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SUMMER TRAINING AT

PANKI THERMAL POWER STATION

PTPSKANPUR

UPRVUNL

SUBMITTED BY: SUBMITTED TO:

SHAILENDRA PRATAP SINGH Mr. T.C.GUPTA

B.TECH, 3rd YEAR EXECUTIVE ENGINEER

MECHANICAL ENGINEERING MAINTENANCE AND

PLANNING DIVISON

(MPD)PTPS,KANPUR(U.P)

ROLL NO. : 1004540046

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HARCOURT BUTLER TECHNOLOGICAL INSTITUTE,

KANPUR-208002

ACKNOWLEDGEMENT

I am extremely thankful to the members of Panki Thermal Power Station

(PTPS), Kanpur for their kind support and co-operation during my 4 weeks

of training period.

I would like to acknowledge Mr. T.C.Gupta(Assistant Engineer,

Maintainance and Planning divison (MPD IV) for giving me this fortunate

chance to learn the various applications of mechanical engineering in reallife. I express my sincere gratitude towards him for his wonderful guidance

in the department and making me understand the various stages of thermal

power generation.I also express my respectful gratitude towards all other

engineers and technical staff at MPD for their help and guidance during my

training period.

Finally, I thank all those who have helped me in the success of my training

program. They have added a lot to my knowledge.

SHAILENDRA PRATAP SINGH

B.Tech 3rd year

Mechanical Engineering

HBTI Kanpur

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CERTIFICATE

It is certified that SHAILENDRA PRATAP SINGH, student of 3rd B.Tech

Mechanical Engineering H.B.T.I. Kanpur has worked on the Project on

PTPS Kanpur under my guidance and supervision. He has shown sincere

efforts and keen interest during preparation of this project report. My best

wishes are with him, his efforts and his future endeavours.

Mr. T.C.GUPTA

Assistant Engineer

MPD IV

PTPS Kanpur

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INDEX

S. NO. CONTENTS PAGE NO.

1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

Acknowledgement

Index

Introduction

Organisational Set-up

Various divisions for effective working of PTPS

Water Treatment Plant

Boiler and Boiler auxiliaries system

Oil Handling Plant

Coal Handling Plant

Milling System

Coal firing system in the boiler furnace

Details of Boiler at PTPSSpecifications of the boiler

Steam generating units and auxiliaries

Technical specifications of the Milling Plant and

Fuel Firing System

2

4

6

8

11

13

15

15

16

17

19

2023

25

28

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15.

16.

17.

18.

19.

Turbine Maintenance Department (TMD)

Compounding of the steam turbines

Governing system of turbine

Turbine protection testing

Turbine oil pressure regulating system

Specifications of 110 MW Turbine

Important features of Turbine

Electronic instruments useful for the plant

Training in Electrical Maintenance Division (TMD)

Rating of Transformers of Unit 3 and Unit 4Current Transformer (CT)

Potential Transformer (PT)

Generator and Exciter

Introduction to Switch gears, Circuit Breakers and

Relays

Devices used for circuit breaking (making)

Fuse and Iron Clad Switches

Isolators

Circuit BreakersThermal Relays

Grid Substation

Wave Trap

Switch Yard

Tracks for Transformer

Control & Instrumentation Division

Various instruments of the C & I department

Turbo Supervisory equipments

Water Pollution Control

Air Pollution Control

Conclusion

30

31

31

31

32

33

34

34

35

3536

36

37

38

38

38

38

3942

43

44

44

44

45

45

46

4850

52

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INTRODUCTION

In India there is a very long chain of thermal power project including the

project in UP. Some of the power projects under Uttar Pradesh Rajya

Vidyut Utpadan Nigam Ltd. (UPRVUNL) are as follows:

S.No. Name of Power Project No. of Units Capacity(MW)

1 Harduaganj A 3 90

2 Harduaganj B 4 2103 Harduaganj C 3 230

4 Panki, Kanpur 2 210

5 Obra 8 550

6 Obra ext. 5 1000

7 Anpara 3 630

8 Anpara ext. 2 1000

9 Pariksha 2 220

Panki Thermal Power Station:

With the industrial development of Kanpur, a thermal power station was

established at the banks of river Ganga, in the year 1923, which was known

as Riverside Power House (RPH). In the year 1947, RPH was taken over

by the Government of UP under the name of Kanpur Electricity Supply

Administration (KESA). In 1962, RPH reached its maximum capacity of

100 MW leaving no scope of future development. Government of India

approved setting up of power station having capacity of 64 MW (2x32 MW).

The new plant was inaugurated on 17 Sep 1968 by the Prime Minister, Smt.Indira Gandhi.

In the year 1976, two units of 110 MW each were installed to meet the

increasing power demand. These units were inaugurated on 30 Jun 1976, by

the Chief Minister of UP, Mr. N.D.Tiwari.

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At present 2x32 MW units are not operating due to not having the suitable

Pollution control machinery. The Central government has commissioned a

210 MW unit at Panki Power Station.

At PTPS, 2x105 MW BHEL made coal fired turbo generating units are

presently in operation. These 105 MW machines were manufactured,

supplied and commissioned by M/s BHEL, during 1976-77 with features of

reheating and regenerative feed heating. The Steam Generator is balanced

draft, radiant, dry bottom, single drum, natural circulation, vertical water

tube type construction with skin casing and semi direct type of firing system.

Apart from the above 105 MW units, 2x32 MW Russia made turbo

generating units were also installed at PTPS in 1967-68, however these units

have become obsolete and permanently closed now after running for about

30 years.

Location:

PTPS is located in the West Kanpur in between Kalpi Road & the famous

Grand Trunk Road and is 16 km distant from the Kanpur Central Railway

Station. It is situated on the banks of lower Ganga canal and is connected

with the Panki railway station for the easy transportation of coal.

Availability of Raw Material at PTPS:

The main raw materials used in the plant are as follows:

Raw Material Source

Water Lower Ganga Canal

Coal Jharia Mines of Coal India Ltd., Bihar

Petroleum Products Indian Oil Corporation Ltd., Kanpur

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ORGANISATIONAL SET-UP

CHAIRMAN

DIRECTORS

GENERAL MANAGER

DGM (1) DGM (2) DGM (3) DGM (4)

Operation & Electrical Coal Handling Headquarters

Maintenance Stare & Civil

DGM(I)

Operation Group Maintenance Group

EE EE EE EE EE EE EEGP(A) GP(B) GB(C) GP(D) TMD BMD OPERATION

GENERAL

AE AE AE AE AE AEAE AE AE AE AE AE

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AE AE AE AE AE AE OG1 OG2

AE AE AE AE AE AE AE AE

AE AE

DGM (2) (ELECTRICAL)

Control & EMD EDD Central Purchase

Instrumentation Division

EE EE EE EE

AE AE AE AE AE AE AE AE AE AE AE AE AE AE

AE

DGM (3)

EE EE EE Transport Central

EFFI TRM Division Purchase Division Division

AE AE AE EE AE

AE AE

AE

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HQ

Store Division Power House Dispensary Civil Maintenance Division

AE AE AE AE AE AE

AE AE

ADMINISTRATIVE STRUCTURE OF PTPS

Employee of factory : GM

Circle officer : Superintending Engineer

Divisional officer : Executive Engineer

Sub-divisional officer : Assistant Engineer

Staff : Operators, Technicians & 4

th

class employee

The whole set up of management is known as a circle. The total number of

employees in PTPS is 1536.

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VARIOUS DIVISIONS FOR EFFICIENT WORKINGOF PTPS

Water Treatment Plant (WTP):

This division separates the physical and chemical impurities of water.

Coal Handling Division (CHD):

This division takes care of efficient supply of coal and oil fuel to the power

plant.

Boiler Maintenance Division (BMD):

This division looks after the efficient working and performance of boiler, its

mounting, its accessories, feed pump, milling system etc.

Turbine Maintenance Division (TMD):

This division looks after the efficient working of turbine and its accessories.

Electrical Maintenance Division (EMD):

This division takes care of the electrical networks and its elements in the

power station.

Control and Instrumentation Division (C & I):

This division takes care of various instruments fitted in the power plants for

controlling the generation of electricity.

Electrical Distributors Division:

This division looks after the distribution of produced electricity to the grid.

Civil Maintenance Division:This division looks after the construction and maintenance of various

structures in the power plant.

Operation General Division (OG 1):

This division takes care of the sanitation and cleaning etc of the power plant.

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Operation General Division (OG 2):

This division is responsible of the management of the power station. It deals

with the salaries of employees, recording and sending data related to the

performance of the power plant to the Head Office.

Store and Purchase Division:

This division deals with the storage and supply of various spare parts

requires in the power house along with their purchase.

Transportation Division:

This division looks after the transportation of coal.

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WATER TREATMENT PLANT

The water treatment plant is required as the water from canal cannot be

directly used in the boiler because it contains physical and chemical

impurities which have an adverse effect on plant operation. The turbidity of

this canal water is 80. The water used in the boiler is Demineralised water

(i.e. DM water).

Water from the canal is drawn by the pump house where large physical

impurities are operated by a screen having a net. This water is converted into

DM water in the following stages:

Flculator Plant:

In this plant the alum is added to water to precipitate dust particles in water.

Aluminium in alum neutralizes charge dust particles and dust particles

become very heavy and settle down. Bleaching powder and limestone is also

added to remove temporary hardness along with chlorine (liquid), which

removes bacteria and organic matter. Chlorine dosing is must during rainy

days. The process of sedimentation is applied to remove heavier particles.

Water is now stored in CST (Condensate Storage Tank).

Note: PAC (Poly Aluminium Chloride) is used instead of alum, when the

impurities in the canal water are more than a reasonable limit, especially

during the rainy season.

Clarifying Pump House:

It consists of five clarifying pumps, four service water pump and two

dividing pumps. Form the clarify pump house, the water goes to the

condenser and the sand filter.

Sand Filter:

These stages are put across the flow of water so as to remove other

suspended particles, if any. Now the turbidity of water is 2-3.

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Activated Carbon Filter:

This filter is employed for removal of bacteria and organic matter through

oxidation. It uses anthracite coal for filter. The turbidity of the water

obtained here is 1-2.

Cation exchanger:

At this stage, the ions (Ca, Mg, Fe) are absorbed by an ion exchange method

liberating H+ ions. HCl and resin (-ve) are principal ingredients of chemical

filters present here. Here the hardness of the water is removed.

Weak base anion exchanger:

Here the weak bases (acetic acid, carboxylic acid etc.) are absorbed by

carefully releasing OH- ions.

Degasser:

Here the gases like CO2, O2 and H2 are removed.

Strong base anion exchanger:

Here a resin is used which absorbs strong anions like SO 42-, Cl2-, phosphate

ion, silica etc. and releases OH-.

Mixed Bed Exchanger:

Here the remaining ions are extracted through both cation and anion resin.

The demineralised water is now ready which has the following

specifications:

Conductivity : 0.004 siemens/cm2

pH : 8.5-9

The desired pH in clear water is between 8.5 and 9. Phosphate dosing is

done at the end for this purpose. The total capacity of water treatment plant

is to provide 60 tonnes of water per hour.

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Low sulphur High stock oil (LSHS)

COAL HANDLING PLANT

A simple schematic diagram of the coal handling plant of PTPS is as shown.

The raw coal (bituminous coal) is brought to the power plant by the means

of railways. The wagon tripplers transfer it into the wagon triple hoppers

(WTH) which empties the coal from the wagons. The wagon capacity is

around 50-60 tonnes. From WTH the coal is transferred to the vibrators, it

separates the stone boulders from the coal from where it is then passed to the

conveyors. The length of the belt is 1000m and speed is approximately 7.2

km/hr.

The conveyor carries around 500 tonnes of coal per hour to crusher house

where the big pieces of coal are separated in a screen and sent to crusher

through conveyor from where the crushed pieces are transferred to other

conveyors. These are smaller particles of size ranging from 20 mm to 40 mm

or below. Then conveyor takes coal from where trippler transfer the coal to

raw coal bunker (RCB).

There are two suspension magnets present over conveyor just before crusher

house. These magnets remove any metallic impurities in the coal moving on

the conveyor belt.

The whole process described is valid when the coal brought by the trains

directly feed the RCB. When there is no train available then the coal comes

from the coal yard. The coal from the coal yard is dropped with the help of

bulldozers in the hopper from where it is transferred to the conveyors and

the process is repeated to carry the coal to the RCB.

When RCBs are full then the coal coming from the wagon trippler hopper,

after being crushed in the crusher house is transferred to conveyor which

carries it to the stacker that spreads the coal in the coal yard with the help of

boom conveyor. The boom conveyor can rotate 360 times on the stacker

which moves itself on a track laid over the length of the coal yard.

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Thus the coal gets stored in the coal yard, which can be used when the train

carrying coal are unavailable. In PTPS, more than one lakh tonnes of coal

can be stored in coal yard.

The coal handling plant also takes care of the storage purification and supply

of fuel oil, which is used for initial lighting up of the boiler furnace, and

generation of constant temperature in the furnace during normal operation.

Mode of operation in Coal Handling Plant:

1. Bunker filling operation: Coal flow from wagon trippler to boiler

house bunker

2. Reclaim operation: Coal flow from stockyard to boiler house bunker

3. Stacking: Coal flow from wagon trippler to stockyard

4. Bunker filling and reclaiming simultaneously

MILLING SYSTEM

A layout of the milling system at the PTPS is as shown in the figure. In a

thermal power plant pulverized coal is used for producing heat in the

furnace. This is because the burning of this state of coal takes place

completely and also there is lesser problem in ash handling. The coal pieces

of size 20 mm to 40 mm are taken from the RCB and through raw coal chainfeeder (RCF) their coal pieces are fed to the ball mills. In the ball mills, there

are steel balls of size 40, 50 and 60 mm and with a net weight of nearly 52

tonnes. These mills rotate about their axis and this makes the balls collide

with the coal pieces to break them into pulverized form.

Ball mills are provided with flue gases at about 300o C that helps drying the

coal and raises its temperature to about 85-90o C. There is a fan in the circuit

called as vapour fan, this fan solves three purposes:

It creates vacuum in the circuit so that the pulverised coal is sucked

out of ball mill with air.

If due to any reasons the supply of coal to the ball mill is broken and

flue gasses are continuously supplied then the temperature of the ball

mill will rise excessively high. To avoid this vapour fan thus

recirculates pulverized coal to the ball mill and so temperature of the

ball mill comes down.

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For cooling dry cold air is also supplied while recirculation. Cooling

is must because if the temperature becomes higher enough then the

coal can catch fire.

Micro particles of coal are directly sucked by the vapour fan with air andsupplied to the furnace chamber for combustion. The pulverised coal from

the ball mills is passed through a classifier that acts as a screen separating

out the bigger particles from the pulverized coal and returning them back to

the ball mill. From the classifiers the coal goes to the cyclone separators

where coal particles are separated from the air. The vapour fan pumps out

the air and the coal particles go to warm conveyor via turnicates. The warm

conveyor delivers the coal to be stored in pulverized coal bunker (PCB).

From PCB the coal goes to pulverized coal feeder that feeds the coal to the

furnace with the help of primary air fan (PAF). This fan takes air from

primary air heater and pushes the pulverized coal from all four corners of thechamber.

Secondary air fan (SAF) supplies hot air (taken from secondary air heater) to

the chamber for combusting the coal properly. Coal is supplied from the all

sides to have a uniform and complete combustion.

In PTPS there are three ball mills and four PCBs for each unit of 110 MW.

From ball mill A, coal can be directly given to PCB A and PCB B via

turnicates. Similarly from mill B to PCB B & PCB C and from mill Cto PCB C & PCB D. For any different combination of ball mill and from

those stated above, warm conveyor is used.

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COAL FIRING SYSTEM IN THE BOILER FURNACE

The steam generating unit has been designed for firing coal and oil at low

loads for stablisation. The fuel firing equipment is designed such that therated parameters would be reached when the fuel is fired. The burners are

located at corners of the furnace tangential to the imaginary circles, having

their centers co-axial with the center of the combustion chamber. At each

corner, there are nine compartments arranged as mentioned below.

There are four coal burner nozzles, three vapour burners and two oil burners

at each corner. The four coal nozzles are provided with air packets, which

flow around the coal fuel system. Each of the engine compartments is

provided with independent air dampers. All the adjustable tips are of

stainless steel to withstand high temperature.

Coal Bunkers:

Total bunkers : 16

Manufacturer : BHEL

Capacity : 3.65 ton/hr

Type : Tilting tangentially

Pulverised coal fired boiler:

With the increase in the size of the turbines, the boiler work also increases.They have to supply steam at a high temperature & pressure and in a bulk

quantity. In such type of the boiler coal is fired in pulverized form, which

has the following advantages:

1. Unlimited output capacity.

2. Even low grade coal can be burned.

3. Even very fine boiler output control is possible.

4. High efficiency.

5. Less possibility if unburned coal.

Fuel Oil System:

In the pulverized fuel fired oil boiler firing is used for safe and quick start up

of boiler ignition of pulverized coal and to bring stability to coal flame under

low output with eight flexible oil guns, two in each corner. The oil guns are

located at the top and bottom of secondary air nozzles and in between coal

nozzles. The oil guns are of pressure atomizing type.

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DETAILS OF BOILER AT PTPS

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A boiler is a closed vessel in which water under pressure is converted into

steam. It is one of the major components of a power plant. It is always

designed to transfer maximum amount of heat to the boiler water by all the

three modes of transformer: convection, conduction and radiation. Boilers

can be classified as water tube boiler and fire tube boiler.

a. Fire tube boiler:

In this type of boiler, products of combustion pass through tubes which

are surrounded by water. Depending on whether the tubes are horizontal

tube boilers they may be internally or externally fed. An internally fed boiler

has grate and combustion chamber enclosed including furnace. The grate is

separate and distinct from the boiler shell.

A fire tube boiler is simple, compact and rugged in construction. Its initial

cost is low. A vertical fire tube boiler occupies less floor space. However,

they are economical only for low pressure and therefore available in small

sizes having steam capacity of about 15,000 kg/hr.

b. Water tube boiler:

In this boiler, water flows inside the tubes and hot gases flow outside the

tube. The tubes are interconnected to common water channels and to steam

outlet. Water tube boilers are classified as vertical, horizontal and inclined.

The number of drums may be one or more. The circulation of water in the

boiler may be natural (due to difference in density between cold and hot

water) or forced through the action pumps. Forced circulation has the

advantages:

1. Lesser weight of boiler and cheaper foundation.

2. Lighter tubes.

3. Freedom from scaling problems.

4. Greater freedom in configuration of furnace, tubes etc.

5. Uniform heating of all parts.6. Better control of temperature.

7. Increased efficiency of boiler.

8. Quick response to load changes.

In view of all these modern boilers use forced circulation. However, forced

circulation means higher investment, more costly maintenance and increase

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in auxiliary power consumption. The unit is designed for minimum

continuous value of 375 tonnes/hr, at a pressure of 135 kg/sq. cm and a

temperature of 540o C. The reheat system steam flows at MCR. The feed

water temperature of the MCR is 240o C. The unit is balanced draft radiant

dry bolt on single drum, natural circulation, vertical tube type construction

with casing and a single reheat system.

The furnace is arranged for dry ash discharge and is filled with burners

located at the four pipes. Each corner burner is supplied with coal, vapour,

and oil filled secondary air components. The unit is provided with three ball

pipes and arranged to operate with intermediate coal power.

The steam super heaters consist of four stages which are ceiling, primary

S/H, platen and final super heaters. The ceiling terms the root of furnace and

horizontal pass and finishes as the rear wall of the second pass. The primarysuper heater is made up of horizontal bands located at the second pass while

the platens are located at furnace exits. The portion above the furnace too

encloses the super heaters. The control of super heater steam is achieved by

two stages of spray attempration which are located before the platen super

heater and the other located before the final super heater.

The re-heaters are in two stages. First and triplex heat exchanges located at

the second pass which absorbs heat from super heater a steam as well as

from flue gases. In the second stage exists re-heater located in the horizontal

pass as penitent tabular loop. Reheated steam temperature control valves and

the other emergency conditions by an attemprator located in the cold reheat

lines.

In order to ensure reliable and continuous operation ample soot blow

equipment is provided. There are start retractable steam soot blower

provided at the top of the furnace fully retractable steam soot blowers are

arranged for the horizontal re-heater and super heater in the rear pass. The

steam soot blowers are electrically operated.

SPECIFICATIONS OF THE BOILER

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Manufacturer : BHEL

Maximum continuous rating : 375 ton/hr

Maximum rating without stabilization : 240 ton/hr

Rated steam pressure at super heater outlet : 139 kg/sq. cm

Rated steam temperature at upper heater outlet : 540o C

Rated temperature of feed water at economizer inlet : 240o C

Rated steam flow through reheater : 324 ton/hr

Rated steam temperature at reheater inlet : 360o C

Efficiency of the boiler : 86 %

Design pressure of the boiler drum : 161 kg/sq. cm

Design pressure of the reheater : 42 kg/sq. cm

Motor for FD Fan:

Type : EL Motor

Rated output : 330 KWFull load current : 44 A

Induced Draft Fans (ID FANS):

It is a continuous type draft fan and its two units are used for each boiler.

The type is BHEL oxiall-430-2240. The induced draught fan does the

function of sucking the gas from the furnace, making the gas to flow through

the various heating surfaces & dust collecting equipment and sending the

gas out through the chimney with required velocity. The ID fan handles the

hot flue gases and sends the fly ash causing rapid erosion of impeller;

enough care is taken at the design stage to select the fan for the worst

condition.

Number : two per boiler

Capacity : 367200 m3/hr

Temperature of flue gases : 1215o C

Speed : 990 rpm

Motor for ID (Induced Draft) Fans:

Type : EL motor

Rated output : 440 KWFull load current : 127 A

Fan design ratings:

Capacity : 44.6x10 e-4 mm/hr

Total head developed : 410 mm

Maximum temperature of medium : 145o C

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Specific weight of medium : 863 Cp/cm

Fan speed : 990 rpm

Fan direction of rotation : clockwise

Blade type : laminated curved blade

Type of regulation : inlet valve regulation

Drive motor:

Manufacturer : MEEP, Haridwar

Frame size : 15-5-00-p

Design : Codena

Power:

Rated : 1000 KW

Actual power required : 740 KW

Rated voltage : 6600No. of phases : 3

Voltage & frequency:

Full load rpm : 990 rpm

Full load current : 104 A

Full load frequency : 94 %

Torque : 4.63

Frequency : 50 Hz

Terminal Connections:

Type : star

Number : 6

Note: The 6 leads taken out in the terminal box and connected on 4 brushes,

form a star.

STEAM GENERATING UNITS AND AUXILIARIES

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Supporting structure: It serves for arranging the suspending water wall

system, steam super heaters, re-heaters, economizers, air pre-heaters,

galleries insulation and sheet casing.

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Galleries and stairways: These provide access for maintenance like root

blowers, valve burners, dampers ant to various main & view holes.

Boiler drum and drum internals: Boiler drum is made of alloy steel plate

of thickness and has a diameter of 1800 mm. The drum is of fusion welded

on hemispherical dished ends. The function of the drum internals is to

reduce the dissolved solid content with the steam to a prescribed limit.

Rough mountings: These contents of access doors into the combustion

regions of super heater, economizers and air burners as well as observation

pots, explosion doors etc. The rough mountings are made of cast iron or are

of fabricated design.

Water walls: The combustion chamber is formed of water wall tubes onfour side diameters 60.3 mm set, at a pitch of 52 mm. In the corner where

the pulverized coal burners are located, the tubes are bent suitably to provide

opening for the sending of the tilting tangential burners.

Re-heaters: The steam re-heaters having a total surface area of 255.1 sq.

mm are made of pendant and horizontal tabular loops and are in two stages.

The first stage of horizontal tabular arrangements and the peripheral if

tabular is used. The steam for super heater flows through bigger tubes

outside diameter of 85 mm while the steam to be reheated flows outside the

tube through bigger tubes outside with a diameter of 70 mm. The super

heated steam from the triflux is drawn through three-way valve arranged in a

connecting pipe between the outlet of platen super heater and inlet of final

super heater. The second stage of super heater is suspended in the horizontal

pass of the boiler as pendant tabular loops. The reheater tubes are welded to

the inlet and exit heater.

Economiser:

The economizer with a heating surface of 4950 sq. cm made of steamless

tabular loops. The tubes of outside diameter of 32 mm are welded by meansof stubs to the inlet and outlet heater. The heater and horizontal loops rest on

supporting structure of second pass of the boiler with provision for free

expansion. The economizer blocks are arranged, with a second pass of the

heat recovery zone of the boiler so as to achieve recovery of heat in a very

common economic manner.

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inlet. The flue gases extraction ducting is made of alloy steel plate in view

of the fact that the hot gases will be around nozzles.

Soot Blower:

Below root in the furnace a top region the super-heater a reheater zone and

the economizer coils. Steam is used as the medium. The steam is tapped

from the pulled of the plate super-heater and the system includes are on the

reduction valves or safety valves. Four box type soot blowers at the trifler

reason and simple feed type root blower for economizers are also provided.

TECHNICAL SPECIFICATIONS OF THE MILLING

PLANT AND FUEL FIRING SYSTEM

Pulverising Mill:

Type : drum mill 800/575

Number of mills : three

Rated capacity : 20 tonnes/hr.

Type of drive : electric motor Speed : 990/990/171 and 170/175/170 rpm

Motor capacity : 6030 KW, 6.6 KV

Lubricating system:

Discharge pump : 22 l/min

Pressure of oil at pump : 80 psi

Quality of lubricated oil reqd. /mill : 350 l

Oil Cooler:Cooling water required : 7.5 com. /hr at 230o C

Raw Coal Feeder:

Type : chain feeder R600

No. of boiler : three

Type of drive : elect motor 7.5 KW

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Coal Burner:

Total no. of feeder : 16

Manufacturer : BHEL

Capacity : 3.65 ton/hr

Type : tilting tangentially

Oil Burners:

Number per boiler : 8 mm to tier

Type : manual with mechanized atomisation

Capacity : 800 kg/hr

Position of burner : at furnace corner

Cyclone Separator:

Type : SEA 1600/2Diameter of unit : 1600 mm

Efficiency : 82%

Vapour Fan:

Type : DL-1600-60

Type of inlet control : damper

No. of inlet : one

Runner : 1800 mm

Speed : 1480 rpm

Motor:

Manufacturer : BHEL, Haridwar

Type : DA 2014-64-67, TPEC

Rated output : 630 KW, 230 rpm

Rating : 6.6 KV, 3 phase, 50 Hz

Weight : 9.76 tonnes

Ball Mill:

Mill capacity : 28 tonnes/hr Mill current : 64-68 A

Coal consumption : 67 ton/hr for 110 MW

Coal consumption in KW/hr : 0.58 kg

Coal fineness : 200 mesh

Classifiers:

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Type : Raymond type 330, Raymond type 880

No. of per boilers : 3

Type of drive : electric motor, 7.5 KW (variable)

Method of control : Vane control

Range & efficiency : Adjustable

TURBINE MAINTENANCE DEPARTMENT (TMD)

The main works of this department are maintenance of turbine and look afterall the things related with turbine. The steam turbine has been used

predominantly as mover in all thermal power stations. It is not likely to be

replaced in the future. Turbines are mainly divided into three groups:

Impulsive turbines

Reaction turbines

Impulsive-reaction turbines

In both types of turbine, first the heat energy of the steam at high pressure is

converted into kinetic energy passing through the nozzles. The turbines areclassified as impulsive in impulsive turbinate steam coming at a very high

velocity through the fixed nozzle impinges on the blade fixed on the

periphery of the rotor. In the reaction turbine the high pressure steam boiler

is passed through the nozzle. When the steam comes out through these

nozzles, the velocity of steam increases relative to rotation and this resulting

force of steam on the nozzles give the rotating motion to the disc and shaft.

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The shaft rotates in opposite direction of steam jet. In an impulsive reaction

turbine the steam expands both in fixed and in moving blades continuously

as it passes over them. Therefore, the pressure drop occurs gradually and

continuously over both moving and fixed blades. For e.g. Parsons turbine.

COMPOUNDING OF THE STEAM TURBINES

If the entire pressure drop from boiler pressure to condenser pressure is

carried out in a single stage nozzle, then the velocity of the steam entering

into the turbine could be very high of the order of 1500 m/s. The turbine

rotor velocity (blade velocity) will be very high of the order of 3000 rpm as

it is directly proportional to the steam entering velocity. Such high rpm of

turbine is not useful for practical purpose and a reduction gear is necessary

between the turbine and external equipment (generator driven by theturbine). There is also a danger of structure failure of the blade due to

excessive centrifugal stresses. Therefore the velocity of the blades is limited

to 400 m/s. The velocity of the steam at the exit of the turbine is sufficiently

high when single stage blades are used. This gives a considerable loss of

kinetic energy (about 10-20 %). The compounding can solve the above

mentioned difficulties associated with the single stage turbine. The

combinations of the stages are known as compounding. There are three types

of compounding which are generally done.

a. Velocity compounding:

In this type of compounding there is only one set of nozzles and two

or more rows of moving blades. There is also a row of fixed blades in

between the moving blades. The function of the fixed blades is only to

direct the steam coming out from first moving row to the next moving

row without altering pressure and velocity of the steam. The heat

energy drop takes place only in the nozzle at the first stage and it

converts into kinetic energy. The kinetic energy of the steam gained in

the nozzles is successively used by rows of moving blades and finally

exhausted from the last row of the blades on the turbine rotor. Aturbine working on this principle is known as velocity compounded

impulse turbine. For e.g. Curtis turbine.

b. Pressure compounding:

A number of simple impulse turbine sets arranged in series is known

as pressure compounding. In this arrangement, the turbine is provided

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with one row of the fixed blades at the entry of each row of the fixed

blades, which work as nozzle. For e.g. Rateau turbine.

GOVERNING SYSTEM OF TURBINE

1. Speed range is 2850 rpm to 3360 rpm corresponding to primary oil

pressure of 2.17 to 2.99 atmosphere at oil temperature of 50o C (3000

rpm corresponds to 2.38 atm primary oil pressure.)

2. The non uniform changer (NUC) enables the exchanging of non

uniformity continuously in the range of 3.5 to 5 %.

3. Before start of increase of secondary oil pressure, safe oil pressure can

be achieved by limiter only when the main relay is in engaged

position.

4. During the starting of machine upto 2730 rpm, safe oil pressure isregulated by limiter.

5. When the turbine has taken over the regulation function, the limiter

works as by-pass valve on the secondary oil system.

TURBINE PROTECTION TESTING

The following protection parameters of turbine have to checked & recovered

in log book:

1. Primary oil pressure should be 3.05 kg/cm 2

2. Control gear pressure should be 7.00 kg/cm 2 (regulation oil pressure)

TURBINE OIL PRESSURE REGULATING SYSTEM

1. Reset the supply turbine.

2. Reduce the turbine oil from turbine local panel as described in T.G.set manual.

3. Further reduce the turbine oil pressure by procedure given above and

watch so that E.O.P. (A.C.) starts at 0.8 kg/cm2. Now further reduce

the pressure & water so that E.O.P. (D.C.) gets started automatically

at 0.7 kg/cm 2.

4. Mechanical shift tripping.

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5. Low vacuum tripping.

SPECIFICATIONS OF 105 MW TURBINE

Rated output at generator terminals : 110 MW

Rated speed : 3000 rpm

Rated steam pressure just before stop valve : 130 kg/sq. cm

Maximum steam pressure just before stop valve : 146 kg/sq. cm

Rated temperature just before stop valve : 540

Reheated steam pressure : 27.4 kg/sq. cm

Maximum steam pressure before MP casing : 36 kg/sq. cm

IMPORTANT FEATURES OF TURBINE

No. of regulated extractions : 8

No. of wheels in HP rotors : 2 row Curtis, 8 HP (impulse)

No. of wheels in MP rotors : 12 impulse

No. of wheels in LP rotors : 4 impulse of double flow design

No. of high pressure control valves : 4

No. of interceptor valves : 2Range of critical speed : 1200 to 2500

Weight of HP rotor : 5.5 Tonnes

Weight of MP rotor : 11 Tonnes

Weight of LP rotor : 24 Tonnes

Direction of rotation : Clockwise from front bearing stand

Material construction : special cast steel

HP MP outer casing : Casting of chromium vanadium steel

HP MP Inner casing : Casting of chromium vanadium

molybdenum carbon steel

ELECTRONIC INSTRUMENTS USEFUL FOR THE

PLANT

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The following instruments are found to be very useful for the power plant:

1. PR6422

2. PR6423

3. PR6424

4. CON 010

5. Conductivity Indicator Controller

6. pH-Redox Transmitter PP9041

7. Linear Displacement Transducers, PR9350 Series (LD 5000)

PR6422, PR6423, PR6424

Operation and construction:

The transducers belonging to the PR6422, PR6423, PR6424 series based on

the eddy currents measuring principle form together with the signal

converter CON 010 an oscillator circuit, whose amplitude of oscillation isdamped by the proximity of the metallic object w.r.t. face of the transducer.

The damping is proportional to the distance between the transducer coil and

the object.

The transducers are available for different static and dynamic measuring

ranges and with different dimensions. The transducers PR6422 and PR6423

are fitted with a 1m long cable. Transducer PR6424 is fitted with a 4m long

cable.

The zero point and gradient of the measuring s/n can be adjusted by means

of components located under a gas tight cover. The units are delivered fully

adjusted so that no onside calibration is required. The transducer is

connected via a self locking, water proof, plug connection. The power

supply and s/n o/p connections are via screw terminals.

Intrinsically safe operation is possible when zener barriers are used. The

units correspond to the relevant VDI, API and ISO standards.

Application:

These units are designed for use in many branches of industries and in

laboratories for measurement and supervision of small displacements and

vibration on ferromagnetic objects. Such various applications are:

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Monitoring distances between rotor parts

Monitoring vibration of mechanical elements

Monitoring deformation or bending of mechanical parts

Contact-less measurement of shaft eccentricity, vibration and small

displacements Transducers operate on the eddy current principle for static and

dynamic measurements

Transducers easy to mount and adjust

Compact design

This contact-less measuring principle as well as the small size, robust

construction and the resistance of the transducer to aggressive chemical

influences, make this system ideal for continuous supervision of all types of

rational machinery.

Measuring chains made up of displacements transducers, signal converter

and the additional electronic equipment belonging to the RMS700 system

moderately priced and maintenance free supervision of small shaft

displacements with respect to the shaft bearing or housing in two different

modes:

1. Radial, static displacement of the shaft and relative shaft vibration.

2. Axial, shaft displacement and relative expansion.

The following static and dynamic relative measurements are necessary for

supervision of the important mechanical parameters governing turbo-

machinery breakdown prevention.

a. Axial position of the shaft with respect to the housing.

b. Radial position of the shaft with respect to the housing.

c. Shaft vibration.

CON 010 (SIGNAL CONVERTER)

The signal converters contain the electronics necessary for energisation andsignal conversion, which is generally identical for all types. The signal

converter must be energized with 24 DC with +5 or -5%. The normal

deviation of the output voltage for the measuring range of connected

transducer is 4-20V. The converter is delivered together with the transducer

for which it was calibrated. Therefore, care must be taken that transducer

and system converter remain together.

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the equivalent conductivity of the fluid at the reference temperature of

25o C for different temperature of the fluid.

pH-REDOX TRANSMITTER PP9041

The Philips PP9041 is a pH-redox transmitter with a spam of 10 pH and with

zero settings at pH 0, pH 2 & pH 4. This allows the following measuring

ranges to be selected:

a. pH 0pH 10

b. pH 2pH 12

c. pH 4pH 14

Furthermore, eight mV ranges can be selected with a spam of 1000 mV,

output current ranges of 0-20 mV of 4-20 mV can be selected to use the

transmitter for the either electronic or pneumatic control to avoid earthingand/or interfacing problems, both electrode inputs are highly ohmic.

This allows the use of any electrode as a reference. The features of the

instrument make it very suitable for water treatment and pressure control

application.

TRAINING IN EMD

Panki Thermal power station has four units for generation. Each unit has a

separate transformer. Transformer rating depends on the generating capacity

of each unit. Units 3 and 4 generate power at 11 KV. Units 1 and 2 are

closed.

Rating of Transformers of Unit 3 and Unit 4

KVA H.V. 87500/12500

L.V. 87500/12500

No Load Volts H.V. 242000

L.V. 11000

Winding Temperature 30 degree c

Amperes H.V. 298

L.V. 656

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Phase H.V. 3

L.V. 3

Types of cooling ON/OFF

Frequency 50 Hz

Impedance Volts 12.15%

Vector group symbol Y d 1 1

Core winding weight 104000 kg

Weight of oil 34700 kg

Total weight 187000 kg

Oil 38550 litres

Oil circulation 2 x 1800 litres/min

Air circulation 24 x 50 m3/min

Type of circuit breaker O.F. (Oil Filter/ A.B.)

The ratings of major electrical equipments such as all transformers, for 110

MW units are as follows:

Power rating of generating transformer : 125 MVA

Power rating of unit auxiliary transformer (UAT) : 16 MVA

Voltage transformation ratio of generating transformer : 11/242 KV

Voltage transformation ratio of UAT : 11/6.6 KV

Voltage transformation ratio of reserve transformer : 132/6.6 KV

In PTPS, the generation of electrical power is done at 11 KV. The generated

power at this voltage goes to the bus bar through transformer which step-up

the voltage. Then power is ready for transmission and is fed into

transmission network.

After the generating transformer, the current transformer and the potential

transformer are located. After the CT and PT, two circuit breakers are

connected. One of the circuit breakers is manual while the other is

automatic. The automatic circuit breaker is air blast circuit breaker (ABCB).

When excessive current or over voltage or sudden dip in voltage occurs then

the circuit breaker disconnects the line.

CURRENT TRANSFORMER (C.T.)

At this substation a number of current transformers are used. These current

transformers are used with low ammeters to measure high current in high

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voltage A.C. circuit where it is not practical to connect instruments or

ammeters directly from high voltage lines. In addition to insulate the

instrument from high voltage it steps down the current in known ratio.

The current transformer has a primary coil of very few turns of thick wire

connected in series with the line whose current is to be measured. The

secondary consists of a large number of turns of thin wire and it is connected

across the ammeter terminals.

At required voltage the current transformer is of step-up type. But it is sure

that the current will be step down. Thus if the current transformer has

primary to secondary ratio of 100:5, then it step-ups the voltage 20 times

whereas it step-downs the current to 1/20 times of it.

POTENTIAL TRANSFORMER (P.T.)

The potential transformers are used to operate as voltmeters. The potential

coil of wattmeter and relays form high lines. The primary winding of the

potential transformer is connected across the line carrying the voltage to be

measured and the voltage circuit is connected across the secondary winding;

the design of a potential transformer is quite similar to that of a proper

transformer but the loading of a P.T. is always small. The potential

transformers are used to measure the high voltage. The potential transformer

is also used for operating the relays in control circuit.

For safety the secondary winding it is completely insulated from the high

voltage of primary side and grounded for boundary protection of the

operators.

Three types of cooling techniques are employed for the transformers. These

techniques are as follows:

a. Oil Natural Air Force

b. Oil Natural Air Natural

c. Oil Force Air Force

GENERATOR AND EXCITER

The electric generator is most important part of the power station. The

principal of electromagnetic induction is used to generate electric power

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with the help of synchronous generator. All modern type of AC generators

essentially consists of fixed starter and revolution rotor. An alternating e.m.f.

is induced when the shaft of the rotor is revolved with the help of a prime

mover.

The rotor provides the magnetic flux to the machine. The winding of three

generators may be connected either in delta or star arrangement. With star

arrangement two voltages can be obtained as the line voltage or as the phase

voltage. The neutral is connected to the earth and this helps in designing a

protective system in order to keep the temperature rise of various parts from

exceeding the respective maximum permissible values. Every generator

requires continuous cooling during its operation. The system cooling

adopted for the cooling purpose consists of a fan that circulates the air

through the alternator and the warm air is cooled by the water coolers before

being circulated again. This system gives good protection against fire inalternator due to restricted air supply. Carbon dioxide can also be easily

injected to extinguish the fire.

The exciter provides the direct current mended to excite the rotor field

magnets. The present on excitation must be absolutely reliable since their

failures will shutdown the alternators. The higher the total load and more the

lagging power factor, the greater excitation is required.

INTRODUCTION TO SWITCH GEARS, CIRCUIT

BREAKERS AND RELAYS

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Switch gear in a broad sense covers a wide range of equipments connected

with switching and protection. A circuit breaker is a switching (current

interrupting or making) device in switch gear. The basic requirements of

switching in power system practice are two fold:1. To permit apparatus and circuits to be conveniently put into or taken

out of service.

2. To permit appropriate and safe isolation of apparatus and circuits

automatically, in a pre-determined time period when they develop

faults.

DEVICES USED FOR CIRCUIT BREAKING (OR MAKING)

1. Fuse and Iron Clad SwitchesFuse is an over-current switch in the sense that when the current

exceeds a pre-assigned value in a circuit or device, it melts and causes

current interruption. The supply is restored only when a healthy one

replaces the damaged (melted) fuse in the line. To permit this without

any danger of shock to the operator, fuses are connected on the load

side of an iron clad switch.

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2. Isolators

An isolator is a switch connected after a circuit breaker. When a

circuit or a busbar is taken out of service by tripping the circuit

breaker, the isolator is then open circuited and the isolated line is

earthed through earth switch so that the trapped line charges are safely

conducted to ground.

These devices are used to break or isolate the circuit. They are

however, slower than circuit breakers in operation. They are used to

locate and rectify faults in circuit elements and therefore they relieve

the CB which may also be used for these operations. (However it is

not advisable to turn CB in off position for a long duration as this may

damage its springs.) In general, two isolators are put in circuit, one

each on both sides of CB, in order to facilitate repair of CB as well ascircuit isolation and repair. Air pressure for isolators at Panki thermal

power station is 16 kg/cm 2.

3. Circuit Breakers

Make or break both normal and abnormal currents.

Appropriately manage the high-energy arc associated with

current interruption.The problem has become more acute due

to interconnection of power stations resulting in very high fault

levels. Current interruption occurs only when it is called upon to do so

by the relay circuits.

In fact they are required to trip for a minimum of the internal

fault current and remain inoperative for a maximum of through

fault current.

Rapid and successive automatic breaking and making to aid

stable system operation.

3-pole and single pole auto-reclosing arrangement.

In addition to these breaking and making capabilities, a circuit breaker is

required to do so under the following typical conditions:

Short-circuit interruption

Interruption of small inductive currents

Capacitor switching

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Interruption of short-line fault

Asynchronous switching

Principles of circuit breaking

a.DC circuit breaking: effect of decreasing current and increasing arc

length.

b. AC circuit breaking: It is performed by several techniques which

are current-zero period, distortion of AC current wave by arc voltage

recovery and restriking voltages, single frequency and double

frequency transients, rate of rise of recovery voltage (RRRV), control

of RRRV, Resistance switching.

Current chopping-interruption of low magnetizing currents-Opening

resistors-capacitive current breaking-Switching of capacitor banks and

unloaded lines-Interrupting terminal faults and short-line faults.

Ratings of Circuit Breakers

Rated Voltage

Rated insulation

Rated FrequencyRated normal current

Rated short circuit breaking current

Rated short circuit making current

Rated opening sequence for auto-reclose CBs

Rated transient recovery voltage for terminal faults (Representation of

TRV by 4-parameters and 2-parameters)

CB interrupting time-its components in relation to fault clearing time

Single-pole auto-reclosing and its effects on system performance

Classification of Circuit Breakers

The circuit breakers are mainly classified as follows:

1. Air-break circuit breaker or miniature circuit breaker

2. Oil circuit breaker

3. Minimum oil circuit breaker

4. Air blast circuit breaker

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c. Oil Circuit Breaker:

In such CB, insulating oil is used as an arc quenching medium. The

contacts are opened under oil and arc is struck between them. The heat of the

arc evaporates the surrounding oil and dissociates its substantial volume of

gaseous hydrogen at high pressure. It has the advantage of better and

efficient arc quenching medium but on the negative side it involves risk of

fire.

d. SF6 CB:

In such circuit breakers SF6 gas is used as the arc quenching medium.

The SF6 is an electronegative gas and has a strong tendency to absorb free

electron. The contacts of the breakers are opened in a high pressure medium

of SF6 gas and arc is struck between them. The conducting free electrons in

the arc are rapidly captured by the gas to form relatively large, immobilenegative ions. This loss of conducting electrons in the arc quickly builds up

enough insulation strength to extinguish the arc. The SF6 CB has been found

to be very effective for high power and high voltage service.

The advantages of SF6 CBs are as follows:

1. Very short arcing time.

2. Can interrupt much larger current.

3. Noiseless operation.

4. No moisture problem.

5. No risk of fire.

6. Low maintenance cost.

The only disadvantage of SF6 CB is that SF6 is costly thereby increasing the

cost of CB.

Types of indoor switchgears:

a. Stationary Cubicle type

b. Draw-out or Truck type

c. SF6 filled switchgeard. Fuse-switch units

e. Flame proof or Explosion proof switchgear

f. Cellular type

g. Corridor switchboard

h. Mimic diagram board

i. Metal-clad switchgear

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j. Isolator and earthing switch-Vertical break isolator-Double break

isolator

THERMAL RELAYS

A thermal relay consists of a bimetallic strip which is heated by the means of

a heating coil that is supplied through a current transformer. An insulated

arm carrying contact is pivoted and is held in contact with the strip with the

help of a spring. The tension of spring can be varied by rotating the sector

shaped plate.

Under normal working conditions, the strip remains straight, but when the

strip is heated it bends and the tension of the spring is released thus the relay

contacts are closed which energises the trip circuit. The setting of relay can

be achieved by varying the tension of the spring. The construction ofbimetallic element consists of two nickel-alloyed strips and steel strips

welded together. These strips have high heat resistivity and are free from

thermal secondary effects and aging. Each of theses strips is subjected to an

artificial aging process and they are individually calibrated under currents.

These relays assume a temperature higher than the surrounding parts and

must have a short circuit capacity corresponding to the breaking capacity of

circuit breaker itself. This is achieved by using the heat resisting bimetal

material of suitable dimensions having large thermal time constant.

These over current tripping relays are used mostly for motor controls and

their heating elements are designed to withstand short time overload upto

seven times the full load current.

Only the smaller size of the indirect current heated bimetallic elements from

4A to 6.5A are used while 30A motor protective circuit breaker will call for

the additional fuses for the protection of winding along with relays. The

smallest thermal relays of 400A circuit breakers are short circuit proof upto

200 times their top current rating, i.e. upto 8 KA which is adequate.

Ratings of thermal relay are as follows:

With winding-temperature indication type R.B. form- H2AW74

Contact capacity for

(a) Cooker control 5A & 230V

(b) For all arms 0.2A & 125V (D.C.)

(c) For trip 0.2A & 125V (D.C.)

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Power supply 230V (A.C.)

Bushing Sec. Thermal Current Ratio VA Accuracy

A6 AS1 + AS2 -- -- --

B6 BS1 + BS2 400/1 60 5P20C6 CS1 + CS2 -- -- --

N N1S1 - N1S2 400/1 60 5P20

N N2S1 - N2S2 -- -- --

GRID SUBSTATION

The Panki grid substation has five buses at different voltage levels namely:

1. 220 KV bus

2. 132 KV bus3. 33 KV bus

4. 25 KV bus

5. 25 KV bus

Some of the power supplied by Panki thermal power station to the grid

substation is fed back for the purpose of operation of auxiliary components.

WAVE TRAP

This is used for communication by means of which, two grid substations

may communicate and receive messages.

SWITCHYARD

The air at high pressure required for ABCB is produced by the compressor.

There are two compressors for this purpose at PTPS. Both the compressors

are run by the diesel engines. This is to ensure that interruption of power

supply does not effect the operation of CB. The compressor maintains thepressure of air in main air tank. The compressor starts automatically when

pressure of air in main tank falls below 33 kg/cm 2 and stops automatically

when pressure in main tank has reached 40 kg/cm 2.

Each ABCB is provided with its own subsidiary air tank. This tank contains

air at pressure of 23 kg/cm 2 which is the operating pressure of the ABCB.

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The subsidiary tank ensures that sufficient air is available for ABCB

operation while its operation does not affect the main tank pressure.

Similarly, subsidiary tank of isolation contain air at pressure of 16 kg/cm 2.

Two sets of contact are provided for each phase of ABCB so that one of

these may operate if the other fails.

TRACKS FOR TRANSFORMER

Transformers are placed on the tracks (similar to railway tracks). This is

done to aid the transportation, loading, unloading and installation of

transformer. Using these tracks, transformer may be taken to the cranes

which then lift and place the transformer on the vehicle. Similarly, cranes

download these transformers which are then transported through the tracksto the site of installation.

CONTROL & INSTRUMENTATION DIVISION

This is the backbone of a thermal power plant. Various parameters in various

auxiliaries are controlled from here. The equipments are very sensitive and

can even pick up minute disturbances. Automatic control compares the

actual value of the plant output with the desired value, determined the

deviation and produces control signal which will reduce the deviation to zeroor a small value. The industrial automatic controllers that are employed in

the control and instrumentation section are as follows:

1. Two position or on-off controllers

2. Proportional controllers

3. integral controllers

4. Proportionally-integral controllers (PI)

5. Derivative controllers

6. Proportionally-integral-derivative controllers (PID)

Various instruments of the C&I department

1. Boiler Drum: There are numerous red and green lights in the control

room. The light continuously indicates the boiler drum steam and

water level. When the level goes in the danger region, on alarm is

activated.

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Since the rotor moves at a very high speed of about 2900 rpm to 3000 rpm,

due to impinging of steam at high temperature, the expansion of rotor takes

place. This is called eccentricity.

Bearing Temperature

Bearings are made of those metals, which melt at 100o C. Therefore

allowable temperature is 7.5o C. Platinum resistance thermometers are used.

The oil pressure is maintained at 35 kg/cm 2 at the header and a pressure of

15.8 kg/cm 2 at ball bearing.

WATER POLLUTION CONTROL

Main source of pollution in PTPS is polluted water that comes out. It is not

made to flow as such into nearby river. Rather it is first purified by effluent

treatment plant. Waste in the water us called sludge is collected in sludge,dyeing beds. From there it is taken away by trolleys once in a year. The

general working of plant is as follows-

Step-1

Polluted water comes for treatment through gate A of inlet drain. It is first

through screen. Before being collected in grease trap which is * feet deep,

big particles, polythene, rappers etc. have already been screened before

collection of water into oil and gases trap. Some dust and heavy parts and

oil, grease come in the upper parts which is sucked by oil and grease pump.

Oil is collected into drum from time to time this oil is sent to boiler for use.

Step-2

Water from oil and grease trap goes to a 17A deep chamber, here water

remains stand still for some time, heavy sludge, particles and impurities that

do not dissolve in water settles down. Water from here goes to aeration tank

through feed pumps.

Step-3

Aeration tanks are deep tank where oil is mined in water. There are 3aerators for this purpose. An aerator is basically a tabulator that is like a fan

and rotates in water. In this way oxygen is mixed in water. This is necessary

for the life of small bacteria that clear the water and makes it natural; 35 kg

lime and 15 kg urea are mined in water. They are used as water purifiers.

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Step-4

From aeration tank water comes to air fan tank. Motor is the center of

purifier which rotates at the speed of two rotations per hour. It amplifies due

to centripetal force created by the rotating sludge and by the particles which

move toward the centre of the tank.

Step-5

Pure water is discharged from the center i=of the air fan tank. Sludge pumps

from the center of air tank fan pit and send it into sludge drying beds. Water

vaporizes from this sludge beds and sludge remarks that are thrown away by

turn from time to time.

AIR POLLUTION CONTROL

Air pollution occurs due to ash present in the exhaust gas released from the

chimney of the power plant. Therefore, fly ash can almost effectively be

prevented from entering into atmosphere by employing electrostatic

precipitation technique.

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CONCLUSION

It was worth an educational experience to see the working of variousmechanical devices in practical, which I had just read about in books.

The process of knowing about the various stages of thermal power

generation (from coal) including the boiler & its auxiliaries, the steam

generating units & auxiliaries and the compounding, governing, protection

testing & regulation of turbines was a great experience.

Observing the practical implementation of the various mechanical devices

like boilers, turbines, pumps, compressors, fans and the electrical

equipments like current transformers, potential transformers, generators,exciters, switch gears, circuit breakers etc. added a lot to my knowledge.

To know about the various stages in a water treatment plant was a new

experience.

And lastly, I would like to mention about the team work, co-ordination and

time management which exists among the various departments of the unit.

This has really helped me to learn about the job skills.

52

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