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STEAM TURBINESTEAM TURBINE

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An Introduction toAn Introduction to

Steam Turbine at Shuweihat S1 throughAn Overview of the Steam Turbine and its

subsystemsBasic logics of some of the systems –

made easy

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What will we do?What will we do?

Take a look at -Technical Data, pictures and section

drawings - MAALube Oil System - MAVControl Oil System - MAXGland Steam System - MAWTurbine Drain System – MALGo around the ST

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What we will cover in a session What we will cover in a session sometime latersometime laterTSE and MarginsSTG Start Up and Shut DownSTG controllerDetailed discussion on ProtectionsLub Oil Purification Unit

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Simple Rankine CycleSimple Rankine Cycle

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2 to 3: Isobaric heat rejection (Condenser)

3 to 4: Isentropic compression (Pump) 4 to 1: Isobaric heat supply (Boiler) 1 to 2: Isentropic expansion (Steam

turbine )

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Name Plate DetailsName Plate Details

Order No - 10445 Year of Manufacture -2003

Steam Press. – 76.5 Bar Steam Temp. – 560 ºC

Speed – 50 rps Rated Capacity – 251.35 MW

Exhaust Steam Pressure – 2.8 Bar

Type- M30-40

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Steam Parameter LimitsSteam Parameter LimitsSteam Flow – 325.44 kg/sSteam Pressures in Bar Absolute

Nominal Long Term Short Term

Main Steam 76.5 85.7 99.5*

Before 1st Stage 75.5 81.5 81.5

Exhaust Steam 2.23 5.0 7.0

Long Term – Upper limit with no time restrictionShort Term – Permissible instantaneous value with cumulative duration not more than 12 hours in a year.* - Set the safety valve so as not to exceed this value

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ST Speed Sensors -Total 6

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Turbine Oil SpecsTurbine Oil Specs

Mineral or Synthetic oil of viscosity class ISO VG 32 or ISO VG 46 (DIN 51 519)

Capable of withstanding 120 ºC in bearings and 80 ºC in the oil tank without physical or chemical degradation.

Hydraulic Oil – ISO-L-HM46 (DIN 51524-HLP46) capable of withstanding 70 ºC.

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Hydro Safe ISO VG 32Hydro Safe ISO VG 32 Non-Toxic - Biodegradable - Environmentally Friendly

Antiwear - Hydraulic Oil Hydro Safe ISO VG 32 is a vegetable based hydraulic fluid formulated to

meet the demand for biodegradable hydraulic oils. It is designed to minimize environmental impact and have low environmental persistance. Hydro Safe ISO VG 32 offers excellent antiwear performance in a wide array of hydraulic components, and can be used as a superior replacement for conventional petroleum oil. It exhibits good thermal and oxidative properties when compared to other vegetable-derived products. Formulated from canola oil, and containing biodegradable, non-toxic chemical additives. Its high vicosity index (VI) allows outdoor operations in winter and summer without the need for fluid changes or equipment modifications.

Viscosity Index ASTM D-567, ASA Z11.45 is an empirical number indicating the rate of change in viscosity of an oil within a given temperature range. A low viscosity index signifies a relatively large change in viscosity with temperature change, while a high viscosity index shows a relatively small change in vicosity with temperature change. Viscosity Index cannot be used to measure any other quality of an oil.

The fluid is totally biodegradable, and exceeds the government criteria of being "readily biodegradable." Readily biodegradable is defined as an attribute of products that have a natural ability to biodgrade quickly and completely. Once the fluid is leaked into the ground, it has the ability of substance to be digested or consumed by naturally occurring microorganisms present in water, air, and soil systems. Complete biodegradability is the conversion of a substance to carbon dioxide and water.

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Steam Purity – Why ?Steam Purity – Why ?

Impurities can cause damage to turbine components by - corrosion, stress corrosion, corrosion fatigue, erosion-corrosion.

Deposition can cause - thermodynamic losses, lower efficiency, upsetting of pressure distributions, clogging of seals and clearances

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Values recommended for continuous Values recommended for continuous operationoperation

Parameter Unit Normal Value Achievable Value

ACC @ 25 ºC μS/cm < 0.2 0.1

Na μg/kg < 5 2

Silica μg/kg < 10 5

Total Iron μg/kg < 20 5

Total Copper μg/kg < 2 1

Mass weighted averaging for multiple sources. i.e. if A – conductivityA = ∑Mi * Ai / ∑Mi

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Limit Values for Start Up and cases of Limit Values for Start Up and cases of deviation from values recommended deviation from values recommended for continuous operation.for continuous operation.

Parameter Unit Action Level 1

Action Level 2

Action Level 3

Action Level 4

ACC @ 25 ºC μS/cm ≥ 0.2 < 0.35 ≥ 0.35 < 0. 5 ≥ 0.5 < 1.0 ≥ 1.0

Na μg/kg ≥ 5 < 10 ≥ 10 < 15 ≥ 15 < 20 ≥ 20

Silica μg/kg ≥ 10 < 20 ≥ 20 < 40 ≥ 40 < 50 ≥ 50

Total Iron μg/kg ≥ 20 < 30 ≥ 30 < 40 ≥ 40 < 50 ≥ 50

Total Copper μg/kg ≥ 2 < 5 ≥ 5 < 8 ≥ 8 < 10 ≥ 10

Hours per event allowable h ≤ 100 ≤ 24 ≤ 4 0

Cumulative time per year h/a ≤ 2000 ≤ 500 ≤ 80 0

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Output Limit During Valve Testing Output Limit During Valve Testing

While testing the Main Steam Stop and Control Valves with Automatic Turbine Tester, the Turbine output should be limited to 80%

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HP Steam from

2 Inlet Pipes

Butterfly Flap

Turbine Drain Valve

ESV 1

ESV & CV Drain Valves

Gland steam exhauster

ESV 2

CV 1

CV 2

Safety Valve

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TLRI 115/52

16.5 + 5% KV, 10462 A

299 MVA, COSØ – 0.85

COLD AIR – 41 ºC

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Turbine Stop & Control ValvesTurbine Stop & Control Valves

2 Stop and Control Valves eachStop and CV combined in a common body

with stems arranged at right anglesStop Valve – Single seat valve with

integral pilot disk. Hydraulic actuation against spring force – will close in case of power failure to solenoid

CV – Tubular disk with relieving holes. Hydraulic actuation against spring force.

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FunctionFunction – ESV – MAA11/12AA051 – ESV – MAA11/12AA051

Rapid and reliable interruption of Steam Supply to the turbine in case of activation of protection.

To allow admission of steam for warm up of the CV during cold start

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Function – CV – MAA12/22AA151Function – CV – MAA12/22AA151

Rapid interruption of Steam Supply to the turbine in case of activation of protection

Allow admission of steam into turbine for warm up during start.

Control the speed gradient during run up to Nominal speed

Control the load of the steam turbine when synchronised

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Example (Not at

S1)

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ST ESV

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ST CV

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TURBINE EXHAUST TURBINE EXHAUST AND SAFETY AND SAFETY

VALVESVALVES

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Functions•Safety Valve – Protects ST exhaust from too high pressure (4.0 bar)•Dump Valve – Opens when ST trips, to limit blading stress•Start-up valve – Protects blading from too high temperature caused by windage

•e.g. start up (Unit CB Off and speed > 47.5 Hz and Exhaust steam temp Prot high)

•Vent Valve – Opens during all starts at SGC ST step 21 and closes at step 22 (& speed > 9 Hz) – commissioning modification to vent out air in the exhaust section.

Globe valve – 10% rated MS flow•Hydraulic operated Safety Valve with steam pressure check device•Control fluid supply from MAX01 system•Opening time – 2s•Closing time – 15s•Has 4 functions

HP Steam from 2 Inlet Pipes

Butterfly Flap

Turbine Drain Valve

ESV 1

ESV & CV Drain Valves

Gland steam exhauster

ESV 2

CV 1

CV 2

Start up / Safety Valve

Steam Press Check DeviceSteam Press Check Device• 3 pressure switches – 1 of 3

actuation• 2 of 3 for turbine trip through TTS• Cyclic self test - If test not OK, test

stop and 1of 2 mode.• Manual check of device allowed

during turbine load operation but load < 80%

ST Exhaust Valve – NAA50 AA001ST Exhaust Valve – NAA50 AA001• Butterfly valve• Hydraulic actuator with closing

spring• 2 trip solenoid valves NAA50

AA013/014 – power supply from Turbine trip system

• Pilot valve NAA50AA011 for part lift test

• Closing time – 2s, Opening time – 150s

• Control fluid by extra unit with 2 pumps + a manual pump for emergency

• Task - To separate ST exhaust from Process steam header

ST Exhaust Valve – NAA50 AA001ST Exhaust Valve – NAA50 AA001• OperationOperation

• Open – dp > 100 mbar and SLC on

• Close – ST trip or Safety Valve open

• Fire Protection actuated – hydraulic system is switched off.

• During ST maintenance – can be locked in close position and seal air can be provided between the 2 ring seats

ST Exhaust Valve – NAA50 AA001ST Exhaust Valve – NAA50 AA001• Start TestStart Test

• Automatic Start by SGC ST, XS51

• Manual test by start command from OM (recommended once in 6 weeks)

• Pilot valve On – Valve closes slowly, 82% limit switch, switches off pilot valve (80% second limit switch)

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Lube Oil System - MAVLube Oil System - MAV

Safe Oil Supply to BearingsJacking up shaft at low speedsDriving the hydraulic turning deviceAvoid escape of oil vapours from the

bearings and the oil tankOil coolingOil PurificationSpecial Op mode during Fire Protn

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Main ComponentsMain ComponentsLub Oil Tank MAV10BB001 2 x 100% LOPs (~ 5.5 Bar) MAV21AP021/022 1 x 100% EOP (~ 2.5 Bar) MAV24AP001 2 x 100% Lift Oil Pps (~ 160 Bar) MAV24AP001 2 x 100% Vapour Extractor fans MAV82AN001/2 2 x 100% Lub Oil Coolers 2 x 100% Lub Oil Filters Thermostatic Temperature CV Oil Purification Unit

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10CT001•Should be > 10 Deg C to enable SGC Oil Supply•SGC Oil Supply maintains Oil Temperature between 25-35 Deg C in Shutdown Steps by Starting & stopping Pre-selected LO Pump

2v3-10FL021L = 1v3 < 1050 AlarmLL= 2v3 < 1000 ST Trip & Emg Operation/Fire Protection Activated

H= 1v3 >1150 AlarmHH=2v3 >1200 ST Trip

SGC Turbine Oil supply Start Enable Condition Oil Level 1170 – 1260 mm

2v3=42FP016If 1v3 < 2.5 Bar – WarningIf 2v3 < 2.3 Bar & Speed>0.25 Hz-Turbine Trip

10MAV

If DP>0.9 Bar -Alarm

Auto Pump Changeover1. If 42CP019<2.5 OR 21CP001<4.8 Bar

then Auto Changeover2. Electrical fault of Running Pump –

ACO3. EOP will start in any Change over

command

42CT001•High Warning at > 57 Deg C•Temp >30 Deg C - SGC ST Release at step 21

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35CT001•Temp > 65 –Warning•Temp > 70 Deg C & Speed < 0.15 Hz & TM HPS < 100 Deg C then Temp TOO High Alarm & Lift Oil Pump OFF

31CP001If Press> 180 Bar High Warning

If < 125 Bar – Low Alarm

35CP001If Press < 125 Bar and

Running Pump Discharge Press < 125

Bar - Press Low AlarmAlso Command for

AUTO CHANGEOVER

10MAV

82CP001 Press> -5 mBar – Auto Changeover

If DP>4.2 Bar -Alarm

If Oil Supply Emergency Operation is triggered by following reasons

1) Fire Protection Manual Switch is activated or detected OR CCR Push Button

2 Tank LOW LOW Level

Then following will be executed1)CF Supply Protection OFF2)Turbine Trip3)GC Oil Supply –Manual4)SGC Turbine OiL Supply –OFF5)Main LO Pumps –Prot OFF & SLC -OFF

6)EOP OFF Enabled7)SGC Check Oil Pumps-OFF8)Lift Oil Pumps OFF & SLC OFF9)Oil Maint System OFF10)Eop Protection ON11)Turning Gear OFF

RESET is required before Oil Supply can be RESTARTED

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HP side Bearing & Hydro-Motor

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Thrust Pads

Journal Bearing

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ST Shaft

Inner Wheel is connected to ST shaft

Outer Wheel is connected to

HYDRO Motor

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HYDRO Motor

Working Principle

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CLUTCH

Hydro motor & ST Shaft

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Manual Turning Gear MechanismManual Turning Gear Mechanism

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Control Fluid System MAXControl Fluid System MAX

Supply the ST ESVs, CVs and Safety Valve actuators with high pressure control fluid (160 Bar)

Fast closing/opening of valves when Trip signal actuated.

Transmission of electrical signals from turbine controller into hydraulic signals for fast and accurate positioning of CVs

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Main ComponentsMain Components

Control fluid tank MAX01BB001 2 x 100% control fluid pps MAX01AP001/002 2 Hydraulic accumulators MAX01BB011/012 2 filters downstream of each pump

MAX01AT011/012 1 Circulating oil pump MAX01AP011 1 Control fluid cooler MAX01AC011 Fine mesh filter d/s of cooler MAX01AT013

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CONTROL FLUID SYSTEM (MAX )

If DP>Max -Alarm

SGC Turbine Valves

01CP003•If Press < 150 Bar for 110secs then OR•If Press < 110 Bar then Low Press Alarm

CT901-2v3Low Low < 5 Deg C - Both Pumps Protection OFFTemp > 15 Deg C Enables SGC Turbine Valves Operation

High > 70 Deg

High High > 85 Deg C then ST Auto Shutdown by SGC Turbine Valves SD and Start Device- Set Point LOWERING

If any two Transmitters deviation > 5 then FAULT is Generated

Auto ChangeoverIf Press < 150 for 100 Secs then OR < 115 Bar then AUTOCHANGEOVER Command

If Both Pumps Discharge < 105 Bar then ST Prot TRIP

Alarm Only

If Discharge Header Press > 150 Bar & any one Pump in service

2v3 Level Switches1) Low2) Low Low3) Low LowAny 2v3 activates ST Protection and SGC Turbine Valves Auto Shutdown and Pumps Prot OFF

If CF Supply Emergency Operation is triggered by following reasons

1) Fire Protection Manual Switch is activated or detected

2) Oil Supply Emg Operaion is triggered

Then following will be executed1)CF Supply Protection OFF2)Turbine Trip3)CF Circulation Pump OFF4)SGC Turbine Valves –Auto Shutdown5)CF Pumps –Prot OFF & SLC –OFF6)Both ESVs Prot OFF

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MAD & MKD

Shaft Axial Position 2v3+ 0.5 mm ALRAM+ 1 mm ST Prot TRIPFault If Deviation between 2 transmitters > 0.09 mm

Bearing Casing Vibrations•Alarm > 9.4•Trip > 14.9•If Deviation between two Transmitters > 1 then FAULT

10MAD11 /12 CY021 / 22(mm/s)•Alarm > 9.3•Trip > 11.8•If Deviation between two Transmitters > 1 then FAULT

Relative Shaft-Brg Vib.

If Speed > 45 Hz and Value > 83 μm =Alarm

And Value > 130μm =High

If all channels of any measurement become faulty then ST TRIP

04/08/2352If all channels of any measurement

become faulty then ST TRIP

TURBINE JOURNAL / THRUST BRGS

1v3 > 90 Deg C -ALARM

2v3 > 130 Deg C –TRIP

GENERATOR BRGS

1v3 > 100 Deg C -ALARM

2v3 > 110 Deg C –TRIP

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DRAIN Valve before ESV MAL09/10AA011Open-OR condition1)SGC ST Step 72)Speed > 47.5 Hz & Steam Superheat Value < 20 o K3)Superheat Value – Fault & Load < 8 MWClose- OR condition1)SGC ST Step 19 or Step 552)Speed > 47.5 Hz & SH > 50 o K3) SH Fault & load > 40 MW

DRAIN Valve before CV MAL11/12AA011Open-OR condition1)SGC ST Step 52)SGC ST Step 18 & Upper Temp Margin Value > 5 K3)ESV & CV are Close & Speed > 47.5 Hz for 5 HrsClose-OR condition1)SGC ST Step 14/26/552)Speed > 47.5 Hz & ESV Opened & CV Position Not Closed

DRAIN Valve after CV MAL15AA011Open-OR condition1) SH HPS Steam - Inner casing OK & < 20 K2) TM HPS Groove < 440 º C & Load < 8 MWClose-OR condition1) SGC ST Step 552) SH HPS Steam - Inner casing OK & > 50 K3) TM HPS Groove > 450 º C & Load > 8 MW

DRAIN Valve Turbine casing MAL11AA011

Open-OR condition1) Level drain LPS Turb Mon > Max1 2) ESV 1 or 2 Opened & SH MS ahead

Turbine ≤ 10 KClose-OR condition1) SGC ST Step 552) (Level drain LPS Turb Mon > Max1 OR

(ESV 1 or 2 Opened & SH MS ahead Turbine ≤ 10 K)) Negated + 30 sec

IF Level drain LPS Turb Mon 10MAL22FL001 > Max2

DRAIN Valve Turbine casing MAL11AA011 will Protection Open and Block AP

GSE SystemIf > Max – Both the exhausters Prot OFFGSE SLC Auto ON in SGC ST Step 17 & Auto OFF in Step 55

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Gland Steam Extraction Points

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GLAND STEAM EXHAUSTER

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Thank You!Thank You!