each item specified before the load rejection and ensure the test data are

qualified;

⑵ The safety measures taken in the over-speed test are totally suitable for the load

rejection test.

⑶ The operator must closely monitor the states of the unit and operate it

corresponding to the states after the load rejection.

⑷ The operation after the load rejection must be fast and accurate. After the steam

turbine rejects a rated load, the no-load operating time should be less 30min.

⑸ The digital tachometer provided by the manufacture must be in charge of an

appointed person. When the rotating speed reaches the reticle (3330r/min), it must

quickly and decidedly trip. If the speed continues to rise or maintains, the emergency

measures of closing the motor-driven main stop valve, each extraction check valve and

breaking vacuum must be taken immediately.

⑹ The vibration values of every bearing must be monitored by a specially-appointed

person. The moment there is abnormal condition, the person must trip quickly to

prevent from happening or wide spreading accident.

⑺ If the servomotors of the HP control valve or the IP control valve are kept starting

after the load rejection test, or the steam turbine is in single cylinder steam admission

state resulting from the starting of them after restoring, the steam turbine must be

stopped immediately.

⑻ The HP, IP and LP differential expansion must be monitored at the idle running and

load variation of the steam turbine. If there is abnormality occurred, take right measure

immediately.

⑼ After the load rejection test, the conditions of the turbine bypass system, the

deaerator, the condenser water level, the extraction regenerative system, the steam

turbine and extraction system drain water, HP cylinder exhaust temperature rise, thrust

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bearing metal temperature, the cylinder metal temperature and so on must be noted. If

there is any abnormity, take right measures immediately.

Chapter III Start-up and Outage of the Unit and Operating Maintenance Thereof

1 Start-up of the Unit

1.1 Start-up Specifications and Requirements

1.1.1 The unit startup after overhaul should be presided over by the chief engineer with

the participation of the directors in charge of the generation and equipment departments,

department heads and relevant personnel.

1.1.2 The startup after minor repair should be presided over by the chief engineer or the

director in charge of the generation department with the participation of the director in

charge of the equipment department, the department heads and relevant personnel.

1.1.3 The duty director assumes unified command and takes charge of the normal startup

of the unit and the generation department heads are charge of on-site technical

supervision and guidance.

1.1.4 Before overhaul and minor repair of the unit, check the relevant devices and system

for their conditions and completion report of construction work and oil quality qualification

report for completion.

1.1.5 Confirm that the overhaul of the unit is finished; the work-order cards are totally

cancelled; the site sanitary conforms to the standards; relevant temporary platform is

removed and the cold test is acceptance.

1.1.6 Confirm that every mainframe and auxiliary interlock and protection test are

completed and qualified; every valves commissioning are finished and locates at right

position of their switches and part of the overhauled auxiliaries has a test run and

operates normally.

1.1.7 The thermal technicians prepares for the interlock and protection tests of relevant

devices and system and then records the test well.

1.1.8 The tools, instruments, meters, various recorder chart paper and operation order for

the startup has been ready and the arrangement for relevant person has been made.

1.1.9 All liquidometers are clean; every pressure gauge indicates right and the primary

and secondary valves of the field measuring device are opened.

1.1.10 Confirm that the centralized control room, every filed control panel and cabinet are

complete, every instruments, alarms, operation and control switches are sound and work

well and all thermal instruments, signals and protection devices are power on.

1.1.11 Check the bearings of every rotating device, i.e. make sure the oil level is normal

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and the oil quality is qualified.

1.1.12 All motor-driven valves, control valves and control dampers are power on and the

display is accordance with the actual condition. After the commissioning of the base type

regulating device is completed and the set value is correct, put the device into automatic

operation.

1.1.13 after confirming that the insulation of every electric device is qualified and the

casing ground connection is complete, delivery power to the working position.

1.1.14 The control and supervisory systems of the DCS, DAS, FSSS, BMS, D-EHG,

MEH,HITASS, TSI, PRP, ASS and bypass are in normal operation and the parameters on

the CRT is correctly indicated.

1.1.15 Check the expansion indicators of the pipes and record their initial values.

1.1.16 the illumination of the plant building at ever place is good; the emergency

illumination system is normal and it can be put into operation at any time.

1.1.17 Site fire control system is in normal operation and the fire fighting device is

complete and sound.

1.2 Start-up Prohibition Conditions of the Unit

1.2.1 The assembly, overhaul and commission affecting on the startup is not completed or

qualified. The work-order cards are not expired and taken back. And the equipment site is

inconformity with the Safety Code for Electric Industry.

1.2.2 Supervisory malfunction of main instrumentation of the unit affects the startup or

normal operation of the unit.

1.2.3 Any one of the protection devices of the unit malfunction

1.2.4 Unqualified main interlock protection test of the unit

1.2.5 The malfunction of the regulating instrument and base type regulating instrument

affects the startup or normal operation of the unit.

1.2.6 Instruments and protective power supply of the unit lose.

1.2.7 The upper and low cylinders metal temperature difference of the HP and the IP

cylinders exceeds 35 and the upper and lower outer casing difference is greater than ℃

50 .℃

1.2.8 The HP and IP cylinders differential expansion greater than 10.3mm or less than

negative 5.3mm; the LP cylinder differential expansion greater than 19.8mm or less than

negative 4.6mm;

1.2.9 The mainframe rotor eccentricity greater than 10% of the initial value

1.2.10 one of the HIP main stop valves, control valves, extraction check valves, HP

cylinder exhaust check valves, V.V and BDV is locked and can not be tightly closed.

1.2.11 Any one of the main thermal interlock protection (mainframe, electric and boiler

interlock, boiler MFT and steam turbine protection) or the generator transformer unit

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functions abnormally.

1.2.12 Any one of the TTOP, MSP, EOP, EH oil pump, journal oil pump and the turning

gear is failed or corresponding interlock test is unqualified.

1.2.13 There is clear metal fricative sound when turning and its current apparently

increases or it vibrates by a wide margin.

1.2.14 The lube oil level of the oil tank and the EH oil tank lower than the limit value or

unqualified oil quality and lube oil temperature less than 27 ;℃

1.2.15 Unqualified steam and water quality;

1.2.16 Abnormal gland steam supply;

1.2.17 Unqualified emergency governor over-speed test of the mainframe;

1.2.18 Generator hydrogen-cooled system failure or unqualified hydrogen purity (less than

96%) and moisture;

1.2.19 Sealing oil system failure;

1.2.20 Non-conforming startup and protection of the unit resulting from the bypass system

failure and abnormal BMS supervisory controller;

1.2.21 Abnormal governing system of the steam turbine so that no-load running can not

be maintained and rotating speed can be not controlled below the action speed of the

emergency governor after the load rejection;

1.2.22 Unqualified insulation of the primary power system of the generator transformer

unit;

1.2.23 The generator voltage regulator in abnormal operation;

1.2.24 The generator synchronization system in abnormal operation;

1.2.25 Emergency diesel generating set failure;

1.2.26 The UPS and AC system has the fault with direct influence on safe operation of the

unit after its startup.

1.2.27 The stator cooling water system of the generator is failure or its water quality is

unqualified.

1.2.28 The field double-colored water level indicator for the boiler drum is failed to

operate.

1.2.29 The leakage test of the generator after the overhaul of the unit is unqualified.

1.3 Start-up State Classification of the Unit

1.3.1 The IP cylinder startup in normal operation is preferential.

1.3.1.1 IP cylinder startup (classified by inner cylinder inner wall metal temperature of the

IP cylinder at the time of startup) 1）Cold state: T is less than 305 ;℃

2）Warm state: T is greater than or equal to 305 or less than 420 ;℃ ℃

3）Hot state: T is greater than or equal to 420 or less than 490 ;℃ ℃

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4）Extreme hot state: T is less than or equal to 490 .℃

1.3.1.2 HIP cylinder combination startup (classified according to the inner wall metal

temperature T at the first stage of the steam turbine at the time of startup) 1）Cold state: T is less than 320 ;℃

2）Warm state: T is greater than or equal to 320 or less than 420 ;℃ ℃

3）Hot state: T is greater than or equal to 420 or less than 445 ;℃ ℃

4）Extreme hot state: T is less than or equal to 445 .℃

1.4 Inspection before the Steam Turbine Start-up

1.4.1 Overall inspection and requirements of the unit

1.4.1.1 All professional maintenance is completed and all work-order cards having

influence on the startup of the unit have expired in accordance with the relevant

regulations.

1.4.1.2 The stairs, rails and platforms are complete and sound, and there are not any

sundries that hinder operation and passing through around the passages and the devices.

1.4.1.3 All systems must be connected well; every man hole and inspection hole is closed

and pipe supports are firm, complete and heat preserved.

1.4.1.4 The illumination of plant building is good and emergency illumination system is

normal.

1.4.1.5 The equipment name, rotating sense of the rotating mechanism and medium

directional arrows of the pipes are complete and correct.

1.4.1.6 The communication system of plant building and tools, instruments and various

record forms specified by the unit startup is ready and complete.

1.4.1.7 The plant water supply system is in normal operation; make-up water of the

cooling tower is up to the normal level; the water circulating system is prepared for

operating; the fire-extinguishing water system is in normal operation and the fire fighting

device is complete.

1.4.1.8 Confirm that the centralized control room, every filed control panel and cabinet are

complete, every instruments, alarms, operation and control switches are sound and work

well and all thermal instruments, signals and protection devices are power on.

1.4.1.9 Confirm that every operational, protection, control, signal and instruments power

supply is disconnected and normal;

1.4.1.10 Make sure the unit control system is operating normally;

1.4.1.11 Confirm that various oil and water systems meet the startup requirements;

1.4.1.12 Check the CRT display screen, signals and audible and viable signals, i.e. make

sure they are normal and correct;

1.4.1.13 Put the valves in the systems at the required states according to the valve check

cards; open every liquidometer isolating valve; check the primary and secondary valves of

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all thermal signals, i.e. make sure they are open;

1.4.1.14 Check every motor-driven actuating mechanism and auxiliary power supply, i.e.

make sure they are power off and confirm the trial running is qualified;

1.4.1.15 Confirm that the trial run step by step and interlock protection tests of every

system and auxiliary after the overhaul and minor repair of the unit are qualified;

1.4.1.16 Confirm that the remote states of every valve and rotating mechanism are

corresponding to the local states and the two states can be well controlled. The

changeover switch is put at the remote position;

1.4.1.17 Check and make sure the interlock and protection signals of all devices and

systems have put into operation before the unit startup;

1.4.2 Inspection before thermal startup

1.4.2.1 Check the oil level and quality of every oil tank of the steam turbine and the boiler

and the bearings of the auxiliaries i.e. make sure they are normal and qualified;

1.4.2.2 Contact the chemical worker to make up water in the condenser make-up water

tank to high level and check their for qualification;

1.4.2.3 Confirm that the TSI, SCS, DAS, MCS, DEH and MEH systems are in normal

operation;

1.4.2.4 Confirm that the turbine water feed protection is in normal operation; every drain

manual insolating valve is opened and every drain control valve acts correctly;

1.4.2.5 Confirm the heat preservation of the steam turbine proper is good;

1.4.2.6 Make sure every HIP main stop valve, control valve and control mechanisms are

normal;

1.4.2.7 Confirm that the sliding key system is normal and the cylinder can freely expand;

1.4.2.8 Confirm that the exhaust cylinder safe valve is complete;

1.4.2.9 Confirm that the emergency drain oil valve is closed and sealed with lead.

1.5 Operation of Auxiliaries and Systems before the Unit Start-up

1.5.1 Operation of Auxiliaries and Systems

1.5.1.1 Start the water circulating pump to supply circulating water for the condenser and

check its system, i.e. make sure it is in normal operation; put the other one into standby as

the pump in operation is confirmed in normal operation; put the rotary strainer and rubber

ball cleaning device into operation as the circumstances many require;

1.5.1.2 Put the open cycle cooling water system into operation and make sure it is in

normal operation;

1.5.1.3 Start the condensate delivery pump and make sure it is operating normally; flush

the condenser, stator cooling water tank and the deaerator, respectively till qualifying and

then make up water to the normal water level;

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1.5.1.4 Put the condensate system into operation and put its attemperating water into

automatic supply as required and put the LP heater water side into operation; if the

condensate water qualified is unqualified, open the #5 LP outlet drain valve to flush and

blow down;

1.5.1.5 Put the auxiliary steam system into operation;

1.5.1.6 Heat the deaerator till its water temperature is greater than the boiler drum wall

temperature, namely 28 ;℃

1.5.1.7 Put the mainframe lubricating oil system and the oil purification plant into operation

and make sure they are operating normally;

1.5.1.8 Put the generator oil, hydrogen and water systems in turn according to the

operating specifications of them;

1.5.1.9 Put the mainframe turning gear into operation:

1) Confirm that the mainframe lubricating oil system is in normal operation, the lube oil

temperature is controlled ranging from 27 to 40 and its pressure is greater than ℃ ℃

0.137Mpa;

2) Put the jacking oil system into operation; check the jacking oil outlet manifold

pressure, i.e. make sure it is 16MPa and record it; check whether the jacking oil

pressure of every bearing is greater than 7MPa and compare the said parameter with

the jacking oil pressure test records;

3) Check the turning gear current, rotating speed and inside sound after the startup of it

and make sure they are normal;

4) Put the turning gear into automatic operation and record the rotors eccentricity;

5) Make the interlock tests for the turning gear and the jacking oil pump in the

cooperation of the thermal technicians as the circumstances require and make sure the

tests are normal;

6) Full record the primary steam and metal temperature once after the turning gear is

put into operation; copy them per hour till the completion of the startup after the gland

sealing system is put into operation;

Note: before the steam turbine rolls, the turning gear at least needs to continuously run for 4h without abnormality and the rotor eccentricity is less than 110％ of the original value so

as to ensure its stable startup.

1.5.1.10 Put the EH system into operation and make sure it is in normal operation.

1.5.1.11 Following tests can be performed as required.

1) Static test of the turbine governing system (static characteristic curve and

measurement for valves off-time);

2) Turbine local and remote trip tests;

3) Main trip solenoid valve action test;

4) ETS protection test;

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5) AC and DC lube oil pump low oil pressure interlock test of the mainframe;

6) EH pump low oil pressure interlock test.

1.5.1.12 Make sure that every pipe drain valve, drain valve of every valve block and the

relevant manual drain valves in the main and reheat steam, bypass and extraction steam

systems had opened already;

1.5.1.13 Pre-warming operation is determined according to the HP cylinder primary outlet

inner wall temperature.

1.5.1.14 Start the motor-driven feed pump; put the HP heater water side into operation

while meeting the requirements and check the system, i.e. make sure it is in normal

operation;

1.5.1.15 Put the gland sealing system into operation; check the gland manifold pressure

and make sure it ranged from 26KPa to 28KPa. The gland steam temperature is matched

with the gland metal temperature. 1）Cold state (150℃～260℃）;

2）Hot state 208℃～375℃）;

3）The gland fan inlet's vacuity is maintained at about 2.5KPa. (Operating principal of

gland steam: in cold startup mode, pump out vacuum first, and feed gland steam

before HP cylinder pre-warming of the unit; in hot startup, feed gland steam prior to

pumping vacuum out. The gland fan must be put into operation immediately after

feeding gland steam or stopped immediately after the gland steam pressure reaches

zero for stopping supply it.

1.5.1.16 Start two sets of vacuum pumps; check their operation, i.e. make sure they

are in normal operation;

1.5.1.17 Prepare for igniting the boiler after the condenser vacuum is in place.

1.6 Unit Start-up Parameters and Mode Selection Principal

1.6.1 No matter what kind of startup modes, the main and reheat steam into the steam

turbine must be ensured above 56 of superheat degree;℃

1.6.2 The warming time should be confirmed based on the startup-loading chart;

1.6.2.1 The warming time of the unit on initial load with the IP cylinder startup mode after

the steam turbine operates at a mid speed and a full speed, and synchronizes is

confirmed in terms of the IP steam admission metal temperature, reheat steam pressure

and temperature prior to staring;

1.6.2.2 When the unit is operating with the automatic startup mode, the time can be set by

referring to the warming time of mid speed, full speed and initial load on the DEH screen

on the premise of ensuring the mainframe differential expansion, the outer wall

temperature difference and the temperature vitiation rate are within the corresponding

limits (see the corresponding curves in appendix);

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1.6.3 In cold startup mode, the time is set based on the requirements of the 1.6.2.2 and

the main and reheat steam pressure and temperature must meet the requirements of the

“cold startup curve” (see the appendix);

1.6.4 In non-cold startup mode, while meeting the requirements of the startup curves

under every state, the unmatched value of the main steam temperature and the HP

primary metal temperature, the reheat steam temperature and the IP steam admission

metal temperature should be ranged from negative 10 to 55 as much as possible and ℃ ℃

28 ℃-55 is optimal. ℃

1.6.5 The metal temperature variation rate must be met the requirement of the

“temperature variation rate and temperature variation relation curves of the HP and IP

rotors under various cycle life consumption” while selecting the steam parameters, usually adopting the life loss less than 0.001％ under the HP and IP cylinders metal temperature

jump.

1.6.6 The IP cylinder startup mode is preferential.

1.7 Cold Start-up of the Unit

1.7.1 HP cylinder pre-warming

1.7.1.1 Pre-warm the HP cylinder before the boiler ignition in case of the cold startup or

the primary inner wall metal temperature less than 150 ;℃

1.7.1.2 Pre-warming steam is from the auxiliary steam (or cold reheats steam). And the pre-warming pressure is required to be 0.4～0.5MPa; temperature is 200～250 and the ℃

degree of superheat is maintained at 28 .℃

1.7.1.3 Warming conditions: 1）The mainframe trips in turning state;

2）The primary inner wall metal temperature is less than 150 ;℃

3）The condenser vacuum is not less than negative 86.8KPa;

4）The cold reheat pipe and the first extraction electric valve inlet drain valve are

opened; 5）The auxiliary steam header pressure ranges from 0.5MPa to 0.7MPa and it is in

normal operation; 6）The mainframe VV is closed;

7）The first extraction motor-driven valve is full closed and the HP cylinder

exhaust check valve is closed.

1.7.1.4 Warming operation

Open the HP cylinder to pre⑴ -warm its insolating valve; warm the pre-warming pipe to

the control valve inlet for cylinder warming; keep a drain trap continuously running after

fully draining and warming pipe;

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Regulate the opening of the HP loop pipe d⑵ rain control valve to 20%;

Close the drain valve of the HP cylinder exhaust check valve inlet pipe;⑶

⑷ Open 10% of the control valve for warming the HP cylinder; 10% of the pre-warming

control valve and open to 30% after maintaining for 20min and continue to open to 55%

after 20min for 30% opening;

Close the first extraction electric valve inlet drain valve in 30min;⑸

Regulate the opening of the control valve for heating the HP cylinder; control the ⑹

primary metal temperature rise rate of the HP cylinder less than 1 /min, so as to ℃

enable the pressure inside the cylinder to gradually rise to 0.4MPa-0.5MPa and the

primary inner wall metal temperature to gradually rise to 150 . ℃

1.7.1.5 Superheat the HP cylinder in case of maintaining current opening after the primary

inner wall metal temperature gradually rises to 150 ; Set the superheating time based on ℃

the “HP cylinder pre-warming superheating time curve” (the following table for reference:

the temperature is the primary inner wall metal temperature before pre-warming)

Temp（℃） 20 40 60 80 100 120 150

Time（min） 220 200 190 180 150 110 0

1.7.1.6 Operations after the completion of cylinder superheating

Full open the HP loop pipe drain valve and the first extraction electric valve inlet drain ⑴

valve;

Put⑵ the HP cylinder exhaust check valve inlet drain valve into automatic operation

and full open it;

Gradually close the HP cylinder pre⑶ -warming control valve; check and make sure the

HP cylinder exhaust vent valve is full opened after full closure of the control valve;

Put the cooling reheat pipe drain valve into automatic operation.⑷

1.7.1.7 Cautions

In order to meet the requirement of the temperature rise rate, the primary outer wall ⑴

metal temperature rise must be less than 1 /min that is maintained an℃ d controlled by

regulating the reverse flow valve, loop pipe drain valve and the HP cylinder exhaust

check valve inlet drain valve.

Pressure inside the HP cylinder when superheating should be ranged from 0.4MPa ⑵

to 0.5MPa and not greater than 0.7MPa; Otherwise additional thrust force can be

generated for the unit.

The upper and lower cylinders temperature difference is less than 35 .⑶ ℃

The cylinder expansion, HLP cylinders differential expansion, axial displacement and ⑷

rotor eccentricity should be within the allowable range.

Notice of monitoring the operating conditions of the turning gear;⑸

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It needs at least 30min to exhaust steam for pressure drop after the completion of the ⑹

superheating.

The valve opening is for reference only and the metal temper⑺ ature rise limit and

superheating pressure should be the main basis.

1.7.2 HP control valve chamber pre-warming

1.7.2.1 As the metal temperature of the control valve chamber is less than 150 , it must ℃

be pre-warmed with pre-warming steam from the #2MSV pre-inlet valve before the steam

turbine startup.

1.7.2.2 The pre-warming steam is from the main steam. It is used for pre-warming the

control valve chamber when the main steam temperature is greater than 271 and the ℃

HP cylinder superheating is completed.

1.7.2.3 Procedures: 1）Check the steam turbine and make sure it trips;

2) Check the EH oil system and make sure it starts normally and the control mechanism

oil pressure is in place;

3) Confirm that the main steam manifold drain, main steam valve block drain and loop

pipe drain valves are opened;

4) Make sure the main steam temperature is greater than 271 ;℃

5) Press the LATCH button on the steam turbine AUTO CONTROL screen and confirm

the steam turbine has latched successfully;

6) Press down the CV CHEST WARMING button; select OPEN in a pop-up window;

pre-warm at the time of 21% opening of the MSVR;

7) Observe the inner and outer walls metal temperature difference of the control valve

chamber; press down the OFF button of the CV CHEST WARMING when the difference

is higher than 80 ;the MSVR is surely closed while the MSVR℃ -CLOSE lamp is on at

this time; press down the ON button to continue to pre-warm as the difference is less

than 70 ;℃

8) Repeat the said operation till the outer and inner walls metal temperatures are totally

up to 180 and their differences are less than 50 ; above 1h pre℃ ℃ -warming means the

completion of the pre-warming for the control valve chamber; and then press the STOP

button of the steam turbine and make sure every valve is closed.

1.7.2.4 The control valve chamber pre-warming is completed and the boiler continues to

rise temperature and pressure.

1.7.3 Rolling and speed rise of the steam turbine

1.7.3.1 Check and confirmation for following parameters:

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Lube oil pressure greater than or equal to 0.137MPa;

Lube oil temperature ranging from 40 to 46 ;℃ ℃

EH oil pressure ranging from 10.7MPa to 11.7MPa;

Jacking oil manifold pressure ranging from MPa to 16MPa;

Eccentricity less than 100% of the original value;

LP differential expansion ranging from negative 4.6mm to 19.8mm;

HP and IP differential expansion ranging from negative 5.3mm to 10.3mm;

HP cylinder primary upper and lower cylinders temperature difference less than

50/35℃ (inner and outer casings)

1.7.3.2 Check and confirmation of following drain valves at every section in open state: 1）HP section: HP main stop valve inlet drain, HP main stop valve block drain, HP loop

pipe drain, the first extraction electric inlet and outlet drain; 2）IP section: the HP cylinder exhaust check valve inlet and outlet drain, the third and

fourth extraction electric valve inlet and outlet drain, IP combination valve block drain

and IP main steam pipe drain and IP cylinder steam exhaust drain; 3）LP section: The fifth and sixth extraction check valve and inlet drain;

4）Check the HP cylinder exhaust check valve and locally check the cylinder of the HP

cylinder exhaust check valve, i.e. make sure they are opened; confirm the HP cylinder

exhaust check valve is free;

1.7.3.3 The TSI measuring data are in allowable range. Record following parameters

before rolling and confirm following protections has put into operation:

1) Low lube oil pressure protection;

2) Low fire-resistant oil pressure protection;

3) Large axial displacement protection;

4) Bearing vibration protection;

5) Electric over-speed protection;

6) Electric failure shutdown protection;

7) The key switch on the ETS thermal control panel in the test is allowed to be at “PUT”

position.

1.7.3.4 The unit steam and water qualities are qualified.

1.7.3.5 The boiler combustion, steam temperature and pressure are stable.

1.7.4 The steam turbine is started by means of cold IP cylinder.

1.7.4.1 Confirmation for rolling steam parameters

Main steam

pressure

6.0MPa Main steam temp

370℃

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Reheat steam

pressure

1.1MPa Reheat steam temp 320℃

Condenser vacuum ＞－86.8KPa HP bypass outlet

flow

1.7.4.2 Operations at the DEH operating station: 1）Click the START MODE button on the AUTO CONTROL screen; select the IP START

in a pop-out window; 2）Press the RUN button to the position of YES on the AUTO CONTROL screen; make

sure the MSV and the RSV are full open after executing the RUN command; 3）Alter the AUTO/MAN button to AUTO; At this time, it is in operator automation mode.

1.7.4.3 Confirm that the VV and the BDV are opened;

1.7.4.4 Locally check and make sure the HP cylinder exhaust check valve is in free status;

1.7.4.5 Click the VALVE POS LIMIT on the AUTO LIMIT screen to set it as 120%;

1.7.4.6 Press down the HEAT SOAK button on the AUTO CONTROL screen, and then

select ON button.

1.7.4.7 Friction check

1) Click the “c and TARGET” button on the AUTO CONTROL screen to select the target

rotating speed as 200r/min and acceleration rate as 100r/min/min;

2) Press the GO/HOLD button on the AUTO CONTROL screen and select the GO to roll

the steam turbine;

3) In case the rotating speed is faster than the turning speed, check the turning gear, i.e.

make sure it is normal; if it automatically trips, latch to stop immediately;

4) In case the turbine rotating speed reaches 200 r/min, press down the FRIC CHK

button on the AUTO CONTROL, confirm all valves are closed and begin to check the

turbine friction;

5) Carefully listen sound inside the steam turbine and keep the stator running during

friction check period;

4) In case the turbine rotating speed reaches 100r/min, stop checking friction and

confirm the unit is in normal operation.

1.7.4.8 In case of unit latching again, operate mid-speed heat soaking, namely 1500r/min. 1）Press down the ACCRATE and TARGET keys to set the acceleration rate and target

rotating speed as 100r/min/min and 1500 r/min, respectively;

2) Check the #1 and #2 MSVs and the #1-#4 CVs, i.e. make sure the MSVs are opened

and the CVs are slightly opened; in case the turning speed reaches 400 r/min, the CVs

are locked and the turbine rotating speed is controlled by the ICV.

3) The turbine speed rises to 1500r/min under the control of the ICV and the heat

soaking mid speed is maintained at 1500r/min. The mid speed heat soaking will be

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completed after the confirmation of the following parameters:

a) The primary inner wall temperature of the HP cylinder greater than 320 ;℃

b) The inner wall metal temperature of the IP cylinder steam admission chamber

greater than 320 ;℃

c) The HIP cylinder expansion greater than 8mm

1.7.4.9 During the mid-speed heat soaking, keep the main and reheat steam pressure

and temperature stable and the bypass control normal; check the cylinder expansion,

HIP differential expansion, axial displacement, upper and lower cylinders temperature

difference and HIP cylinder exhaust metal temperature, vibration of every bearing and

condenser pressure, i.e. make sure they are controlled within the allowable range;

1.7.4.10 Check the lube oil temperature, metal temperature of every bearing and return oil

temperature, i.e. make sure they are normal;

1.7.4.11 After the completion of the mid-speed heat soaking, press down the HEAT SOAK

button and select the OFF; and then confirm the CV is gradually turned down till full

closing. The unit rotating speed is 1500r/min under the control of the ICV and its target

rotating speed is set as 3000 r/min; then the steam turbine speed continues to rise;

1.7.4.12 In the process of speed rising, the unit through the combined critical speed at the

acceleration rate of 300r/min/min should be fast and stable; the vibration of the bearing

covers should be greater than 0.08mm and the bearing vibration should not exceed

0.25mm; otherwise unit trips;

1.7.4.13 When the turbine rotating speed reaches 2500r/min, check the jacking oil pump,

i.e. make sure it is automatically stopped; otherwise, manually stop it and put the standby

pump into operation;

1.7.4.14 When the turbine rotating speed reaches 3000 r/min, warm it up during the

warm-up period provided by the startup modes;

1.7.4.15 When the mainframe operates at the constant speed, overhaul the unit and every

system, i.e. make sure they are operating normally.

1.7.4.16 Selective tests as required:

1) Manual tip test

2) Emergency governor oil injection test

3) OPC test

4) Main trip solenoid valve test

5) Valve leakage test

1.7.4.17 After passing the said tests, stop the TOP and the MSP; check the mainframe

lube oil pressure and the operation of the main oil pump i.e. make sure they are normal;

and completely check whether the main equipment and auxiliaries of the unit are normal;

1.7.4.18 Confirm that the generator hydrogen cooler and the stator cooling system are

automatically controlled and normal;

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1.7.4.19 Place the AUTO SYNC at the position of ON as required by the duty director.

1.7.5 Cautions during rolling and speed raising

1.7.5.1 The steam parameter should be kept stable in the process of speed rising;

1.7.5.2 Every operational parameter during the unit startup should be checked at any time

and their normality should be guaranteed as well;

1.7.5.3 The chemical technician should test the water quality regularly during the unit

startup, so as to guarantee the steam-water quality;

1.7.5.4 During the speed rising, it must ensure that there is no abnormal alarm occurred at

the DEH; otherwise, next step is unavailable at the DEH AUTO mode;

1.7.5.5 Make sure the LP cylinder spray valve has put into automatic operation under the

control of exhaust temperature that is maintained below 50 before the rolling and the ℃

spray valve outlet pressure is about 0.5MPa;

1.7.5.6 The condenser vacuum must reach negative 86.8KPa before the rolling;

1.7.5.7 The main steam flow during the rolling should be controlled in conformity with the

opening of the LP bypass valve that is adjustable in case the reheat steam pressure is

kept at 1MPa;

1.7.5.8 During the rolling, it must closely monitor the exhaust metal temperature variation

of the HP cylinder and confirm the HP cylinder exhaust vent valve is open;

1.7.5.9 During the startup, it must note that the metal inner and outer walls temperature of

every part of the steam turbine should be controlled within the maximum value provided in

the allowable temperature difference chart; the metal temperature change rate should be

controlled within the maximum value provided by its rate change curve chart and the

mainframe axial displaced is within the allowable range;

1.7.5.10 During the speed rising of the steam turbine, it should take note of the variation of

the cylinder expansion, HIP and LP cylinders differential expansion. When the differential

expansion increases apparently, further increase of it can be controlled by means of

regulating the steam parameter and stabilizing the rotating speed (the steam temperature

should reduce in case positive differential expansion increases). In case that the HP

differential expansion is as large as the value of shutdown, it must be stopped by breaking

vacuum and continuously turn till the cylinder temperature is matched with the rotator

temperature. It must avoid unit trip in case of abnormal LP differential expansion increase.

1.7.5.11 During the speed rising, it must listen carefully the fricative sound of the unit in

site and check the vibration and bearings metal temperature. If there is any abnormity,

stop to find the causes in time. And the unit vibration during the heat soaking must meet

the following requirements: When it is warmed up at a low speed, it must focus on the

changes of the bearings vibration, namely below 1300r/min is corresponding to the

bearing cover vibration less than 30μm; Otherwise, trip it immediately. Mid-speed heat

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soaking is forbidden. When it is warmed up at a combined critical speed, the bearing

cover vibration is less than 100μm or the bearings vibration is less than 250μm; otherwise,

trip it immediately. The heat soaking at the speed in excess of the critical speed or speed

reduction is forbidden. The bearing cover vibration should not exceed 50μm above the

first critical speed; otherwise, find out the causes and relief the vibration till it is less than

30μm. Long-term idle at large amplitude is not allowed. As the bearing cover vibration

reaches 80μm or the bearing vibration is up to 250μm, latch immediately; after the rotor is

still, put the continuous turning gear into operation; check the rotor's bending and the

outer and inner walls temperature difference of the upper and lower cylinders; listen

carefully; find out the causes and remove them; and then restart it.

1.7.5.12 During speed rising, the rotating speed should be maintained and the operation

at the speed in excess of the critical speed in case the speed is within the critical speed

should be kept as well under following conditions:

1) The bearing vibration greater than 0.125mm;

2) The HIP differential expansion greater than 10.3mm or less than negative 5.3mm; the

LP differential expansion less than negative 4.6m or greater than 19.8m

3) High LP cylinder exhaust temperature (80 )℃

4) Low mainframe vacuum (less than negative 86.8Kpa)

1.7.5.13 Temperature rise rate range of every part of the unit 1）Main steam temperature less than 1.5 /min℃

2）Reheat steam temperature less than 2 /min℃

3）HIP cylinder wall temperature rise less than 1.5 /min℃

4）Main and reheat steam pipe walls temperature rise less than 6 /min℃

5）Main control valve casing temperature rise less than 6 /min℃

1.7.5.14 The temperature difference of every part of the steam turbine should be within

the range as follows: 1）The outer and inner walls temperature difference of the HIP cylinder outer casing and

the HP inner casing should be less than 80 ;℃ 2）The outer and inner walls temperature difference of the HP main stop valve casing is

less than 80 ;℃ 3）The outer and inner walls temperature difference of the HIP cylinder outer casing and

the HP cylinder inner casing is less than 80 ;℃ 4）The outer wall upper and lower halves temperature difference of the HIP cylinder

outer casing is less than 80 ;℃ 5）The outer wall upper and lower halves temperature difference of the HIP cylinder

inner casing is less than 80 ;℃

6) The inner wall upper and lower halves temperature difference of the HIP cylinder

inner casing is less than 35 ;℃

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1.7.5.15 As the unit is operating at a constant speed and a water spray device is put into

operation, the LP cylinder exhaust temperature is excessively high, namely 107 as well ℃

after disposal, manual shutdown should be applied.

1.7.5.16 After the unit is operating at a constant speed, if there is superheating occurred at

the HP cylinder and its exhaust steam temperature is up to 432 after disposal, manual ℃

shutdown should be applied.

1.7.5.17 Rotating speed acceleration and reduction by manually setting valve position is

forbidden during normal rolling and speed rising of the steam turbine.

1.7.5.18 Before reaching the synchronous revolution, the lube oil temperature of the steam turbine should be ranged from 38 to 42 , EH oil pressure should be 10.7℃ ℃ ～

11.7MPa and the oil temperature should be 45 .℃

1.7.5.19 As the turbine rotating speed reaches 3000r/min, the main oil pump inlet pressure

must be ranged from 0.098MPa to 0.147MPa and the bearing lube oil pressure should be

ranged from 0.137MPa to 0.176MPa. In case its pressure is not less than 1.372MPa, the

TOP and MSP can be stopped; otherwise, causes must be found out, repair and

adjustment are required.

1.7.5.20 When the generator rotating speed reaches 1500r/min, its carbon brush should

be checked, i.e. making sure there are no abnormality and jump.

1.7.5.21The excitation can be put into operation at the time of receiving the

synchronization command in the cooperation of the duty director while the unit is stable

and has not abnormal alarm signal after the turbine rotating speed reaches 3000r/min.

1.7.6 Generator synchronization

To ensure the normal operation of every device, complete inspection for every system is

required after the generator synchronizes.

1.7.7 Unit load-up

1.7.7.1 Low load warm-up 1）After the unit synchronizes, it operates on 5% load, namely 30MW for 60min;

Meanwhile, the LP cylinder exhaust temperature should be monitored and less than

52 ;℃

2) The main reheat steam parameter must be kept stable during initial load warm-up

period and the bypass must be constant pressure mode;

3) The control indexes of the unit including expansion, differential expansion, and

temperature difference and so on are required to be checked and monitored. And it

must ensure they are normal.

4) During the low load warm-up period of the unit, start and check a set of feed pump,

and warm up the steam turbine.

5) Confirmation for automatic operation of following control systems and valve control:

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a）Deaerator pressure control;

b）Deaerator water level control;

c）Furnace draft and air supply volume control;

d）Auxiliary air baffle plate control;

e）Air pre-cooler cooling end temperature control;

f）Steam turbine proper and HIP drain valves control;

g）Generator stator cooling water control;

h）Exciter air temperature control.

6) In case the steam turbine differential expansion, total expansion, bearing vibration,

bearing shell temperature, oil temperature and pressure, warm-up time totally meet the

requirement, it can be confirmed the completion of warming.

7) Inform of the chemical technician to test the condensate; recovery it to the deaerator

after it is qualified; put the deaerator water level control valve into automatic operation;

put the condensate polishing unit into operation when the condensate temperature is

less than 50 and close the polishing manual bypass valve;℃

8) Put the turbine, generator and boiler interlock protection into operation. 1.7.7.2 Switchover of the HP and IP cylinders

1）Switchover of the HP and IP cylinders is automatically applied to the unit in case the

load is greater than 7% after warming up on initial load. 2）It must note that the main steam temperature through the HP governing-stage

working should be matched with the metal temperature before the switchover of the HP

and IP cylinders. In general case, the temperature ranges are as follows: Main steam: 6.0MPa 380～390℃

Reheat steam: 1.1MPa 360～370℃

3）The main steam must be kept basically stable in the process of switching IP cylinder

single steam admission to HP and IP cylinders combined steam admission.

4) The HP cylinder check valve must be opened and the VV must be automatically

closed during switching over. 5）With the load increase, the #1 and #2 IP control valves are widely opened and the

BDV is automatically closed. 6）Completely check the relevant drain valves and ensure they are automatically closed

after the completion of the switchover. 7）The LP heater sliding starts at random. The HP heater steam side can be put into

operation from high to low side after the completion of the switchover. 8）During switching over, the unit loads up on 5％/min load rate till the HP and LP

bypass valves are full closed. At this time the switchover is completed.

1.7.7.3 Loading up to 180MW 1）Set the target rotating speed and loading rate on the DEH control screen as 180MW

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and not greater than 3MW/min（0.5%/min）, respectively; press the GO/HOLD key to set

it as GO state and load up; 2）Start up the second milling system as the output of the coal pulverizer in operation

reaches 80% according to the main steam pressure requirement; inform of the ash

control attendant to operate the slag and dust removal systems after the pulverizer

starts; 3）Check the drain valve at HP section in the steam system, i.e. make sure it is closed

when the load is up to 60MW; 4）Gradually rise temperature, pressure and load based on the startup curves of the

unit; 5）The unit after being reassembled or overhauled should be firstly started up on

180MW load for 3-4h stable operation, and then it is desynchronized after normally

loading down. A mainframe over-speed test should be made for it as well. 6）When the fourth extraction pressure of the deaerator is greater than 0.15MPa, it is

heated with steam provided by the fourth extraction instead of the auxiliary steam, and

then it is in sliding pressure operation. 7） Check the drain valve at the IP section in the steam system, i.e. make sure it is

closed when the load is up to 120MW. 8）Combine one turb-feed pump that had warmed up with the feed water system in case

the load ranges from 120MW to 150MW; closely monitor the boiler feed water flow

during combination operation, i.e. make sure it is stable; meanwhile, roll the second

feed pump to warm up the steam turbine. 9）After the steam drum water level is stabilized, it will be automatically controlled based

on the operating condition of the turbo-feed pump. 10）After the unit load is stabilized on 150MW load, put the cold reheater to the

self-sealing system into operation and provide gland steam instead of auxiliary steam.

12) When the unit load is above 150MW, cold reheat steam supply is instead of the

auxiliary steam supply. And the auxiliary steam is provided for the steam gland station

system for thermal standby instead. The system should automatically keep the pressure

of the steam supply manifold.

13) When the third extraction steam pressure is higher than the deaerator pressure

(0.2MPa), drain the water of the #3 HP heater to the deaerator.

14) After the unit load reaches 180MW, confirm the relevant LP drain valves of the unit

are normally closed, warm up according to the startup curves and put the power circuit

and TPC into operation as required. 15）If an over-speed test is necessary for the unit, it can be performed after the steam

turbine over-speed test is made, and the unit is desynchronized with a reduced load and

had stably operated on 180MW load for 3-4h.

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1.7.7.4 Loading to 300MW 1）When the target load is set as 300MW, the loading rate and pressure rising rate are

controlled not exceeding 3MW/min and 0.1MPa/min, respectively. 2）Slowly load up the boiler according to the main steam pressure requirements;

3）The unit is in automatic sliding pressure operation and in CCS control instead of DEH

control, and it exits HP bypass automatic operation as its load approximates to 240M.

The signal for the CCS system is sent out by the DEH control system. The unit begins to

load up with the boiler pressure rise till 90% of HP control valve’s opening after it is

controlled by the CCS. (Switchover of the DEH and the CCS: after receiving the request

signal of the CCS, the CCS AUTO REQUEST on the DIGITAL SIGNAL screen of the

DEH turns green. Then press the CCS CTL key and select ON; at this time the target

load of the DEH is set by the CCS; automatically cut off “load feedback” and “governing

stage pressure feedback” and alter the inherent frequency modulation to 30r/min; at last

the CCS is put into operation. If it needs to cut off the CCS, press the CCS CTL key and

select OFF.) 4）After the unit load reaches 240MW, merge the second turbo-feed pump in the feed

water system; stop the motor-driven pump and open the pumps’ outlet valve for

standby. 5）When the load is up 300MW, the main steam pressure should be 10.0MPa, the main

steam temperature and the reheat steam temperature approximates to 510 , ℃

respectively.

1.7.7.5 Loading to 600MW 1）When the target load is set as 600MW, the loading rate and pressure rising rate are

controlled not exceeding 6MW/min and 0.16MPa/min, respectively. 2）When the load is 360MW, the auxiliary steam header steam is supplied from the

fourth extraction. By stopping providing steam for the cold reheater to the steam gland

system, the unit is self-sealed. 3）When the load is 480MW, perform a vacuum leakage test for the steam turbine

according to requirements. 4）When the load is greater than 540MW, the main steam pressure should reach the

rated value and the constant pressure operation should be instead of the sliding

pressure operation. 5）Completely check and adjust the unit to make its devices and systems operate

normally and put all thermal automatic control devices into operation; 6）Put another circulating water pump into operation on a case basis or regulate the

operating mode of the circulating water.

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1.7.8 Cautions during loading of the unit

1.7.8.1 Cautions for the steam turbine 1）Take note of the condenser, deaerator, heater and stator cooling water tank water

level, oil tank level and oil temperature during startup, i.e. make sure they are normal

and conforming; 2） Check the automatic temperature control of every cooler, i.e. make sure it is normal.

3） During the startup of the unit, the chemical technician should continuously monitor

the steam, oil and water qualities, i.e. make sure they are qualified. 4）Switching the DEH control to the CCS control can be applied after completing steam

admission switchover and confirming the valve position command displayed by the

DEH is matched with the CCS load command. 5）When the LP cylinder exhaust temperature is higher than 52 , to avoid overheat LP ℃

exhaust cylinder, it is unsuitable for accelerating load. And attemperating water

condition is required to be monitored. 6）It is unsuitable for long-term operation on the load less than 180MW and it is required

to take note of the HP cylinder exhaust metal temperature variation. 7）The loading rate of the unit is set to at least make the metal temperature change rate

of the cylinder and the valve chamber, the inner and outer walls temperature difference

meet the requirements of the metal temperature changes rate and the temperature

difference control curves. Load stabilization if necessary can be realized by improving

the variation of the metal temperature and differential expansion through adjusting the

steam parameter. 8）Make gland steam overflow flow to the #8A LP heater after the unit operates

normally; 9）Start up the second circulating water pump in time depending on the situation of the

mainframe vacuum and the cooling water temperature; 10）Make up hydrogen for the generator in time to boost up its pressure to the rated

value during the unit loading; 11）Put the steam turbine-boiler coordinate control mode into operation as early as

possible in case the unit load is greater than 50%.

1.8 Warm and Hot Start-up of Unit

1.8.1 Operating principal

1.8.1.1 What is the key for the warm and hot startup of the unit is matchup of the main and

reheat steam temperature with the HP and IP inner cylinders metal temperature of the

steam turbine. The operation is similar to the cold startup of the unit. To avoid the

production of excessive thermal stress resulting from rotor metal temperature drop, the

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unit must be loaded as soon as possible at the warm and hot startup modes.

1.8.1.2 In addition to strict execution of relevant regulations and operating procedures of

the cold startup, the acceleration, warm-up and loading must be executed according to the

warm and hot startup curves. 1.8.4 The mismatch value between the main, reheat steam temperature and the HP cylinder primary, IP admission chamber metal temperature should be ranged within -55～

+110 and the degree of superheat of the main and reheat steam temperature should be ℃

above 56 as the steam turbine rolls.℃

1.8.5 At turning state, gland steam must be supplied prior to pumping out vacuum. The

gland steam source selection is more inclined to the high temperature steam that is able

to match with the gland metal temperature on the basis of the cylinder temperature. Full

water drainage and pipes warming is required before supplying the gland steam.

1.8.6 To meet the requirement of unit service life, the steam turbine bypass system must

be put into operation in time and the main, reheat steam temperature must be strictly

controlled in accordance with the temperature and pressure rising rate after the boiler

ignition.

1.8.7 All turbine water induction prevention valves must be opened at the time of hot

(warm) startup; drain time at every drain point of the main and reheat steam pipes must be

not less than 5min before the turbine rolling.

1.8.8 It must be confirmed that the steam turbine is in turning state or idle running but not

at the critical speed zone before the turbine rolling. Idle running at the critical speed zone

is strictly forbidden.

1.8.9 The acceleration rate, loading rate and warm-up time are determined according the

startup and loading chats.

1.8.10 The HEAT SOAK will be not executed for the steam turbine at the IP cylinder

startup mode. It is rolled to 400r/min with the HP control valve.

1.8.11 It must closely monitor the primary metal temperature change rate of the HP and IP

cylinders, the HP and LP differential expansion, the cylinder expansion, axial

displacement variation and the unit vibration condition when the steam turbine speeds up

by rolling.

1.8.12 Mid-speed heat soaking for the steam turbine can be avoided at the allowable

condition. To protect the cylinder from cooling, it can be fast rolled to raise speed.

1.8.13 Cautions for warm and hot startup of the unit

1.8.13.1 All turbine water induction prevention valves must be opened at the time of hot

(warm) startup; the main and reheat steam pipes and loop pipe drain valve must

continuously drain water for not less than 5min before the turbine rolling.

1.8.13.2 Not less than 5min water drain before the rolling is required in case the inner

walls upper and lower casings temperature difference of the HP and IP cylinders is not

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greater than 35 ; and the inner and outer walls metal temperature difference of the HP ℃

and IP valve blocks ranges within the requirements of the metal temperature difference

curves. To avoid steam-water attack, high water level operation of the condenser during

the water drain is forbidden.

1.8.13.3 During rolling and synchronizing, the main steam flow of the steam turbine must

be corresponding to the opening of the LP bypass valve and the reheat steam pressure is

within adjustable range, namely 1.0MPa. The main steam flow before switchover of HP

and LP cylinders must meet the requirements of the steam flow of corresponding load

after the completion of load-up.

1.8.13.4 After the unit operates on initial load, its fast load-up can be realized in case of

ensuring the LP cylinder exhaust temperature less than 52 . ℃

1.8.13.5 During the unit loading, similarly, the metal temperature change rate and the

inner and outer walls temperature difference of every part of the steam turbine must be

controlled to meet the requirements of relevant curves.

1.8.13.6 The inspection and pre-warming for the turbo-feed pumps must be timely. The

first pump must be rolled to raise speed as soon as possible and merged into the feed

water system.

1.9 Extreme Hot Start-up of Unit

1.9.1 It must be confirmed that the unit is at extreme hot state displayed on the DEH.

1.9.2 With IP cylinder rolling at the extreme hot startup, to protect the boiler against fast

cooling, the boiler must be slowly depressurized by draining water and putting the bypass

system into operation.

1.9.3 Extreme hot startup rolling parameters

Main steam pressure 12.9MPa Main steam temp ＞500℃

Reheat steam

pressure

1.1MPa Reheat steam

temp

＞480℃

Condenser vacuum ＞－90KPa HP bypass valve

outlet flow

＞190t/h

1.9.4 Relevant specifications and cautions for extreme hot startup

1.9.4.1 In case the unit in operation trips resulting from failure, but can be restarted

immediately, vacuum breaking is unnecessary. 1.9.4.2 What is the key for the extreme hot startup of the unit is matchup of the main and

reheat steam temperature with the HP and IP inner cylinders metal temperature of the

steam turbine. The operation is similar to the cold startup of the unit. To avoid the

production of excessive thermal stress resulting from rotor metal temperature drop, the

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unit could roll, rise sped and synchronize fast to be loaded according to the cylinder

temperature and temperature difference curves.

1.9.4.3 All turbine water induction prevention valves must be opened at the time of

extreme hot startup; the main and reheat steam pipes and loop pipe drain valve must

continuously drain water for not less than 5min before the turbine rolling. Not less than

5min water drain before the rolling is required in case the inner walls upper and lower

casings temperature difference of the HP and IP cylinders is not greater than 35 ; and ℃

the inner and outer walls metal temperature difference of the HP and IP valve blocks

ranges within the requirements of the metal temperature difference curves. To avoid

steam-water attack, high water level operation of the condenser during the water drain is

forbidden.

1.9.4.4 During rolling and synchronizing, the main steam flow of the steam turbine must be

corresponding to the opening of the LP bypass valve and the reheat steam pressure is

within adjustable range, namely 1.0MPa. The main steam flow before switchover of HP

and LP cylinders must meet the requirements of the steam flow of corresponding load

after the completion of load-up.

1.9.4.5 After the unit operates on initial load, its fast load-up can be realized in case of

ensuring the LP cylinder exhaust temperature less than 52 . ℃

1.9.4.6 During the unit loading, similarly, the metal temperature change rate and the inner

and outer walls temperature difference of every part of the steam turbine must be

controlled to meet the requirements of relevant curves.

1.9.4.7 The inspection and pre-warming for the turbo-feed pumps must be timely. The first

pump must be rolled to raise speed as soon as possible and merged into the feed water

system.

2. Normal Operation and Maintenance of Unit

2.1 Routine Maintenance and Requirements

2.1.1 Patrol and inspect every device in operation and their standby devices on time with

necessary tools and safety appliance by carefully watching, touching, smelling and

listening, i.e. make sure they are operating normally; compare the readings of the filed

meters with the centralized control meters, if there is any abnormality, find out the causes

and take right measures to solve them to ensure the unit in normal operation.

2.1.2 The operator and inspector should check the meters on time and compare, analyze

their readings. At the time of finding any parameter deviating from the normal value, they

must find out the causes and take right measures, and then report to the duty director.

2.1.3 If there is defect, they must take necessary precautionary measures, record carefully

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the defects that have possible influence on safe and economic operation of the unit or

equipment and systems in accordance with the Defect Management System and report to

the duty director.

2.1.4 Complete routine switchover and test work in compliance with the requirements of

Equipment Routine Switchover and Test System;

2.1.5 Regularly check the auxiliary mechanical bearing oil level and oil quality, i.e. make

sure they are normal, add oil or refresh it in time;

2.1.6 Supervise the condenser, feed water, boiler water, steam, generator stator cooling

water, lube oil, EH oil quality in coordination with the chemical technician;

2.1.7 Fulfill the other relevant work assigned by the supervisor;

Regulate the operational parameters of the unit, every device and system in time;

1 To meet ambient load need, regulate the load in time by means of constant-sliding

pressure according to the dispatching requirement; control the load variation within 6MW～15MW/min;

2 Regulate the steam temperature and pressure in time and keep them normal; control the

boiler evaporation capacity within the rated value;

3 Check the automatic regulation condition of the condenser sump make-up water,

condensate and feed water based on the unit load and main steam flow; keep the

condenser, deaerator and steam drum water levels within normal range;

4 Reasonably regulate the operating mode of the circulating water system and the open

cooling water system according to operation of the unit and the seasonal variation;

5 Regulate the cooling water flow according to oil, air and water conditions of every device

to keep then in normal range;

6 Monitor other devices and systems’ parameters and regulate them to normal range.

2.2 Operational Parameters of Unit

2.2.1 Operational parameter limit of steam turbine

Name Unit Normal Value

Maximum Value

Minimum Value Remarks

Main steam flow t/h 1787 2028 — —

Main steam pressure MPa 16.7 17.5 — —

Main steam temp ℃ 538 546

Reheat steam pressure MPa 3.3 3.63 — —

Main reheat steam

parameters

Reheat steam temp ℃ 538 546 — —

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Main or reheat steam parallel pipes bilateral temp difference

℃ ≤41 —

一 less than 11 ℃within the year

Governing stage pressure MPa 11.7 —

HP cylinder exhaust pressure

MPa 3.67 4.58 — —

HP cylinder exhaust temp ℃ 321 420 — 432 trip

Condenser back pressure kPa(a) ＜13.5 13.5 — ≥ trip

LP cylinder exhaust temp ℃ ＜52 80 — ≥107 trip

Axial displacement mm ﹣1.05～

0.6 ≥0.6 ≤﹣1.05 ≥+1.2 or ≤－1.65 trip

HIP differential expansion mm ﹣5.3～

10.3 ≥10.3 ≤﹣5.3 ≥11.6 or ≤－6.6 trip

LP differential expansion mm ﹣4.6～

19.8 ≥19.8 ≤﹣4.6 ≥30 or ≤－8.0 trip

Mainframe eccentricity mm ≤original

value×1.1＞original value×1.1 — —

Bearing vibration mm ＜0.125 ≥0.125 — 0.25 trip

Steam turbine proper

parameters

Bearing cover vibration mm ＜0.05 ≥0.05 ≥0.08 trip

Lube oil pressure MPa ≥0.176 — 0.103 0.069 trip

Lube oil temp ℃ 40～50 ≥50 ≤40 27～40 as turning

Journal bearing metal temp ℃ ＜107 ≥110 —

Generator high limit: 105

Thrust bearing metal temp ℃ ＜85 ≥85 — —

Thrust bearing abrasion mm ＜0.6 ≥0.6 ≥0.8 trip

Lubricating oil system

parameters

Bearing return oil temp ℃ ＜75 ≥75 — —

Generator oil-hydrogen differential pressure

MPa(a) 0.056±0.02 0.076 0.036

AC sealing oil pump in automatic operation as the pressure is as less as 35kPa

Generator hydrogen pressure

MPa 0.414 — 0.2 —

Generator oil,

hydrogen and water

parameters

Generator hydrogen purity % 98 — ≥96 —

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Generator hydrogen dew-point temp

℃ ≤－21

Generator hydrogen leak volume

m3/d ≤13～19 — — —

Hydrogen cooler inlet temp

℃ ≤65 65 — —

Hydrogen cooler outlet temp

℃ 35～46 46 35 —

Generator sealing oil pump outlet pressure

MPa ＞0.68

≤0.68 MPa standby pump interlock

Sealing pad inlet oil temp ℃ 35～45

Sealing pad outlet oil temp ℃ ≤75

Vacuity in vacuum tank KPa -90～-96 ≤-88 alarm

Generator stator entering water temp

℃ 42～48 48 42

Water temp must be higher than hydrogen temp

Generator hydrogen-water differential pressure

MPa ＞0.04 — 0.04

Hydrogen pressure must be higher than water pressure

Generator stator water flow

m3/h 92 — 72 —

Generator entering water pressure

MPa 0.196

2.3 Adjustment and Maintenance for Normal Operational Parameters of Unit

2.3.1 Task and purpose of operational adjustment for the unit

2.3.1.1 Meet the requirements of unit load and maintain the evaporation capacity within

the rated range;

2.3.1.2 Maintain the normal steam pressure and the main and reheat steam temperature

in normal range according to the sliding-constant pressure curves of the unit;

2.3.1.3 Balance the feed water and maintain the boiler steam drum water level in normal

range;

2.3.1.4 Ensure the quality of the boiler water and steam is qualified;

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2.3.1.5 Strengthen adjustment to try to keep the unit operating at sound state, so as to

improve the efficiency of the unit.

2.3.2 Supervision and adjustment for main operational parameters of the unit

2.3.2.1 Load adjustment

1) The CCS control mode is usually used for the load adjustment. Other control modes

can be employed in case the CCS is failed or the actual operating condition requires.

2) Too fast load variation rate is unallowable. It must be controlled about 1.5

%( 9MW/min) and not exceeding 2.5%/min under normal condition and its maximum

and minimum values should be limited.

3) To guarantee the safe operation of the unit and meet the operating requirements, as

the load fluctuates greatly, the load adjustment should be performed by stages in

accordance with the constant-sliding-constant pressure operating curves, the

requirements of the metal temperature change rate and temperature difference of every

part of the steam turbine, and the metal temperature change rate and temperature

difference control curves of the mainframe.

4) Take note of the variation of the steam temperature and pressure, coal pulverizer as

the unit load increases and reduces; and adjust the air volume and furnace draft in time;

5) Prepare in advance for convenient and timely stop and startup when coal pulverizer

and other devices in the process of load increase and reduction needs to be stopped or

started;

6) Manually adjust the automatic regulating equipment that is out of service for failure as

required in the process of load variation, so as to keep it stably operating;

7) Monitor every water level and temperature and make sure them in normal range, so

as to make them fit the load variation of the unit.

2.3.2.2 Main steam pressure adjustment

1) Maintain the main steam pressure of the steam turbine in normal operation at steam

turbine follow mode by regulating the opening of the control valve;

2) Keep the main steam pressure invariable at the boiler follow mode by changing the

combustion rate of the boiler;

3) Control the unit load and main steam pressure in combination of the steam turbine

and the boiler in coordinate mode of the boiler follow mode;

4) Before performing manual and automatic switching, try to keep the actual pressure

accord with the automatic set value first; while altering the main steam pressure, the set

value is not suitable for being changed largely, i.e. not exceeding 0.2MPa/min at a time;

5) Keep the main steam pressure within 17.47±0.2MPa when the unit operates normally

under the rated condition; fuel quantity control method is allowable for the steam

adjustment except of the approach to affecting on the stable combustion;

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6）The application of safety valve for steam depressurization under non-accident

condition is forbidden. In case of happening excessive pressure of the boiler, the EBV

should be opened first.

2.3.3 Varying duty operational limitation of the unit

2.3.3.1 Allowable variation range of the main and reheat steam pressure and temperature

and allowable continuous operating time thereof under abnormal condition

Parameter Name Limit Value

Average pressure in any 12-month cycle ≤1.00Po

Allowable deviation value in case of maintaining the

average pressure ≤1.05Po

Main steam

pressure Allowable deviation value in exceptional case, but

the accumulative time in 12-month cycle must be

less than 12h

≤1.2Po

Cold reheat steam pressure ≤1.25Pr

Average temperature in any 12-month cycle ≤538℃

Allowable deviation value in case of maintaining the

average temperature ≤538+8℃

Allowable deviation value in exceptional case, but

the accumulative time in 12-month cycle must be

less than or equal to 400h

≤538+(8～14)℃

Allowable deviation value for less than or equal to

15min in exceptional case, but the accumulative

time in 12-month cycle must be less than or equal to

80h

≤538+(14～28)℃

Main and

reheat steam

temperature

Unallowable value Not exceeding

538+28℃

Note: Po and Pr in the table are rated pressure of the main and reheat steam; T

stands for rated temperature of the main steam or the reheat steam.

2.3.3.2 Possible operating conditions capable of being borne by the steam turbine,

comprising:

1) Its shat system is able to bear the moment of torsion resulting from abrupt

short-circuit with any from of the generator outlet busbar or bidirectional reclosing or

asynchronous closing

2) Idle runtime for the steam turbine after the load rejection is not less than 15min and

not allowed to exceed speed.

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3) The steam turbine is able to operate without load at rated speed. And the allowable

duration must meet the requirements of the generator test.

4) Longer-term operation for the steam turbine at the exhaust temperature below 65 ℃

is allowable as well as low-load continuous operation at the temperature not exceeding

79 . It is also able to operate in a short term for 15min at the temperature not ℃

exceeding 107 . ℃

5) The steam turbine peak is allowed to be ranged from 60MW to 600MW.

6) The unit is able to safely operate at the back pressure up to 18.6KPa under abnormal

condition.

7) The steam turbine is able to adapt to the variation of 50% rated load and the unit has

the function of RB.

8) The unit is able to constantly operate stably at a cyclic wave ranging from 48.55Hz to

50.5Hz.

9) The turbo-generating set is able to automatically control the turbine rotating speed to

prevent the unit from tripping and decelerate to a synchronous revolution when the

steam turbine load is rejected from 100% to zero.

10) The unit is allowed to constantly operate with a rated load as the exhaust pressure

rises to 13.3KPa.

11) The steam turbine at least has the ability of operating for 1min without steam within

the range from normal back pressure to the alarm back pressure as the generator is still

synchronized to the grid and the main stop valve is abruptly closed so that any damage

to the devices can be avoided.

12) The turbo-generating set is able to stably operate at the load range from the TMCR

to the minimum load in accord with the boiler. Hybrid variable pressure operation for the

unit is applied. The sliding pressure operation for the steam turbine is ranged from

30%THA to 90%THA.

3. Normal Shutdown of Unit

3.1 Preparations before Shutdown

3.1.1 After receiving the command of preparing for stop, the duty director informs of the

coal, ash and chemical control personnel about the predicated unused time and schedule,

and the requirements of well preparation for the outage and enough oil reserve in the oil

bunker that can meet the needs of the boiler outage.

3.1.2 Contact the duty director for replacing the auxiliary steam supply with adjacent

steam or startup steam supply;

3.1.3 Give a trial run for the mainframe AC auxiliary oil pump, mainframe DC emergency

oil pump, AC startup oil pump, jacking oil pump and turning gear motor to confirm they are

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normal and automatic. If the trial run is unqualified under non-failure outage condition,

hold down till solving the causes;

3.1.4 Confirm the DEH control system is at AUTO mode;

3.1.5 Select the smaller load decreasing rate (not greater than 15MW/min) between the

“sliding pressure outage curves” allowable rate and the boiler allowable rate as the

loading limit of the unit;

3.1.6 Make an overall copy of the steam and metal temperatures once, and then copy

them per hour at the beginning of load reduction and in the process of the load reduction

till normal outage of the mainframe turning gear;

3.1.7 Completely check all devices once and record their defects.

3.2 Shutdown with Variable Parameter

3.2.1 Shutdown with variable parameter is usually applied to the normal shutdown of the

unit.

3.2.2 After receiving the variable-parameter shutdown command, the duty director begins

to reduce thermal load of the boiler, and lower the temperature and depressurize

according to the requirements of the variable parameter shutdown curves.

3.2.3 The unit loads from 600MW to 540MW;

3.2.3.1 Constant pressure operating mode is applied as the load of the unit is between

600MW and 540MW;

3.2.3.2 Maintain the main steam pressure at the rated steam pressure; slowly reduce the

boiler fuel quantity; gradually reduce the load command of the steam turbine and control

the load variation rate not greater than 15MW/min.


3.2.4.1 Sliding pressure operating mode is applied as the unit load is ranged from 540MW

to 180MW;

3.2.4.2 Maintain the turbine load command invariable; control the load variation rate not

greater than 15MW/min and the main steam pressure variation rate not greater than

0.446MPa/min; maintain the main and reheat steam temperature at the rated parameter;

slowly reduce the combustion rate of the boiler. The unit load reduces with the main steam

pressure drop till the target pressure 10MPa;

3.2.4.3 While loading to 360MW, check the mainframe gland steam pressure, i.e. make

sure it is normal and take note of the switchover of the gland steam source;

3.2.4.4 While loading to 300MW, start up a motor-driven pump and stop a turbo-feed

pump after the motor-driven pump operates normally.


3.2.5.1 Sliding pressure operating mode is applied as the unit load is ranged from 300MW

to 180MW;

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3.2.5.2 Maintain the turbine load command invariable; control the load variation rate not

greater than 9MW/min and the main steam pressure variation rate not greater than

0.1MPa/min; 3.2.5.3 Reduce the load to 180MW, main steam pressure 8.62MPa, reheat

steam pressure about 1.0MPa, main steam temperature 525 and reheat steam ℃

temperature 520 ;℃

3.2.5.4As loading to 180MW, check the HP section drain valve of the steam system and

confirm it is open;

3.2.5.5 Stop a water circulating pump or adjust the operating mode of circulating water

according to the vacuum condition;

3.2.5.6 Keep the load stable and the main steam pressure invariable, lower the

temperature of the steam turbine to cool; lower the main steam temperature to the target

temperature 420 with a rate of temperature drop not greater than 1 /min and th℃ ℃ e

reheat steam temperature to the target temperature 355 with a rate of tempera rue drop ℃

not greater than 1.5 /min.℃


3.2.6.1 Constant pressure operating mode is applied as the unit load is ranged from

180MW to 60MW;

3.2.6.2 Contact the duty director for preparing disconnection;

3.2.6.3 Continue to reduce the load of the unit with the variation rate not greater than

6MW/min; lower the temperature and maintain the main steam pressure at 8.62MPa;

3.2.6.4 Gradually reduce the load of the second turbo-feed pump and pay attention to

track the output of the motor-driven pump, i.e. make sure it is normal; stop the second

turbo-feed pump, take not of its steam drum water level, i.e. make sure it is normal and

switch the control mode of the water level to single impulse control;

3.2.6.5 With 120MW load, alter the fourth extraction steam supply for the deaerator to the

auxiliary steam header supply;

3.2.6.6 With 120MW load, check the IP section drain valve of the steam system and

confirm it is open;

3.2.6.7 Check the LP cylinder of the steam turbine, i.e. make sure it is automatically put

into operation and maintain its exhaust temperature not greater than 50 ;℃

3.2.6.8 Stop the steam sides of the HP and LP heaters while paying attention to its water

level variations;

3.2.6.9 With 60MW load, start up the TOP and MSP, make sure they are normal; check

the LP section drain valve of the steam system, i.e. make sure it is open;

3.2.6.11 The unit load falls to 60MW;

3.2.6.12 Contact the duty director for preparing steam turbine shutdown by tripping;

3.2.6.13 Press the TURBO TRIP button on the control panel or locally manual trip; check

the IP main stop valve, HIP control valve, every stage of extraction check valve, HP

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cylinder exhaust check valve, i.e. make sure they are closed and tight; confirm the V.V and

BDV are open. And the rotating speed trends to slow down.

3.2.7 Generator disconnection

3.3 Operations after Generator Disconnection

3.3.1 Turbine operations after generator disconnection

3.3.1.1 Note that the rotating speed of the steam turbine begins to slow down after tripping;

record the idle runtime; note the lube oil pressure and temperature, i.e. make sure they

are normal;

3.3.1.2 Adjust or close the HP and LP bypass valves based on actual conditions;

3.3.1.3 As the rotating speed reaches 2500r/min, check the jacking oil pump and make

sure it is automatically started; otherwise, manually start one; check the jacking oil

manifold pressure and the jacking oil pressure of every bearing, i.e. make sure they are

normal;

3.3.1.4 Check the turbine back cylinder water spray valve, i.e. make sure it acts normally

and the LP cylinder exhaust temperature less than or equal to 47 ;℃

3.3.1.5 As the rotating speed is zero, check and confirm the turning gear is automatically

meshed; otherwise, manually put it into operation; after the mainframe turning gear is put

into operation, regularly record the rotor eccentricity, HIP cylinder expansion, differential

expansion, HIP cylinder primary temperature and axial displacement etc.;

3.3.1.6 As the rotating speed reaches zero, it is able to stop the MSP;

3.3.1.7 Close the drain valve of the main steam pipe till the boiler pressure is relieved to

zero;

3.3.1.8 After the unit flames out, confirm the bypass system is out of service, there is no

steam but having pressurized drain water entering the condenser; stop the condenser and

open the vacuum break valves of the HP and LP condensers;

3.3.1.9 As the condenser vacuum is pumped out fully, stop the gland sealing system;

3.3.1.10 Stop the EH oil pump and maintain the EH oil circulating system in operation as

required;

3.3.1.11 Cut off the condensate polishing unit;

3.3.1.12 Stop the motor cooling water system and reversely flush the stator with cooling

water as required;

3.3.1.13 As the boiler is completely unnecessary for feeding water, stop the deaerator

heating and the motor-driven feed pump;

3.3.1.14 As the steam drum pressure approximates to zero, the LP cylinder exhaust

temperature of the steam turbine is below 50 and no high temperature steam and water ℃

enters into the condenser. Stop the other water circulating pump and note to adjust the

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temperature of every auxiliary operating device;

3.3.1.15 Stop the condensate pump as there is no user for the condensate;

3.3.1.16 Stop the turning gear as the highest cylinder temperature of the steam turbine is

below 150 ; stop the jacking oil pump after the rotor is static; ℃

3.3.1.17 Gas displacement for the generator is generally performed after the mainframe

continuous turning is stopped. Closely monitor the oil level variation of the sealing oil tank

during gas displamcnet to prevent oil from entering the generator;

3.3.1.18 Stop the sealing oil system after the completetion of the gas displacmnt and

steam turbine turning;

3.3.1.19 Stop the mainframe lubricating oil system and the purification plant after the

highest metal temperature is below 120 ;℃

3.3.1.20 Get maintenance and isolation work done after stop.

3.4 Cautions for Unit Shutdown

3.4.1 Temperature and pressure of the steam turbine and boiler during the variable

parameter shutdown of the unit should be coordinated reduced without rising again. It

must closely note of the variation of the main stop steam pressure, temperature, and

furnace pressure and steam drum water level while stopping the coal pulverizer. Take not

of falling speed of the steam temperature and steam cylinder wall temperature; that is, the

falling speed of the steam temperature must strictly meet the requirement of the variable

parameter shutdown curves and the steam cylinder wall temperature difference is within

the allowable range.

3.4.2 During the variable parameter shutdown, it must strengthen the supervision to the

main steam parameter, especially the degree of superheat greater than 56 . If the steam ℃

temperature sharply drops to 50 in 10min, trip to stop immediately.℃

3.4.3 During the variable parameter shutdown, the falling speed of the reheat steam

temperature should follow that of the main steam temperature as much as possible. The

temperature departure of the main and reheat steam should meet the requirements of the

main, reheat steam temperature departure curves; otherwise, trip to stop immediately.

3.4.4 During the variable parameter shutdown, the steam parameter variation should be

controlled to make the metal temperature variation and difference of very part of the steam

turbine proper meet the requirements of the metal temperature change rate and difference

curves. Otherwise, suspend further reducing the parameter and load to moderate the

temperature difference and thermal stress of the metal parts.

3.4.5 Closely monitor the unit vibration, axial displacement, thrust pad temperature and

differential expansion etc., i.e. make sure they are normal; as reaching the alarm value,

stop the variable parameter shutdown mode and adjust the parameter to normal.

3.4.6 During the load reduction of the steam turbine, note that there is no jam occurred at

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the HP and IP control valves and the water levels of the deaerator, condenser and heater

are normal.

3.4.7 In low load operation, it is necessary for closing the normal drain valve in order to

avoid steam from returning between the heaters resulting from insufficient pressure

difference. And the emergency drain valve can be used for maintaining the heaters water

level in normal operation.

3.4.8 Try to avoid the unit from long-term operating on 180MW load, fast reduce the active

power to 15MW as it loads to 60MW, disconnect the generator-transformer unit as the

reactive power of the generator reaches 5MVar; manually trip the steam turbine, check the

HIP main stop valve, HIP control valve, every-stage extraction check valve, HP cylinder

exhaust check valve, i.e. make sure they are closed and check the V.V and BDV, i.e. make

sure they are open.

3.4.9 Note that the rotating speed of the steam turbine is to reduce after tripping, but

opening the vacuum break valve at the rotating speed above 2000r/min in unexceptional

case is forbidden.

3.4.10 During the turning, keep the lube oil temperature ranging from 27 to 40 and ℃ ℃

maintain the sealing oil system of the motor operating normally; regularly listen carefully

sound of the HLP gland.

3.4.11 Stop turning the mainframe when the turning gear continuously operates till the

maximum cylinder temperature of the steam turbine is less than 150 as well as the ℃

lubricating oil system; and note that the sealing oil system is in normal operation.

3.4.12 Do not overhaul the systems associated with the steam turbine proper during

turning after shutdown; prevent the cold steam and water from entering the steam turbine;

note monitoring the cylinder metal temperature variation tendency of the steam turbine.

Every drain valve can be operated according to following requirements:

3.4.12.1 In case of outage maintenance of the unit and without special requirement, the

drain valve and loop pipe drain valve directly connected with the cylinder are not opened

before the cylinder temperature is down to 150 .℃

3.4.12.2 After shutdown, it should take note of the temperature differences of the upper

and lower cylinders, the upper and lower temperature differences of main, reheat steam

pipes and every extraction steam pipes, and water level, pressure and temperature

variation of every water container; if the temperature differences of the cylinders are

sharply increased, it should find out the causes of entering water or feeding cold steam

immediately, cut off the water and steam, and drain the water.

3.4.13 During the turning period, the principles of stopping continuously turning or

stopping for turning gear failure in need of work are as follows:

3.4.13.1 In case the turning gear fails or it is actually necessary for stopping immediately

for the purpose of overhaul, it needs to mark the rotator at corresponding position after

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stopping turning and memorize the stop time.

3.4.13.2 With the HP cylinder primary inner wall temperature above 350 , the stop time ℃

of turning is not allowed to exceed 3min. With the temperature ranging from 220 to ℃

350 , the stop time will not exceed 30min. if the turning operation can not be completed ℃

during the period said above, reversely rotate the rotor 350 at intervals of the said tim℃ e,

and then continue to turn.

3.4.13.3 Rotate the rotor for 180°before continuous turning is available after its

interruption; continue to turn after passing half of stop time; at this time, pay special

attention to the rotor eccentricity and make sure the turning gear current does not

excessively fluctuate.

3.4.13.4 During turning in special case, the jacking device can be stopped on the premise

of monitoring the turning gear current. As the turning gear current increases not greater

than 120% of the normal value, the jacking device can be stopped to continue to turn;

otherwise, the jacking device must be put into turning.

3.4.13.5 During the continuous turning, if there is apparent metal fricative sound in the

cylinder and the turning gear current fluctuates by a large margin (but not turning gear

failure), it must be stopped immediately. And shaft can be straightened by manual turning

in accordance with the said principal till recovering continuous turning.

3.4.13.6 If the steam turbine rotor is locked, forced turning is not allowed. (The use of

steam supply for the unit or crane rotation is available.)

3.4.13.7 If there is creepage caused by the malfunction of the jacking oil system,

continuous turning must be stopped while the phenomena can not be removed after

reducing oil temperature (not less than 27 ) by additionally starting the DC lube oil pump. ℃

Maintain the rotator straightening by rotating it for 180°at every 10min till the continuous

turning is reset but without creepage phenomena.

Chapter Ⅳ Accident Management of Unit

1. General Principles

1.1 The operator shall handle failures in strict accordance with the Operating Manual as

those failures occur. The duty director and the attendant shall process those special

failures out of the Manual’s range according to the operating knowledge and experience

under the principal of ensuring the safety of person and devices.

1.2 As the failures occur, the operator should quickly lift personal and devices out of

danger and find out the causes in time and solve them. They must guarantee the station

auxiliary power system in normal operation and keep the non-failure devices in operation.

1.3 Procedures for removing failures are as follows:

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1.3.1 No matter what failures are occurring in the unit, the operator should quickly and

carefully confirm the character, development tendency and hazard degree, and then take

correspondingly measures.

1.3.2 While the failure occurs, there is corresponding acousto-optic alarm displayed on the

turning gear and MMI, and so the operator should confirm and take corresponding

measures.

1.3.3 It must quickly lift the personnel and devices out of danger and disconnect the failed

devices immediately if necessary, so as to maintain the non-failure devices in normal

operation.

1.3.4 No matter what failures are occurred, it must check the indication or status of the

meters and confirm it in site if necessary.

1.3.5 Each stage for removing the failure must report to the duty director and associated

leaders as fast as possible so as to timely and correctly take adequate measures to

prevent the accident from widely spreading.

1.3.6 As the failure occurs, the operators in charge of every position must quickly handle

the failure under the unified command of the duty director in close coordination, so as to

recover normal operation of the unit as fast as possible.

1.3.7 Removing the failure must be quick and correct. The operators must repeat the

command after receiving it. If it is unclear, the operators must make it clear. After

completing, they must report to the commander as fast as possible.

1.4 Relevant leaders and full-time engineers must arrive in site as soon as possible to

assist to handle failures as the unit failure occurs and give necessary instruction to the

operator on the premise of subjecting to the command of the duty director.

1.5 At the moment of failure occurrence and processing, the operator must stick to his

post. If the failure occurs at the time of handover, it should be delayed. Before the

handover, the operator must keep working and the operator on duty must remove the

accident in coordination with the operator till the unit recovers normal operation.

1.6 The person unrelated with the accident treatment is forbidden staying at the position of

fault.

1.7 After removing the fault, the duty director and operator on duty must correctly record

the process and time of fault occurrence and measures for removing the fault etc. in detail,

and report to every stage of schedulers and leaders in time.

1.8 During the accident treatment, operation order can be unused, but relevant regulations

are required to be complied.

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2. Regulations on the Handling of Unit Accidents

2.1 Emergency Outage Conditions of Unit

2.1.1 In case there is accident that endangers the person and devices, the unit shall be

shut down immediately;

2.1.2 Vacuum break and emergency shutdown of the steam turbine shall be operated

under one of following conditions:

2.1.2.1 The steam turbine is over-speed with the rotating speed greater than or equal to

3330r/min and the emergency governor is failed to actuate;

2.1.2.2 The generating set of the steam turbine has suddenly severe vibration with the

bearing vibration greater than or equal to 0.25mm, and the protection is failed to operate;

2.1.2.3 The axial displacement of the rotor is greater than or equal to 1.2mm or less than

or equal to negative 1.65mm, and the protection is failed to operate;

2.1.2.4 The time delays for 2s as the unit load is greater than or equal to 50% and the

main steam temperature is lower than 474 ; it is to alarm as the load is less than 50% ℃

and the main steam temperature is less than 490 , and 2s delay is required as the ℃

temperature is reduced to 460 . The protection is failed to operate;℃

2.1.2.5 There is apparent metal friction or impact sound inside the generating set of the

steam turbine;

2.1.2.6 Oil level in the main lube oil tank falls sharply and oil make-up is unavailable;

2.1.2.7 There is water attack occurred in the steam turbine. Upper and lower temperature

differences of the inner cylinder of the HIP cylinder reaches 55.6 or main steam ℃

temperature decreases by 50 in 10min;℃

2.1.2.8 The thrust pad metal temperature is greater than or equal to 110 and lasts for 2s. ℃

The protection is failed to operate;

2.1.2.9Metal temperature of any bearing of the steam turbine rises to following values:

115 of #1℃ -#6 journal bearings, 105 of #7℃ -#9 journal bearings and 110 of thrust ℃

bearing. The protection is failed to operate;

2.1.2.10 The HIP differential expansion is less than negative 6.6mm or greater than

11.6mm; the LP differential expansion is less than negative 8.0mm or greater than 30mm;

2.1.2.11 Return oil temperature of any bearing of the steam turbine exceeds the limit or it

reeks and lacks of oil;

2.1.2.12 The turbine gland sparkles resulting from abnormal friction;

2.1.2.14 The generator reeks and catches fire or the hydrogen system blasts;

2.1.2.15 The generator slip ring and carbon brush seriously sparkle and are unable to

extinguish;

2.1.2.16 The turbine oil system is on fire and unable to be extinguished quickly, so as to

severely threats safe operation of the unit;

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2.1.2.17 The lube oil pressure continues to drop in case an auxiliary lube oil pump is

started up after the lube oil is cut off or the pressure drops to 0.103MPa.

2.1.3 Vacuum break to emergency shutdown is required under one of following conditions:

2.1.3.1 The steam pipe and the water pipe are unable to keep normal operation resulting

from high pressure and broken pressure part, respectively;

2.1.3.2 The safety valve is failed to operate as the boiler pressure boosts up to the action

pressure of the valve; 2.1.3.3 One of the main and reheat steam temperature rises to 552～564 at rated ℃

pressure for excessive 15min continues operation or exceeds 564 ;℃

2.1.3.4 The stator coil of the generator is cut off cooling water supply and unable to

resume the water caused by inactive protection; or the cooling water temperature rises to

78 and is unable to be reduced with the load reduction;℃

2.1.3.5 The protection is failed to operate as the unit reaches the action value;

2.1.3.6 The steam turbine operates over 1min without steam;

2.1.3.7 The condenser vacuum drops to negative 77.5KPa and is unable to recovery as

the load drops to zero;

2.1.3.8 The unit is unable to control its rotating speed or load resulting from abnormal

operation of the DEH;

2.1.3.9 The EH oil pump and EH system failure endangers the safe operation of the unit;

2.1.3.10 All sealing oil pumps are failed and sealing oil is supplied by the main lube oil

pump only;

2.1.3.11 The operating supervisory meters of the steam turbine, especially the speed

indicator, indicate incorrectly or invalidly, and there are no other effective measures

instead of these meters;

2.1.3.12 The main transformer, high voltage auxiliary transformer and excitation

transformer catch fire or smoke;

2.1.3.13 The severe water leakage of the generator body endangers safe operation of the

devices;

2.1.3.14 Hydrogen purity in the generator drops quickly below 92%;

2.1.3.15 A/B LP cylinders exhaust temperature is greater than or equal to 107 and the ℃

protection is failed to operate;

2.1.3.16 The exhaust pipe metal temperature of the HP cylinder rises and exceeds 432 ; ℃

and the protection is failed to operate;

2.1.3.17 The turbine room on fire endangers the safe operation of the unit.

2.1.4 Emergency shutdown treatment of the unit

2.1.4.1 Stop the unit by pressing corresponding EMERGENCY TRIP button in case of

meeting any emergency shutdown condition of the steam turbine, boiler and generator;

2.1.4.2 Check the interlocks of the boiler, steam turbine and generator, i.e. make sure they

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acts correctly; confirm the boiler fuel are totally cut off, the HP and IP main stop valves and

control valves are closed tightly and the rotating speed of the steam turbine drops rapidly;

break the steam turbine vacuum as required;

2.1.4.3 Confirm the station auxiliary power system switches over normally; otherwise,

replace it with manual switchover;

2.1.4.4 Check the AC auxiliary oil pump, startup oil pump and jacking oil pump, i.e. make

sure they are automatically started; otherwise, manually start them immediately; check the

sealing oil system of the generator, i.e. make sure they are operating normally;

2.1.4.5 Note the idle condition, differential expansion, vibrating, axial displacement,

cylinder expansion and upper and lower temperature difference etc. of the steam turbine;

listen the sound generated inside of the steam turbine, i.e. make sure it is normal;

2.1.4.6 Make sure the turning gear is to automatically operate as the rotating speed of the

steam turbine is zero; check the oil pressure and temperature, and turning gear current,

i.e. make sure they are normal;

2.1.4.7 Change the gland steam supply fast to auxiliary steam supply after the unit trips;

regulate the gland steam pressure in time; stop supply the gland steam as the vacuum

reaches zero; isolate the gland attemperating water;

2.1.4.8 Check the relevant water prevention valves of the steam turbine i.e. make sure

they are automatically open; otherwise, manually open them;

2.1.4.9 Check whether the cooling water of the drain flash tank is automatically put into

operation; otherwise, manually put it into operation;

2.1.4.10 Check whether the water levels of the condenser and the deaerator are

automatically and normally adjusted; otherwise, manually adjust to keep them normal;

2.1.4.11 Check the lube oil temperature, sealing oil temperature, generator hydrogen

temperature and stator cooling water temperature of the mainframe, i.e. make sure they

are normal; adjust them if necessary;

2.1.4.12 Check the LP cylinder, i.e. make sure its water spray function is normally put into

operation;

2.1.4.13 As it is on fire or hydrogen explosion occurs inside of the steam turbine,

extinguish the fire with carbon dioxide and discharge the hydrogen; in case idle speed of

the rotator approximates to 200r/min, close the vacuum break valve till the creation of

vacuum and try to maintain the rotating speed till extinguishing the fire;

2.1.4.14 Close the main steam drain valve;

2.1.4.15 In case the induced and forced draft fans do not trip, total blast volume of the

boiler must be adjusted to that under 25-30%BMCR to purge for 5min. Otherwise, they are

started to purge for the furnace after opening the air-flume system baffle plate for naturally

ventilate for 15min. If it will not be ignited in a short-time, Stop the fans after purging, and

then superheat the boiler;

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2.1.4.16 Complete other normal shutdown operations of the unit;

2.1.4.17 Report the failure conditions to the dispatcher and relevant leader;

2.1.4.18 Copy relevant curves and emergency records; keep them well; and carefully

record the emergency conditions;

2.1.5 Emergency shutdown operating procedures by breaking vacuum:

2.1.5.1 Press the EMERGENCY SHUTDOWN button on the control panel or disconnect

the turbine trip handle at the turbine head by hand; confirm the TURBO TRIP lamp is on,

the unit load reaches zero, the generator is disconnected, the auxiliary power is changed

successfully ; Check the HP and IP main stop valves and control valves, every extraction

electric valve and check valve, and HP cylinder exhaust check valve, i.e. make sure they

are closed; check the HP cylinder exhaust vent valve, HIP cylinder emergency dump valve,

i.e. make sure they are opened; make sure the rotating speed of the steam turbine

continuously drops;

2.1.5.2 Check the AC lube oil pump and the startup oil pump, i.e. make sure they are

started successfully; make sure the lube oil pressure is normal;

2.1.5.3 Check the relevant water prevention valves of the steam turbine i.e. make sure

they are automatically open; otherwise, manually open them;

2.1.5.4 Confirm the jacking oil pump automatically starts as the rotating speed of the

steam turbine drops to 2500 r/min; release the vacuum pump interlock, stop the vacuum

pump and open the condensers A/B vacuum break valves as the rotating speed drops to

2000r/min;

2.1.5.5 Check whether the HP and LP bypass valves work, if they are opened, manually

close them immediately;

2.1.5.6 Close the drain valves on the main, reheat steam pipes; if the circulating water is

cut off, close all drain water supply to the condenser;

2.1.5.7 Check the turbo-feed pumps A/B and confirm they are triggered to trip; check the

motor-driven feed pump, i.e. make sure they are jointly started normally;

2.1.5.8 Check that the fourth steam extraction user is normally switched to the

auxiliary steam supply and the gland steam is automatically and normally

switched;

2.1.5.9 Check the water levels of the condenser and the deaerator, i.e. keep them in

normal range;

2.1.5.10 Check that the LP cylinder spray valve is automatically opened and adjust the

exhaust temperature within normal range;

2.1.5.11 Stop the gland sealing system as the vacuum is zero;

2.1.5.12 completely check and listen carefully the sound inside of the unit while the

rotating speed drops;

2.1.5.13 Put the turning gear into operation while the rotating speed is zero, and record

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the idle time and rotor eccentricity;

2.1.5.14 Complete other operations relevant with normal shutdown.

2.1.6 Operating procedures for emergency shutdown on the premise of keeping original

vacuum:

2.1.6.1 Press the EMERGENCY SHUTDOWN button on the control panel or disconnect

the turbine trip handle at the turbine head by hand; confirm the TURBO TRIP lamp is on,

the unit load reaches zero, the generator is disconnected, the auxiliary power is changed

successfully and the rotating speed of the steam turbine continues to reduce;

2.1.6.2 Check the HP and IP main stop valves and control valves, every extraction electric

valve and check valve, and HP cylinder exhaust check valve, i.e. make sure they are

closed; check the HP cylinder exhaust vent valve, HIP cylinder emergency dump valve, i.e.

make sure they are opened;

2.1.6.3 Check the AC lube oil pump and the startup oil pump, i.e. make sure they are

started successfully; make sure the lube oil pressure is normal;

2.1.6.4 Check and confirm the HP and LP bypass valves are automatically opened;

2.1.6.5 Check and confirm the corresponding drain valves are opened;

2.1.6.6 Check and start up the motor-driven feed pump, and confirm it is operating

normally;

2.1.6.7 Check the turbo-feed pumps A/B, i.e. make sure they trip and put the turning gear

into continuous operation;

2.1.6.8 Check and adjust the water levels of the condenser and the deaerator, and keep

them normal;

2.1.6.9 Check and adjust the LP cylinder spray valve and drain flash tank spray valve, and

make sure they are able to automatically open;

2.1.6.10 Check and adjust the gland steam pressure, and keep it within normal range;

2.1.6.11 Completely check and listen carefully the sound inside of the unit while the

rotating speed drops;

2.1.6.12 Put the turning gear into operation while the rotating speed is zero, and record

the idle time and rotor eccentricity;

2.1.6.13 Complete other operations relevant with normal shutdown.

2.2 Fault Shutdown Conditions of Unit

2.2.1 Report to the dispatcher and chief engineer to apply for fault shutdown under


2.2.2 Fault shutdown conditions

2.2.2.1 The main, reheat steam parameters exceed the specified value and are unable to

be recovered in specified time;

2.2.2.2 The measures for preventing slow drop of the condenser vacuum are unavailable,

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even zero load;

2.2.2.3 The axial displacement approximates to the limit value and can not recovery after

processing;

2.2.2.4 The upper and lower cylinders temperature differences of the HP and IP cylinders

exceed the limit (50 );℃

2.2.2.5 EH oil pipe rupture or low oil level in the EH oil tank makes oil make-up operation

unavailable;

2.2.2.6 The DEH control system or HP and IP control valves are failed to maintain

operating;

2.2.2.7 The major auxiliary is failed to maintain its operation;

2.2.2.8 The steam-water pipe is unable to work resulting from leakage;

2.2.2.9 The stator cooling water has electric conductivity as 9.9µS/cm or is cut off; or the

generator stator coil leakage problem is unable to be solved;

2.2.2.10 The turbine lubricating oil system is failed to normally operate;

2.2.2.11 The adjustment for the abnormal steam exhaust temperature rise of the LP

cylinder is unavailable;

2.2.2.12 The water quality of the condenser is deteriorated for serious leakage and

isolation for half condenser is unavailable;

2.2.2.13 The idle time of the steam turbine exceeds 15min after load rejection of the

generator;

2.2.2.14 The hydrogen temperature of the generator exceeds the limit resulting from

hydrogen cooling system failure and the adjustment for it is ineffective;

2.2.2.15 Hydrogen leak of the generator enables hydrogen pressure maintenance to be

failed;

2.2.2.16 Sealing oil system failure of the generator makes necessary oil pressure and

level maintenance be failed;

2.2.2.17 The DEH, DCS and TSI failures leads to some important operating parameters of

the steam turbine unable to be monitored and the normal operation of the steam turbine

and its auxiliaries can not be maintained;

2.2.2.18 The generator slip ring and carbon brush seriously sparkle and are unable to

extinguish.

2.2.3 Fault shutdown operations of the unit

2.2.3.1 In case any one of the fault shutdown conditions is met, it should be reported to

the duty director and dispatcher, and asked for the leaders to apply for shutdown;

2.2.3.2 As the unit shuts down resulting from faults, quickly reduce load in prior to

transforming auxiliary power; as the unit load is less than 150MW, start the MSP and the

TOP;

2.2.3.3 Press down the EMERGENCY SHUTDOWN button by hand or locally latch the

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steam turbine handle by hand; check the HP and IP main stop valves and control valves,

every extraction electric valves and check valves, i.e. make sure they are totally closed;

confirm the generator is disconnected, the VV and BDV are opened, and the rotating

speed of the steam turbine is decelerated as the unit load drops to zero;

2.2.3.4 Check that the HP and LP drain valves are automatically opened; note the mains

team pressure and close the HP and LP bypass valves in time;

2.2.3.5 Close the drain valves of the main and reheat steam pipes; stop the vacuum pump;

open the vacuum break valve; cut off drain water to the condenser completely in case of

stopping circulating water supply;

2.2.3.6 Check that the turbo-feed pumps A/B trip, and the motor-driven feed pump is able

to be tandem driven normally;

2.2.3.7Check and make sure the fourth extraction steam for the user is able to be

replaced by auxiliary steam supply normally;

2.2.3.8Check and make sure gland steam can be automatically and normally switched;

2.2.3.9Start a jacking oil pump as the unit rotating speed drops to 2500r/min and make

sure its oil pressure is normal;

2.2.3.10 Stop gland steam supply as the vacuum is zero;

2.2.3.11As the rotating speed reaches zero, check whether the turning gear is

automatically put into normal operation; if not, manually put it into operation; record the

idle time and eccentricity of the rotor, turning gear current, cylinders temperature etc.;

2.2.3.12 Check the unit and listen the sound generated from the rotating parts of the

steam turbine; in case there is apparent metal impact sound inside or rotor idle time is

significantly shortened, immediate restarting of the unit is forbidden;

2.2.3.13Note that the vibration, axial displacement, differential expansion, lube oil

pressure and temperature, sealing oil-hydrogen pressure difference and water levels of

each heater are normal during shutdown of the unit;

2.2.3.14 Other operations are similar to that of the normal shutdown. Complete

other operations according to the Operating Manual.

2.3 Comprehensive Accident Management of Unit

2.3.1 Main Fuel Trip (MFT) of Boiler

2.3.1.1 MFT action presentations

1) Audible and visual alarm occurs, and TURBO TRIP and GENERATOR TRIP

indicating lamps are on as MFT works; 2）The main stop valves and control valves of the steam turbine, main stop valves and

control valves of the reheater, and steam extraction electric valves and check valves of

the heater are closed. The main steam pipes drain valves of the steam turbine, drain

valves of the steam turbine body and steam extraction pipes drain valves are opened;

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3）The generator outlet and extraction switches trip, and auxiliary power supply is fast

switched to reserve power supply; 4）The re-circulating water valve of the feed pump is automatically opened.

2.3.1.2 Principles of steam turbine side management 1）Confirm the steam turbine trips, rotating speed decelerates, the HP and IP main stop

valves, control valves and extraction check valves are closed, relevant water prevention

valves are opened, the BDV and VV are automatically opened; 2）Close the electric valve for switching the cold reheat steam to the auxiliary steam;

confirm the auxiliary steam pressure, gland pressure and turbine vacuum are normal;

put the deaerator into hearing; 3）Confirm that the parameters of the steam turbine is normal as it is in idle operation,

the jacking oil pump is automatically started as the rotating speed is 2000r/min, the

turning gear is automatically meshed and its motor is automatically started as the

rotating speed is zero, the current and eccentricity of the turning gear are normal; 4）Prepare for restart in case the faults are able to be removed fast or the protection

malfunctions; 5）In case the unit is unstable to be started, it can be handled by the principal of normal

shutdown.

2.3.1.3 Handling principles as MFT works

1) Every protection is required to be put into operation and any protection is forbidden to

exit temporarily in the process of handling the MFT;

2) It must be tripped immediately in case the causes for MFT working are not found out

or the unit is unable to be restarted for its apparent defects;

3) Note that the AC auxiliary oil pump and startup oil pump are automatically started;

otherwise, manually start them; check that the oil pressure and temperature are normal;

take note of the idle time of the steam turbine, in case of fast deceleration of its rotating

speed, automatically start the jacking oil pump and put the turning gears of the steam

turbine and small steam turbine into operation in time;

4) Open the drain valves of the steam turbine in time; check the exhaust steam

temperatures, i.e. make sure they are within the range specified by the Operating

Manual;

5) Closely monitor the differential expansion, axial displacement, upper and lower

cylinders temperature difference, vibration of every bearing and bearing shell

temperature of the steam turbine in the entire process, i.e. make sure they are within

the range specified by the Operating Manual; otherwise, trip it.

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2.3.2 Entire Auxiliary Power Failure

2.3.2.1 Symptoms

1) AC illuminating lamp is off and DC emergency illuminating lamp is on so that control

room light becomes dimmed.

2) The MFT works, the steam turbine and generator trip.

3) Overall AC motors in operation stop, AC standby motors are not tandem driven and

every current indicates to zero. The main and small steam turbines lube oil pump and

DC sealing oil pump are automatically started.

4) The diesel generator is automatically started.

2.3.2.2 Causes

1) The unit is failed, meanwhile the standby transformer is failed or in outage state or

6kV busbar reserve power supply is failed to automatically operate;

2) The unit and power system are failed at the same time.

3) Working power supply and reserve power supply are failed at the same time.

2.3.2.3 Handling principles

1) After entire auxiliary power failure, it is required to check that the main and small

steam turbines trip and rotating speed is reduced; otherwise, manually trip them;

2) Handling for the boiler is operated according to the principle that the MFT works;

3) Immediately check the DC lube oil pump and DC sealing oil pump of the main and

small steam turbine and make sure they are operating normally;

4) In case of auxiliary electricity loss, the handling for the steam turbine should be

operated according to the “emergency shutdown procedures by breaking vacuum”; pay

attention to the lube oil pressure and temperature of the main and small steam turbines

and metal temperature of every bearing;

5) In case the safety busbar loses electricity, it is required to regularly turn the main and

small steam turbines till the busbar is electrified. And then Continuous turning is put into

operation after straightening shaft according to specifications;

6) Close drain water isolation valve of the main steam pipe; check that the mainframe

bypass valve is closed, otherwise close it by means of manually relieving oil pressure;

7) Open the mainframe vacuum break valve as the rotating speed of it is less than

2000r/min;

8) Pay attention to the condenser exhaust steam temperature; in case the temperature

drops below 50 , circulating water pump for s℃ upplying water for the condenser is

forbidden.

9) In case of auxiliary power failure and the sealing oil pump unable to be started, it

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must quickly discharge hydrogen for the generator, so as to prevent from blasting for

hydrogen leakage;

10) After the auxiliary power failure, the instrument air compressor of the steam turbine

for power supply trips and the standby automatically starts so that the former one should

be reset as fast as possible;

11) After the auxiliary power failure, the closed cooling water is cut off. It should monitor

the variation of the lube oil temperature of the mainframe. The public closed cooling

water user is replaced by adjacent steam turbine that is operating stably;

12) Release the interlocks of every auxiliary and exit the automatic adjustment;

13) After insolating or removing the trouble spot, gradually recovery the auxiliary power

supply for every section; start the systems to prepare for the thermal startup of the unit

after recovering the auxiliary power.

2.3.3 Electricity Loss of Uninterrupted Power Supply (UPS)

2.3.3.1 Symptoms

1) Failure of two UPS failure for some reasons at the same time leads to output power

supply interruption. Electricity loss of the UPS busbar makes the FSSS lose electricity,

the MFT, steam turbine and transformer trip, all transformers lose auxiliary power supply,

and the OS and IS lose electricity.

2.3.6.2 Handling principles

1) Confirm the steam turbine and turbine-driven pump trip and the turbine rotating

speed decelerates; 2）Stop the electric pump under the condition that there is no monitor on the water level

of the steam drum; 3）Start the AC lube oil pump and startup oil pump of the mainframe on the CD

immediately in emergency; send a person to the site to check whether they are

operating normally; if the remote startup is failed, locally start the DC lube oil pump of

the mainframe immediately and make sure it is operating normally, so as to prevent

from burning the bearing liner for lacking of oil; meanwhile start the AC lube oil pump

and the startup oil pump at the switch room. In case the jacking oil pumps of the main

and small steam turbine are not started, they can be started in emergency at the switch

room. Check whether the AC sealing oil pump is operating normally, if not, start the

emergency sealing oil pump in time and stop the AC sealing oil pump to prevent the

generator from leaking hydrogen; 4）Locally check that two sets of turbine-driven pump and main oil pump are operating;

start the standby main oil pumps and jacking oil pumps A/B; locally check that every oil

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pump are operating normally; if the safety power supply loses, locally start the DC oil

pump of the turbine-driven pump at local control box of the DC oil pump of the small

steam turbine; 5）Check that the steam turbine and its auxiliaries are normally operating;

6）Feed water for the boiler by the electric pump according to specifications after the

UPS is recovered; if the steam drum is seriously lack of water, handle it with the

principle of less water in the boiler.

2.3.4 Full Load Rejection of the Unit

2.3.4.1 Symptoms 1）The unit load reaches zero and its sound changes suddenly.

2）The steam turbine trips and the generator switch trips to alarm.

3）The main stop valves and governing stem valves are closed with a zero opening

indication. The rotating speed decelerates after rising. 4）The steam extraction check valves and electric valves are closed.

5）The governing-stage pressure is zero.

6）The HP and LP bypass valves are opened.

7）The MFT works in case the load of the unit at that time is greater than 30%.

8）In case the MFT does not work after the unit trip, the steam pressure and temperature

will rise sharply, the water level in the steam drum lowers first, and then rises and a

solenoid relief valve works.

2.3.7.2 Causes 1）The 220kV main transformer switch trips.

2）The steam turbine or electric trip protection works or malfunctions.

3）MFT works.

4）The operator trips by mistake.

2.3.7.3 Handling principles 1）In case of full load rejection of the unit, it is processed in accordance with the

“emergency shutdown operating procedures without breaking the vacuum”. 2）If the rotating speed continuously accelerates after the full load rejection, it must be

processed in accordance with the “emergency shutdown operating procedures by

breaking the vacuum”. 3）If the electric protection works, it is processed in accordance with the “generator

transformer unit trip procedures”. 4）In case the unit load before the load rejection is greater than 30%, the MFT works. If

the MFT does not work, manually operate it and stop the boiler in emergency.

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5）In case the unit load is less than 30% before the load rejection and the main stop

valve of the steam turbine is closed resulting from generator transformer unit switch trip,

the boiler is able to continuously operate while processing as follows:

a) To keep the main steam pressure stable, the HP and LP bypass valves of the steam

turbine automatically open;

b) In case the main steam pressure continues to rising after opening the said valves,

oil should be fed to support combustion. And the pulverizing system should be

stopped to keep the combustion stable and the main steam pressure normal;

c) Check that the rotating speed of the motor-driven pump is normally governed and

the water level of the steam drum is normal;

d) In case the bypass valves of the steam turbine failure to operate on command,

process it according to the principal that the MFT works;

e) Loading speed is not greater than 15MW/min while recovering;

f) The boiler should be stopped in case the unit trip causes are unclear and it can not

be recovered in a short term;

g) If the main fuel trips resulting from inappropriate adjustment in the process of

treatment, process it according to the principal that the MFT works;

h) If the protection works, it should find out the failure causes and inform of relevant

person to check the associated professional treatment; start the unit after removing

the failures or being approved by the deputy general manager( chief engineer);

6) Contact the duty director for recovering the operation of the unit if the failures are

caused by miss operation of the operator.

2.3.4 Partial Load Rejection of Unit (under RB condition)

2.3.4.1 RB occurs in case that single forced draft fan, induced draft fan, primary air fan

and air preheater trip and the unit load is greater than the maximum allowable output of

one the device;

2.3.4.2 RB occurs in case a feed pump trips and its standby is failed to be started jointly in

5s, and the unit load is greater than the maximum allowable output of one said pump;

2.3.4.3 RB occurs in case a coal pulverizer trips and the unit load is greater than the

maximum allowable output of the machine in operation.

2.3.4.4 Steam turbine side handling after occurrence of RB 1）In case the operating mode of the unit is “coordinate control”, the target load is

automatically switched to the maximum allowable output of the device causing the RB; 2）As the “coordinate control” mode is switched to “turbine following boiler” mode, the

steam turbine is applied to controlling the main steam pressure;

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3）Cut off AGC as RB occurs.

2.3.4.5 Following operations should be applied as automatic treatment is ineffective after

the RB works: 1）Find out the causes that RB works;

2）Take not of the variation of water level and steam temperature and control them

within normal range; 3）The unit resumes normal operation after removing the causes of RB.

2.3.5 DEH Failure

2.3.5.1 Symptoms

1) There is no any process display or reaction although there is the display on the DEH

screen;

2) DEH screen loses;

3) The unit trip is possibly happened.

2.3.5.2 Causes

1) Mouse failure

2) Display, DEH software and hardware failure

3) Power loss of operator station

4) DEH power loss

2.3.5.3 Disposal principles

1) Inform the thermal technician to the scene in time to process the DEH failures;

2) Check that the OIS screen displays normally;

3) Report to the provincial transfer to exit AGC and to stop loading up or down; try to

keep the operating mode of the unit invariable on the premise of without affecting the

stable operation of the unit;

4) Strengthen the monitoring on the important parameters of the OIS and the local

inspection to keep the parameters stable;

5) Locally check that each steam valve is closed and front header rotating speed

counter continues to reduce in case of unit trip;

6) Start every oil pump of the mainframe; open the HP cylinder vent valves and

emergency dump valves; monitor the relevant parameters of the mainframe through the

OS screen, i.e. make sure they are normal;

7) Complete the normal shutdown operations of the unit.

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3. Abnormal Operation and Accident Management of Steam Turbine

3.1 Condenser Vacuum Drop

3.1.1 Symptoms

3.1.1.1 The condenser vacuum drops; exhaust and condensate temperature rises;

3.1.1.2 Alarm for low vacuum and high exhaust temperature;

3.1.1.3 The unit load reduces correspondingly under the conditions that the main steam

flow, pressure and temperature, and valves opening are invariable;

3.1.2 Causes of vacuum slow drop

3.1.2.1 Vacuum system leak

3.1.2.2 Vacuum pump failure of abnormal cooling system of the vacuum pump

3.1.2.2 Pretty low gland steam pressure, abnormal gland vacuum and water level and

blocked gland drain water

3.1.2.3 Reduced circulating water flow resulting from dirty and blocked condenser steel

pipe or tube plate and secondary filter screen, circulating water system failure of miss

operation and so on

3.1.2.4 Excessively high hot well water level

3.1.2.5 Miss operation of the vacuum system valves

3.1.2.6 The HP and LP bypass valves in pen condition

3.1.2.7 The valve of the water induction prevention system in operation is opened by

accident or the condenser heat load is excessive.

3.1.2.8 Pretty low water level of condensate make-up tank or broken water seal of

multi-stage U pipe

3.1.3 Causes of vacuum sharp drop

3.1.3.1 Circulating water interruption

3.1.3.2 Gland steam interruption

3.1.3.3 Excessively high water level of the hot well till reaching the extraction opening

3.1.3.4 The vacuum break valve to be opened by error

3.1.3.5 Bypass system mis-operation

3.1.4 Disposal principle of vacuum drop 3.1.4.1 ；Confirm the vacuum drop by comparing it with the exhaust temperature while

finding it; find out the causes quickly and take corresponding measures to treat it and

report to the duty director;

3.1.4.2 As the condenser vacuum drops to negative 87.5KPa, the standby vacuum pump

automatically starts, if it does not, manually start it; if the vacuum continues to drop, begin

to reduce load. As the vacuum drops to negative 74.7KPa, the load is reduced to zero,

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and trip protection works, otherwise manually trip to stop;

3.1.4.3 Take close note to the LP cylinder exhaust temperature in the process of vacuum

drop; put the back cylinder spray valve of the LP cylinder into operation as the exhaust

temperature rises to 50 ; as the temperature continues to rise to 107 , the protection ℃ ℃

works to trip, otherwise manually trip it;

3.1.4.4 Take note of the operating and load conditions of the turbo-feed pump as vacuum

drop; switch to the motor-driven pump operation if necessary;

3.1.4.5 The protection works to trip the unit if the vacuum drops fast and reaches negative

74.7KPa in the process of treatment; otherwise manually trip it;

3.1.4.6 Cut off all pressurized drain water to the condenser and mainframe bypass system

as the unit stops for low vacuum;

3.1.4.7 Strengthen the supervision on temperature and vibration of every bearing of the

unit.

3.1.5 Disposal principles for full water of the hot well

3.1.5.1 Check the field water level indicator while the condenser water level indicator is

filled with water;

3.1.5.2 Confirm the condenser is filled with water and the standby condensate pump is

started; open and adjust the #5 LP outlet drain valve; stop making up water for the

condenser, meanwhile note that the water level of the condenser is normal;

3.1.5.3 Check and confirm every valve of the process pump and condensate system

meets the operating requirement, otherwise, correct them;

3.1.5.4 Check whether the condenser makeup water system is automatically operated

normally; if not, replace it with manual operation;

3.1.5.5 If full water leads to sharp vacuum drop, it must be stopped as the vacuum

reaches the shutdown value;

3.1.5.6 Inform the chemical technician to test the condensate quality; if the steel pipe

leaks, find out the leakage by half isolation and take note of unit vibration and bearing

temperature. Contact the chemical technician to strengthen supervision on the

condensate quality; if it is unqualified, forbid to feed to the deaerator and process it

according to the failure shutdown principles.

3.1.6 Circulating water interruption treatment

3.1.6.1 Treat it according to the emergency shutdown procedures as confirming the

circulating water is cut off and can not be recovered; maintain the condensate system and

vacuum pump operating;

3.1.6.2 Close the HP and LP bypass valves, and the drain water from the main and reheat

steam pipes to the condenser;

3.1.6.3 Open the vacuum break valve to protect the safety film of the LP cylinder against

breaking in case the condenser vacuum drops to negative 60KPa or exhaust temperature

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reaches 90 , and the unit rotating speed decelerates below 2000r/min;℃

3.1.6.4 Take note of the operation of the open cooling water system; close the inlet and

outlet valves of the condenser if necessary and open the circulating water connection

valve to maintain the operation of the open water pump; monitor the temperature variation

of all devices and the water level in the cooling water tower;

3.1.6.5 Strengthen the supervision on the lube oil temperature, bearing metal temperature

and bearing return oil temperature; break vacuum to emergency shut down if the bearing

metal temperature of return oil temperature rises and approximates to the limit;

3.1.6.6 Close the circulating water inlet and outlet valve of the condenser till the exhaust

temperature drops to below 50 , and then recovery them;℃

3.1.6.7 Check and confirm that the safety film of the LP cylinder is complete, otherwise

inform the technician to repair it in time.

3.2 Steam Turbine Water Attack

3.2.1 Symptoms

3.2.1.1 The main and reheat steam temperature drops sharply and the degree of

superheat reduces;

3.2.1.2 The temperature difference of the upper and lower cylinders of the steam turbine

increases and it alarms;

3.2.1.3 There is water hammer inside the steam turbine or the steam pipes; the vibration

of the unit or steam pipes intensifies;

3.2.1.4 The load fluctuates and reduces; the differential expansion reduces; the axial

displacement increases; the thrust bearing temperature rises. There is white smoke

reeked or water drop sparkled out from the steam pipes flanges, valve stems, contact

surface of the steam cylinder and steam gland etc.;

3.2.1.5 The turning gear current increases under turning condition.

3.2.2 Causes

3.2.2.1 Full water of the steam drum or abrupt and excessive increased steam flow leads

to steam-water priming;

3.2.2.2 The boiler combustion is inappropriately adjusted or out of control;

3.2.2.3 The attemperating water of the main and reheat steam of the boiler is

inappropriately adjusted or malfunctions;

3.2.2.4 The warming pipe has incomplete or blocked drain while the unit startup;

3.2.2.5 Water of the heater or deaerator overflows into the steam turbine;

3.2.2.6 The gland sealing system or extraction pipe has unsmooth and stored up drain

water or their drain water flows into the cylinder;

3.2.2.7 The HP bypass attemperating water valve is failed during startup and shutdown of

the unit. It must be fed by the cold reheat pipe;

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3.2.2.8 The main and reheat steam temperature indicator indicates abnormally.

3.2.3 Treatment

3.2.3.1 Check relevant meters to confirm the steam temperature drops actually when the

main or reheat steam temperature drops abnormally;

3.2.3.2 Break the vacuum to stop immediately while confirming there is water attack

occurred in the unit;

3.2.3.3 Strengthen the supervision on the metal temperature and temperature difference

of the upper and lower cylinders of the steam turbine while the main or reheat steam

temperature drops abnormally; break the vacuum to emergency shut down immediately

when there is white smoke reeked or water drop sparkled out from the steam pipes

flanges, valve stems, combination surface of the steam cylinder and steam gland etc.;

break the vacuum to emergency shut down immediately and open all drain valves

communicated in case the upper and lower cylinders temperature difference of the HP

inner cylinder reaches 35 and the outer cylinder's temperature difference is up to 50 ; ℃ ℃

3.2.3.4 Break vacuum to stop immediately while the main or reheat steam temperature

abruptly drops more than 50 in operation;℃

3.2.3.5 Checks that the drain valves communicated with the steam turbine proper and

related with the steam pipes are open and able to fully drain water;

3.2.3.6 Find out the causes of water attack and completely remove them or isolate the

faulty devices;

3.2.3.7 Open the drain valves of corresponding pipes and check the corresponding steam

extraction temperature and water level of the heater as the upper and lower cylinders

temperature difference of the mainframe increases as well as the upper and lower walls

temperature difference of the extraction pipes and HP cylinder pipes; in case of confirming

that rather high or abnormal water level of the heater or abnormal HP bypass

attemperating water valve leads to the increase of temperature difference, it should break

the vacuum immediately to emergency shut down;

3.2.3.8 Uncover the cylinders to check in case there is water attack, axial displacement,

thrust bearing temperature out of limit, abnormal sound inside the steam turbine and

friction between the rotary and static parts, and idle time is apparently shorten;

3.2.3.9 If there is water entered into the turning gear of the steam turbine, the turning gear

must be kept running till the upper and lower cylinders temperature difference recoveries.

Meanwhile, it must strengthen to monitor the sound inside the steam turbine, rotors

eccentricity, turning gear current etc,;

3.2.3.10 Correctly record and analyze the idle time; put the turning gear into continuous

operation in time; measure the bending of the major shaft and listen the sound inside the

steam turbine. It should be restarted by contacting the duty director after removing the

causes of water attack and completely draining the steam turbine proper, main, reheat

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steam pipes and extraction pipes in case the idle time, thrust bearing temperature, axial

displacement, differential expansion, vibration and upper and lower cylinders temperature

difference are normal and there is no friction between the rotary and static parts and no

abnormal sound inside the steam turbine;

3.2.3.11 Restarting conditions of the steam turbine after it is shut down resulting from

water induction:

1) Water resource is found and cut off. It is confirmed that there is no water induction

any more;

2) Rotors should be continuously and fully turned for at least 4h. If there is halt during

turning, time delay is required;

3) The mainframe eccentricity does not depart the original value multiplying by 1.1. The

original value is measured first after the overhaul;

4) There is no metal fricative sound at turning state;

5) The upper and lower cylinders temperature difference of the outer casing of the HIP

cylinder does not exceed 50 and the temperature difference of the inner casing is not ℃

exceeding 35 .℃

3.3 Abnormal Vibration of Steam Turbine

3.3.1 Symptoms

3.3.1.1 The unit bearing vibration rises and alarms;

3.3.1.2 The field unit vibration apparently increases;

3.3.1.3 The journal bearing metal temperature and return oil temperature are possible to

rise.

3.3.2 Causes

3.3.2.1 The unit load and steam admission parameters abruptly change;

3.3.2.2 The lube oil pressure and temperature or generator sealing oil temperature

change;

3.3.2.3 There is friction between the rotary and static parts of the unit or the major shaft is

bent;

3.3.2.4 There is water attack inside the unit;

3.3.2.5 Water enters into the steam turbine resulting from the abnormal operation of the

heater;

3.3.2.6 The gland steam temperature is seriously not matched wit the gland metal

temperature;

3.3.2.7 Steam turbine blade is broken;

3.3.2.8 The steam turbine sliding key system is jammed;

3.3.2.9 The center of the rotary and static parts of the steam turbine is not aligned, the

coupling is loose or rotary part sheds;

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3.3.2.10 The bearing fixation is not firm or broken;

3.3.2.11 The outlet hydrogen temperature of every hydrogen cooler of the generator is

rather high or deviation is too large;

3.3.2.12 The stator and rotor current of the generator is unbalanced;

3.3.2.13 There is vibration occurred in the generator or system;

3.3.2.14 The heat soaking during startup of the unit is not enough;

3.3.2.15 There is oil film vibration of the unit;

3.3.2.16 The meters fail.

3.3.3 Treatment

3.3.3.1 Trip immediately to shut down and find out the causes as the bearing vibration at

any journal exceeds 0.125mm before the rotating speed of the steam turbine reaches the

first critical speed after rolling; do not warm up by decelerating speed.

3.3.3.2 Complete inspection must be applied after shutdown for vibration during the unit

startup. After confirming that the unit load meets the starting condition and the unit has

continuously turned for more than 4h, restarting is allowed. Forbid to blindly start.

3.3.3.3 In case it alarms due to 0.125mm of the bearing vibration, it must load down

appropriately, find out the causes and remove them, report to the duty director and inform

of maintainer to overhaul if necessary.

3.3.3.4 In case the bearing vibration amplitude of the generating set of the steam turbine

abruptly changes and exceeds 0.05mm under stable condition, it means that there is

damage or failure happened to the unit. Measures for stabilizing the amplitude within the

allowable range should be taken immediately. Otherwise, an emergency shutdown must

be applied decidedly.

3.3.3.5 If a big change of the unit load or steam admission parameters leads to the

vibration increase, it must check whether there is change in the total expansion,

differential expansion, axial displacement and upper and lower cylinders temperature

difference while stabilizing the load and parameters. Load variation is applied after

confirming that the said parameters totally meet the requirement and the vibration

recoveries. Treatment for the water attack is according to the “steam turbine water attack”

and abnormal axial displacement is according to the “axial displacement increase”.

3.3.3.6 For smooth water drain circuit, if the unit abnormally vibrates resulting from steam

reflowing into the steam turbine caused by abnormal operation of the heater, the operating

mode of the heater must be adjusted and its water level must be ensured within normal

range.

3.3.3.7 If the gland steam temperature is seriously unmatched with the steam gland metal

temperature, check the operating condition of the gland sealing system and match the

temperature in time;

3.3.3.8 Check whether the lube oil pressure and temperature, and generator sealing oil

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temperature are normal; regulate them timely as required;

3.3.3.9 Listen the sound inside the steam turbine; check whether the metal temperature

and return oil temperature of every bearing rise and judge whether the bearings are

damage;

3.3.3.10 Check whether the outlet hydrogen temperature of every hydrogen cooler of the

generator is normal; try to regulate and keep it in normal range in case the temperature or

deviation is out of limit;

3.3.3.11 Check the stator and rotor current of the generator and remove the unbalances;

3.3.3.12 Report to the duty director immediately while the unit vibration is abnormal due to

electric power system vibration; emergency shut down as the vibration is out of limit;

3.3.3.13 Break vacuum to emergency shut down in case the said operation is ineffective,

the bearing vibration reaches 0.250mm, vibration of any bearing is up to 0.125mm or there

is apparent metal fricative sound or impact sound inside the unit;

3.3.3.14 Regulate it again by the maintainer after shutdown if said symptoms are caused

by unskilled installation or maintenance.

3.4 Increased Axial Displacement

3.4.1 Symptoms

3.4.1.1 The axial displacement has increased indication;

3.4.1.2 There is alarm for ultra-limit of the axial displacement;

3.4.1.3 The thrust bearing metal and return oil temperature rises;

3.4.1.4 The unit vibration is possible to increase.

3.4.2 Causes

3.4.2.1 Load or steam flow changes dramatically;

3.4.2.2 The main, reheat steam temperature drops largely or there is water attack of the

steam turbine;

3.4.2.3 There is serious scaling or breaking of the blade;

3.4.2.4 The abrasion of the thrust bearing or gland increases;

3.4.2.5 HP heater failure of condenser vacuum drop leads to excessive load of the flow

passage;

3.4.2.6 The generator rotor shifts;

3.4.2.7 Electric network cycle drops;

3.4.2.8 Meters malfunction.

3.4.3 Treatment

3.4.3.1 As the axial displacement increases, check the unit load, steam parameters,

condenser vacuum, lube oil pressure, thrust bearing temperature, differential expansion,

vibration, sound inside the steam turbine, electric network cycle and operation of the

generator; report to the duty director to appropriately reduce the unit load; find out the

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causes and handle them accordingly;

3.4.3.2 Handle the abnormal thrust bearing metal temperature or return oil temperature

according to “bearing temperature rise”;

3.4.3.3 In case the axial displacement increases and there is metal sound inside the

steam turbine or the unit vibrates violently, break the vacuum to emergency shut down;

3.4.3.4 If the said operation is ineffective, the axial displacement increases by 1.2mm or

reduces to -1.65mm and the protection works, break the vacuum to emergency shut

down.

3.5 Damaged or Broken Blade

3.5.1 Symptoms

3.5.1.1 There is apparent metal impact sound inside the steam turbine or variable degrees

of fricative sound at the flow passage;

3.5.1.2 The unit vibration apparently increases;

3.5.1.3 Under the condition that the steam parameters, vacuum and opening of valves are

invariable, the unit load reduces, governing stage or extraction pressure at some stage

reduces;

3.5.1.4 Water level of the hot well rises; electric conductivity and hardness of the

condenser increases or water level of some heater abnormally rises.

3.5.2 Causes

3.5.2.1 Defects of the blade

3.5.2.2 Unqualified steam; partially excessive load or corrosive damage resulting from

blade scaling

3.5.2.3 Long-term super low or high cycle operation

3.5.2.4 Foreign substance entering the steam turbine or water attack

3.5.2.5 Overload operation of the unit

3.5.2.6 Friction between the rotary and static parts

3.5.3 Treatment

3.5.3.1 Report to the duty director to request for load reduction or shutdown as the unit

load reduces, the governing stage of extraction pressure of some stage and intra-stage

differential pressure are abnormally variable, the vibration increases and the axial

displacement and thrust bearing temperature apparently change under same operating

condition;

3.5.3.2 Break vacuum to emergency shut down as there is apparent metal impact sound

or fricative sound inside the steam turbine;

3.5.3.3 Break vacuum to emergency shut down while there is abnormal sound at the flow

passage and violent vibration occurred in the unit;

3.5.3.4 To prevent the steam turbine from inflowing water, water level rise of the heater

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pipes caused by broken and fallen blade should be solved according to “full water of

heater”;

3.5.3.5 Break the vacuum to emergency shut down while the water level of the hot well

abnormally rises due to broken condenser steel pipe caused by fallen blade and

strengthen the supervision on the condensate quality.

3.6 Lubricating Oil System Failure

3.6.1 Descendant or ascendant oil level in the tank

3.6.1.1 Symptoms

1) The oil level indicator has a descendant or ascendant indication;

2) There is alarm due to high and low oil level in the main oil tank.

3.6.1.2 Causes

1) The mainframe lubricating oil system, oil purification system, oil treatment system

and sealing oil system leak or pipes rupture and generator has oil entered; 2）Oil level drops resulting from the malfunction of the valves of the said systems;

3) Main reasons of ascendant oil level: excessively large clearance of the mainframe

gland, oil containing water resulting from abnormal gland sealing system pressure,

mistake startup of the oil delivery pump and oil cooler leak;

4) Abnormal indication for the oil level 5）Inappropriate operating adjustment of the gas exhaust fan

6）Return oil filter screen of the main oil tank to be blocked

7）Bearing oil scraper ring damage

3.6.1.3 Treatment

1) Check the field oil level indicator; confirm the main oil tank level is abnormal; find out

the causes and remove them; 2) Oiling as the main oil tank level drops to the normal oil level, namely －80mm; Oiling

in time if the descent speed is fast;

3) Break the vacuum to emergency shut down as the oil level is not able to be

maintained by taking various measures after the main oil tank level continues to drop to the normal oil level, namely －100mm;

4) In case the oil pipes leak due to rupture, safety measures for preventing firm caused

by sparkling oil onto the high temperature pipes or devices;

5) When the oil level rises, drain water from the bottom of the oil tank and inform the

chemical technician to sample for test or inform of the maintainer for oil filtration if

necessary;

6) If excessively high or low gland steam pressure or gland vacuum leads to a great

deal of steam loss, adjust the steam pressure or vacuum to reduce the loss;

7) If the oil cooler leaks, change over it, and then isolate it to find the leakage and inform

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of the maintainer;

8) If misoperation of the system leads to abnormal oil level, change over it to the normal

operating mode; 9）If the return oil filter screen of the main oil tank is blocked, contact the maintainer for

cleaning; 10）Check the gas exhaust fan and adjust it to normally operate.

3.6.2 Oil pressure drop

3.6.2.1 Symptoms

1) The lube oil pressure has a descendant indication;

2) It alarms due to low lube oil pressure;

3) The thrust metal and return oil temperature is possible to rise;

4) The unit is possible to vibrate more violently;

5) The axial displacement is possible to increase.

3.6.2.2 Causes

1) The main oil pump or turbine pump malfunctions;

2) The oil level of the main oil tank is too low;

3) Outlet check valves of the AC auxiliary oil pump and DC emergency oil pump leak;

4) The pressure oil pipes leak;

5) The valves of the lubricating oil system are operated by mistake;

6) Outlet overflow valve of the turbine pump is inappropriately adjusted or it can not

return back;

7) Meters indicate abnormally.

3.6.2.3 Treatment

1) Check every lube oil pressure gauge and confirm the pressure drops;

2) Check the inlet and outlet oil pressure of the main oil pump; judge whether the main

oil pump and turbine pump are in normal operation; start the AC auxiliary oil pump and

startup oil pump if necessary and take note of the oil pressure variation;

3) Check whether the oil level of the main oil tank is normal; if the oil level drops, fill the

tank in time;

4) Check whether the outlet check valve of the standby oil pump is tight; start the oil

pump with an un-tight outlet check valve; inform of the maintainer for repair if

necessary;

5) If the valves of the lubricating oil system are operated by mistake, correct the

operation in time;

6) As the outlet overflow valve of the turbine pump can not return due to failure, inform

of the maintainer in time for repair; during its fault, closely monitor the lube oil pressure

and take corresponding measures according to the pressure variation;

7) As the lube oil pressure drops to 0.103MPa, the AC auxiliary oil pump should be

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automatically started, if not, manually start it; as the outlet oil pressure of the main oil

pump is below 1.205MPa, the startup oil pump should automatically start, if not,

manually start it. As the lube oil pressure is normal, request for shutdown;

8) As the lube oil pressure drops to 0.069MPa, the steam turbine trips, and the DC

emergency oil pump automatically starts, if not, manually start it. As the rotating speed

is less than 2000r/min, break the vacuum to emergency shut down; meanwhile, check

the lubricating system and find out the causes of pressure drop.

3.6.3 Bearing temperature rise

3.6.3.1 Symptoms

1) It alarms due to bearing and return oil temperature rise;

2) The lube oil temperature rises;

3) The unit is possible to vibrate more violently;

4) The axial displacement is possible to increase.

3.6.3.2 Causes

1) Cooling water of the oil cooler is cut off or filthily blocked or inappropriate adjustment

for the cooling water leads to high lube oil temperature;

2) The lube oil pressure is too low or the oil inlet pipes of the bearings are blocked;

3) The violent unit vibration and broken oil film leads to friction between the rotary and

static parts;

4) The lube oil is unqualified;

5) The fixed parts of the bearings are loose or the mounting process is not good;

6) Meters malfunction.

3.6.3.3 Treatment

1) If the temperature of each bearing generally increases, check whether the lube oil

temperature and pressure are normal. If the lube oil pressure is low, it will be treated

according to the “low lube oil pressure”;

2) If the lube oil pressure is normal and lube oil temperature rises, check automatic

regulation of lube oil temperature and the operation of cooling water system; if the

automatic regulation of lube oil temperature fails, it should be switched to manual

control; if necessary, open the oil temperature bypass control valve to control the oil

temperature, and notify the thermal engineer to eliminate defects; if the oil cooler is dirty

and blocked, put an oil cooler into use for standby, isolate the oil cooler in operation and

notify the maintainer for cleaning;

3) If the cooling water is interrupted and can not be restored, and the lube oil

temperature continues to rise without downward trend, immediately break the vacuum

and emergency shut down;

4) If the valve is misoperated, immediately return to the normal operating conditions;

5) If the bearing temperature rises, strengthen surveillance of the lube oil pressure,

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bearing metal temperature and return oil temperature, unit vibration and axial

displacement;

6) If the shaft vibration increases, it should be processed according to abnormal

vibration of the unit;

7) If the temperature of individual bearings rises, check whether the bearings have

metal friction sound, and determine correctly whether the bearings are damaged or oil is

lacked of;

8) If the metal temperature or return oil temperature of the thrust bearing increases,

check whether the axial displacement is normal, and it should be processed according

to axial displacement increased;

9) Identify the metal temperature or return oil temperature of the host bearing rises

abnormally, adjust the unit load, eliminate the upward trend, and report to the duty

director and require preparations for shutdown;

10) If any one bearing of turbo-generator unit smokes due to lack of oil or the return oil

temperature suddenly rises to 75 , break the vacuum and emergency shutdown;℃

11) When the metal temperature of any one bearing of turbine-generator unit reaches

the following provided values: up to 115 for #1 ~ #6 support bearings, up to 90 for ℃ ℃

#7 ~ #9 support bearing, and up to 110 for thrust bearing, break the vacuum and ℃

emergency shutdown.

3.7 EH Oil System Failure

3.7.1 Common failures

3.7.1.1 The oil level of EH oil leak system and EH oil tank declines;

3.7.1.2 EH oil pressure shakes or declines;

3.7.1.3 EH oil temperature rises or falls.

3.7.2 Causes for failure

3.7.2.1 The oil system pipe and equipment breakdown leak oil;

3.7.2.2 The oil discharge and water drain valve of EH oil system are opened by mistake;

3.7.2.3 Overflow valve does not normally act, and the servomotor servo valve leaks;

3.7.2.4 EH oil pump fails or inlet and outlet filter screens are dirty and blocked;

3.7.2.5 Accumulator fault;

3.7.2.6 Regeneration device fails, and EH oil quality is substandard;

3.7.2.7 Servomotor servo valve leaks;

3.7.2.8 Meters malfunction.

3.7.3 Treatment of common fault of EH oil system

3.7.3.1 It is found that EH oil pressure drops, check the field meter, confirm EH oil

pressure drops, quickly identify the reason to treat correspondingly, and report to the duty

director;

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3.7.3.2 When the EH oil pressure drops to 9.2MPa, the standby pump shall self-start, and

the oil pressure is maintained 11.2MPa, or else the standby pump manually starts;

3.7.3.3 If the EH oil pump fails, immediately start the standby pump, stop running the

original pump, report the duty director and isolate, and inform of maintainer to treat it;

3.7.3.4 Check the action of the pump outlet overflow valve, and if the action pressure is

low, report the duty director and notify the maintenance and adjustment. Check whether

the EH outlet filter pump pressure is normal, and whether the standby pump outlet check

valve is tight; if necessary, switch the operation of EH oil pump;

3.7.3.5 If the EH oil pressure fluctuates, check the operation of the small steam turbine; if

necessary, start the electric pump, stop the steam pump, and adjust the unit load to not

more than 30%;

3.7.3.6 Check whether the valve of the EH oil system is mistakenly opened, and close it if

so;

3.7.3.7 Check whether the EH oil system leaks, and if so, on the premise of ensuring that

the system is running, isolate the leakage point, and note the changes in the oil level of

the EH oil tank; when the oil level of the oil tank drops to the low and the system alarms,

notify the overhaul person for refueling;

3.7.3.8 If the EH oil pipe of the small steam turbine leaks, immediately start the electric

pump, adjust the unit load, stop the steam pump with EH oil leakage, and make the

appropriate isolation;

3.7.3.9 If the system leakage can not be isolated, the oil level of the oil tank drops and it is

yet invalid after various measures are taken, it will affect the EH oil pressure and threaten

the normal safe operation of the unit; when the EH oil pressure drops to 7.8MPa, the

steam turbine should trip, or else manually open the valve to stop, and stop the EH oil

system;

3.7.3.10 If the servomotor servo valve leaks, report the duty director, and the duty director

requires a decrease in the unit load under circumstances, makes the appropriate isolation,

and then notifies the maintenance;

3.7.3.11 If the oil pipe ruptures and leaks oil, take measures for preventing fire to be

caused by oil splashing to the heat pipe;

3.7.3.12 If the EH oil temperature fluctuates unusually, check whether the EH oil recycling

system works properly, and make manual adjustment.

3.8 Feed Pump Failure

3.8.1 Turbo-feed pump unit emergency, failure stop

3.8.1.1 Emergency shutdown conditions when small steam turbine breaks vacuum:

1) When steam pump group vibrates violently or metal friction sound or impact sound in

the small steam turbine or the pump is clearly heard;

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2) When the small steam turbine speed is up to 5972r/min and the emergency governor

does not move;

3) Water impact of the small steam turbine;

4) When the small oil system is on fire, which can not be timely out, thus posing a

serious threat to safe operation of the unit;

5) When the metal temperature or return oil temperature of any one bearing of the

steam pump group is overrun, or the bearing lacks of oil or smokes;

6) When the oil level of the small steam turbine oil tank drops to a low limit and is unable

to resume although refueling;

7) When the oil pressure drops to 0.08MPa, and the emergency governor does not

move;

8) When the booster pump motor smokes and catches fire; 9）When the small steam turbine seal gland sparkles;

10) When the auxiliary power is interrupted;

11) When feed water flow rate is less than 300t/h, 10s delays and the recirculation valve

trips; 12）The inlet pressure of the feed pump in operation less than 1.25MPa (30s delay).

3.8.1.2 Emergency shutdown conditions when small steam turbine breaks vacuum:

1) When small steam turbine speed control system substantially shakes and can not

maintain running;

2) When steam supply pipe or water supply pipe ruptures, and can not be isolated;

3) When small steam turbine vacuum declines continuously and can not be restored;

4) When the feed pump is seriously vaporized;

5) When the oil system leaks and can not sustained operate;

6) When the feed pump body leaks seriously, and a lot of steam water emits,

threatening the safe operation of the pump group;

7) When the booster pump current is ultralimit and can not reduce;

8) When it is up to the protection action value of steam pump group and the emergency

governor can not move.

3.8.1.3 Procedures for emergency and failure stop of turbo-feed pump group:

1) Two steam pumps operate, a steam pump stops, and the unit derates 50% rated load

correspondingly. Other operations are treated in accordance with the relevant

provisions of RB;

2) Press the "SHUTDOWN" button of the small steam turbine or knock the emergency

breaker handle of the small steam turbine locally with hand, check the main stop valve

of the small steam turbine, close the control valve rapidly and the speed slows down;

3) Adjust the unit load and the drum water level is normal; start the electric pump in

parallel operation;

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4) If breaking the vacuum, close the exhaust butterfly valve and the relevant drain

valves of the small steam turbine body first, and then stop the seal gland steam;

5) Pay attention to the idle time of the small steam turbine, and put the continuous

turning gear in time;

6) Complete other operations of normal shutdown of the small steam turbine.

3.8.2 Emergency shutdown of electric feed pump group

3.8.2.1 In the following cases, stop the pump group emergently:

1) The electric pump motor or coupling smokes and catches fire;

2) The metal temperature or return oil temperature of any one bearing of the electric

pump group is ultralimit or the bearing lacks of oil and smokes;

3) The feed water pipe ruptures and can not be isolated;

4) The feed pump is seriously vaporized;

5) The motor current is overloaded and can not reduce;

6) When the feed pump body leaks seriously, and a lot of steam water emits,

threatening the safe operation of the pump group;

7) When the pump group emergency governor acts and can not move;

8) When the main oil pump of the electric pump fails or the oil system can not maintain

normal oil pressure (less than 0.08MPa), and it is invalid to start the auxiliary pump;

9) When the electric pump group vibrates strongly or there is obvious metal friction

sound or impact sound within the pump;

10) When the electric pump oil system leaks oil seriously, and the oil level suddenly falls

and can not be restored;

11) When the working oil temperature of the fluid coupler of the electric pump rises, and

the oil drain temperature rises to 130 .℃

3.8.2.2 Procedures of emergency shutdown of the electric pump

1) Centralized control and stop the electric pump or press the electric pump accident

button on the site;

2) Check that the auxiliary oil pump should be automatically input, or else should

manually start immediately and check whether the oil pressure is normal;

3) Put the electric pump spoon pipe to the "0" bit, and immediately close the outlet

electric valve and intermediate tap electric valve;

4) Complete other operations of normal shutdown of the pump;

5) Note that idle time and do a good job in accidents and treatment records.

3.8.3 Other accidents and treatment of feed pump

3.8.3.1 The lube oil pressure of the feed pump drops

1) Symptoms

a) The lube oil pressure drops;

b) The lube oil pressure is low and the system alarms;

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c) The temperature of each bearing of the feed pump group rises or the temperature

is high and the system alarms.

2) Causes

a) The pressure oil pipe leaks;

b) The working oil pump works in disorder;

c) The outlet check valve of each auxiliary oil pump and accident oil pump of the

steam pump or electric pump is not closed and leaks oil;

d) The lube oil filter screen is blocked;

e) The fuel tank oil level is too low; f） The lube oil temperature is high;

g）The overflow valve does not act normally;

h）The lube oil is unqualified

i) Meters malfunction.

3) Treatment

a) If it is found that the lube oil pressure drops, identify the causes and try to

troubleshoot in a timely manner;

b) If the working oil pump works in disorder, timely start the standby oil pump or

auxiliary pump to maintain the oil pressure normal;

c) If the outlet check valve of the standby oil pump is loose, isolate it and notify the

maintenance;

d) If the system alarms when the front and back differential pressure of the oil filter

screen is more than 0.06MPa, should switch to the standby oil filter screen to run, and

notify the maintainer to clean the filter screen;

e) If a lot of oil is leaked from the oil system, isolation measures should be taken; stop

the pump due to failure when it can not be isolated;

f) If the tank oil level is low, promptly contact the maintainer to refuel; when the oil

level drops to a low limit and can not be restored or the lube oil pressure drops,

should stop the pump due to failure;

g) When the lube oil pressure of the electric pump drops to 0.10MPa, and the small

steam turbine lube oil pressure drops to 0.11MPa, the corresponding AC auxiliary oil

pump shall self-start, or else start up manually;

h) When the small steam turbine lube oil pressure drops to 0.08MPa, DC oil pumps

should self-start, or else start up manually;

i) When the lube oil pressure drops to 0.08MPa, the electric pump or small steam

turbine should trip, or else stop manually. When the oil pressure lowers, closely

monitor the temperature, oil flow and other situations of each bearing; when the

bearing temperature rises or is near the limit value, reduce the load appropriately;

when the bearing temperature is ultralimit, emergency shutdown the pump;

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j) If the oil temperature of the pump group is abnormal, check whether the

corresponding oil cooler is working properly, and try to eliminate failure.

3.8.3.2 The feed pump vaporizes

1) Symptoms

a) The electric pump current swings and declines; the steam pump speed fluctuates,

and the booster pump current swings;

b) The feed pump outlet pressure swings and declines;

c) The feed water flow rate swings and declines;

d) There is steam emitting out of the mechanical seals at the combination face of and

at both sides of the water pumps

e) The water pump has noise or impact sound internally, the vibration of pump group

and pipe system increases, and the rotor plays.

2) Causes

a) Deaerator pressure suddenly drops drastically, incompatible with the decrease in

the deaerator water temperature;

b) The inlet pump pressure is too low caused by blockage of the inlet filter screen;

c) When the flow rate is lower than the minimum flow protection value, the

re-circulating valve is not open;

d) The steam pump runs for a long time at low speed;

e) The deaerator water level is too low, resulting in inadequate water into the pump.

3) Treatment

a) When the electric pump vaporizes, the boiler is in the stage of ignition and step-up,

the electric pump should stop emergently, and the unit will restart after the steam

reason is removed; if water feed needs to be strengthened in the course of load

because the vaporization of the electric pump is caused by low water level of the

deaerator, the load should be transferred to the steam pump and then the electric

pump should stop immediately; if the steam pump has not yet started, the electric

pump should immediately stop and the unit stops operating.

b) When the steam pump vaporizes, start immediately the electric pump and at the

same time stop the vaporized steam pump, and in accordance with the water flow

rate, reduce the load appropriately.

c) Open the main pump body of the vaporization pump slightly to release the air valve

to discharge steam, and re-start it after the steam pump turning gear is flexible and

the input turning gear is normal; after re-startup, should carefully listen to the internal

sound and vibration.

3.9 Deaerator Failure

3.9.1 Deaerator pressure is abnormal

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3.9.1.1 Symptoms

1) Deaerator pressure indication increases or decreases;

2) Deaerator pressure is high or low and the system alarms;

3) Deaerator water temperature increases or decreases accordingly;

4) Deaerator safety valve starts; 5）Deaerator steam inlet electric valve is jointly closed.

3.9.1.2 Causes

1) Causes for the increase in deaerator pressure: the deaerator steam inlet valve is

improperly adjusted, the high-pressure heater is in water-free operation, the volume of

condensed water is reduced or discontinued, and the opening of continuous discharge

is too large;

2) Causes for the reduction in deaerator pressure: the safety valve acts but does not

return to the block; the volume of input steam drops; the high-pressure heater and

low-pressure heater step out; the volume of condensed water increases sharply;

3) The too fast unit load rate of change can cause abnormal deaerator pressure.

3.9.1.3 Treatment

1) If it is found that the deaerator pressure is abnormal, immediately check the meter

and determine whether it is true that the deaerator pressure increases or decreases;

2) If the deaerator pressure is abnormal, check that it corresponds to the load at the

time, and control the unit load within the name-plate rating; if necessary, reduce the unit

load;

3)When the deaerator pressure increases, adjust the volume of deaerator inlet steam,

and pay attention to starting seat of the safety valve; if necessary, shut down the steam

inlet valve from the auxiliary steam, four-pump and continuous discharge to the

deaerator, to prevent serious super-pressure on the deaerator from endangering the

personal safety and equipment safety;

4) Check the action of high-pressure heater drain valve, and if necessary, adjust the

high-pressure heater water level to the setting;

5) Check the action of the deaerator water level regulation station, check and adjust the

condensing water flow, and can intervene manually to maintain the normal deaerator

water level;

6) If the deaerator safety valve acts but does not return to the block, close the deaerator

steam inlet valve, reduce the deaerator pressure so that the safety valve returns to the

block, and maintain after shutdown;

7) If the deaerator steam inlet pipe ruptures, should try to isolate it, and the deaerator

runs after depressurization. When it is unable to maintain normal operation of the unit,

report the duty director and contact to shut down.

3.9.2 Deaerator water level is abnormal

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3.9.2.1 Symptoms

1)The deaerator water level indicator rises or declines;

2) The deaerator water level is high or low and the system alarms;

3) The opening of the deaerator water level control valve is abnormal.

3.9.2.2 Causes 1）The deaerator water level fails to automatically adjust;

2）The overflow and drain valve of the deaerator are opened by mistake;

3）The boiler pipe bursts, and the feedwater or condensate system seriously leaks;

4）Switch all high-pressure heater drain valves to the condenser in operation;

5）The condensate system fails;

6）The deaerator pressure drops suddenly

7）The condenser water level is low;

8）The condensate recycling is opened by mistake;

9）The feed pump does not work properly.

3.9.2.3 Treatment

1) When it is found that the deaerator water level is abnormal, should check the balance

of the unit load and steam water, and check the local water level gauge and determine

whether the deaerator water level is true; 2）If the condensed water flow is not normally regulated, timely regulate it manually;

3）If the condensate pump is not working properly, timely switch the operation of the

condensate pump; 4）If the condensate system is misused, correct it timely;

5）If the condenser water level is low, replenish water timely;

6）If the condensation water recycling is mistakenly opened, close it timely;

7）If the feed pump is not working properly, switch the operation of the standby pump

timely, and pay attention to adjusting the drum water level; 8）When the deaerator water level drops to a low value, check that the feed pump Ⅱ

and booster pump should trip, or else should stop the pump due to failure, and complete

other operations of normal shutdown; 9）When the deaerator water level rises to a high value, check that the overflow valve Ⅱ

is automatically open, and the water level control valve should be closed; otherwise,

should manually intervene, and pay attention to the action of the condensate recycle

valve and the hot well water level should be normal, and pay attention to the changes in

condensing steam pressure; if necessary, open the release valve at the bottom of the

deaerator to a normal level before closing it; 10）When the water level continues to rise to a high value, check the steam inlet Ⅲ

electric valve and check valve from four-pump to the deaerator, and the drain valve from

#3 high-pressure heater to the deaerator should be automatically closed, and the

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relevant drain valves are automatically open; 11）If it is invalid after inspection and adjustment, and it is unable to maintain normal

operation of the unit, should report to the duty director and require shutdown.

3.10 Heater Failure

3.10.1 Emergency shutdown of the heater

3.10.1.1 Conditions for emergency shutdown of the heater

1) When the heater steam and water pipes and valves burst, threatening the safety of

persons and equipment;

2) When the heater water level continues to rise, but is invalid after being treated;

3) When the heater water level rises to the value and the emergency governor does Ⅱ

not act;

4) When the heater water level display and water level alarm malfunction, and the

heater water level can not be monitored and determined.

3.10.1.2 Procedures for emergency shutdown of the heater

1) Close the heater extraction check valve and extraction electric valve; 2）Open the water bypass valve of the heater, close the water inlet and outlet electric

valve of the heater, and pay attention to monitoring the flow rate of condensed water or

feed water; 3）Reduce the unit load in accordance with the regulations;

4) When the high-pressure heater stops emergency, should adjust the main and

reheated steam temperature in the normal range, and pay attention to the main and

reheated steam temperature and drum water level should be normally adjusted. Monitor

the work of the steam turbine thrust bearing;

5) Close the normal drain valve from the previous heater to the fault heater, and confirm

that the previous accident drain valve moves normally and that the heater water level is

normal;

6) Note that the steam pressure of the failure heater should not go higher, and when

necessary, relieve the pressure, and note the changes in the condenser vacuum;

7) When #8A low-pressure heater stops running, should switch the seal gland overflow

in a timely manner to the condenser.

3.10.1.3 Requirements for load limit when the heater stops running.

1) When the high-pressure heater procedures out, as long as the boiler parameters

meet the requirements, it can operate with full load;

2) When #1 high-pressure heater runs, and other arbitrary adjacent two heaters stop

running due to fault, the unit output drops to 90% rated load in operation. If another

adjacent heater stops, should further reduced 10% rated load, and so on; 3）Load limit of the low-pressure heater shutdown:

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Disable

No.

#5 #6 #7 #8 #5#6 #6#7 #7#8 #5#6#8 #6#7#8 #5#6#7#8

Load

rate %

100 100 100 100 90 90 90 80 80 70

4) When all heater steam sides are isolated, the maximum load of the unit shall not

exceed 50% of name-plate rating.

3.11 Generator Sealing Oil System Failure

3.11.1 The sealing oil pressure drops

3.11.1.1 Symptoms

1) Sealing oil pressure indication drops and alarms;

2) Oil - Hydrogen pressure difference indication decreases and alarms; 3）The hydrogen pressure drops.

3.11.1.2 Causes

1) Sealing oil pump fails;

2) The sealing oil differential pressure regulator fails;

3) Sealing oil filter screen is dirty and blocked; 4）Vacuum tank oil level is low;

5）Sealing pad clearance is too large;

6）The safety valve leaks or re-circulating valve drain leaks.

3.11.1.3 Treatment

1) When it is found that sealing oil pressure drops, should check the local pressure

gauge, confirm whether the oil pressure declines and identify the causes; if necessary,

switch the pump to the standby AC sealing oil pump in operation, and restore the

system in normal operation as soon as possible;

2) When two AC sealing oil pumps fail, start DC sealing oil pump, but must do the

following work:

a) When DC pump operates, discharge and supplement hydrogen to the generator

every 8 hours. Discharge hydrogen slowly through the release valve S-78/S-79 on the

expansion slot of the return oil valve, in order to ensure the purity of hydrogen in the

generator is more than 96%, and pay attention to the oil-hydrogen differential

pressure is normally regulated;

b) If the DC sealing oil pump operates, and it is estimated that the AC sealing oil

pump can not be restored to normal operation within 12 hours, should stop the

sealing oil recycling pump and sealing oil vacuum pump, close the oil inlet valve of

the vacuum tank and the inlet valve of the sealing oil vacuum pump, and stop

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operating after breaking the vacuum of the vacuum tank;

3) When each sealing oil pump fails, the generator should emergency shutdown and

discharge hydrogen until the lube oil pressure can seal hydrogen in the generator;

4) When the host lube oil to the sealing oil supply stops, should pay attention to

monitoring that the tank oil level and oil hydrogen differential pressure should be normal

and that the vacuum of the sealing oil vacuum tank should be normal, and monitoring

the hydrogen pressure inside the generator and supplementing hydrogen timely;

5) When the oil-hydrogen differential pressure regulating valve fails, should contact the

maintainer to re-adjust, and during the period can use oil-hydrogen differential pressure

bypass control valve to adjust the differential pressure within the normal range;

6) If the sealing oil pressure is low due to the high differential pressure of sealing oil filter

screen, should switch the filter screen timely and isolate well and inform the maintainer

to clean; 7）If the sealing pad clearance is too large, reduce the oil-hydrogen differential pressure

appropriately and pay attention to monitoring the generator hydrogen pressure and the

hydrogen purity, and supplement and discharge hydrogen timely; 8）If the safety valve leaks or re-circulating valve leaks, isolate the safety valve and

tighten the re-circulating valve manually; 9）When the generator leaks hydrogen seriously, start the plant ventilation equipment

timely.

3.11.2 Abnormal oil level in the oil tank

3.11.2.1 Symptoms

1) The oil level indication of sealing oil vacuum tank, expansion tank and float tank is

abnormal;

2) Monitor and alarm the oil level of the sealing oil vacuum tank and expansion tank.

3.11.2.2 Causes

1) The vacuum tank float valve fails to act or the pipe is dirty and blocked;

2) The abnormal increase in the generator sealing pad clearance will lead to the

vacuum tank to be always running at low oil level;

3) The float valve of the float tank fails to act or the pipe is dirty and blocked.

3.11.2.3 Treatment

1) When the oil level of the sealing oil vacuum tank is high, close the oil inlet valve of the

vacuum tank, and re-start it after the oil level drops, and activate the float valve in this

way to restore the control of the float valve;

2) When the oil level of the vacuum tank is low and can not be restored, should stop the

sealing oil vacuum pump, recycling pump and AC sealing oil pump, change a DC

sealing oil pump, quit the vacuum tank in operation, and notify the maintainer. During

the period, discharge and supplement hydrogen of the generator every 8 hours in order

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to maintain the hydrogen purity within the generator;

3) When the oil level of the sealing oil expansion tank is high, adjust it by use of the float

tank bypass valve, and contact the maintainer to shake the float valve box with a rubber

hammer. At this time, pay attention to whether there is oil in the oil-water monitor and

discharging it promptly, and note that the hydrogen pressure in the steam turbine is

normal and keep that the oil level of the observation window of the float tank is at the

normal position;

4) If the oil level of the float tank is too low, check the float tank bypass valve is closed. If

the float tank float valve fails, isolate the float tank from the bypass and treat it by the

maintainer after discharging the oil and steam in the float tank. The hydrogen pressure

inside the generator should be noted during the period. If the hydrogen pressure drops

too quickly, take appropriate remedial measures, or lower the unit output to run. In the

event that a lot of hydrogen leaks out of the generator and can not be inhibited, shut

down emergently.

3.12 Generator Hydrogen Cooling System Failure

3.12.1 Hydrogen pressure drops

3.12.1.1 Symptoms

1) Hydrogen pressure indication drops or alarms;

2) The volume of supplemented hydrogen increases;

3) The generator wind outlet temperature rises;

4) The temperature of the generator rotor coil and stator core rises.

3.12.1.2 Causes

1) The hydrogen supply control valve fails or the hydrogen system pressure drops;

2) Sealing oil pressure drops;

3) The hydrogen temperature at the hydrogen cooler outlet drops suddenly;

4) The hydrogen system leaks or is misused;


3.12.1.3 Treatment

1) When it is found that the hydrogen pressure drops, check the field meter, confirm that

the hydrogen pressure drops, and must immediately identify the reason and deal with,

increase the volume of supplemented hydrogen to maintain the rated hydrogen

pressure within the generator, and meanwhile enhance the monitoring of the hydrogen

purity and generator core and coil temperature;

2) If the hydrogen supply control valve fails, switch to the manual adjustment, and if the

hydrogen supply main pressure is low, notify the chemical person to improve the

hydrogen supply pressure;

3) If the hydrogen pressure drops as a result of the drop in sealing oil pressure, treat it

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the same as "the sealing oil pressure drops";

4) Check whether the hydrogen temperature is automatically adjustly normal, and if it

fails, switch to the manual adjustment;

5) If the hydrogen cooling system leaks, identify the leakage point and report to the duty

director, and require the chemical, electrical persons to coordinate and check leakage;

at the same time take fire-fighting and explosion-proof safety measures. When checking

leakage, the leakage indicator or soap water should be used;

6) If the hydrogen pressure declines and the rating can not be sustained, based on the

temperature of the stator core, contact the duty director to reduce the load value of the

corresponding unit until the engine stops; 7）If the hydrogen system leaks, add and start the ventilation equipment on top of the

steam turbine room, chemical personnel regularly measure the hydrogen content in the

air inside the steam turbine room, and the fire work in all the steam turbine rooms

should stop to prevent explosion because the hydrogen content in the air inside the

steam turbine room exceeds the standard.

3.12.2 Hydrogen temperature increases or decreases.

3.12.2.1 Symptoms

1) The hydrogen temperature indication increases or decreases;

2) The hydrogen temperature is high or low and the system alarms;

3) The stator core temperature increases or decreases.

3.12.2.2 Causes

1) Fail to automatically adjust hydrogen temperature;

2) Open cooling water pressure and temperature change;

3) The unit load increases or decreases suddenly;


3.12.2.3 Treatment

1) When it is found that the hydrogen temperature increases or decreases, identify the

causes and try to eliminate, and return to the normal operation;

2) Check the automatic adjustment of hydrogen temperature, and if it fails, switch to the

manual adjustment or use the bypass valve to adjust;

3) Check the open cooling water pressure and temperature and maintain in the normal

range;

4) Strengthen to monitor the unit vibration, and if necessary, lower the unit load in

operation;

5) Enhance the monitoring of the hydrogen pressure and stator core temperature, and if

the hydrogen temperature rises, considering the core temperature, should contact the

duty director, and the unit reduces the corresponding load.

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3.13 Generator Stator Cooling Water System Failure

3.13.1 Stator cooling water pressure drops.

3.13.1.1 Symptoms

1) Stator cooling water pressure drops;

2) Stator cooling water flow declines;

3) Stator water inlet pressure is low and the system alarms;

4) Stator cooling water and return water temperature and stator coil cooling water

temperature rise.

3.13.1.2 Causes

1) Fail to run the stator cooling water pump;

2) Stator cooling water tank water level is too low;

3) Stator cooling water filter screen is dirty and blocked;

4) Stator cooling water system is mis-operated;

5) Stator cooling water pressure regulating valve fails;

6) The inner cooling water system leaks; 7）The standby pump exit valve is not closed;

8）Meters malfunction

3.13.1.3 Treatment

1) When it is found that the stator cooling water pressure decreases, immediately check

the above causes and take appropriate measures to deal with decisively, and try to

resume the normal operation;

2) If the outlet pressure of the stator cooling water pump is as low as 0.74Mpa, the

standby pump should self-start, and the originally running pump should automatically

stop;

3) If the stator cooling water pressure regulating valve fails, manually adjust, and

maintain the water inlet pressure of the stator coil at 0.196MPa and the flow rate is not

less than 92t/h;

4) If it is invalid after the above-mentioned treatment, the water inlet flow rate of the

stator coil is lower than 63t/h and 30s is delayed, the emergency governor acts and

jumps, or else the engine stops due to failure.

3.13.2 The water level of the stator cooling water tank drops

3.13.2.1 Symptoms

1) The water level indication of the stator cooling water tank drops or the low water level

alarms (the normal water level of the water tank is 60mm above the tank center line);

2) The stator cooling water pressure and flow rate may drop;

3) The generator leak detection device alarms.

1) The make-up water solenoid valve malfunctions or the make-up water system valve

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is closed by mistake;

2) The water drain valve of the cooling water system is opened by mistake;

3) The water cooler leaks, or the ion exchanger leaks or the valve is opened by mistake;

4) The stator cooling water system pipe leaks;

5) The stator cooling water sampling flow is too big.

3.13.2.3 Treatment

1) When it is found that the water level of the stator cooling water tank drops abnormally,

check the above-mentioned causes and take corresponding measures. Strengthen

surveillance of the stator cooling water pressure, and check whether there is leakage

symptom in the generator;

2) Immediately open the make-up water valve, and try to maintain the water level of the

stator cooling water tank;

3) Check the running status of system equipment, and close the mistakenly opened

valve;

4) If the pipe ruptures or the stator cooling water cooler leaks, isolate part of the pipe

that can be isolated, switch and isolate the stator cooling water cooler, and notify the

maintainer; if it can not be isolated, and the water level of the stator cooling water tank

can not be sustained, should report to the duty director to request shutdown.

3.13.3 Stator cooling water temperature rises.

3.13.3.1 Symptoms

1) The water outlet temperature indication of the stator cooling water cooler rises or

alarms;

2) The stator cooling water and return water temperature indication rises or alarms;

3) The stator coil temperature generally increases or alarms.

3.13.3.2 Causes

1) The stator cooling water cooler is dirty and blocked;

2) Fail to automatically adjust the stator cooling water temperature;

3) The cooling water valve of the stator cooling water cooler pipe is mistakenly closed or

the valve core falls off;

4) Open cooling water pressure reduces or the temperature rises; 5）The generator heat increases;


3.13.3.3 Treatment

1) When it is found that the stator cooling water temperature rises, check the above

causes and take appropriate measures;

2) If the stator cooling water cooler is dirty and blocked, put into the standby water

cooler, isolate the originally running stator cooling water cooler, and notify the

maintainer for cleaning;

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3) If the stator cooling water temperature fails to automatically adjust, check that the

running stator cooling water cooler pipe, shell-side entry and exit valves are all on the

fully open position; if the valve core falls off or the stator cooling water cooler is blocked,

should promptly put into the standby stator cooling water cooler, and quit the fault stator

cooling water cooler;

4) If the open cooling water pressure drops or the temperature increases, try to restore

the normal operation of the open cooling water system; if necessary, put into two stator

cooling water coolers in parallel operation;

5) When the stator water inlet temperature rises to 49 or the return water temperature is ℃

as high as 73 , closely monitor the stator coil temperature, report to the duty director, and ℃

in accordance with the provisions, lower the unit load correspondingly until the unit stops.

Part II Auxiliary System Operation

Chapter Ⅰ General Rules on Start-up (in operation) and Shutdown (out of service) of

Auxiliaries and systems

1. General Operating Rules of Auxiliaries

1.1 Transfer and Operating Conditions of the Auxiliaries and Systems after Overhaul

1.1.1 Confirm that the repair work has been ended, the scaffolding has been removed,

and the site is clean without debris;

1.1.2 Overhaul the devices and system and make sure they are well connected, pipe

support and hangers are reliable, thermal insulation is good, and all manholes and

inspection doors should be closed tightly;

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1.1.3 An appropriate amount of qualified lube oil has been added to the power equipment,

motor and other bearings; the turnaround coupling shield, motor casing grounding lines,

cooling water pipes and others are well connected;

1.1.4 If the equipment has alternations in the course of maintenance, the maintainer

should provide a report on the equipment alternations and related drawings, and tell

operators the notes to equipment operation;

1.1.5 The on-site roads are smooth, the ground groove decking, stairs and railings are

intact, and lighting is adequate;

1.1.6 The thermal, electric meters related to auxiliaries and systems are intact and can be

used;

1.1.7 Work sheets have been ended, and the maintenance of equipment, systems that

can be put into operation is explained.

1.2 Auxiliaries Inspection before Startup 1.2.1 Confirm that all the repair work related to the equipment, systems has been ended,

the work sheets have been ended, the safety measures have been restored, and the

safety badges, warning signs have been removed;

1.2.2 Inspect that the oil quality and oil level of the bearings of rotating equipment, change

speed gear boxes and lubrication-related components are normal;

1.2.3 Rotate the rotors of rotating equipment, and check the clamping stagnation, the

anchor bolts not loose and the protective covers complete and solid;

1.2.4 Check that the seal water and cooling water of the relevant equipment have been

put into normal;

1.2.5 Check that all relevant meters of the auxiliaries and systems should be complete

and put into use, and the meter indications are correct;

1.2.6 The control loop, electrical interlocking, automatic devices, thermal protection and

mechanical adjustment devices of all auxiliaries and systems related to valves should be

checked as required and be supplied with control power and control steam source;

1.2.7 The static calibration of the interlocking and protection device of the auxiliaries and

systems is normal, and the electric valve, pneumatic valve and regulating valve checked

are intact;

1.2.8 Inspect the system comprehensively according to the system check card, confirm

the status of all valves is in place before startup, and discharge the residual steam in the

related oil-water system;

1.2.9 Check that each motor casing is well grounded, and measure the insulation qualified

before power up;

1.2.10 Check the status of the relevant devices and valves on the MMI is indicated

correctly, and all the alarm signals are correct.

1.3 Auxiliaries Start-up and Attentions

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1.3.1 Contact the relevant posts before the auxiliaries start, and monitor and inspect

operation after startup;

1.3.2 There must be personnel on the site to monitor the auxiliaries in the course of start,

stop, or commissioning, and after startup, if an unusual situation is found, it should be

reported immediately and an emergency outage is needed;

1.3.3 Before the mainframe, small steam turbine and sealing oil DC pump start, confirm

that the busbar voltage of the DC system is normal before operation;

1.3.4 Before 6KV auxiliaries starts, first confirm the corresponding 6KV busbar voltage is

normal, and when starting, monitor the start current and start time of 6KV busbar voltage

and auxiliaries,;

1.3.5 When the 6KV auxiliaries stop, pay attention to maintaining a basic balance between

bus loads at all levels;

1.3.6 The re-start of 6KV auxiliaries should be consistent with the electrical requirements;

under normal circumstances, allow starting twice in the cold state and once in the hot

state;

1.3.7 Do not allow to start the volumetric pump and axial flow pump when the outlet valve

is closed, and start the centrifugal pump valve when the outlet valve is closed, but after it

starts, open the outlet valve promptly;

1.3.8 After the auxiliaries start normally, there are standby auxiliaries that should be

promptly put into the "automatic" or "interlocking" position;

1.3.9 When the auxiliaries start, the duration of starting current shall not exceed the

provision of the manufacturer; otherwise, it shall immediately stop;

1.3.10 It is prohibited to start the auxiliaries in the case of reverse operation;

1.3.11 For the first time test run after top overhaul, minor overhaul and motor outage,

should first turn the motor idle and check whether the change direction is correct.

1.4 Inspection Items after the Auxiliaries Startup 1.4.1 Motor current, inlet and outlet pressure, flow rate and inlet filter screen differential


1.4.2 The sealing part of the relevant equipment is good, the cooling water system is

running normally, and the bearing temperature and motor coil temperature are normal;

1.4.3 Confirm that the interlock protection and automatic control have been put into

normal;

1.4.4 Standby pump check valve is tight, with no reverse operation symptoms;

1.4.5 All the vibration components and motor have no abnormal friction sound, and their

vibration meets the provision;

1.4.6 Check the bearing box oil level is normal, and there is no oil leakage symptom;

1.4.7 The adjustment of the coupling device to be intact, without shedding;

1.4.8 Inspect the system owned by the auxiliaries has leakage symptoms;

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1.4.9 Check the lube oil temperature of each bearing is normal, and the return oil

temperature should be within the prescribed range. When manufacturers have no special

provisions, implement the standards in the following table:

Rolling bearing Sliding bearing Bearing type

Motor Machinery Motor Machinery

Bearing

temperature ≤80℃ ≤100℃ ≤70℃ ≤80℃

1.4.9 Check the motor temperature rise does not exceed the value in the following table

(ambient temperature 40 ):℃

Insulation

Class Class A Class E Class B Class F

Motor

temperature

rise

65℃ 80℃ 90℃ 115℃

1.4.10 Check that each bearing vibrates normally, and when the manufacturers have no

special provisions, implement the standards in the following table:

Rated speed

rpm 3000 1500 1000

750 and

below Remarks

Vibration mm 0.05/0.06 0.085/0.1 0.1/0.13 0.12/0.16 Motor/Machi

ne

2 General Outage Rules of Auxiliaries

2.1 Before auxiliaries stop, contact the relevant posts, carefully consider the impact of the

auxiliaries’ outage on the related systems or equipment, and take appropriate safety

measures.

2.2 Before auxiliaries stops, withdraw from the standby auxiliaries "automatic" or

discharge the self-start "interlocking".

2.3 After the auxiliaries stop, the speed should be reduced to zero, with no reverse

operation symptoms. If so, the outlet valve should be closed to eliminate the reverse

operation, and it is strictly prohibited to eliminate reverse operation by closing the inlet

valve.

2.4 Outage Maintenance of Auxiliaries or Systems

2.4.1 Maintenance of systems or equipment is subject to approval by the duty director and

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maintenance work sheet is handled.

2.4.2 Take good power-off, pressure relief and isolation measures of equipment.

2.4.3 Disconnect the power supply and control power of the maintenance equipment,.

2.4.4 Close the pump outlet valve, and make sure it is closed tightly.

2.4.5 Close the pump inlet valve and exhaust valve of inlet tube. In the process of closing

the inlet valve, in particular close to the fully closed state, should closely monitorthe inlet

pressure gauge, and operate slowly, to prevent the outlet valve and other isolation valves

connected to the high-pressure system from being loose, resulting in damage to the

low-pressure pipe and flange at the inlet part due to overpressure.

2.4.6 Close the bearing cooling water inlet and outlet valve, and open the pump discharge

valve and relieve the overflow valve pressure to zero.

2.4.7 Take safety measures as required by the work sheet, and hang safety signs and

warning signs.

2.5 Pressure relief operation of pressure vessels and pipes

2.5.1 Close all inlet valves of pressure vessel, and ensure they are tightly closed.

2.5.2 Close all outlet valves of pressure vessel, and ensure they are tightly closed.

2.5.3 Open the drain valve of pressure vessel, and pay attention to the pressure inside the

vessel should be lowered. After water drainage has been completed, close the drain valve

associated with the vessel, but open the drain valve of the separate trench.

2.5.4 Open the pressure vessel exhaust valve, and confirm that the vessel pressure is

fully relieved.

2.5.5 Cut off power supply for the electric valve of the vessel in which external working

fluid may enter, cut off the pneumatic valve and make a measure against mistake.

2.5.6 Hang a warning sign of "Prohibition of operation, and in work" on all electrical,

pneumatic, manual isolation valves connected with the vessel.

2.5.7 Take overhaul and safety measures as required by the thermal work sheet, and

handle the work sheet procedures for permission after the work sheet licensor and the

person responsible for work sheets inspect and confirm that safety measures are correct,

and make relevant records.

Chapter II Auxiliaries and Systems

1. Lubricating Oil System

1.1. Check and Operation before Startup 1.1.1 Check the lubricating oil system according to General Rules for Auxiliaries;

1.1.2 Check that all interlock protection tests have been duly conducted and passed.

1.1.3 Check that all instruments and meters are complete, inlet valves of pressure gauges

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are open and all instruments and meters are working properly;

1.1.4 Use the valve check card to check that all valves of the system are in a proper

position;

1.1.5 Shut the oil injection testing valve and oil injection solenoid valve (for the turning

gear) for the emergency trip device and open the outlet check valve for the jacking oil

pump;

1.1.6 Check that the oil cooler changeover valve is placed on one side and locked in place,

the cooling water system is working well for the oil cooler and the inlet and outlet valves of

the cooler is open;

1.1.7 Actuate the oil cooler by starting the cooling water valve when the lube oil reaches

38 .℃

1.1.8 Check and confirm that the generator sealing oil system meets the requirements for

commissioning and the loops for the H2 side return oil expansion header, floater oil tank

and air exhaust header of the sealing oil system are unobstructed. Check that the lube oil

and sealing oil supply valves are closed;

1.1.9 Check and confirm that all oil/water drain valves of the system are shut;

1.1.10 Check the oil level in the main oil tank is normal and ensure oil quality is qualified

and there is no accumulated water at the bottom;

1.1.11 Delivery power for the AC auxiliary oil pump, AC startup oil pump and emergency

oil pump after confirming they are qualified;

1.1.12 Start the electric heater to heat oil in the oil tank to 35 ℃ when oil temperature drops

below 20 . Then switch off the heater and allow all oil pumps to be started. ℃

1.2. System Startup 1.2.1 Lubricating oil system Startup

1.2.1.1 Start the smoke exhaust fan for the main oil tank and check that the motor

temperature, vibration and sound are normal. Adjust the outlet valve of the fan to maintain

the micro-negative pressure around -50Pa. for the main oil tank. Actuate the two smoke

exhaust fans in an interlocked mode;

1.2.1.2 Start the AC startup oil pump (or MSP) and AC auxiliary oil pump (or TOP) and

check that the motor, bearing and cooling water system have normal temperature,

vibration, sound parameters. Check that the inlet pressure of the main oil pump is

between 0.098MPa-0.147MPa and the pressure in the bearing lube oil manifold is

between 0.137MPa-0.176MPa;

1.2.1.3 Check that the parameters on the temperature and pressure gauges for the main

lubricating oil system are correctly indicated;

1.2.1.4 Check and confirm that the lube oil system pipe has no leak. View through the

peepholes to check oil flow in the bearing of the turbine generator;

1.2.1.5 Check that the oil level in the main oil tank is not lower than -100mm after a refill

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into the oil system;

1.2.1.6 Trial-run the DC oil pump and actuate the interlock after it works normally. Then

actuate the interlock for the AC auxiliary oil pump.

1.2.2 Jacking Oil Pump System Startup

1.2.2.1 Check and confirm that the oil pressure at the jacking inlet exceeds 0.039MPa;

1.2.2.2 Start a jacking oil pump to check that the motor temperature, vibration and outlet


1.2.2.3 Check that the system has no leak and the oil pressure at the bearing jacking is

normal;

1.2.2.4 Actuate the interlock for the jacking oil pump.

1.2.3 Turning Gear Startup

1.2.3.1 Prior to start the turning gear for a new or overhauled generator unit, operate the

gear manually in a continuous way to ensure no abnormality;

1.2.3.2 Check and confirm that the lubricating oil system and the jacking oil system are

working properly;

1.2.3.3 Start the turning gear via the LCD to locally check that the oil injection solenoid

valve for the turning gear opens and meshes normally;

1.2.3.4 Maintain records of such parameters of the turning gear as startup time, startup

current, operating current and rotor eccentricity. Inspect the sound from the interior of the

gear to check that it is normal;

1.2.4 If adjustment from the maintainer is needed for the throttle valve, bypass valve and

overflow valve fitted on the oil turbine in case that the pressure of lube oil supplied by the

pressure pump and the main oil pump fails to meet the requirements, or the unit is

commissioned for the first time or after an overhaul, the adjustment must be finished at a

time when the turbine is operating stably at 3,000rpm but before the TOP and MSP are

deactivated;

1.2.4.1 Adjust the throttle valve to maintain the inlet pressure at the main oil pump of the

front bearing box at the required value;

1.2.4.2 Check the leak at the overflow valve and the oil supply manifold for the bearing;

1.2.4.3 Adjust the bypass valve and the throttle valve to meet the requirements for the

pressure of the bearing oil supply manifold & oil pump inlet and the leak of the overflow

valve;

1.2.4.4 The front bearing box must comply with the following normal pressure values at a

rated turbine rotating speed:

1) Inlet pressure of main oil pump: 0.098-0.147MPa

2) Pressure of oil supplied to bearing: 0.137-0.176MPa 3）Outlet pressure of main oil pump: 1.55MPa

1.2.4.5 Lock the throttle valve and overflow valve at the finally adjusted position;

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1.2.5 After the steam turbine attains to a speed of 3,000rpm, complete the tests while

maintaining the main oil pump in normal operation. Then stop the AC auxiliary oil pump

and AC startup oil pump and check that the two pumps have not reversed rotation

direction and the lube oil pressure is normal.

1.3. System Shutdown 1.3.1 Check and confirm that the seal gland and vacuum system have been suspended

from operation;

1.3.2 Check and confirm that the maximum turbine cylinder temperature drops below

150 ;℃

1.3.3 Suspend the turning gear for the main steam turbine from operation; then shut down

the jacking oil pump;

1.3.4 See to it that the sealing oil system works normally;

1.3.5 Release the DC oil pump of the main steam turbine from interlock;

1.3.6 Shut down the MSP and TOP as the cylinder temperature changes; check the rising

oil level in the main oil tank to prevent an overflow;

1.3.7 Shut down the cooling water inlet and outlet valves for the oil cooler to disable the

cooling water system for lube oil;

1.3.8 Shut down the smoke exhaust fan for the main oil tank;

1.3.9 After the turning gear is stopped, start the auxiliary oil pump immediately to cool the

bearing once the bearing metal temperature rises again and exceeds the limits;

1.4. Operation Adjustment and Maintenance 1.4.1 In normal unit operation, ensure that the turning gear, jacking oil pump, AC auxiliary

oil pump and AC startup oil pump work properly. The parameters must be controlled within

the following normal range and adjusted in case of any deviation. In case of an alarm,

check for the cause and correct the abnormality. If the trip value is attained but there is no

trip operation, shut down the system manually;

Item Unit Normal Value Alarm Value Trip

Lube Oil Pressure MPa 0.137-0.176 0.115 0.07

Lube Oil Temperature ℃ 40-50 -

Inlet Oil Pressure of Main Oil Pump MPa 0.098-0.147 - -

Outlet Oil Pressure of Main Oil Pump MPa 1.55 - -

Inlet Oil Pressure of Jacking Oil Pump MPa 0.03 - -

Outlet Oil Pressure of Jacking Oil Pump MPa 12-16 - -

Jacking Oil Pressure of Different Bearings MPa 12-16 - -

Micro-Negative Pressure of Main Oil Pump MPa -50 - -

1.4.2 Adjustment of Bearing Lube Oil Temperature:

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1.4.2.1 When the turning gear is in operation, the bearing lube oil temperature must be

controlled between 27-40 ;℃

1.4.2.2 When the turbine reaches the synchronized rotating speed, the bearing inlet oil

temperature must be at least 38 ; ℃

1.4.2.3 When the turbine is in normal operation, the bearing lube oil temperature must be

controlled between 40-50 .℃

2. EH Oil System

2.1. Check before EH Oil System Startup 2.1.1Finish the operations as specified by General Rules for Pre-Startup Check of

Auxiliaries and System;

2.1.2 Check and confirm that the oil level in the EH oil tank is slightly higher than the

normal level. Confirm that the oil is limpid and free of impurities, all gauges and

instruments (including differential pressure gauge) are complete and have been

commissioned and the oil level gauge has correct and reliable indication;

2.1.3 Use the valve check card to check that all valves of the system are in a proper

position;

2.1.4 Check that the control power supply has been correctly provided and the signals are

normal;

2.1.5 Check and confirm that all interlock protection tests on the EH oil system have been

passed and the system is correctly commissioned;

2.1.6 Check that the service water system is operating normally. Then open the inlet and

outlet valves of the EH oil cooler and commission the water side of the cooler to operation;

2.1.7 Ensure that the energy accumulator has a normal nitrogen pressure (8MPa),

otherwise conduct a nitrogen makeup;

2.1.8 Measure and ensure the motors of all oil pumps are satisfactorily insulated before

power supply is delivered.

2.2. EH Oil System Startup 2.2.1 Startup of EH Oil Circulating Pump

2.2.1.1 Open the manual inlet valve of the EH oil circulating pump to refill the pump with

oil;

2.2.1.2 Start an EH oil circulating pump to check that it works normally, has no leak and

has a normal oil tank level, otherwise conduct an oil makeup;

2.2.1.3 Check that the EH oil circulating pump has a normal outlet pressure and the safety

valve works properly;

2.2.1.4 Fill the EH oil regeneration devices with oil to displace the air inside; put an oil

regeneration device into operation to check that the differential pressure is normal;

2.2.1.5 Fill the EH oil coolers with oil to displace the air inside; put a group of oil coolers

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into operation and monitor closely the oil level in the tank to prevent the EH oil from

seeping into the cooling water system;

2.2.1.6 After the system is duly checked, put another EH oil circulating pump into

operation for standby;

2.2.1.7 The EH circulating oil purifier must be continuously operated for at least over 4

hours.

2.2.2 Start the electric heater for EH oil automatically. Check that the oil temperature in the

tank exceeds 32 , otherwise the electric heater must be started in the interlock mode; ℃

2.2.3 Startup of EH Oil Pump

2.2.3.1 Open the manual inlet valve of the EH oil pump to refill it with oil;

2.2.3.2 Start an EH oil pump to check that it works properly, has not leak and the outlet

pressure is maintained around 11.2MPa;

2.2.3.3 Check that the EH oil pump has normal outlet pressure and the EH oil pressure of

the energy accumulator is normal. Check that no alarm is sounded when there is a

differential pressure at the strainer for the outlet of the EH oil pump. The oil temperature in

the oil cooler must be capable of automatic adjustment;

2.2.3.4 Ensure that the EH oil pipe system has been cleaned of air;

2.2.3.5 Put another EH oil pump into operation after a thorough check.

2.3. System Shutdown 2.3.1 Ensure that all shutdown conditions are met;

2.3.2 Release the EH oil system from automatic standby mode and shut down the pump;

2.3.3 Shut down the circulating pump;

2.3.4 Shut down the oil cooler.

2.4. Monitoring and Adjustment of System Operation 2.4.1 Check that the oil level in the EH oil tank is slightly higher than the low level alarm

value (30mm-50mm). The oil level must not be too high, otherwise an overflow will occur

in case of a trip operation. If the oil level drops, identify and rectify the cause promptly.

When necessary, contact the maintainer for a refill;

2.4.2 Check that the following parameters of the EH oil pump are normal: bearing vibration,

temperature, internal noise and outlet pressure. Check that the pressure of the EH oil

system is between 10.7MPa and 11.7MPa. Ensure that the differential pressure at the

strainer of the outlet of the pump is normal. If the differential pressure rises by 0.5MPa at

the strainer, contact the maintainer for a repair or replace the strainer;

2.4.3 Check that the following parameters of the circulating oil pump are normal: bearing

vibration, temperature, internal noise, outlet pressure and EH oil system pressure;

2.4.4 Check that the pipes and equipment of the EH oil system have no leak;

2.4.5 Check that the EH oil temperature is between 32 and 54 and the automatic oil ℃ ℃

temperature adjustment for the oil cooler is normal. In case that the oil temperature comes

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to 54 and above and a manual adjustment is ineffective, commission the standby oil ℃

cooler, isolate the faulty oil cooler and submit it to the maintainer for cleaning and

re-commissioning;

2.4.6 Check that the nitrogen charging pressure for the high-pressure energy

accumulators is sufficiently normal. If the charging pressure drops, scatter the

accumulators and recharge one at a time;

2.4.7 Check that the visual mechanic indicator of the air filter is triggered. If it is triggered,

replace it;

2.4.8 Check and confirm that the pressure of the circulating system is less than 1MPa;

2.4.9 Before isolating the small steam turbine for an overhaul during the operation, close

the EH oil shutoff valve leading to the small steam turbine;

2.4.10 Fulfill the periodic changeover and testing tasks as per the requirements in Rules

for Periodic Changeover and Testing of Equipment.

2.4.11 Limits of Operational Parameters of EH Oil System

Item UnitNormal

Value

Upper

Limit

Lower

Limit Remarks

EH Oil Tank Level mm

30mm higher

than low level

alarm value

EH Oil Tank Temperature ℃ 32-54

Differential Pressure at

Inlet/Outlet of Strainer of EH

Oil Pump

MPa ＜0.5

Differential Pressure at

Strainer of EH Regeneration

device

MPa ＜0.138

EH Oil Pressure MPa 10.7-11.7 The turbine trips

at 7.8

Nitrogen Charging Pressure

for High-Pressure Energy

Accumulator

MPa 8±0.2 Nitrogen

Charging

Operating Value of Overflow

Valve of EH System MPa 14±0.2

Operating Value of Overflow

Valve at Outlet of Circulating

Pump

MPa 0.5±0.1

2.5. System Accidents Treatment

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2.5.1 Solution to EH Oil Pressure Fluctuation:

2.5.1.1 In case of an EH oil fluctuation, check if the EH oil safety valve and the check valve

at the outlet of the standby promptly are working properly. If necessary, contact the

maintainer for a solution;

2.5.1.2 Check the oil level in the EH oil tank; if necessary, contact the maintainer for a

refill;

2.5.1.3 If necessary, change over to the standby pump;

2.5.1.4 If the EH oil pressure fluctuation fails to be corrected and affects the normal unit

operation, report it and ask for a shutdown;

2.5.2 Treatment to EH Oil Pressure Drop

2.5.2.1 Symptoms

1) The CRT or the local gauge indicates a drop in EH oil pressure;

2) The CRT indicates a low EH oil pressure.

2.5.2.2 Causes:

1) Low oil level in the EH oil tank;

2) Leak in the EH system;

3) Fault of the EH oil pump;

4) Dirt retained on the strainer at the inlet/outlet of the EH oil pump;

5) Misoperation of the safety valve of the EH oil system;

6) Un-tight sealing of the check valve at the outlet of the standby EH oil pump

2.5.2.3 Treatment:

1) When the oil pressure drops to the interlocked pump value, check and confirm that

the standby pump is correctly started by interlock, otherwise start it manually;

2) If the commissioning of 2 EH oil pumps still fails to maintain the pressure, prepare for

a shutdown;

3) When the shutdown protection value is reached, the protection operation must be

normal; otherwise, enforce a shutdown manually;

4) In case of a leak of the EH oil system, try to isolate the leak spots while maintaining

the EH oil pressure. Contact the maintainer for a prompt repair and refill. If the isolation

measure fails in face of a serious leak, report it and ask for a shutdown;

5) Check the operation of the safety valve. In case of a misoperation, contact the

maintainer for a prompt repair;

6) If the differential pressure at the strainer of the operating pump is too high, shut

down the pump and start up the standby pump. Contact the maintainer for a repair;

7) In case of a malfunction of the operating pump, change over to the standby pump

and contact the maintainer for a repair.

2.5.3 Treatment to EH Oil Leak:

2.5.3.1 If a system leak is confirmed, locate the leak spot promptly and evacuate

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operators from the site;

2.5.3.2 If the leak spot is inside the oil cooler, change over to the standby oil cooler and

isolate the leaking cooler. Contact the maintainer for a repair.

2.5.3.3 In case of a serious leak which hinders the maintenance of the EH oil level, contact

the maintainer for a prompt refill and prepare for a shutdown;

2.5.3.4 If the oil pressure drops as a result of a low level, solve the problem accordingly.

2.5.4 Treatment to EH Oil Level Drop

2.5.4.1 Generally, a drop in the EH oil level results from a leak in the system pipes or oil

cooler. Check for, locate and isolate the leak spot;

2.5.4.2 If the oil level drops too quickly, contact the maintainer for a prompt refill;

2.5.4.3 If the normal operating oil level fails to maintained, prepare for a shutdown.

3. Unit Bypass System

3.1. Pre-Startup System Check 3.1.1 Check that the high & low bypasss are shut down;

3.1.2 Push the “valve check card” button to check that all valves are in the correct

position;

3.1.3 Check that the condensate system, feed water system, instrumentation air system

and the vacuum system for the main steam turbine are working normally;

3.1.4 Check that the attemperating water for the high/low bypass has a normal pressure

and the drain valve for the attemperating water pipe for the high/low bypass is closed.

Close the vent valve after air is discharged. Ensure that the manual isolating valve is open

and there is no leak;

3.1.5 Check that the control air supply for the high/low bypass is normal (pressure:

0.6-0.8MPa);

3.1.6 Check that the isolating valves for the front and rear heat pipes of the steam

converter valve for the high bypass are open;

3.1.7 Check that the front and rear drain traps of the steam converter valve for the low

bypass are started and the water level in the drain trap is normal;

3.1.8Order the thermal engineering operator to provide control air supply for the

pneumatic pressure relief valve for the high/low bypass, the attemperating water control

valve and the front and rear steam trap valves for the steam converter valve of the low

bypass. Check that the air supply has a pressure between 0.6MPa and 0.8MPa and the

pneumatic control part is reliably connected to the valve part;

3.1.9 Check and confirm that the isolating valve is open to the air supply for the high/low

bypass.

3.2. System in Operation 3.2.1 Control Mechanism of High bypass

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3.2.1.1 Boiler is ignited and the pressure rises, press the “Auto-startup-On” button to

switch the bypass system to the minimum opening position. The high bypass will be maintained at a minimum opening position (Ymin_HP 5％). At the startup stage, the

high-pressure bypass valve must not be less than this opening in order for a small amount

of steam to circulate for the cooling of overheaters and reheaters;

3.2.1.2 After the main steam pressure reaches 2.0MPa, the high bypass changes over

to pressure rise mode. The settings of the pressure controller for the high bypass are

determined by calculations. The pressure settings rise at different rates (0.04MPa/min in

cold state, 0.08MPa/min in warm state, 0.14MPa/min in heated state and 0.18MPa/min in

overheated state) to different final pressures (Psync_HP: 5.9MPa in cold state, 8.52MPa

in warm state, 8.52Mpa in heated state and 12.8MPa in overheated state). Meanwhile, the

low bypass is in constant pressure control mode with a pressure setting of 1MPa;

3.2.1.3 When the main steam pressure attains to the final pressure, the high bypass

changes over to constant pressure control mode, where the high bypass is maintained in

automatic mode with a pressure setting of Psync_HP. After steam is admitted into the

turbine, the high bypass will be gradually shut down as the main steam pressure drops;

3.2.1.4 When the high bypass is shut down and “turbine synchronized” and “cylinder

transfer completed” signals will be emitted and the high bypass will change over to follow

mode, where the steam pressure fluctuates with the boiler load. The pressure setting for

the high bypass equals to the actual pressure value plus the offset value

( P_follow_HP(0.4MPa)) to ensure the shutdown of the high bypass. When the main △

steam pressure rises abruptly (the rate of pressure rise exceeds

max_gradient_follow_HP(0.6MPa/min)), retain the pressure settings and abandon the

offset value. The pressure control valve for the high bypass actuates control pressure until

the valve is reclosed and reverted to follow mode;

3.2.2 Control Low bypass

3.2.2.1 After the boiler is ignited, the low bypass must adopt minimum opening control.

After the boiler is ignited and the pressure rises, press the “Auto-startup-On” button to

switch the bypass system to the minimum opening position. The high bypass will be maintained at a minimum opening position (Ymin_HP 5％);

3.2.2.2 The pressure of the low bypass increases as the opening of the high bypass and

the main steam pressure rise. The two low bypass control valve will be maintained at

minimum opening until the reheated steam pressure attains to 1MPa and the low bypass

switches to the constant pressure control mode, where the low bypass will be still open in

order to maintain the pressure settings at 1MPa;

3.2.2.3 As the turbine speed escalates, the synchronization and load increase, the low

bypass closes and the minimum opening mode is abandoned. When “Load-UP” signal is

emitted, the settings of the low bypass pressure controller change from 1MPa to 0.5MPa

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at a rate of 2MPa/min until the interceptor valves are all open and all low bypasses are

closed;

3.2.2.4 When the “cylinder transfer completed” signal is emitted, the low bypass

synchronously switches to the follow mode with the high bypass;

3.2.2.5 In the follow mode, the settings of the low bypass pressure controller equal to the

actual reheated pressure plus the offset value (0.2MPa). When the main steam pressure

rises abruptly (the rate of pressure rise exceeds max_gradient_follow_HP(0.6MPa/min)),

retain the pressure settings and abandon the offset value. The pressure control valve for

the low bypass is actuated and starts to control steam pressure until until the two low

bypass valves are reclosed and reverted to follow mode;

3.3 The bypass system will execute the following operations when the turbine trips at a

motor load of 6-90MW:

3.3.1 The bypass will be fast-opened;

3.3.2 The high/low bypass pressure is controlled in minimum opening mode;

3.3.3 The operating mode of high/low bypass is switched to constant pressure control

mode;

3.3.4 The settings for the high/low bypass pressure controllers are retained;

3.4 The bypass system will execute the following operations when the turbine trips at a

motor load of 90MW and above:

3.4.1 The boiler MFT is started in the event of a turbine trip;

3.4.2 The bypass system will be switched to pressure control mode and the settings

equal to the main steam pressure prior to the trip;

3.5 Load-Down of High/Low Bypass

3.5.1 When the unit is unloading, the high/low bypass is maintained in follow mode;

3.5.2 When the motor load drops below 35MW and the “Load Down” signal is emitted,

the high/low bypass is switched to constant pressure control mode and the offset value in

the follow mode is abandoned. The new pressure settings are respectively 5.9MPa for the

high bypass and 0.4MPa for the low bypass.

3.5.3 The high/low bypass pressure controller works at a pressure variation rate of

0.3MPa/min.

4. Gland Sealing System

4.1. Pre-Startup Check and Operation 4.1.1 Conduct a thorough check of the system as per the requirements in Commissioning

Rules for Auxiliary Equipment;

4.1.2 All tests have been conducted and passed prior to the startup;

4.1.3 Ensure that the auxiliary steam system, instrumentation air system, condensate

system and circulating water system have been commissioned and are working well;

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4.1.4 Ensure the turning gear has been operating for over 1 hour and the eccentricity is

less than 0.076mm;

4.1.5 Ensure that the overheat of the seal gland steam exceeds 50 ;℃

4.1.6 Ensure that the temperature difference between the feed steam pressure of the

high/medium pressure seal gland and the rotor metal is less than 110 (allowable ℃

temperature for cold-state startup);

4.1.7 Ensure that the setting for seal gland steam temperature of the low pressure cylinder

is 150 ;℃

4.1.8 Never feed attemperating water to the low-pressure seal gland before the seal gland

is properly commissioned. This is meant to prevent water inclusions in seal gland steam or

the cylinder;

4.1.9 Confirm that the seal gland fan and the pipes have been drained;

4.1.10 Confirm that the seal gland steam system have proper drainage;

4.1.11Confirm that the turning gear has been actuated for the turbine and the circulating

water system, condensate system and auxiliary steam system have been properly

commissioned;

4.1.12 Refill the sealing water pipe for the seal gland heater with water and vent the air.

Switch the backwater to the condenser;

4.1.13 Commission the water side of the seal gland heater to operation;

4.1.14 Confirm that all control valves of the gland sealing system have proper air supply,

all instrumentation isolating valves have been opened and liquid level gauges and

negative pressure gauges of the seal gland heater have been commissioned. All of these

devices must be in a manual mode;

4.2. System Startup

4.2.1 Select the correct steam supply for the seal gland depending on the turbine metal

temperature;

4.2.2 Heat Pipe Transferring Auxiliary steam to Pipes in Seal gland Steam Control Station

4.2.2.1 Check that the heat pipe transferring auxiliary steam to pipes in the seal gland

steam control station has proper drainage and the steam temperature matches the rotor

metal temperature;

4.2.2.2 Open the electrically-operated isolating valve fully, which connects the auxiliary

steam header to the shaft steam; open the isolating valve partially, which connects

auxiliary steam to the seal gland steam;

4.2.2.3 Open the isolating valve fully, which connects auxiliary steam to the seal gland in

10min;

4.2.2.4 After a vacuum is formed in the condenser, switch auxiliary steam to the seal gland

steam trap and maintain the trap in constant draining state.

4.2.3 Heat Pipes of gland sealing system

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4.2.3.1 Check that the system has proper drainage;

4.2.3.2 Check that the valves connecting the seal gland steam manifold to the seal gland

sections in different cylinders are closed;

4.2.3.3 Check that the seal gland steam control valve is in manual mode and is closed.

Actuate the electrically operated isolating valve connecting auxiliary steam to the seal

gland steam control valve. The isolating valve guides the steam through the orifice plate

into the heat pipe of the seal gland steam system until the steam reaches the seal gland

steam valves of the different cylinders.

4.2.4 The seal gland steam must be commissioned as per the following principles: Pump a

vacuum prior to a cold-state startup and commission the seal gland steam before the

high-pressure cylinder is preheated. If a high-pressure cylinder is not preheated,

commission the seal gland steam 30 minutes before the unit rolls; in a warm/heated state,

commission the seal gland steam before pumping the vacuum;

4.2.5After seal gland steam is commissioned, start the seal gland fan immediately. Check

that the fan vibration, vacuum degree of the seal gland heater and inlet/outlet water

temperature rise are normal. Commission the shaft-seal fan in an interlock. A negative

pressure of 95-99KPa (a) must be maintained for the return steam pipe for the steam seal;

4.2.6 After the pipe heating process, commission the control valve of the low-pressure

seal gland steam supply station in an automatic mode. Check that the control valve works

properly and the seal gland steam manifold has normal pressure;

4.2.7 Check and open the seal gland steam leak-off valves for the cylinders of the main

steam turbine;

4.2.8 Commission the low-pressure seal gland steam supply, overflow valve and the

low-pressure seal gland attemperating water to deliver seal gland overflow back to the

condenser. Check that seal gland steam manifold pressure is maintained at 0.124~0.127

(a) MPa. The temperature of the seal gland steam is respectively 150-260 in the cold ℃

state and 208-375 in the heated state. ℃

4.2.9 Open all the steam supply valves to all seal gland sections of the high/medium

pressure cylinders to confirm that no steam leaks from the seal gland into the atmosphere.

Otherwise, adjust the vacuum degree of the seal gland heater or the pressure of the seal

gland manifold until no external leak is detected;

4.2.10 When the unit load exceeds 25% of the rated load, check that the seal gland steam

is automatically switched to self-sealing mode. At this stage, ensure that the reheated cold

section provides sealing steam, otherwise, close the control valve for low-pressure seal

gland steam supply and maintain the pressure of the seal gland manifold until the control

valves are all closed. When the load rises to 60% and above, the steam volume leaked

through the shaft end of the high/medium-pressure cylinders into the steam supply

manifold has exceeded the steam supply volume required for the seal gland of

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low-pressure cylinders. At this stage, the control valves for all the steam supply stations

will be automatically closed, and the control valve for the overflow station will be

automatically opened to discharge excess steam into #8A low-pressure heater in order to

maintain the steam pressure of the steam seal manifold at 0.13MPa (a);

4.2.11 When the seal gland steam is in self-sealing operation, monitor the seal gland

overflow and check that it is operating normally. After it works normally, close the

electrically operated check valve connecting the cold reheater to the gland sealing

system;

4.2.12 Before the main steam turbine is synchronized, commission seal gland steam from

the small steam turbine. Open the bypass valve of the steam vent valve for the small

steam turbine to pump a vacuum;

4.3. System Shutdown

4.3.1 While the unit is being shut down, if the unit load drops below 25%, check the seal

gland steam supply and ensure that it is automatically switched to low-pressure seal gland

steam supply;

4.3.2 After the unit trips and shuts down and the vacuum degree of the condenser reaches

0 while the turning gear is working normally, close the valves for the seal gland steam and

release the interlock for and shut down the seal gland fan;

4.3.3 Release the sources of seal gland steam supply and the control valves for seal

gland attemperating water from the automatic mechanism. Close the steam supply,

attemperating water control valve and the front and rear isolating valves;

4.3.4 Open the steam trap valves for the seal gland steam system.

4.4. Operation Monitoring, Adjustment and Maintenance

4.4.1 Check if the bearing return oil has water inclusion on a regular basis to determine if

the pressure settings for seal gland steam are too high, and if the seal gland steam has

proper drainage support;

4.4.2 Check that the pressure in the seal gland steam manifold and the operation of all

feed steam control valves & overflow valves are normal. Monitor the pressure settings for

the seal gland steam to prevent too low a value which may affect the vacuum degree;

4.4.3Check that the temperature of the seal gland steam manifold and the temperature

control of the seal gland steam are normal. Monitor the seal gland temperature of the

low-pressure cylinder to prevent a breakdown of the temperature control valve, which may

cause water inclusions in the seal gland;

4.4.4 Monitor the fan seal gland heater to ensure normal operation. Internal negative pressure of the seal gland heater must be maintained between 95～99KPa (a) to prevent

seal gland steam from outflow.

4.4.5 Monitor the seal gland heater to ensure a normal water level. If no high/low-level

alarm signal is emitted by the seal gland heater, drainage from the heater must be

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discharged via the sealing water pipe. The water seal in the sealing water pipe must be

working normally. Ensure the inlet/outlet water temperature of the seal gland heater is

normal;

4.4.6 Fulfill the periodic changeover and testing tasks to ensure normal operation;

4.4.7 Adjustment and Operation of Control valves at Different Control Stations

Steam Seal

Manifold

Pressure

High-Pressure Steam

Supply Control

Station

Auxiliary Steam

Supply Control

Station

Overflow

Control

Station

Operation

0.124 Closed Open and

adjusted Closed

Vacuum

pumping (cold

startup)

0.127 Closed Open and

adjusted Closed

Rated load: Up

to 25%

0.13 Closed Closed Self sealing

0.118 Open and adjusted Closed Closed Load rejection

0.118 Open and adjusted Closed Closed

Vacuum

pumping

(warm startup)

4.5. Common Faults and Simple Solutions

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Fault Cause Fault Treatment

Manifold Overpressure

1) The pressure control

valve for the steam

supply is not tightly

closed

2) External steam

sources enters the

system

3) The seal gland has undetected leak spots

1) Check the control signals and the

tightness of the valves. If insufficient

tightness is confirmed, report it to the

manufacturer or the accessory

manufacturer

2) Locate the external steam source

and cut off steam supply

3) Locate the leak spot nearest to the seal gland

Steam Leak from Seal gland

1) The outlet portal of

the seal gland fan is

closed

2) There is too small a

quantity of cooling

water for the seal gland

heater

3) The return steam/gas pipe is irrationally arranged, or there is a drainage problem at the low point

1) Open the outlet valve of the seal

gland fan

2) Adjust the cooling water amount for

the seal gland heater to maintain the

pressure in the steam seal heater

below 95KPa(a)

3) Tilt the return steam/gas pipe

towards the steam seal reheater until a

gradient of 1/50; when the return

steam/gas is delivered into inlet pipe

for the steam seal heater, try not to let

the steam/gas enter from the lower part

of the pipe

4) Keep a proper drainage at the low point

Low-Pressure Steam

Overtemperature

1) The nozzle of the

attemperator is

clogged

2) The water filter is

clogged

1) Clean the nozzle

2) Clean the water filter

3) Check the power supply and control signals for the control valve

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3) The water spray control valve does not function normally

Low-Pressure Steam

Undertemperature

The water spray control valve is not tightly closed

1) Check the power supply and control

signals for the control valve

2) Check if the control valve has an internal leak; if it is the case, contact the manufacturer or the accessory manufacturer for a repair

5. Vacuum System

5.1. Pre-Startup System Check 5.1.1Finish the operations as specified by General Rules for Pre-Startup Check of

Auxiliary Equipment and System. Ensure that all systems related to vacuum formation are

duly checked and proved to be working normally;

5.1.2 Check that the drain valve for the steam/water separator is closed, the water level

gauge is working properly and the drain valve at the bottom of the vacuum pump is closed;

5.1.3 Check and confirm that the service water system and condensate system have been

satisfactorily commissioned;

5.1.4 Check that the makeup water pressure for the steam/water separator is normal.

Open the makeup water bypass valve to make up the water level to normal. Then launch

the automatic control mechanism for the water level;

5.1.5 Check that the circulating water system works normally and the open circulating

water system have a normal pressure;

5.1.6 Open the cooling water inlet/outlet valve of the cooler to replenish it with water;

5.1.7 Check that the instrumentation manifold has normal pressure and the

pneumatically-controlled butterfly valve at the inlet of the vacuum pump has normally

working control air supply;

5.1.8 Check and confirm that the vacuum breaker of the condenser is closed and the

vacuum system meets the commissioning conditions;

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5.1.9 Check that the seal gland steam system is commissioned and works normally while

the unit is in a heated state (in the case of a cold state, pump the vacuum before

commissioning the seal gland, and vice versa in the case of a heated state);

5.1.10 Check and confirm that the motor of the vacuum pump has sound insulation before

electric power is fed to the control power supply of the local control cabinet;

5.1.11Ensure that the seal gland steam system is commissioned and works normally while

the unit is in the heated state (in the case of a cold state, pump the vacuum before

commissioning the seal gland, and vice versa in the case of a heated state);

5.1.12 Check and confirm that all manual valves are prepared for actuation. Open the

manual check valve at the inlet of the vacuum pump unit;

5.2. System Startup 5.2.1 Check and confirm that the vacuum pump meters and condenser vacuum

transducers are correctly commissioned;

5.2.2 Start a vacuum pump and the pneumatic valve at the inlet of the pump must be

automatically opened. The vacuum degree of the condenser rises gradually;

5.2.3 Check that the sound, vibration and temperature of the vacuum pump are normal.

Keep records of the current;

5.2.4 Check that the steam/water separator of the vacuum pump has a normal water level;

5.2.5 Switch the other vacuum pumps to the automatic mode after they are confirmed as

normal. Actuate the pumps in the manual mode;

5.3. System Shutdown 5.3.1 The shutdown of the vacuum system must meet the following conditions:

5.3.1.1 The rotating speed of the turbine has dropped to zero and the turning gear has

been commissioned;

5.3.1.2 The condensate pump must start another recirculation process and the

condensate polisher has been decommissioned;

5.3.1.3 The turbine must have an exhaust steam temperature below 47 ;℃

5.3.1.4 The temperature of the first stage of the turbine metal is less than 150 ;℃

5.3.2 Vacuum Breaking

5.3.2.1 Stop the vacuum pump and start the vacuum breaker to break the vacuum;

5.3.2.2 In the event of an emergency unit shutdown, reduce the idle time by breaking the

vacuum promptly;

5.3.3 If a vacuum pump needs to be stopped while the unit is in operation, check and

confirm that the pneumatic valve at the inlet of the pump is shut and the condenser has a

normal vacuum. If the vacuum pump needs to be stopped for an overhaul, isolation

measures must be taken accordingly;

5.4. Operating Monitoring and Maintenance 5.4.1 Check that the vacuum pump has normal vibration, no friction, no abnormal noise

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and normal motor current;

5.4.2 Monitor the steam/water separator of the vacuum pump to ensure a normal water

level and normal makeup water pressure. Ensure that the cooler works reliably;

5.4.3 Check and monitor the condenser to ensure a normal vacuum for the condenser and

no leak for the system.

5.4.4 Check that the steam/water separator has normal discharge on the top;

5.5. System Fault Treatment 5.5.1 Drop in Condenser Vacuum

5.5.1.1 Symptoms

1) Vacuum indications of local condensers and condensers in the centralized control

station;

2) The temperature of the exhaust steam rises and the temperature of the condensate

rises;

3) Under the same load, the steam flow rate increases and the pressure at velocity

stage rises;

4) The vacuum drops to 13.5KPa (a), or the exhaust steam rises to 80 . An alarm is ℃

sounded.

5.4.1.2 Causes:

1) The circulating water pump has a failure or trip; the butterfly valve at the outlet of the

pump has a smaller opening or is fully closed; or the inlet and outlet circulating water

valves for the condenser are closed by mistake, causing a decrease or cutoff of

circulating water supply;

2) The stainless steel pipe of the condenser is not clean;

3) The mechanical vacuum pump has a failure or trip;

4) The vacuum breaker is opened by mistake, or is not tightly closed; the pipes of the

vacuum system and other systems have a failure or leak; or the valve of the vacuum

system has an external leak.

5) The steam supply pressure of the seal gland drops perceptibly and the water level

and negative pressure of the seal gland heater are abnormal;

6) The hot well of the condenser has too high a water level;

7) The vacuum system of the small steam turbine develops a leak;

8) The explosion vent in the low-pressure cylinder of the main and small steam turbines

develops a crack.

5.4.1.3 Treatment

1) If a drop of condenser vacuum degree is detected, check up promptly the indications

of the vacuum gauges and confirm the drop by comparative studies of temperature

rises of the exhaust steam;

2) Conduct the following checks on the circulating water system:

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a) Check if the circulating water pressure is normal; it is too low, check if there is any

leak or blockage in the circulating water system;

b) Check if the water level at the inlet of the circulating pump; if it is too low, promptly

start the filth removal unit;

c) Check if the circulating water temperature rises;

d) If the inlet water pressure and the outlet water temperature of the condenser rise,

there must be a filth accumulation in the pipe system. Clean the steel pipe of the

condenser at this stage;

e) Check that the circulating water pump functions properly, otherwise start the

standby pump.

3) Check the vacuum system and carry out isolation steps as follows:

a) Check that the vacuum pump functions properly;

b) Check that the vacuum system has a leak;

c) Check that the vacuum system pipes and the low-pressure continuous vent pipes

of the low-pressure heater have been damaged;

d) Check if the vacuum breaker is tightly shut and if the sealing water is normal;

e) Check if the steam supply pressure for the seal gland is normal, if high/low

pressure steam supply control valves and overflow valves of the seal gland is working

properly and if the sealing water for the seal gland heater is working properly. If there

is a fan failure or low negative pressure of the seal gland heater, the standby fan may

be commissioned;

f) Check if the small steam turbine steam vent system is functioning normally; if

necessary, start the electric pump, shut down the small steam turbine and close the

steam vent butterfly valve;

4) Check if the condensate pump has properly working sealing water, if the pump

develops a leak and if the water level is too high;

5) If the condenser vacuum drops to 13.5KPa (a), the standby vacuum pump will be

automatically started; otherwise, start the pump manually. If the vacuum keeps dropping,

reduce the load to maintain the vacuum. When the vacuum drops to 25.3KPa (a), the

protection mechanism will trip, otherwise, manually trip and shut down the pump;

6) While the vacuum is dropping, observe closely the exhaust steam temperature for

the low-pressure cylinder. When the temperature rises to 47 , the water spray valve ℃

will be commissioned; when the temperature reaches 80 , the valve will be fully ℃

opened; when the temperature rises up to 107 , the protection ℃ mechanism will trip to

shut down the machine;

7) When the vacuum drops to 0.07MPa, the small steam turbine will trip; otherwise shut

it down manually.

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6. Circulating Water System

6.1. Pre-Startup System Check 6.1.1 ；Finish the operations as specified by General Rules for Pre-Commissioning Check

of Auxiliary Equipment and the System;

6.1.2 Check that the static interlock test on the circulating water pump is passed;

6.1.3 Check and confirm that the gate valve of the pump is open and the water level in the

intake chamber is normal;

6.1.4 Check that the service water system has been commissioned to provide reliable

water supply;

6.1.5 Check that the lubricating & cooling water has been commissioned for the circulating

pump and cooling water has been commissioned for the air cooler of the pump motor;

6.1.6 Check that the lubricating and cooling water supply for the pump bearing has a

normal flow rate, pressure and return water supply;

6.1.7 Check and confirm that the motor bearing lube oil for the circulating pump has

acceptable quality and oil level;

6.1.8 Check that the hydraulic oil station for the butterfly valve at the outlet of the

circulating pump has a normal oil level and acceptable oil quality;

6.1.9 Start the hydraulic oil pump of the butterfly valve at the outlet of the circulating pump

to check that the system has normal pressure. Commission the control interlock for the oil

pump;

6.1.10 Before starting the first circulating pump, check that the butterfly valve at the pump

outlet operates smoothly and normally with no jam;

6.1.11 Check and confirm that the strainer of the filth removal unit has a normal water

head on the two sides of strainer;

6.1.12 Check and confirm that the vent valve of the circulating pump is open when the

pump is started;

6.1.13 Check that all the drain valves on the circulating water pipe are closed, the vent

valves of the water chamber of the high/low pressure condensers are open and all vent

valves of the circulating water valves are open;

6.1.14 Check that all the inlet and outlet valves for circulating water for condensers.

6.2. Startup of Circulating Water System 6.2.1 Check and confirm that all preconditions for the startup of the circulating water pump

are met; close the butterfly valve at the outlet of the pump and configure the control mode

as manual mode;

6.2.2 Open the outlet valve of the pump at a 15% opening, wait till the vent valve gives off

water and shut it off. After the venting process in the water chamber is completed, close all

vent valves in the chamber;

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6.2.3 Start up the circulating pump and check that the following parameters are normal:

pump current, rotational direction, vibration, sound, lubrication and cooling water flow rate;

6.2.4 Commission the control interlock for the outlet valve for the pump and confirm that

the valve is automatically opened at a full opening;

6.2.5 Shut down the circulating pump and start up the vent valve;

6.2.6 After the circulating pump works stably, check that the circulating water manifold has

normal pressure;

6.2.7 Start the second circulating water pump if necessary;

6.2.8 When the second circulating water pump is started, the butterfly valve at the outlet

may be directly configured as automatic mode;

6.2.9 Check that the temperature of all the pump bearings is normal;

6.2.10 Check that the coil temperature of the pump motor is normal;

6.2.11 Check that the sound and vibration of all the parts of the pump motors are normal;

6.2.12 Configure the filth removal unit of the circulating water system and the dredge

pump in the pump room as automatic mode;

6.2.13 Conduct a cross examination to confirm that the circulating water system and

equipment function reliably.

6.4. Shutdown of Circulating Water System 6.4.1 First, shut down the open circulating water pump; then shut down the other pump;

6.4.2 Release the standby circulating pump from the interlock; 6.4.3 ；Check and confirm that the vacuum degree of the condenser drops to zero and the

gland sealing system is shut down;

6.4.4 Check and confirm that the exhaust steam temperature of the low-pressure cylinder

is below 50 ;℃

6.4.5 Check and confirm that all users of the circulating water system agree to shut down

the system;

6.4.6 Release the pilot-controlled butterfly valve at the outlet from the interlock. Shut the

butterfly valve;

6.4.7 Check that the butterfly valve at the outlet is closed, shut the circulating water pump

and see to it that the pump develops a reversed rotation;

6.5. Operation Monitoring and Adjustment of Circulating Water System 6.5.1 Check the current of the circulating water pump to ensure that it is normal, the oil

level in the motor bearing is normal, the oil quality is acceptable and there is no abnormal

noise emitting from the pump body;

6.5.2 Monitor the following parameters closely to prevent an exhaust stem temperature

rise or vacuum drop in the condenser, attributable to insufficient pump capacity: outlet

pressure of the circulating water pump and the inlet/outlet pressure of the circulating water

for the condenser;

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6.5.3 The temperature difference of circulating water for the inlet and outlet of the

condenser must be less than 8 and must not exceed the maximum of 12 ; if the ℃ ℃

requirement is not met, identify and correct the cause promptly;

6.5.4 Check that the oil level and pressure of the oil system for the pilot-controlled butterfly

valve at the outlet of the circulating water are normal;

6.5.5 Check that the water level in the circulating water collecting sump is normal and the

sump pump has normal interlock; otherwise, start and shut down the sump pump

manually;

6.5.6 Check that the water levels of the intake chamber, cooling tower, bearing and motor

are normal; check that the flow rate in the cooling tower is constant;

6.5.7 Monitor the filth removal unit in the circulating water intake chamber to check that an

automatic flush is operable; otherwise, flush it manually.

7 Open Circulating Cooling Water System

7.1. Pre-Startup System Check 7.1.1 Check that the open pump meets the following startup conditions:

7.1.1.1 Check that the electric valve at the inlet of the pump is open;

7.1.1.2 Check that the electric valve at the outlet of the pump is open;

7.1.1.3 Check that the filter at the outlet of the open water filter is correctly put into

operation, or the bypass valve of the open water filter is open;

7.1.1.4 Check that the inlet and outlet valves of the coolers in the open circulating water

system is open;

7.1.2 Check that the circulating water system is commissioned and is working normally;

7.1.3 Check that the valves of the open circulating water system are in a good working

condition by pushing the valve check card;

7.1.4 Check that the water injection and air discharge process has been finished for the

open circulating water system;

7.2. Open Cooling Water System Startup 7.2.1 Check that the open pump has met all startup conditions specified in General Rules

for Auxiliary Equipment Operation;

7.2.2 Check and confirm that the circulating water system has been satisfactorily

commissioned;

7.2.3 Start up an open pump; ensure that the return current is normal and the outlet valve

of the pump opens automatically;

7.2.4 Check that the open pump has normal outlet pressure;

7.2.5 Open the vent valves of all coolers; if there is water, shut them;

7.2.6 Open the inlet valve of the standby open pump and commission the interlock;

7.2.7 Commission the coolers to operation as required;

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7.3. Open Cooling Water System Shutdown 7.3.1 Check and confirm that all users of the open water pump meet the relevant

requirements;

7.3.2 Release the standby pump from the interlock; shut the outlet valve of the open pump

and then shut down the pump;

7.3.3 Check that the check valve at the outlet is shut and the pump does not develop a

reversed rotation;

7.4. Open Cooling Water System Monitoring and Adjustment 7.4.1Check that the pipes and equipment pertaining to the open circulating water system

have no leak;

7.4.2 Check that the following pump parameters are normal: pump current, pump vibration,

sound, bearing temperature, outlet pressure and seal gland leak;

7.4.3 Check that the differential pressure on the two sides of the open water filter is

normal;

7.4.4 Check that the standby open pump meets the interlock and standby requirements;

7.4.5 Check that the changeover and testing tasks are satisfactorily accomplished;

7.4.6Limits of Operational Parameters of the Open Circulating Water System:

Item UnitNormal Value

Upper Limit

Lower Limit

Outlet Pressure of Open Pump MPa

Differential Pressure on Two Sides of Open Water Filter

MPa

Bearing Temperature of Open Pump ℃

Bearing Temperature of Pump Motor ℃

Pump Current A

7.5. Open Circulating Water System Accidents Treatment 7.5.1 If the open water pump trips in operation, the standby pump must be started up in an

interlock mode, otherwise start the standby pump manually;

7.5.2 If all open pumps are shut down and can not be started temporarily, promptly reduce

the pump load and cut off water supply to minor users. Open the inlet and outlet valves for

the two pumps to ensure uninterrupted cooling water supply to important equipment;

8. Condensate System

8.1. Pre-Startup Check and Preparation 8.1.1 Finish the operations as required by General Rules for Pre-Startup Check of

Auxiliary Equipment and System;

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8.1.2 Check that all valves are in the correct position as indicated by the valve check card

before the system starts up;

8.1.3 Confirm that the service water system is operating reliably;

8.1.4 Contact the chemical engineer to start the demineralization pump to supply makeup

water to the condensate storage tank. Confirm that the water level in the tank is normal

and the water quality is acceptable;

8.1.5 Check that the condensate delivery pump meets the relevant requirements, the inlet

valve and the recirculating valve of the pump are open and the outlet valve is closed.

Close the drain valve on the steam side of the condenser, start the condensate delivery

pump and check that the system is working properly before supplying makeup water to the

condenser;

8.1.6 Open the injection valve connecting the condensate delivery pump to the

condensate system to inject water. Open the vent valves of the condensate pipe system to

discharge the air. The vent valves will close on contact with water;

8.1.7 Open the sealing water valve for the condensate pump to deliver sealing water;

8.1.8 Open the vent valves at the inlet/outlet of the condensate pump and at the inlet of

the strainer. After water makeup and air discharge operations are completed, close the

vent valves at the inlet/outlet of valves for the condensate pump and the vent valve for the

strainer;

8.1.9 Commission the cooling water for the motor bearing of the condensate pump and

check if the backwater is working properly;

8.1.10 Check if the oil level in the bearing of the condensate pump is normal;

8.1.11 Open the air valve for the condensate valve;

8.1.12 When makeup water in the condenser reaches a normal level, close the makeup

water bypass valve;

8.1.13 Open the front and rear cut-off valve of the makeup water control valve for the

condenser and commission automatic control for the water level.

8.2. Condensate System Startup 8.2.1 Startup of Condensate Pump

8.2.1.1 Check and confirm that the condenser water level is normal, the cooling water

supply to the condensate pump and the motor is normal and all interlock protection tests

have been passed;

8.2.1.2 Check and confirm that the inlet water valve of the condensate pump and the

condensate recirculating valve are open;

8.2.1.3Start one of the condensate pumps and observe the starting current and the current

return time. Check that the outlet water valve is automatically and promptly opened.

Check that the following parameters of the pump are normal: pump vibration, sound,

bearing & motor coil temperature, motor current, outlet pressure, differential pressure on

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two sides of the strainer, sealing water pressure and condenser water level. Check that

the system has no leak;

8.2.1.4 Contact the chemical engineer to test the quality of the condensate water. If the

quality is unacceptable, the condensate water must not be delivered to the deaerator.

Close the outlet valve for #5 low pressure heater and open the drain valve on the water

outlet pipe to replace water. Condensate water must not be delivered to the deaerator

unless the quality is acceptable;

8.2.1.5 Commission the condensate polisher as required by the system;

8.2.1.6 Check that the condensate recirculating valve is automatically closed as the flow

rate of condensate increases;

8.2.1.7 Commission the users of the reclaimed condensate as required.

8.2.2 Commissioning of another Condensate Pump on Standby

8.2.2.1 Check and confirm that the drain valves at the pump inlet/outlet and the vent valve

of the pump are closed;

8.2.2.2 Commission the sealing water for the standby condensate pump;

8.2.2.3 Open the evacuation valve at the inlet of the pump. If the condenser is in a vacuum

state, open the valve slowly and monitor the condenser vacuum and the operation of the

working pump;

8.2.2.4 Open the inlet valve of the condensate pump to inject water. Monitor the vacuum

change of the condenser;

8.2.2.5 Check that the condensate flow rate and the manifold pressure are normal. Open

the outlet valve of the standby pump and see to it that the pump rotation must not be

reversed. Check that the standby condensate pump meets the standby requirements

before commissioning the interlock for the pump.

8.3. System Shutdown 8.3.1 Confirm that the vacuum system is shut down after the unit is shut down, the

exhaust steam temperature of the low-pressure cylinder is lower than 50 and the users ℃

of the condensate system approves a system shutdown or have switched to the standby

water supply;

8.3.2 Check and confirm that the deaerator has stopped water intake and all the

condensate users have shut down the system and met the shutdown requirements;

8.3.3 Contact the chemical engineer to decommission the condensate polisher;

8.3.4 Switch the standby pump to the manual mode and shut the outlet valve;

8.3.5 Shut down the condensate pump and shut all outlet valves via the interlock. Ensure

that the pump current drops to zero and the pump develops no reverse rotation.

8.4. System Operation and Maintenance 8.4.1 Monitor the water levels in the condensate storage tank and the condenser hot well

to check that they are normal. Check that the automatic control for water makeup is

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normal. In case that the automatic control fails for the water level or in the case of an

emergency, manual operation is allowed;

8.4.2 Check that the following parameters of the condensate pump are normal: outlet

pressure, flow rate, current, coil temperature and bearing temperature. Conduct a site

inspection to ensure that the condensate pump has normal sound and vibration;

8.4.3 Check if the standby pump is in a sound standby condition;

8.4.4 Changeover of Condensate Pump:

8.4.4.1 Check that the standby pump is in a sound standby condition and is ready to be

commissioned reliably;

8.4.4.2 Check that the sealing water has been correctly commissioned for the standby

condensate pump;

8.4.4.3 Confirm that the inlet valve of the standby condensate pump is open;

8.4.4.4 Confirm that the outlet valve of the standby pump is closed;

8.4.4.5 Check that the condensate water system is working reliably;

8.4.4.6 Confirm that the evacuation valve at the inlet of the standby pump is open;

8.4.4.7 Release the standby condensate pump from the standby mode;

8.4.4.8 Start the standby pump and monitor the opening process of the interlocked electric

valve at the outlet;

8.4.4.9 Check that the following parameters are normal after the standby pump is started:

motor current, vibration, sound, etc. Check that the LCD indicator lamp has correct

indication;

8.4.4.10 Stop the working pump and check that the current drops to zero. Check that the

check valve at the outlet is closed and the electric valve at the outlet is closed by the

interlock;

8.4.4.11 Check that the manifold at the pump outlet has emitted no “low pressure” signals.

Commission the original pump in standby mode as required;

8.5 System Accidents Treatment 8.5.1 Trip of Condensate Pump

8.5.1.1 Symptoms

1) The CRT sounds an alarm and the current drops to zero;

2) The flow rate of the condensate manifold drops sharply and the outlet pressure drops

slightly;

3) The water level in the condenser hot well rises and the level in the deaerator drop;

8.5.2.2 Treatment

1) First confirm that the standby pump is automatically started, otherwise start it

manually;

2) Adjust the water level in the condenser and the deaerator to normal;

3) If the standby pump is not successfully started, force a startup attempt on the tripped

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pump. If the attempt is unsuccessful, consider a reduction of the present load;

4) Identify the cause of tripping.

8.5.3 Idling Condensate Pump

8.5.3.1 Symptoms

1) The current drops and fluctuates;

2) The outlet pressure and the condensate flow rate of the pump drop;

3) When two condensate pumps are operating, one pump develops a rise in flow rate.

8.5.3.2 Treatment

1) Arrive promptly on the site to locate any abnormal noise;

2) Shut down the faulty pump and manually start up the standby pump;

3) Adjust the water levels of the condenser and the deaerator to normal;

4) Identify the cause of the idling pump;

9. Regeneration and extraction Steam System

9.1. Pre-Startup Check and Operation

9.1.1 Pre-Startup Check and Preparation of Deaerator

9.1.1.1 Complete the operations as required by General Rules for Pre-Startup Check of


9.1.1.2 Push the system check card to ensure that the valves are in the correction

position;

9.1.1.3 Check that all the following valves are in a proper working condition: deaerator

startup vent valves, continuous vent valves, all isolating valves connecting deaerator

overflow valves to condenser pipes and all bypass valves connecting the overflow valves

to the condenser;

9.1.1.4 Check and confirm that the deaerator startup vent valvex is open and the normal

vent valve is closed;

9.1.1.5 Confirm that the auxiliary steam system has been commissioned, the condensate

system has been adequately filled and the water quality is acceptable;

9.1.1.6 Confirm that all control air supply has been properly commissioned for the system,

the power supply for the electric valves is commissioned and the valves are in a correctly

position;

9.1.1.7 The pre-startup check and preparation work must precedes the same work for the

high/low pressure heaters, so that auxiliary steam-heated feed water may be supplied

once the conditions are met;

9.1.1.8 Check that deaerator has passed the water level test and the pressure interlock

protection test. Commission water level & pressure metering devices and protection

devices for the deaerator;

9.1.1.9 Confirm that the auxiliary system is operating normally and the auxiliary steam

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pressure and temperature meet the requirements;

9.1.1.10 Confirm that the condensate delivery pump is working stably and the water

quality is acceptable;

9.1.2 Heater Commissioning & Decommissioning

9.1.2.1 While the unit is in operation, if #7 and #8 low-pressure heaters develop a leak

which actuates the water level protection mechanism, reduce the load to 540MW (in the

event of a rated unit load), open the bypass valves on the water side of the two heaters

and close the electric valves for inlet/outlet water;

9.1.2.2 If the unit is operating in a rated load condition, decommission all four

low-pressure heaters to reduce the unit load to 70%, decommission three low-pressure

heaters to reduce the unit load to 80%, or decommission two low-pressure heaters to

reduce the unit load to 90%. If all high-pressure heaters are decommissioned, the rest of

the unit parameters can support a unit load of 100%;

9.1.2.3 If the high/medium pressure cylinders are simultaneously started, the heater

generally has a random startup in response to the rolling of the unit. If the medium

pressure cylinder is used to start up the high-pressure cylinder, the heater will be

commissioned after a cylinder changeover. Commission the low-pressure heaters before

the high-pressure heaters, and the water side before the steam side. Decommission the

high-pressure heaters before the low-pressure heaters, and the steam side before the

water side. Ensure that the rate of temperature rise/drop is less than 2 /min;℃

9.1.2.4 The heater must not be started in case any of the following faults occurs: 1）The heater protection & interlock fails;

2）Check that the safety valves on the steam/water side of the heater have a

malfunction; 3）he steel pipe of the heater develops a leak;

4）The main supervisory instruments of the heater have a fault;

5）The check valves of the different extraction steam sections have a failure;

6）The major steam/water delivery valves and steam trap valves have a control failure;

7）The heater has any other defect that seriously affects a safe operation;

8）The high pressure heater is commissioned before the low-pressure heater (the

reverse is correct).

9.1.3 Pre-Startup Check and Preparation of Low-Pressure Heater

9.1.3.1 Complete the operations as specified by General Rules for Pre-Startup Check of


9.1.3.2 Confirm that the heater and pipes are acceptably flushed;

9.1.3.3 Confirm that the water quality of the condensate system is acceptable;

9.1.3.4 Confirm that the compressed air system is functioning reliably;

9.1.3.5 As required by the check card for low-pressure heater commissioning system,

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adjust the valves to the required position and confirm that the steam trap valves are

working properly and the automatic control mechanism has been actuated;

9.1.3.6 Check that the local water level gauge for the low-pressure heater is sound and

working properly;

9.1.3.7 Contact the heat engineer for commissioning of the water level protection for

low-pressure heaters;

9.1.4 Pre-Startup Check and Preparation of High-Pressure Heater

9.1.4.1 Confirm that the overhaul work is completed, the worksheets are completed and

the equipment is complete and sound;

9.1.4.2 Confirm that the heater and the pipes are acceptably flushed;

9.1.4.3 Confirm that the water temperature of the deaerator feed water tank is normal and

the water levels of all high-pressure heaters are normal;

9.1.4.4 Contact the heat engineer for required power supply to meters, instruments and

signal lamps. Contact the electrical engineer for required power supply to electric valves.

Ensure that the equipment has smooth and flexible operation.

9.1.4.5 Confirm that the compressed air system is working properly;

9.1.4.6 As required by the valve check card, adjust the valves to the required position and

commission the water level gauges as required;

9.1.4.7 Confirm that all steam trap valves are working properly and the automatic control

mechanism has been actuated;

9.1.4.8 Confirm that all protection and automatic mechanism tests are passed and the

protection mechanism for all heaters is commissioned;

9.2. System Startup 9.2.1 Deaerator Startup

9.2.1.1 Refill the deaerator to the starting water level with the condensate delivery pump

or condensate pump;

9.2.1.2 Open the steam trap valve between the auxiliary steam and the deaerator heat

pipe to effect a drainage; confirm that the circulating water has been properly

commissioned for the condenser;

9.2.1.3 Commission the auxiliary steam for the heating process, open the front and rear

isolating valves between the auxiliary steam and the deaerator, slowly open the pressure

control valve between the auxiliary steam and the deaerator and maintain the rate of

temperature rise of the feed water for the deaerator below 1.5 /min;℃

9.2.1.4 After the water temperature of the deaerator reaches 100 , open the electrical ℃

continuous vent valve, close the pressure control valve between auxiliary steam and

commission the deaerator in the automatic mode. Check that the rate of temperature rise

is lower than 1.5 /min. When the pressure rises to 0.15MPa, the deaerator works under ℃

a constant pressure;

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9.2.1.5 The deaerator water level may be controlled by opening the electric valve between

the discharge outlet and the drain flash tank. Hot-flush the deaerator as required;

9.2.1.6 After the condensate pump is started, commission the loop between the overflow

valve of the deaerator to the drain flash tank of the condenser to operation. The automatic

mechanism must be actuated for the deaerator water level control;

9.2.1.7 If the condensate water quality is acceptable, switch the condensate water to the

deaerator. Commission the deaerator water level in the automatic mode and check that

the deaerator and the condenser have a normal water level;

9.2.1.8 When the 4th extraction reaches a pressure of 0.15MPa, check that the pressure

and water level of the deaerator are normal; open the electric valve between the 4th

extraction and the deaerator. For the deaerator, the auxiliary steam will switch to the 4th

extraction and the pressure control valve between the auxiliary steam and the deaerator

will be closed. Check that all steam trap valves for the 4th extraction pipes are closed and

the deaerator switches from constant pressure operation to sliding pressure operation;

9. Ensure that the water inflow speed is so controlled that the deaerator will maintain

constant temperature and pressure;

9.2.1.10 While the deaerator is in sliding pressure operation, open the isolating valve

between the continuous drain valve of the boiler and the deaerator, depending on valve

condition and water quality;

9.2.2 Startup of Low-Pressure Heater

9.2.2.1 Commissioning of Water Side

1) Commission the condensate pump, open the water inlet valves of the low-pressure

heaters to inject water into #8 heater through to #5 heater. If the vent valve on the water

side is in contact with water, check that the water level of the gauge for the low-pressure

heater does not change in times of water injection and the condensate flow rate doesn’t

change on completion of water injection;

2) Check that the inlet and outlet valves on the water side of the low-pressure heater are

fully open;

3) Flush the low-pressure heater as required for an acceptable quality;

9.2.2.2 Commissioning of Steam Side

1) Commission the steam side of #7A/#7B and #8A/#8B low-pressure heaters in the

random mode while the turbine is rolling;

2) After a vacuum is created for the turbine, shut down #6/#5 heaters in turn and start

the vent valve for the low-pressure heater slowly. Observe the vacuum changes in the

condenser. If there is a major change, shut the valve quickly and identify the leak.

Correct the leak before starting the continuous air vent process;

3) After the turbine rolls, commission #6/#5 heaters for the steam side and check that

the steam trap valves of the extraction pipes are open. If the extraction check valve of

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the low-pressure heater is in a free state, open the electric valve slightly for a preheating.

Control the rate of outlet temperature change of the low-pressure heater below 3 /min. ℃

Then open the electric valve fully and the normal drainage control valve must be

working properly;

4) When check valves of the 5th and 6th extraction sections are open, check that all

steam trap valves of the 5th and 6th extraction pipes are closed.

9.2.2.3 Commissioning of Low-Pressure Heater during Unit Operation

1) Ensure that all the overhaul work has been completed, the worksheets have been

recalled and the site has been cleaned. There is no object that may pose a hindrance to

system startup;

2) Ensure that all pre-startup checks and operations are completed;

3) Inject adequate water supply and exhaust the air when the water side is

commissioned. During the injection, monitor the water level in the drain valve closely to

ensure there is no change; when condensate water is switched from the bypass to the

main loop, monitor the condensate flow rate in case of a cutoff in water supply;

4) Open the continuous vent valve of the low-pressure heater slowly and monitor the

condenser vacuum closely in case of a rapid drop in vacuum. If there is a rapid drop in

vacuum, shut the valve immediately, check the heater and confirm the correction of the

leak before further operations are allowed;

5) When the steam side is commissioned, ensure that the pipes have been adequately

heated. Control the rate of temperature rise on the outlet water side of the

commissioned heater below 3 /min;℃

6) After the extraction check valve is open, check that all steam trap valves of the

extraction steam pipes are closed;

9.2.3 Commissioning of High-Pressure Heater

9.2.3.1 Commissioning of the Water Side

1) Check that the feed pump is operating reliably and the electric valve at the outlet has

been opened;

2) Contact the heat engineer for the commissioning of water level protection for the

high-pressure heater; 3）Slightly open the electric water injection valve at the outlet of the high-pressure

heater to carry out a water side leak test by water injection. When water overflows from

the vent valves on the water side of #1, #2 and #3 high-pressure heaters, observe the

water level change at the steam side; 4）After the internal water pressure of the high-pressure heater reaches to the full value,

slowly open the electric outlet valve of the heater and switch the bypass to the inlet side

of the heater. Observe the flow rate and pressure changes of the feed water.

9.2.3.2 Commissioning of Steam Side

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1) Confirm that the water side of the high-pressure heater has been commissioned, the

water-level interlock protection test on the high-pressure heater has been passed and

the condenser vacuum is normal;

2) Ensure that the system has switched to the high-pressure cylinder of the turbine.

When the unit load reaches 30% of the rated load, commission the steam side of the

high-pressure heaters (sequence: #3, #2 and #1)

3) Check that all related steam trap valves of the extraction steam pipe have been open.

If the extraction check valve of the high-pressure heater is in a free state, open the

electric valve for the extraction steam slightly to preheat the heater. Control the rate of

outlet temperature change of the low-pressure heater below 3 /min.;℃

4) After steam is admitted into the high-pressure heater, close the startup vent valve and

open the continuous vent valve on the steam side;

5) After the preheating, slightly open the steam extraction electric valve for the

high-pressure heater and check that the normal drainage control valve functions

reliably; 6) ；When the check valves for the 3rd, 2nd and 1st steam extractions are opened, check

that all steam trap valves for the extraction steam pipes are closed;

7) While the high-pressure heater is being commissioned, try to maintain the load

balance of the unit and check that the water level automatic control for the heater is

normal; 8）When the steam side pressure of #3 high-pressure heater exceeds 0.2MPa, deliver

the drainage from the heater into the deaerator and monitor and control the pressure

and water level of the deaerator.

9.2.3.3 Commissioning of High-Pressure Heater during Unit Operation 1）After the feed water system is commissioned, commission the water-side of the high

pressure heater as required by the relevant operation codes; 2）Check that the water side of the heater has no leak, high water level alarm is not

available for the steam side and alarm signals for the heater parameters are working

properly; 3）Contact the relevant staff to commission water level protection for the heater;

4）Check the valve status prior to the startup of the heater. Open the continuous vent

valves on the steam side and close the startup vent valves on the steam side; 5）In the event of a simultaneous startup of high/medium pressure cylinders (the

medium pressure cylinder starts up after the cylinder transfer), open the check valves

and electric valves for the 1st, 2nd and 3rd steam extractions. The steam pressure in the

heater will rise as the load increases; 6）When the unit load exceeds 20%, confirm that the steam trap valves behind the

extraction steam check valves and the drain valves in front of the extraction steam

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electric valves are closed. When the pressure on the steam side of #3 high pressure

heater exceeds 0.2MPa, deliver the drainage from #3 high-pressure heater into the

deaerator and monitor and control the pressure and water level of the deaerator; 7）After the drainage from the high-pressure heater is adjusted to normal in the

downgrade flow mode, commission the automatic mechanism for the water level in the

high-pressure heater and check that the automatic adjustment of the water level is

normal; 8）The pipe must be heated adequately before the steam side of the high-pressure

heater is commissioned. Maintain the rate of temperature rise at the outlet of the heater

below 3 /min. In the commissioning process, monitor the variation of the following ℃

parameters: unit load, axial displacement and differential expansion.

9.3. System Shutdown 9.3.1 Shutdown of Low-Pressure Heater

9.3.1.1 Shut down of Steam Side of Low-Pressure Heater

1) Allow #5, 6, 7A/B and 8A/B low-pressure heaters to shut down in the random sliding

mode;

2) Confirm that the electric valve and the check valve for steam extraction are

automatically shut and all steam trap valves for the steam extraction pipe are

automatically open; 3）Close #1 and #2 continuous vent valves between the low-pressure heater and the

condenser;

9.3.1.2 Shutdown of Water Side

1) Before the water side of the low-pressure heater is shut down, open the bypass valve

before closing the other inlet and outlet valves. Monitor the change of the condensate

flow rate;

2) If the heater is to be disused for a long time, drain it out and charge it with nitrogen for

storage and maintenance;

9.3.1.3 Shutdown of #5 and #6 Low-Pressure Heaters during Unit Operation

1) Reduce the turbine load to a specified value, depending on the shutdown condition of

low-pressure heaters; 2）Release the automatic mechanism for the water level of #5 low-pressure heater, open

the emergency steam trap valve between #5 heater and the condenser and close the

drainage control valve and isolating valve between #5 heater and #6 heater; 3）Release the automatic mechanism for the water level of #6 low-pressure heater, open

the emergency steam trap valve between #6 heater and the condenser and close the

drainage control valve and isolating valve between #6 heater and #7 heater; 4）Close the electric steam inlet valve for #6 low-pressure heater and close the check

valves for the 6th steam extraction. Ensure that the drain valves in front of the electric

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valve and behind the check valve are open; 5）Close the continuous vent valve between #6 low-pressure heater and the condenser;

6）Close the drain valve behind the check valves for the 6th steam extraction;

7）Close the emergency drainage control valves and the front and rear isolating valves

for #6 low-pressure heater. Open the drain valve for pipes in front of the emergency

drainage control valve of #6 low pressure heater; confirm that the isolating valve in front

of the emergency drainage control valve is tightly closed; 8）Check that steam side pressure of #6 heater drops to zero. Open the start-up vent

valve of #6 heater to observe the air discharge conditions and confirm that the electric

valve, check valve and emergency drain valve are tightly closed. Open the drain valve

on the steam side of #6 heater to drain it out; 9）Open the electric bypass valve on the water side of #6 heater and slowly close

inlet/outlet valves of #6 heater. Monitor the flow rate of condensate to ensure a steady

flow; 10）Confirm that the inlet/outlet valves of #6 low-pressure heater are closed. Open the

drain valve on the water side of the heater to monitor and ensure a steady flow rate of

condensate water; 11）Carry out other isolation steps for the overhaul work. Follow the above steps in the

shut down process of #5 low-pressure heater.

9.3.1.4 Shutdown of #7 and #8 Low-Pressure Heaters during Unit Operation

1) Reduce the turbine load to a specified value, depending on the shutdown condition of

low-pressure heaters 2） Release the automatic mechanism for the water level of #6 low-pressure heater,

open the emergency steam trap valve between #6 heater and the condenser and close

the drainage control valve and isolating valve between #6 heater and #7 heater; 3）Open the bypass valves for the water side of #7 and #heaters and gradually shut the

inlet valves of #8 heater (#8A and #8B). Monitor the change of condensate flow rate; 4）Open the emergency drainage control valve for #8A or #8B low-pressure heater;

5) Before opening the drain valves and vent valves, close the normal manual steam trap

valve, manual emergency steam trap valve, continuous vent valve and normal manual

steam trap valve between the upstream heater and the low-pressure heater;

6) Carry out other isolation steps for the overhaul work.

9.3.2 Shutdown of High-Pressure Heater

9.3.2.1 Shut the continuous air vent valve between #1 high pressure valve and the

deaerator;

9.3.2.2 Check that the automatic mechanism has been commissioned for the emergency

drainage control valve between #1 heater and the drain flash tank. Close the normal

drainage control valve and the isolating valve of #1 high-pressure heater in turn;

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9.3.2.3 Close the electrical steam inlet valves of #1 heater. Open the steam trap valves in

front of #1 steam extraction and behind the check valve. Take care to maintain the

temperature drop of the feed water temperature at the heater inlet below around 56 /h. ℃

The temperature drop must not exceed 111 /h;℃

9.3.2.4 Decommission the steam side of #2 and #3 heaters as specified by 9.3.2.1.

through to 9.3.2.3. Observe closely the change in temperature difference and load of the

upper and lower cylinders;

9.3.2.4Switch the three-way valve at the inlet of the water side of the heater to the bypass,

shut the electric outlet valve and observe closely the change in feed water flow rate;

9.3.2.5 Release the three high-pressure heaters from water level protection, close the

control valves and isolating valves between the emergency drainage valves and the drain

flash tank and close the steam trap valves behind the extraction steam check valves;

9.3.2.6 After confirming that the high-pressure heater has been reliably isolated from the

operating system, open the drain valve leading to the gutters on the steam/water side.

9.3.2.1 Shutdown of Steam Side

1) When the load drops to 30% of the rated load, slowly the steam extraction electric

valves in turn (#1, #2 and #3);

2) When the extraction steam check valve is automatically shut, all the steam trap

valves for the extraction pipe must open automatically;

3) Close the manual isolating valve between the continuous vent valve of the

high-pressure heater to the deaerator; 4）Observe the change in temperature difference and load of the upper/lower cylinders.

9.3.2.2 Shutdown of Water Side

1) After the heater is shut down, decommission the water side as required; 2）Switch the water side of the high-pressure heater to the bypass, close the electric

valve at the outlet side of the heater and watch closely the change in feed water flow

rate;

3) If the heater is to be disused for a long time, drain it out and charge it with nitrogen for

storage and maintenance.

9.3.2.3 Shutdown of High-Pressure Heater during Unit Operation

1) Before shutting down the high-pressure heater, reduce the turbine load to a specified

value;

2) Shut the continuous vent valves for the heater;

3) Slowly close the steam extraction electric valve and check that the change in turbine

differential expansion and axial displacement is within the controllable range. Ensure

that the temperature drop of outlet water is below 3 /min; ℃

4) After the steam side is decommissioned, switch the water side of the high-pressure

heater to the bypass, close the electric valve at the outlet side of the heater and watch

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closely the change in feed water flow rate;

5) Before opening the drain valves and the vent valves, shut all manual emergency

drainage valves and isolating valves between the high-pressure heater and the

condenser;

6) Carry out other isolating steps of the overhaul work;

9.3.2.4 Random Sliding Shutdown of High-Pressure Heater 1）Under normal shutdown condition, adopt a random sliding shutdown mode for the

high-pressure heater; 2）After the turbine trips, check that the feed steam check valves and the electric valves

are shut through interlock. Check that the normal drainage valve is closed and the

emergency steam trap valve is opened through interlock; 3）Shut the primary and secondary continuous vent valves between the high-pressure

heater and the deaerator.

9.3.3 Deaerator Shutdown

9.3.3.1 When the unit load reaches 20% of the rated load, check that the steam trap

valves for the 4th extraction pipes are automatically opened;

9.3.3.2 When the pressure of the 4th extraction drops below 0.15MPa, the steam supply to

the deaerator switches from the 4th extraction to the auxiliary steam. Close the isolating

valve connecting the 4th extraction to the deaerator, open the pressure control valve

between auxiliary steam and deaeratorand maintain the deaerator pressure at a constant

value of 0.15MPa;

9.3.3.3 After the continuous drain valve is shut down, close the isolating valve connecting

the continuous drain valve to the deaerator;

9.3.3.4 After feed water supply to the boiler is cut off, switch the heating control valve

between the auxiliary steam and the deaerator to the manual mode before shutting it.

Close the heating isolating heater valve between the auxiliary steam and the deaerator; 9.3.3.5 ；After the feed pump is shut down, switch the deaerator water level adjustment to

the manual mode and shut it;

9.3.3.6 If the deaerator is to be disused for over one week, adopt nitrogen blanketing

protection, cut all steam supply and water supply and drain out the water tank. Shut the

drain valve. After the deaerator is fully isolated, start the master nitrogen charging valve

and the isolating valve. While charging the deaerator with nitrogen, maintain constant

pressure.

9.4. System Maintenance 9.4.1 Operating Monitoring and Adjustment of High/Low-Pressure Heater

9.4.1.1 Patrol the steam extraction pipes of the heater on a regular basis. Check that the

drain pipes have no leak and vibration;

9.4.1.2 An abrupt change of load may cause a change of the heater’s water level. Adjust

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the water level promptly;

9.4.1.3 Avoid prolonged heater operation at zero (low or high) water level;

9.4.1.4 Monitor the following parameters of the heater, including but not limited to

temperature of steam extractions, pressure, feed water temperature rise, terminal

temperature difference and water level; adjust the terminal temperature difference within a

tolerable, feasible and economically viable range;

9.4.1.5 Under rated working conditions, the pressure, temperature and extraction capacity

of the steam extractions must be constant. In the event of a deviation from the design

value, analyze the cause.

9.4.2 Operation Monitoring and Adjustment of Deaerator

9.4.2.1 Ensure that the deaerator operates in the fixed-sliding-fixed mode. The

deaerator’s range of sliding pressure is between 0.15-1.05MPa. When the unit load varies,

monitor the pressure and temperature of the deaerator to ensure that they conform to the

local conditions; 9.4.2.2 ；Check that the water level automatic adjustment is sound for the deaerator and

the adjusted water level displayed on the CRT;

9.4.2.3 Adjust the opening of the normal vent valve according to the feed water oxygen

content. Ensure that the deaerator works in accordance with economical requirements;

9.4.2.4 Check that the deaerator has no vibration and the deaerator and the system have

no leak;

9.4.2.5 Check that the heating control valve between the auxiliary steam and the

deaerator are commissioned in the automatic mode. Heat the pipe in front of the control

valve properly;

9.4.2.6 If the deaerator is heated by auxiliary steam, maintain the deaerator pressure

under a constant pressure of 0.15MPa. The deaerator must not be overloaded in

operation.

9.5. Accidents Treatment 9.5.1 An emergency shutdown of the low-pressure heater must be enforced in any of the

following cases:

9.5.1.1 When the steam/water pipes and valves of the heater burst and endangers

personal safety and the safety of equipment;

9.5.1.2 When the heater water level rises, a solution is not effective or the low-pressure

heater is filled with water;

9.5.1.3 When all water level indications fails and the water level fails to effectively

monitored;

9.5.1.4 When the extraction check valve jams;

9.5.1.5 When the heater works under overpressure and the safety valve fails to work;

9.5.2 Water Level Rise of Low-Pressure Heater

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9.5.2.1 Causes:

1) The water side has a leak or burst;

2) The steam trap valve fails;

3) The water level transducer fails;

9.5.2.2 Treatment: Decommission the steam/water side of the heater.

9.5.3 Deaerator Vibration

9.5.3.1 Causes:

1) The water inflow into the deaerator increases or decreases sharply;

2) The steam inflow into deaerator increases or decreases sharply;

3) The abrupt rise or fall of feed water causes rapid fluctuation of the deaerator water

level;

4) The deaerator has a leak;

5) A great quantity of drainage from the high-pressure heater abruptly penetrates into

the aerator;

9.5.3.2 Treatment

1) Adjust the water inflow into a deaerator;

2) Adjust the steam inflow into a deaerator;

3) Adjust the flow rate of feed water;

4) Adjust the water level of the deaerator;

5) Adjust the drainage and draining type of the high-pressure heater.

9.5.4 Increase of Deaerator Oxygen Content

9.5.4.1 Causes

1) Insufficient dosage or dosing interruption of hydrazine;

2) Insufficient supply or interrupted supply of steam inflow;

3) Abrupt rise of deaerator pressure;

4) Vent pipe blockage;

5) Serious blockage or detachment of nozzles in the deaeration piece;

9.5.4.2 Treatment

1) Adjust the hydrazine dosage;

2) Increase steam inflow or switch to other steam supply;

3) Maintain a constant load;

4) Enforce a shutdown or take corresponding steps before a solution is implemented.

9.5.5 Abrupt Drop of Deaerator Pressure

9.5.5.1 Causes

1) Interrupted steam inflow;

2) Infiltration of large quantities of condensate water as a result a malfunctioning water

level control valve of the deaerator;

3) The steam trap valve and safety valve of the deaerator are open by mistake;

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9.5.5.2 Treatment: Identify the cause of the pressure drop of the deaerator and take

corresponding steps.

9.5.6 Abrupt Rise of Deaerator Pressure

9.5.6.1 Causes

1) The condensate pump trips, or the water level control valve fails, causing a cut of

water inflow;

2) The unit is overloaded.

9.5.6.2 Treatment

1) Restore the water inflow for the deaerator promptly;

2) Reduce the load to normal.

9.5.7 The high-pressure heater must be shutdown in an emergency state in the following

cases;

9.5.7.1 When there is a burst of steam/water pipes and valves, which endangers personal

safety and equipment safety;

9.5.7.2 When the heater water level rises, a solution is not effective or the low-pressure

heater is filled with water;

9.5.7.3 When all water level indicates fail and the water levels fait to be monitored;

9.5.7.4 When the extraction check valve jams;

9.5.7.5 When the heater works under overpressure and the safety valve fails.

9.5.8 Rise of Water Level

9.5.8.1 Causes

1) The water level transducer fails;

2) The drainage control valve fails;

3) The water side has a leak or burst.

9.5.8.2 Treatment

1) Calibrate the water level transducer;

2) Check the drainage control valve;

3) De-commission the steam side and water side of the heater.

10. Feed pump System

10.1.1 Pre-Startup Check of Electric Pump

10.1.1.1 Check that the deaerator water level is normal and the condensate water system

has been properly commissioned;

10.1.1.2 Check that the scoop tube controller is in the manual position and manual

operation is smooth and has no jam or skip. Check that the rotational direction is correct

and the controller is adjusted to the lower limit;

10.1.1.3 Check that all interlock protection tests of the electric pump have been passed;

Commission all interlock protection mechanism and the meters and instruments;

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10.1.1.4 Confirm that the open circulating water and service water have been correctly

commissioned. Commission the mechanical seal cooling water for the booster pump and

the electric feed pump. Commission the service oil and cooling water for the lube oil cooler

as required by the oil temperature. Check that the oil level in the pump oil tank is normal

and the oil system meets all preconditions of commissioning;

10.1.1.5 Check that the pump and drain valves for the pipes are shut;

10.1.1.6 Check that the water level in the deaerator tank is normal, the water quality is

acceptable and the water temperature meets the boiler filling requirements. Open the

electric inlet valve for the booster pump slightly and inject water into the booster pump,

feed pump and pipes to displace the air. The air valve will shut on contact with water. On

completion of the water filling and air displacement, open the electric inlet valve fully for

the booster pump;

10.1.1.7 Check that the coupler has normal oil level and acceptable oil quality;

10.1.1.8 Check that one unit of lube oil strainers are commissioned and the other unit of

strainers are on standby;

10.1.1.9 Check that the fore and rear electric valves for the recirculation control valve are

open for the electric pump and the recirculating valve is commissioned in the automatic

mode;

10.1.2 Pre-Startup Check of Steam Pump

10.1.2.1 The small steam turbine must not be started in the following cases:

1) The emergency cutoff device, solenoid valve, overspeed protector, lube oil low

pressure protector or low vacuum protector does not function normally;

2) The main steam valve or the steam control valve fails to shut tightly or work properly;

3) The speed control system fails to operate stably or the rotating speed fails to be

controlled;

4) The main instruments and meters fail to monitor the following parameters properly:

feed steam pressure & temperature, vacuum, rotating speed, operating oil pressure,

lube oil pressure, etc.;

5) The main operating oil pump, DC oil pump or turning gear fails to function properly;

6) The turning gear emits abrasion noise from the interior;

7) The oil quality is unacceptable or the oil level is low.

10.1.2.2 Check that all meters & instruments, automatic mechanism and heat protection

have been correctly commissioned;

10.1.2.3 Push the pre-startup check card to check that the small steam turbine meets

pre-startup requirements;

10.1.2.4 Check that the rotating speed of the steam pump is in the manual mode, the

manual trip lever is in the trip position, and the main steam valve, steam control valve and

steam vent butterfly valve are closed;

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10.1.2.5 heck that the EH oil system of the main steam turbine has been correctly

commissioned;

10.1.2.6 Commission cooling water for the booster pump;

10.1.2.7 Check that cooling water for the mechanic seal has been commissioned for the

steam pump;

10.1.2.8 Carry out opening/shutting tests on the steam vent butterfly valve for the small

steam turbine before vacuum is created for the main steam turbine. Check that the steam

vent valve doesn’t jam and shuts tightly.

10.2. Startup of Feed pump 10.2.1 Electric Pump Startup

10.2.1.1 Start up the auxiliary oil pump to check that the following parameters of the pump

are normal: pump vibration, sound, temperature, bearing return oil, oil tank level, etc.

Check that the lube oil pressure exceeds or is equal to 0.15MPa;

10.2.1.2 Confirm that the recicurlating valve is fully open and has been commissioned in

the automatic mode for the pump. Start the pump;

10.2.1.3 After the motor is started, check it that the following parameters are normal:

starting current, current return time, rotating speed, pump vibration, bearing temperature,

interior noise, inlet/outlet pressure and minimum flow rate;

10.2.1.4 When the lube oil pressure reaches 0.3MPa, the auxiliary oil pump will be

automatically shut down;

10.2.1.5 Gradually step up the pump rotating speed to the speed required by the system.

Commission the rotating speed control mechanism;

10.2.1.6 Check and confirm that the electric pump is working properly. When the pump

outlet pressure is slightly greater than the manifold pressure, open the outlet valve of the

pump and commission the automatic mechanism for the feed water (CAUTION: The outlet

valve must not be fully opened when the feed water manifold at the outlet has zero

pressure. Rather, the outlet valve must be used to control the inflow into the manifold and

must not be fully open until the pressurization for the manifold is completed).

10.2.1.7 Open the midpoint tap valve for the electric pump as per boiler requirements;

10.2.1.8 When switching between an electric pump and a steam pump, check that the flow

rate of the two pump types matches;

10. When the electric pump experiences a fluctuation of feed water flow rate, check that

the minimum flow valve has a properly working automatic mechanism. When the flow rate

drops below 200t/h, the valve must automatically open; when the flow rate exceeds 400t/h,

the valve must automatically shut down.

10.2.2 Steam Pump Startup

10.2.2.1 Start the main oil pump and the smoke exhaust fan for the small steam turbine

and check that the following parameters are normal: vibration, sound, temperature,

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bearing return oil and oil tank level. There must be no oil leak in the oil system. Check that

the lube oil pressure is maintained around 0.25MPa, the oil temperature is maintained

above 35 a℃ nd the interlock for the oil pump has passed the test;

10.2.2.2 Check that the service water has normal pressure. Feed cooling water to the oil

cooler, booster pump and the main pump bearing, open the front and rear isolating valve

for the attemperating water control valve of the seal gland steam, feed sealing water to the

steam pump and open the unloading valve;

10.2.2.3 Confirm that all drain valves in the system are shut and open the electric inlet

valve for the booster pump slightly. Open the vent valve, discharge the air and close the

valve. Open the electric inlet valve fully for the booster pump;

10.2.2.4 Commission the turning gear 2 hours before the small steam turbine rolls. Check

that the turning gear rotates at around 100rpm and the interior of the unit and the pump

has no noise;

10.2.2.5 If the temperature of the inner wall of the cylinder flange is below 100 , the unit ℃

is considered as being in the cold state; if the temperature exceeds 100 , the unit is ℃

considered as being in the heated state;

10.2.2.6 Use the electric pump to boost the main steam turbine load to 200MW and the 4th

extraction pressure to 0.25MPa and above. Only after that may the first steam pump be

started (high-pressure steam supply may also be selected accordingly);

10.2.2.7 Commission seal gland steam and check that the seal gland steam pressure is

normal;

10.2.2.8 Vacuum-pumping may be synchronized with the main steam turbine or be

operated prior to the startup of the small steam turbine:

1) Pump for vacuum before the small steam turbine starts up. First, open the bypass for

the steam vent butterfly valve slightly and the vacuum for the small steam turbine will

gradually step up. Observe the vacuum for the main steam turbine to check that it

doesn’t drop substantially;

2) When the small steam turbine vacuum approaches the main steam turbine vacuum,

open the steam vent valve;

10.2.2.9 Commission the automatic mechanism for the steam trap valve for the small

steam turbine. Open the steam trap valves for the high/low pressure steam supply pipes,

high/low pressure main steam valves and control valves to provide drainage for the small

steam turbine and the steam supply system;

10.2.2.10 Check that the minimum flow recirculating valve is open for the steam pump.

Start the booster pump for the steam pump. After the motor starts up, check that the

following parameters are normal: starting current, current return time, pump vibration,

bearing temperature, pump noise, inlet/outlet pressure and minimum flow;

10.2.2.11 Check that the small steam turbine meets all rolling conditions:

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1) Vacuum: Above 84.5KPa;

2) Resistance to fuel oil pressure: Above 8MPa;

3) Lube oil pressure: 0.25MPa; oil temperature: Above 35℃

4) Safety oil pressure: Normal;

5) Steam pressure: Normal; steam overheat: 50 ;℃

6) The booster pump and the turning gear must operate reliably for at least 2 hours on

end; 7）Select steam supply accordingly and confirm that the steam supply meets the

relevant requirements and the steam pipe before the main steam valve is sufficiently

heated;

10.2.2.12 Press “BFPT Reset” on the MEH control panel and latch on the small steam

turbine;

10.2.2.13 Enter 900r/min as the target rotating speed; After confirmation, the small steam

turbine is started and the flow of the control valve starts to escalate. Check that the turning

gear automatically trips. The rotating speed will automatically rise from 300r/min and 900r/min.

Heat the unit for 15min;

10.2.2.14 Enter 1,800r/min as the target rotating speed; after confirmation, the rotating speed

will automatically rise from 300r/min to 1,800r/min. Heat the unit for 15min;

10.2.2.15 Input 3,000r/min as the target rotating speed; After confirmation, the rotating speed

rises automatically from 1,200r/min to 3,000r/min. Heat the unit for 10min. Check that

everything goes well and slowly open outlet valve of the steam-operated feed pump to

observe the change in flow rate;

10.2.2.16 The first critical rotating speed of the unit is 2,336r/min and the second critical

rotating speed is 7,713r/min. When the rotating speed reaches the critical value, the rate

of the unit automatically increases to the maximum. At this stage, it is ineffective to

attempt any modification of rate;

10.2.2.17 Push the “BOILER AUTO CTRL” button on the MEH panel to effect an

automatic control;

10.2.2.18 If the inlet steam pressure of the small steam turbine is low, the speed control

system will automatically switch to a higher pressure to admit part of the main steam and

meet the requirements for a larger load. When the main steam turbine load reaches the 4th

extraction pressure and can meet the requirements of the small steam turbine, the speed

control system will automatically effect a switchover to cut off high-pressure inlet steam

and drive the water pump by low-pressure inlet steam (if high-pressure steam supply is

selected for a startup, the small steam turbine will switch from low-pressure steam to

high-pressure steam after the unit load reaches 40% of the rated load);

10.2.2.19 After the main steam turbine load reaches 300MW, start the second steam

pump;

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10.2.2.20Close all steam trap valves between the small turbine cylinder and the steam pipes.

10.3. Shutdown of Feed pump 10.3.1 Shutdown of Electric Pump after Startup of Steam Pump

10.3.1.1 Release the auxiliary oil pump from interlock, start it and check that it works

normally and the lube oil pressure is normal;

10.3.1.2 Check that the steam pump attains to a rotating speed of 3,000rpm and

commission the automatic control mode. Switch the speed control of the electric pump to

the manual mode and gradually reduce the pump rotating speed. Shift the electric pump

load wholly to the steam pump;

10.3.1.3 When the flow rate of the electric pump drops below 200t/h, the recirculating

pump will automatically open;

10.3.1.4 Shut down the pump to observe the idle operation of the feed pump and the

motor and check that the lube oil pressure is normal;

10.3.1.5 After the electric pump is shut down, switch the rotation control mechanism of the

electric pump to automatic mode and commission the pump on standby;

10.3.2 Shutdown of Steam Pump

10.3.2.1 When the main steam turbine load drops below 50%, one steam pump may be

shut down;

10.3.2.2 Before the shutdown of the steam-operated feed pump, trial-run the standby oil

pump and DC oil pump to check that they work reliably;

10.3.2.3 When the unit load drops to 180MW, startup the electric pump as per the

requirements to check that it operates reliably;

10.3.2.4 Switch the rotating speed of the first small steam turbine to be shut down to the

automatic mode;

10.3.2.5 Step down the steam pump rotating speed gradually. See to it that the rotating

speed of the electric pump must be increased accordingly;

10.3.2.6 When the steam pump has a flow rate less than 300t/h, the recirculating pump

must open automatically;

10.3.2.7 After the full load of the steam pump is shifted to the electric pump, reduce the

rotating speed of the steam pump below 3,000rpm and open the steam trap valve for the

small steam turbine;

10.3.2.8 Trip the small steam turbine via the control panel or via the local control

mechanism. Check that the main steam valve and the steam control valve are closed. The

rotating speed of the small steam turbine drops;

10.3.2.9 Check that the water spray valve automatically opens for the steam vent pipe;

10.3.2.10 When the small steam turbine drops to 43r/min, the turning gear must be

commissioned automatically;

10.3.2.11 Close the electric steam inlet valve for the small steam turbine and open all the

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steam trap valves;

10.3.2.12 If the steam pump is used for a standby heating source, the seal gland and the

turning gear should operate continuously. The steam vent butterfly valve must be open.

Maintain pipe heating for the small steam turbine;

10.3.2.13 In the event of a seal gland steam supply, the turning gear must not be shut

down. If the main steam turbine and the small steam turbine are synchronously shut down,

seal gland steam supply may be stopped. If the small steam turbine is shut down

separately, close the steam vent butterfly valve and stop seal gland steam supply when

the inner wall temperature of the cylinder flange drops to 100 . ℃

10.4. Operation Monitoring and Adjustment of Feed pump System 10.4.1 Operation Monitoring and Adjustment of Electric Pump

10.4.1.1 Check that the pump, feed water pipes and equipment have no leak;

10.4.1.2 Check that the following parameters are normal: pump current, bearing vibration,

bearing & motor coil temperature, feed water flow rate, inlet/outlet pressure, differential

pressure on the two sides of the strainers of the main pump and the booster pump and

motor air temperature;

10.4.1.3Check that the following parameters are normal: lube oil & service oil pressure,

temperature, bearing oil flow rate and the differential pressure on the two sides of the oil

strainer. Check that the oil tank level and oil quality are acceptable and the oil pipe has no

leak;

10.4.1.4 Check that the scoop tube position and the automatic control are normal;

10.4.2 Operation Monitoring and Adjustment of Steam Pump

10.4.2.1 Check that the following parameters are normal: booster pump current, motor

vibration, sound and bearing temperature;

10.4.2.2 Check the steam pump body as is done for the electric pump;

10.4.2.3 Check that the small steam turbine control system works properly;

10.4.2.4 Check that the following parameters of the Lubricating oil system for the small

steam turbine are normal: service oil pressure/temperature, bearing oil flow rate and the

differential pressure on the two sides of the oil strainer. Check that the oil tank level and oil

quality are normal and there is no leak in oil pipes;

10.4.2.5 When the steam-operated feed pump is in operation, monitor the exhaust steam

temperature to avoid cylinder overheating;

10.4.2.6 If the rotor is stationary, do not supply steam to the steam seal for a long time. This is

intended to prevent a steam seal deformation.

10.5. Feed pump System Accidents Treatment 10.5.1 Emergency Shutdown of Steam Pump

10.5.1.1 Enforce an emergency shutdown in case of a small steam turbine vacuum break

in the following cases:

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1) When the steam pump vibrates violently or there is audible noise of metallic abrasion

or impact within the small steam turbine or the pump;

2) When the rotating speed of the small steam turbine increases to 5,972r/min and the

emergency protector fails;

3) When the small steam turbine is subject to a water impact;

4) When the small steam turbine oil system catches fire, the fire fails to be quickly

smothered and the safe operation of the unit is endangered;

5) When oil supply to the steam pump bearing is exhausted or the return oil temperature

exceeds 75 ;℃

6) When the oil tank level of the small steam turbine drops to the lower limit and the

measures taken fail to maintain the oil level;

7) When the lube oil pressure drops to 0.08MPa but the protection mechanism fails;

8) When the booster pump motor gives off smoke and catches fire; 9）When the axial displacement reaches 0.9mm but the protection mechanism fails;

10）When vacuum drops below 47.7KPa(a) but the protection mechanism fails;

11）When the Babbitt metal temperature of the bearing reaches 90 ;℃

12）When the fluctuation of the small steam turbine rotating speed cause a failure to

control the water level of the steam drum;

10.5.1.2 Emergency Shutdown of Small steam turbine without Breaking Vacuum

1) When the speed control system of the small steam turbine experiences violent

vibration and operation fails to be maintained;

2) When the steam/water supply pipe bursts and fails to be isolated;

3) When the exhaust steam pressure continues to climb and fails to be restored;

4) When the steam pump has a serious vaporization;

5) When the oil system has a leak and operation is interrupted;

6) When the main body of the pump has a serious leak and large quantities of

steam/water spurt, which endangers the safe operation of pumps;

7) When the booster pump motor has an overcurrent and fails to be corrected;

8) When the pump protective action value is reached but the protection mechanism fails

to work;

10.5.1.3 When both steam pumps are commissioned, if one pump is shut down in the

emergency mode, the electric pump must automatically start in a parallel mode;

10.5.1.4 If an emergency shutdown of the small steam turbine is required, push the

“SHUT DOWN” button or operate the emergency breaker lever locally. Check that the

main steam valve and the steam control valve are shut and the rotating speed drops. If a

vacuum breaking is required, shut the steam vent butterfly valve and the steam trap

valves of the small steam turbine before cutting off steam supply to the seal gland;

10.5.1.5 Complete other operations required for a small steam turbine shutdown;

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10.5.2 Emergency Shutdown of Electric Pump

10.5.2.1 Emergency Shutdown of Electric Pump

1) Pump motor or coupler gives off smoke or catches fire;

2) Any bearing metal temperature or return oil temperature exceeds the limits, or oil

supply to the bearing fails, or the bearing gives off smoke;

3) The steam supply pipes or feed water pipes burst and fail to be isolated;

4) The electric pump has a serious vaporization

5) The pump motor has an overcurrent, which fails to drop to normal;

6) The main body of the electric pump has a serious leakage, which spurts large

quantities of steam/water and endangers pump operation safety;

7) When the pump protective action value is reached but the protection mechanism fails

to work;

8) The pump vibrates violently and there is clear and audible metallic abrasion or impact

sound;

9) The oil system electric pump has a serious leakage, the oil level drops to the lower

limit and corrective measures fail.

10.5.2.2 In the case of an emergency shutdown of the electric pump, operate in the

central control room or push the emergency button locally.

10.5.2.3 Check that the auxiliary oil pump has been automatically commissioned;

10.5.2.4 Throw the scoop tube to zero and promptly shut the electric valve at the pump

outlet and the midpoint tap valve.

10.5.2.5 Complete other operations required for the shutdown of the pump.

10.5.3 Vaporization of Feed Pump

10.5.3.1 Symptoms

1) The pump current oscillates and drops, the rotating speed of the steam pump

oscillates and the booster electric pump/steam or has a current oscillation;

2) The outlet pressure of the electric/steam pump oscillates and drops;

3) The feed water flow rate oscillates and drops;

4) The contact surfaces and the seal glands at both ends have steam leakages

5) The interior of the pump gives off noise or impact noise, pump vibration escalates or

the rotor floats at the end;

10.5.3.2 Causes

1) The deaerator pressure drops sharply;

2) The strainer at the pump inlet is clogged, causing an under-pressure at the inlet;

3) When the flow rate is low, the recirculating pump is not open;

4) The steam pump operates for too long a time at a low rotating speed;

5) The deaerator water level is too low.

10.5.3.3 Treatment:

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1) If the electric pump has vaporization, shut down the pump when the boiler is in the

ignition process. Locate and correct the cause and restart the pump. If the vaporization

of a loaded pump is caused by a low deaerator level, shift the load to the steam pump

and shut down the electric pump immediately;

2) If the steam pump has a vaporization, start up the electric pump and shut down the

steam pump immediately. Reduce the pump load according to the feed water flow.

3) Open the vent valve for the main body of the steam pump to discharge the steam. Do

not restart the pump until the turning gear operates flexibly and restores to normal.

Monitor the internal noise and vibration of the small steam turbine and the pumps.

11. Auxiliary Steam System

11.1. Pre-Start-up Check and Preparation 11.1.1 Carry out a cross examination of the auxiliary steam and confirm that the pipes

have sound connections, the front and rear manual valves of the steam traps are open

and the steam trap bypass valves are closed. If the system is commissioned for the first

time or is to be decommissioned for a long time, use the bypass for drainage. The

drainage should find its way into the floor drain before vacuum is created. After vacuum is

created, the drainage must be poured into the condenser.

11.1.2 Before the auxiliary steam system is commissioned and close all the steam

converter valves and isolating valves for all users;

11.1.3 Check that all control valves and electric valves are working properly and closed;

11.1.4 Check that all temperature and pressure gauges are commissioned;

11.1.5 Confirm that the condenser and the constant flash tank are ready to accept

drainage.

11.2. Auxiliary System into Operation 11.2.1 Commissioning of Auxiliary System

11.2.1.1 Check that the steam trap valves of the auxiliary steam header and of the steam

supply pipes are open. Check that the auxiliary steam system has met all commissioning

conditions;

11.2.1.2 Open the isolating valve connecting the boiler to the auxiliary steam manifold or

the communication valve for the auxiliary steam manifold of the adjacent unit. Maintain the

steam pressure between 0.05MPa and 0.1MPa and heat the pipe for 20 minutes. Fully

open the isolating valve between the boiler and the auxiliary steam manifold or the

communication valve for the auxiliary steam manifold of the adjacent unit;

11.2.1.3 Slightly open isolating valve at the steam inlet of the auxiliary steam header.

Maintain the header pressure between 0.05MPa and 0.1MPa and heat the header for

20minutes;

11.2.1.4 After the header heating process, adjust the isolating valve at the steam inlet of

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the auxiliary steam header to boost the pressure to 0.6MPa-1.2MPa. Check that the

header temperature is above 250 ;℃

11.2.1.5 After vacuum is established for the condenser, switch the auxiliary steam trap to

the condenser. Check that the vacuum of the main steam turbine is normal and the

condensate quality is normal;

11.2.1.6 Commission the auxiliary steam for different users according to their needs;

11.2.1.7 When the cold reheater has a pressure higher than that of the auxiliary steam,

switch to the cold reheater for steam supply to the header; 1）Open the electrical steam supply valve between the colder reheater and the header;

2）Commission automatic pressure control mechanism for the pipes between the cold

reheater and the auxiliary steam. Check that the automatic control and the header

pressure are normal; 3）Slowly close the steam supply isolating valve between the boiler (or adjacent unit) to

the header. Check that the header has normal pressure; 4）The rear steam trap for the pressure control valve of the cold reheater must operate

reliably;

11.2.1.8 When the 4th extraction has a pressure exceeding that of the auxiliary steam,

switch to the 4th extraction for steam supply to the header: 1）Open the electric valve between the 4th extraction and the auxiliary steam;

2）Check that the pressure and temperature of the header are normal and the steam

supply control valve between the cold reheater and the auxiliary steam is automatically

shut; 3）Ensure that the steam trap of the 4th extraction is operating continuously;

11.3. Shutdown of Auxiliary Steam System 11.3.1 Confirm that all users have stopped the use of steam. Switch steam supply for

users of the shared system to the adjacent unit. A prior consent of the shift supervisor

must be obtained;

11.3.2 Shut the isolating valves leading to different users;

11.3.3 Close the steam supply valves leading from the colder reheater, 4th extraction,

adjacent unit and startup boiler to the header;

11.3.4 After the steam trap valve between the auxiliary steam system and the condenser

is closed, open the steam trap valve for the auxiliary steam system and drain out the

header and the pipes.

11.4. Operating Monitoring and Adjustment 11.4.1Check that the header pressure and temperature are normal;

11.4.1Promptly switch the auxiliary steam supply and maintain the pressure within

tolerance according to load changes;

11.4.1Check that the system has no leak and the pipes have no vibration;

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11.4.1Limits of Operational Parameters of Auxiliary Steam System

Item Unit Normal Value

Boiler Steam Pressure MPa

Boiler Steam Temperature ºC

Cold Reheater Steam Pressure MPa 3.67

Cold Reheater Steam Temperature ºC 321

4th Extraction Steam Pressure MPa 1.052

4th Extraction Steam Temperature ºC 363.1

Header Pressure MPa 0.6-1.29

Header Temperature ºC 370

11.5. Accidents Treatment of Auxiliary Steam System 11.5.1 High Header Pressure

11.5.1.1 Symptoms

1) The header pressure is higher than the normal value.

2) The safety valve has a response;

11.5.1.2 Causes

1) The pressure control valve of the cold reheater is open by mistake;

2) The auxiliary steam pressure transducer has a fault;

11.5.1.3 Treatment

1) Switch the pressure control valve promptly to manual mode and close it. Monitor the

pressure drop. Prevent a pressure drop of the auxiliary steam. Contact the maintenance

staff for a solution;

2) If the pressure transducer has a fault and fails to monitor the pressure, no steam

supply must be provided from the cold heater of the unit;

11.5.2 Low Header Pressure

11.5.2.1 Symptoms

1) The supply of seal gland steam and soot-blowing steam has too low a pressure and

the system sounds an alarm;

2) The header has a low pressure;

11.5.2.2 Cause

1) The unit has a low load, the 4th extraction has a low pressure and the pressure

control valve of the cold reheater is not correctly commissioned;

2) The auxiliary steam pressure transducer for the unit has an abnormality.

3) The unit consumes too much auxiliary steam; 11.5.2.3 处理Treatment

1) If the problem results from a malfunctioning pressure control, switch to the auxiliary

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steam header for steam supply and contact the maintenance staff;

2) If the problems results from too much auxiliary steam, reduce or readjust steam

supply to a proper extent;

3) Ensure steam supply to the seal gland;

12. Generator Sealing Oil System

12.1. Pre-Startup Check 12.1.1 Finish the operations as specified by General Rules for Pre-Startup Check of


12.1.2 Check that the valve is in a correct position by pushing the valve check card prior to

startup.

12.1.2 Check that the Lubricating oil system for the main steam turbine has been

commissioned and is operating reliably;

12.1.3 Check that the interlock protection test on the sealing oil system has been passed

and the system has been commissioned;

12.1.4 Check that the sealing oil vacuum box has been refilled and the oil level is normal;

check that the air exhaust header is operating normally and the sealing oil pumps have all

been refilled;

12.2. Sealing Oil System in Operation 12.2.1 Start a smoke exhaust fan of the air exhaust header to confirm that the negative

pressure is between -25 mmH2O ~ -50 mmH2O. Check that the fan is working properly.

Commission another smoke exhaust fan in the standby mode;

12.2.2 Open the isolating valve of the main steam turbine between the lube oil to the

sealing oil system;

12.2.3 Check the differential pressure control valve works properly and the oil/gas

differential pressure is normal;

12.2.4 Check that the floater sealing oil tank has properly oil drainage. Open the bypass

valve of the floater oil tank when the internal pressure falls below 50kPa;

12.2.5 Check that the sealing oil expansion header has normal oil level and no alarm

signal; 12.2.6 ；Conduct a gas displacement for the generator in the mode where sealing oil is

provided for the lube oil of the main steam turbine bearing; 12.2.7 ；After all the gas in the generator is displaced with acceptable purity hydrogen,

commission the sealing oil system in the normal working mode;

12.2.8 Commission the oil/hydrogen differential pressure control valve in the automatic

mode and check that the differential pressure is normal;

12.2.9 Start the sealing oil vacuum pump and maintain the vacuum degree around

-0.07MP;

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12.2.10 Start a main sealing oil pump and open the oil outlet valve to check that the outlet

pressure is normal. Start the sealing oil recirculating pump and check that it works reliably;

12.2.11 After the oil level in the sealing oil vacuum tank returns to normal, open the

evacuation valve widely to increase the vacuum degree to the rated value (between

-0.09~-0.096KPa)

12.2.12 Check that the oil/hydrogen differential pressure control valve for the sealing oil is

working reliably and the differential pressure is normal;

12.2.13 Check and confirm that the floater sealing oil tank has normal oil level. When the

interior pressure exceeds 50KPa, open the inlet/outlet valves of the tank and close the

bypass valve;

12.2.14 After the sealing oil system operates stably, confirm that the inlet/outlet oil valves

of another main sealing oil pump and of the DC sealing oil pump are open. Actuate the

interlock on standby and confirm that the standby pump has no reversed rotation;

12.2.15 Check that the sealing oil system operates properly before charging hydrogen into

the generator to increase the pressure to 0.414MPa.

12.3. Operation and Maintenance 12.3.1 Ensure that the oil/hydrogen differential pressure control valve of the sealing oil is

correctly adjusted. When the rotor is stationary, maintain the oil/hydrogen differential

pressure between 0.036MPa and 0.076MPa; when the rotor is in operation, maintain the

oil/hydrogen differential pressure between 0.05MPa and 0.07MPa. Too high or too low a

differential pressure is unacceptable. This is intended to prevent a hydrogen leak or oil

ingression into the generator;

12.3.2 Commission one sealing oil strainer and maintain the other on standby. Clean the

strainer on a regular basis;

12.3.3 The vacuum oil tank and the floater oil tank for the sealing oil must have normal oil

level. Vacuum degree must exceed -0.088MPa;

12.3.4 While the sealing oil vacuum tank is in normal operation, maintain the vacuum

above -0.09MPa to separate and drain the vapor in the oil;

12.3.5 Check if the oil separator of the sealing oil vacuum pump has accumulated water in

it. If there is accumulated water, drain it immediately;

12.3.6 Check the oil/water detector on a regular basis to check if there is accumulated

water. If there is accumulated water, check the system operation;

12.3.7 While the sealing oil system is in operation, the vent valves on top of the floater oil

tank must not be shut;

12.3.8 The sealing oil system of the generator operates in any of the following modes in

order to provide sealing for hydrogen in the generator under different conditions;

12.3.8.1 While the generator is in normal operation, commission one of the main sealing

oil pump and maintain the other one on standby. The oil supply comes from the lube oil for

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the main steam turbine;

12.3.8.2 When the main sealing oil pump fails or the AC power supply fails, switch to the

DC sealing oil pump to intensify monitoring of hydrogen purity. When hydrogen purity

drops perceptibly, drain the pump and replenish it with hydrogen once every eight hours;

12.3.8.3 When the AC/DC sealing oil pump fails, the oil/hydrogen differential pressure is

maintained by the lube oil for the main steam turbine. Enforce an emergency shutdown

and drain the hydrogen. Reduce the internal pressure to 0.02-0.05MPa;

12.3.8.4 While the Lubricating oil system of the main steam turbine fails, the sealing oil

system can operate independently. Maintain a high vacuum degree for the sealing oil

vacuum tank. A high vacuum degree will maintain the sealing oil for short-term operation;

12.3.10 Limits of Operational Parameters of Sealing Oil System

Item Unit Normal Value Upper Limit

Lower Limit

Sealing Oil Temperature ℃ 35-45 - -

Sealing Pad Return Oil

Temperature ℃ ≤75

Sealing Oil Return Oil

Temperature ℃ ≤70 - -

Vacuum Oil Tank Level m 0 (Oil tank center line) 65-75 35-45

Vacuum Oil Tank Vacuum MPa -0.09～-0.096 - -0.088

Oil/Hydrogen Differential

Pressure MPa

Oil pressure exceeds

hydrogen pressure

0.056±0.02

- -

12.4. Sealing Oil System Shutdown 12.4.1 Shutdown Conditions

12.4.1.1 All hydrogen within the unit has been displaced with air with purity above 95%.

The internal pressure is above 50KPa;

12.4.1.2 The turning gear of the turbine has stopped (the sealing oil system must not be

shut down when the rotor is rolling, otherwise the sealing pads will be damaged);

12.4.2 Sealing oil System Shutdown

12.4.2.1 Release the standby main sealing oil pump and the DC sealing oil pump from the

interlock;

12.4.2.2 Shut down the sealing oil vacuum valve;

12.4.2.3 Decommission the sealing oil pump and the recirculating pump;

12.4.2.4 Shut the isolating valve for lube oil supply to the sealing oil;

12.4.2.5 Check and confirm that the oil/water detector doesn’t sound an alarm; otherwise,

open the bypass valve for the floater oil tank to reduce the oil level in the expansion

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header;

13. Generator Hydrogen Cooling System

13.1. Gas Displacement Mechanism for Hydrogen Cooling System 13.1.1 Gas displacement should be conducted when the rotor is stationary or when the

turning gear is operating (Gas consumption rockets up when the turning gear is in

operation).

13.1.2 Before the hydrogen cooling system is commissioned, displace the air with carbon

dioxide. When the carbon dioxide content in the unit exceeds 85%, displace carbon

dioxide with hydrogen;

13.1.3 When the hydrogen cooling system is decommissioned, displace hydrogen with

carbon dioxide. When the carbon dioxide content in the unit exceeds 95%, displace

carbon dioxide with air;

13.1.4 Maintain the gas pressure in the unit around 0.02MPa-0.03Mpa all through the gas

displacement process;

13.1.5 The operation of the hydrogen dryer must be synchronized with the gas

displacement process for the generator;

13.1.6 Vent the following valves at regular intervals during the whole gas displacement

process. Each venting operation must continue for 5 minutes. One venting operation is

needed before the purity of each gas approaches the specified value (purity: up to 95%).

The valves are closed after the venting process;

13.1.6.1 Vent Valve S-79 is used for the vent pipes at the excitation end of the sealing oil

expansion header;

13.1.6.2 Vent Valve S-78 is used for the vent pipes at the steam end of the sealing oil

expansion header;

13.1.6.3 Displaced Gas Outlet Valve 142 is used for the hydrogen dryer;

13.1.6.4 Blow-Down Valves 126 and 127 are used for Oil/Water Detectors A and B;

13.1.6.5 Valve 104 is used for the generator gas purity detection pipes;

13.1.7 When operating the vent valve of the sealing oil expansion header, do it slowly to

control the pressure drop speed for the interior of the unit and prevent large fluctuations of

the oil level from causing oil infiltration into the generator;

13.1.8 During the gas displacement, remove the hydrogen hydrograph on the inlet/outlet

pipes of the dryer and open the bypass valve;

13.1.9 During the gas displacement, check that the sealing oil system works properly for

the generator and the oil/gas differential pressure is maintained around 0.056MPa;

13.1.10 During gas displacement for the generator, fire operations or electrical operations

are prohibited around the hydrogen system;

13.1.11 Before the hydrogen inflow/outflow process, commission the rooftop-mounted

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ventilator.

13.1.12 During the gas displacement for the generator, check the oil levels in the main oil

tank, vacuum oil box, return oil expansion header, floater oil tank and generator leak

detector;

13.2. Pre-Startup Check of Hydrogen Cooling System 13.2.1 Finish the operations as specified by General Rules for Pre-Startup Check of


13.2.2 Check that the valve is in a correct position by pushing the valve check card prior to

startup.

13.2.3 Confirm that the main steam turbine Lubricating oil system and the generator

sealing oil system have been correctly commissioned. If the pressure in the generator is

below 50KPa, the oil for sealing the gas within is directly supplied by the main steam

turbine lubricating oil system;

13.2.4 Check that the quantity of carbon dioxide is adequate;

13.2.5 Contact the chemical engineer for preparation of an adequate quantity to maintain

a normal pressure for the hydrogen manifold;

13.2.6 The operation of the hydrogen dryer must be synchronized with the gas

displacement process for the generator;

13.2.7 Finish the water filling and venting operation for the water side of the hydrogen

cooler and commission automatic temperature control for the cooler;

13.2.8 Contact the heat engineer, who must provide at least 2 hours of electric preheating

for the gas displacement detector;

13.2.9 During the gas displacement process for the generator, fire operations or electrical

operations are prohibited around the hydrogen system;

13.3. Hydrogen Cooling System in Operation 13.3.1 Displace the air with carbon dioxide;

13.3.1.1 Check that the inlet valves (A and B) of the hydrogen pressure reducer are shut;

13.3.1.2 Open the outlet/inlet valve (11) for carbon dioxide control;

13.3.1.3 Open the carbon dioxide inlet valve (117) of the gas displacement control station

for a generator gas displacement;

13.3.1.4 Open the hydrogen outlet valve (120) of the gas displacement control station for

the generator;

13.3.1.5 Open the gas outlet valve (119) of the gas displacement control station for the

generator. Adjust the opening of the valve to control the internal pressure within the range

of 0.02-0.03MPa;

13.3.1.6 Open the isolating valves (140 and 144) of the inlet pipes of the analyzer and

adjust the gas inflow into the analyzer;

13.3.1.7 Open the outlet valve for the carbon dioxide cylinder;

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13.3.1.8 Adjust the pressure reducer for carbon dioxide control and maintain the pressure

between 0.05MPa and 0.1MPa for the reducer. Make sure that the carbon dioxide inlet

pipe must not have dews within 3 meters of the generator. When the outlet pressure of the

carbon dioxide cylinder drops to 0.5MPa, use another cylinder;

13.3.1.9The indication of carbon dioxide purity must be 85%. Contact the chemical

engineer for a sampling check;

13.3.1.10 When the purity attains to 90%, close the cylinder outlet valve;

13.3.1.11 Close the inlet/outlet valve (11) for carbon dioxide control;

13.3.1.12 Close the carbon dioxide inlet valve (117) of the control station for generator gas

displacement;

13.3.1.13 Close the hydrogen outlet valve (120) of the control station for generator gas

displacement;

13.3.2 Displacement of Carbon Dioxide with Hydrogen

13.3.2.1 Open the carbon dioxide outlet valve (121) of the control station for generator gas

displacement;

13.3.2.2 Open the gas outlet valve (119) of the control station for generator gas

displacement;

13.3.2.3 Open the inlet/outlet valves (3 or 5; 4 or 6) of the hydrogen pressure reducer;

13.3.2.4 Open the inlet/outlet valve (1 or 2) for hydrogen control;

13.3.2.5 Adjust the outlet pressure of the hydrogen pressure reducer to control the inlet

hydrogen pressure and maintain the internal pressure between 0.02MPa and 0.03 MPa;

13.3.2.6 The hydrogen purity in the generator must attain to 95%; contact the chemical


13.3.2.7 After the hydrogen purity is acceptable, keep the following valves open: hydrogen

outlet valve (120) for the control station, gas outlet valve (119) and carbon dioxide outlet

valve (121) of the control station. Boost the hydrogen pressure for the unit and the sample

gas will be delivered to the gas analyzer for hydrogen purity determination;

13.3.2.8 Switch the generator sealing oil system to normal mode;

13.3.2.9 Raise the hydrogen pressure in the generator step by step to 0.414MPa. Check

that automatic control mechanism for the sealing oil pressure works properly and maintain

the oil/hydrogen differential pressure around 0.056MPa;

13.3.3 Commission the hydrogen dryer to operation;

13.3.4 Open the inlet/outlet valve of the hydrograph on the inlet/outlet pipes of the

hydrogen drier, close the bypass valve and commission the hydrograph. Check that the

indicated dew-point temperature is equal to or below -21 . ℃

13.4. Operation and Maintenance of Hydrogen Cooling System 13.4.1 Check that the interior of the generator has proper hydrogen pressure, purity and

humidity;

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13.4.2 Check that the inlet/outlet hydrogen temperature and the automatic temperature

controller of the hydrogen cooler are normal;

13.4.3 Check that the hydrogen supply pressure and the hydrogen pressure reducer are

normal;

13.4.4 Check that there is no water/oil accumulation in the leak detectors at regular

intervals. If there is water/oil, analyze and correct the cause. If necessary, increase

draining frequency and report to the shift supervisor;

13.4.5 Check the blow-down valves on the inlet/outlet pipes of the hydrogen purity

analyzer and arrange for drainage at regular intervals to ensure proper operation of the

purity analyzer;

13.4.6 Drain and check the hydrogen drier at regular intervals. If any rise in drainage is

detected, check that the drier operates reliably and correct the fault;

13.4.7 Check the surroundings of the generator on a regular basis to ensure that the

hydrogen content in the potential accumulation areas is within a normal range;

13.4.8 Monitor any hydrogen leak. The normal leak of this unit must be below 13-19m3/d.

If the leakage increases, identify the cause and ask the responsible department for

coordination;

13.4.9 For gas discharging in normal unit operation, use the hydrogen vent valve (120) of

the control station. Do not use the vent valve on top of the sealing oil expansion header;

13.4.10 Limits of Operational Parameters of Hydrogen Cooling System

Item UnitNormal Value

Upper Limit

Lower Limit

Hydrogen Supply Manifold Pressure MPa ＜3.2 - -

Hydrogen Supply Dew Point ℃ ≤-21 - -

In-Generator Hydrogen Pressure MPa 0.414 - -

Dryer Outlet Temperature ℃ 18 - -

In-Generator Hydrogen Purity % ＞98 - 96

Hydrogen Cooler Outlet

Temperature ℃ 46

- -

Ambient Oxygen Content % ＜2 - -

13.5. Shutdown of Hydrogen Cooling System 13.5.1 Stop the hydrogen drier;

13.5.2 Check if there is an adequate quantity of carbon dioxide;

13.5.3 Close the hydrogen outlet/inlet valve (1 or 2) and the inlet and outlet valves of

hydrogen pressure reducer (3 and 5; or, 4 and 5);

13.5.4 Remove the hydrogen hydrograph on the inlet/outlet pipes of the hydrogen drier.

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13.5.5 Close the carbon dioxide outlet valve of the control station for generator gas

displacement;

13.5.6 Follow these steps when displacing hydrogen with carbon dioxide:

13.5.6.1 Slowly reduce the interior hydrogen pressure to 0.02MPa-0.03MPa, using the

gas displacement& outlet valve of the hydrogen drier. Adjust the operation mode of the

sealing oil system promptly to switch to the main steam turbine Lubricating oil system for

supply of sealing oil. Prevent oil penetration into the generator;

13.5.5.2 Open the main inlet valve (11) for carbon dioxide control;

13.5.5.3 Open the carbon dioxide inlet valve (117) of the control station for generator gas

displacement;

13.5.5.4 Open the hydrogen outlet valve (120) of the control station for generator gas

displacement;


displacement and adjust the opening of the valve to control the specified internal

pressure;

13.5.5.6 Open the outlet valve of the carbon dioxide cylinder;

13.5.5.7 Adjust the carbon dioxide pressure reducer to maintain the pressure around

0.4MPa. When the outlet pressure drops to 0.5MPa, use another cylinder;

13.5.5.8 The indication of carbon dioxide purity must be 95%. Contact the chemical


13.5.5.9 If the purity is acceptable, close the outlet valve of the cylinder;

13.5.5.10 Close the inlet/outlet valve (11) for carbon dioxide control;


displacement;

13.5.6 Follow these steps when displacing carbon dioxide with air:

13.5.6.1 Check and confirm that the inlet/outlet valves of the hydrogen pressure reducer

and the inlet/outlet valves (11) for carbon dioxide control have been shut;


displacement;

13.5.6.3 Close the hydrogen outlet valve (120) of the control station for generator gas

displacement;

13.5.6.4 Open the carbon dioxide outlet valve (121) of the control station for generator gas

displacement;


displacement;

13.5.6.6 Open the displacement air on-off valve (115) and the displacement air inlet valve

to charge the generator with air;

13.5.6.7 The charging of compressed air must not be stopped unless the carbon dioxide

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content is below 5%;

13.5.6.8 After the displacement is finished, close all the aforesaid valves;

Date post:	01-Nov-2014
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Turbine Operation Manual 600 MW Dongfang

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