Rajat Report

CHAPTER 1

INTRODUCTION

For the power generation with 2 x 110 MW, 3 x 210 MW and 1 x 195 MW of KSTPS

authorities are required to be operative to active full operation. The auxiliaries are basically

operation either on L.T. System i.e. 415 V power supply is made available to the system after

providing the station transformer of 3 x 50 MVA capacity with voltage 220 KV/7.2/7.2 KV

& different service transformers of capacity 1.0 MVA, 1.5 MVA, 2.0 MVA which are located

near the load center as the transformer having the voltage of 6.6 KV/415 V. The 6.6 KV

power is distributed through 6.6 KV interconnected Bus System for all the five units with a

control through DC of 220 V.

The 415 V power supply is done through a L.T. SWGR (Switchgear) which are located

nearby the distribution transformer as well as the load centers. The all in-comers, which are

breaker controlled, are having the control the L.T. SWGR are having the control system on

110/220 V AC. The 6.6 KV power supply which are either MOCB (Minimum Oil Circuit

Breaker) of JYOTI MAKE or Air Circuit Breakers.

The 6.6 KV power supply to various draining equipment’s i.e. more is made through

breakers which are either MOCB of make air circuit breaker which are either of voltage

makers as well as SF 6 of NGEF make. The LT supply is also controlled through air break

circuit breaker which are either L&T make or English Electric Company of India. The

various H.T. motors are switched on / started through on direct ON line (DOL) in order to

inverse the availability of equipment at full efficiency without time gap.

Further, the .6 KV system which is delta configuration and terms, as an unearthed

system so also to keep the running motor complete in operating condition in case of any one

phase of motor winding is earthed due to any one reason. Earthling is detected by an

protection system with alarm facility to take remedial measures immediately and at the same

time to maintain the generation level in the same condition, prior to occurring the earth fault

the single phase earth fault is detected in due course till the motor is not earthed to other or

another phase.

“PUBLIC ADDRESS SYSTEM” is available through in area of each unit which helps in

fast communication for prompt remedial measure.

(AIET/DOEC/2011-12/PTS/1)

Soot Blowers are there in the boiler area on the furnace side or Zone which helps in

blowing the soot / ash deposition regularly of the furnace wall / economizer tubes to keep

heat transfer at the required parameter.

In April 1973, Central Electricity Authority prepared a Project Report for power station

comprising of the two units of each of capacity 110 MW for RSEB subsequently in

September, 1975 this was revised by the Consultant Super Thermal Design Organization,

Central Electricity Authority for invention of 2 x 110 MW units being manufactured by

BHEL, Hyderabad in 1st Stage.Ist unit of 110MW was commissioned on 17thJan, 1983. The

IInd 110MW unit was firstly synchronized in July 1983.The second stage units are

synchronized in 1989. The second unit of second stage was commissioned in Oct. 1989. After

then unit of 210MW as started in 11 April, 1984. The commencements of unit VI th, in stage

fourth started in July 2001 and the synchronization of the unit was done in July 2003. The

VIIthunit of 195MW was commissioned on 30thMay, 2009. The total power generated in

KSTPS is 1240MW.

The planning commission cleared the project report in September, 1976 for installation of

two units each of 110 MW in first estimated cost of Rs. 143 Crores.

KSTPS IS DESISIGNED IN FOUR STAGES

* Stage I - 2 x 110 MW

* Stage II - 2 x 210 MW

* Stage III - 1 x 210 MW

* Stage IV - 1 x 195 MW

* Stage V - 1 x 195 MW

Total Power Generation - 1240 MW

1.1 Location:

The Kota Super Thermal Power Station is ideally on the left bank of Chambal River

at Up Stream of Kota Barrage. The large expanse of water reached by the barrage provides an

efficient direct circulation of cooling system for the power station. The 220 KV GSS is within

½ Kms from the power station.


Figure 1.1 Location Of K.S.T.P.S.

1.2 Selection reason for K.S.P.T.S. in Kota

1.2.1 Land:

Land measuring approx. 250 hectares was require for the project in 1976, For disposal of

ash tank very near to power station is acquired which the ash in slurry form is disposed off

through ash and slurry disposal plants.

1.2.2 Coal:

Coal India Limited owns and operates all the major coal fields in India through its coal

producing subsidiary companies viz. Eastern Coal Fields Limited, Western Coal Fields

Limited. Coal India Limited is supply coal from its coal mines of coal producing subsidiaries

BCCL, SECL & ECL to Kota Super Thermal Power Station through railway wagons. The

average distances of SECL, ECL & BCCL are 800, 950 and 1350 Kms. respectively.


1.2.3 Water:

The source of water for power station is reservoir formed by Kota Barrage on the

Chambal River. In case of large capacity plants huge quantities of coal and water is required.

The cost of transporting coal and water is particularly high. Therefore, as far as possible, the

plant must be located near the pit rather than at load center for load above 200 MW and 375

MW. The transportation of electrical energy is more economical as compared to the

transportation of coal.

1.2.4 Transportation:

K.S.T.P.S. is located at Station on broad gauge main Delhi-Bombay Railway line, so

transportation of raw materials i.e. of coal is made very quickly

1.3 Design Feature:

The Satisfactory design consists of the flowing steps.

Estimation of cost.

Selection of site.

Capacity of Power Station

Selection of Boiler & Turbine.

Selection of Condensing Unit.

Selection of Electrical Generator

Selection of Cooling System

1.3.1 Design of Control & Instrumentation System:

The design of steam power station requires wide experience as the subsequent operation

and maintenance are greatly affected by its design. The most efficient design consist of

properly sized component designed to operate safely and conveniently along with its

auxiliaries and installation.

1.4 Layout of K.S.T.P.S. & basic idea:

Any control system basically works on rankine cycle.produced Steam in Boiler is

exported in prime mover and is condensed in condenser to be fed into the boiler again. In


practice of good number of modifications are affected so as to have heat economy and to

increase the Super Thermal efficiency of plant.

A general layout of modern steam power plant is shown

Figure 1.2 Layout of K.S.T.P.S.

The Kota Super Thermal Power Station is divided into four main cycle.

Fuel and Ash Cycle

Air and Gas Cycle

Feed water and Steam Cycle

Cooling Water Cycle


1.4.1 Fuel & Ash Cycle:

Fuel from the storage is fed to the boiler through fuel handling device. The fuel used in

KSTPS is coal, which on combustion in the boiler produced the ash. The quantity of ash

produced is approximately 35-40% of coal used. This ash is collected at the back of the boiler

and removed to ash storage tank through ash disposal equipment.

1.4.2 Air & Gas Cycle:

Air from the atmosphere is supplied to the combustion chamber of Boiler through the

action of forced draft fan and induced draft fan. The flue gas gases are first pass around the

boiler tubes and super heated tubes in the furnace, next through dust collector (ESP) & then

economizer. Finally, they are exhausted to the atmosphere through fans.

1.4.3 Feed Water & Steam Cycle:

The condensate leaving the condenser is first heated in low pressure (LP) heaters through

extracted steam from the lower pressure extraction of the turbine. Then its goes to dearator

where extra air and non-condensable gases are removed from the hot water to avoid pitting /

oxidation. From dearator it goes to boiler feed pump, which increase the pressure of the

water. From the BFP it [passes through the high-pressure heaters. A small part of water and

steam is lost while passing through different components therefore water is added in hot well.

This water is called the make up water. Thereafter, feed water enters into the boiler drum

through economizer. In boiler tubes water circulates because of density difference in lower

and higher temperature section of the boiler. The wet steam passes through superheated.

From superheated it goes into the HP turbine after expanding in the HP turbine. The low-

pressure steam called the cold reheat steam (CRH) goes to the reheater (boiler). From

reheater it goes to IP turbine and then to the LP turbine and then exhausted through the

condenser into hot well.

1.4.4 Cooling Water Cycle:

A large quantity of cooling water is required to condense the steam in condenser and

marinating low pressure in it. The water is drawn from reservoir and after use it is drained

into the river.

1.5 Electricity Generation at KSTPS:

Super Thermal power station burns the fuel and use the resultant heat to raise the steam,

which drives the turbo-generator. The fuel may be “Fossil” (Coal, Oil and Natural Gas)


whichever fuel is used the object is same to convert the heat into mechanical energy to

electrical energy by rotating a magnet inside the set of winding. In a coal fired super Thermal

Power Station other raw materials are air and water. The coal is brought to station by train or

other means travels from the coal handling system.

i) By conveyer belts to coal bunkers from where it is fed to pulverizing mills.

ii) Mills grind it fine as face powder

iii) Then this powdered coal mixed with preheated air is blow into boiler by a fan

known as primary air fan (PA fan).

iv) When it burns more like a gas as solid in conventional domestic or industrial grate

with additional amount of air called secondary air supplied by “Forced Draft Fan”.

As the coal has been grinded so resultant ash is also as fine as powder. Some of its

fine particles bind together to form lumps, which fall into the ash pit at the bottom

of furnace.

v) The water-quenched ash from the bottom of furnace is carried out boiler to pit for

subsequent disposal.

vi) Most of ash still in fine particles form is carried out to electrostatic precipitators

where it is trapped by electrode charged with high voltage electricity. The dust is

then conveyed to the disposal area or to bunkers for sale.

vii) Now after passing through ESP few gases is discharged up to chimney by

“Induced Draft Fan”

Meanwhile kilometers long tubes have absorbed the heat reloaded from the coal, which

lies in boiler walls inside the tubes “Boiler Feed Water” which is transferred into turbine

blades and makes them rotate. To the end of the turbine rotor of generator is coupled, so that

when Turbine rotates the rotor turns with it. The rotor is housed inside the stator having coil

of copper bars in which electric is produced through the movement of magnetic field created

by rotor. The electricity passes from the stator winding to the transformer, which steps up the

voltage so that it can be transmitted effectively over the power line or grid.

The steam, which has given up its heat energy in, changed back into a condenser so that it

is ready for reuse. The cold water continuously pumped in condenser. The steam passing

around the tubes looses heat and rapidly changes into water. But these two types of water


(boiler feed water and cooling water) must never mix together. The cooling water is drawn

from the river but the Boiler Feed Water must be pure than potable water (DM Water.)

Now the Question arises why we change steam from turbine to water when it is to be

heated up again immediately.

Laws of Physics give the answer, which states that the boiling point of water is related to

pressure. The lower the pressure lowers the boiling point temperature. Turbine designer

wants boiling point temperature as low as possible because it can only utilize the energy from

steam when change back to water, he can get no more work out at it. So there is a condenser,

which by rapidly changing the steam into water a vacuum. The vacuum results in a must

power at lower boiling points which in turn mean it can continue getting out of steam will

below 1000 C at which it would change into water.

To condense volume of cooling water is huge and continuous volume of cooling water is

essential. In most of the power station, the same water is to be used over and over again, so

the heat which the water extracts from the steam in the condenser is removed by pumping

water out of cooling tower. The cooling tower is simple concrete shall acting of air. The

water is sprayed out at top of top of tower and as it falls into pond beneath it cooled by the

upward draft of air. The cold water in the pond is then re-circulated by pumps to condensers.

Invariably however some of the water drawn upwards as vapor by the draft.


CHAPTER 2

GENERATORS:

Two-turbo generators of 110 MW each are phase synchronous generators with hydrogen

cooling and gear driven D.C. exciter.

The generator stator is tight construction, Supporting and enclosing stator winding core

land hydrogen coolers. The cooling machine hydrogen is contained within the frame and

circulated by fans mounted at either ends of rotor. The generator is driven by a direct-coupled

steam turbine at a speed of 3000 rpm. The generator is designed for continuous operation at

its rated output parameter and will withstand within the prescribed limits. The condition

identical operation such as sudden three-phase short circuit etc. Temperature detectors and

other device installed or connected within the machine permits the measurement of winding,

teeth core and internal section plants provides stiffness to support the core decrease vibration

and impart necessary mechanical strength to withstand the gas pressure encounter even under

extreme operating condition. The stator frame is supported on the foundation through footing

welded to sides of shell. The end shield coolers, hydrogen from the generator and the entire

generator is leak proof owing the exposure nature of the design to withstand any undesired

explosion and over pressure that may develop according to internal conversion the stator

casing listed hydraulically with a pressure of 7 atm.

2.1 Main Parts of Generator:

2.1.1 Stator Core:

The Stator core is build-up of segment core, annealed insulating lamination of hot and

cold rolled high quality silicon steel to give minimum electrical losses. The laminations are

insulated with a thermo setting quarters and insulators. The arrangement reduce additional

losses due to circulating current which would otherwise be present due to self inducing non

uniform flux distribution in the coil slot. The main insulation for the bar consists of resin

mica based thermosetting insulating.


Figure 2.1 Internal View of A Generator – Turbine Coupling

2.1.1.1 Stator Winding:

The stator winding is double layer lap wound, single-phase short pitch. The top and

bottom are bronzed and insulated at either end to form a turn several such transform a double

layer, lap-wound single-phases short pitch type. The end winding formed within the volute

shaped broad end is included towards the machine axis by 20’, thus forming a “basket”

winding with total included concave angle of 40’, this minimizes the stray load losses in the

stator and zone. The end winding has been thoroughly reinforced with epoxy glasses laminate

spaces to avoid vibration during running condition and also to withstand the forces resulting

from the fault condition such as short circuit or improper synchronizing.


Figure 2.2 Stator Windings

2.1.1.2 Generator Terminal Bushing:

Since output leads 3-longer and three have been brought out at the bottom of the casing of

the exciter side, external connection are to be made of three short terminals which are

intended for natural and to be extra length enables. Suitable dimensioned ring type/current

transformer to be inserted. The conductor of the generator terminals bushing is hollow copper

with a copper pieced bronzed at the end to avoid leakage of hydrogen. The hollow position

enables the bushing also to be hydrogen cooled. The ends of bushing are individually tested

for hydrogen leakage and also for high voltage before assembling in stator casing.

2.1.1.3 Bearing:

Generating bearing have spherically seats and consist of steel bodies, metal is on the inner

surface of bearing browse to provide a smooth bearing surface which can be easily removed.

The bearings are forced lubricated by oil and a pressure of 2 to 3 atm. From the same pump

that supplies oil to the turbine, bearing and governing provision has been made to measure

the rotor bearing temperature by inserting a resistance thermometer in an oil pocket directly

with the bearing and the shaft steel housing at either end of the machine are insulated from

the generated frame to prevent the flow of current.


2.1.2 Rotor:

The turbo generator rotor is forged upon a single piece in get of special chromium, nickel

and molybdenum alloy steel. Additional dummy slots and sub slots and sub slots provide

adequate passage for the cooling medium for rotor body and winding.

The field coils are held in the slots against centrifugal forced by wedges; both magnetic and

non-magnetic type being used to ensure a better waveform of flux distribution.

2.1.2.1 Rotor Winding:

The coils are manufactured of rectangular cross-section with ventilation holes punched in

it. The individual terms of every coil are insulated by epoxy glass laminated ‘L’ shaped

thoughts. Epoxy glasses laminate space in the end winding separate and support the oil and

restrict the movement under the stress due to rotational forces.

2.1.2.2 Rotor Balancing:

Finally balancing of the fully assembled rotor is carried out at the rated speed in a

purpose dynamic balancing machine, incorporate specially designed bearings and electronic

apparatus to indicate the location specially provided along the rotor body or filled in the

groove in the end rings, fans and coupling.

2.1.2.3 Slip Rings:

The slip rings are made of forged steel. They are located side by side on the exciter

side of the generator shaft. The slip rings towards the exciter side are to be given positive

polarity and one towards the retaining side is to be given negative polarity initially. Positive

polarity is defined here as that which results in an upscale reading when the positive lead of a

D.C. voltmeter is connected to the ring. They have helical grooved and screwed holes in the

body for cooling purpose by the air excitation current is supplied to the rotor winding through

the slip-rings which are connected through semiconductor, steel excitation loads suitably

insulated and assembled in the bore at the center of rotor forging. The excitation leads is

connected to the winding on one end of slip ring on the other side with insulated studs

passing through the radial holes in the rotor shaft.


CHAPTER 3

TRANSFORMER

A transformer is a static device which transfer the electrical energy from one circuit to

another circuit by magnetic field, A transformer may be defined as equipments based on

electromagnetic induction, alternating current and voltage without affecting frequency. It is

static equipment i.e. it has no movable part.

Figure 3.1 Working Of Transformer


The fundamental theory of transformer is that if on a magnetic core two winding are

placed then the current produced on primary winding on account of alternating voltage,

imposed voltage in secondary and if the circuit is closed than current in the secondary

winding. They may be single phase or three phase type.

The main parts of transformer are:-

(1) The core

(2) The winding

(3) On load tap changer

(4) Tanks

(5) Bushings

(6) Auxiliary equipment

(7) Insulating oil

(8) Cooling system

Various type of cooling is employed in transformer according to the need like air cooling,

water cooling.

Description about the transformer installed in K.S.T.P.S. is follow.

3.1 Main Power Transformer:

These are two is numbers for the stage – 1, Each of the two 110MW, 110MW generator is

connected to the 220 KV system thoughts a step up generator transformer is rated for 25

MVA, 11KV/240KV, Y/D and is provided with an on off circuit tab switch on high voltage

variation up to +- 10% in equal steps of 2.5% each.

For stage II, there are also two generator transformer, each for one 210 MW generator

There are also B.H.E.L. made transformer is rated for 250 MVA.15.75/240 KV and is

provided with a circuit on off switch.

Presently stage III or fifth unit has also one generator transformer of

15.75/240KV’250MVA. Thus there are over all 5 generating transformer.

Stage – I (generator unit I & II) each of 110 MW contain the 2 generating transformer.

Stage – II (generator unit III & IV) each of 110 MW contain the 2 generating transformer.


Stage – III (generator unit V & of 210 MW) each contains the 1 generating transformers.

Generator transformers are of big size and large weight transformer and are site

assembled. The heavy current carried by generator transformer and consequent heavy

conductor required from generator terminals to the L.V. side of transformer comples the

installation of later directly opposite to the alternator and outside the turbine house wall in a

bay outdoors.Each transformer after installation on heavy pads design for carrying the large

weight is built around the RCC walling to combine the damage due to the fire and

explosiousetc.The suppression of noise of large transformer close to the station remains a

problems but some amooilation may be achieved by mounting them on pads.

The L.V. from the generator terminals to the transformer carried out of twin post insulator

mounted on three separated tanks on the non magnetic sheeting. The through piece the

turbine house walls and bolts used for connecting the conductor to the terminals.

S.NO. DATA SPECIFICATION

1. Manufacturer BHEL

2. No. /Unit 1&2

3. Type of construction Core Type

4. No. of phases 3

5. Type of connections H.V.-Star, L.V. –Delta

6. No. of taps 9

7. Rating 125MVA, 11/240 KV

8 Allowable temp rise of oil 40 C

Table 3.1 Specifications Of Generating Transformer - 1 & 2




2. No./Unit 3,4,5&6

3. Rating 250 MVA

4. Transformation Ratio 15.75/220 KV

5. Winding Connection Delta-Star

6. %Age impedance 14%

7. Allowable temp. rise in winding 50 C

8. Line Current HV & LV 602.12 Amp. & 9175.15 Amps.

Table 3.2 Specifications Of Generating Transformers- 3, 4, 5 & 6

3.2 Station Transformer:

The power requirement of unit auxiliaries during unit step-up or shut down and off all

station auxiliaries is met by 3 station transformer. The station transformer has two winding.

On its secondary side, each of three station transformers is rated for 50/25/25 MVA, 20/7/7

KVA, Y/D and is provided with an on load tap changer on H.V. winding. This permits a

voltage variation up to +- 10% in equal 16 intervals of 1.25% each.

These station transformers are main source of supply for the station. But the unit type

plant, as well as they installed for taking the load (auxiliary load) until the unit transformer

loaded. After the generator is synchronized. These transformers are located adjacent

switching station but are never the less controlled from generating station.

3.3 Unit Auxiliary Transformer:

BHEL made 2 numbers have been provided, one for each unit. This transformer normally

meets the all power requirements of when unit is synchronized with a grid and has become

stable. Its primary winding is connected to the 11KV unit switchgear, Each of VAT’s is rater

for 11/7/15 MVA and is provided with an on load top changer on H.V winding,. Which

permits the variation of voltage up to +- 10% in 1 equal steps.




2. Type of cooling ON/AN

3. Rating 15MVA

4. Rated Primary Voltage 11KV

5. Rated Sec. Voltage 6.6KV

6. Phases 3

7. Rated Current HV-787 A, LV-1237 A.

8. Oil Temp. Rise 40 C

Table 3.3 Specification Of U.A.T. – 1 & 2



2. Type of cooling ON/AN

3. Turns Ratio 15.75KV / 7KV

4. Rated current LV-1238.65 A & HV-550.51A

5. Allowable temp. rise in winding 50C

6. Phase 3-phase

7. Temp. Rise in oil 40C

8. Frequency 50Hz.

Table 3.4Specification Of U.A.T. – 3, 4, 5 & 6

3.4 Station Service Transformer:


When the unit is in running condition the power required for the L.T. panels or L.T.

switchgear is provided by this transformer. The ratio of transformer is 220 KV/7 KV. In this

type of transformer primary is star connected.

3.5 Unit Auxiliary Service Transformer:

When the unit is running power required for L.T. panels or L.T. switchgear is also

provided by this transformer, the ratio of this transformer is 7KV/433V. In this type of

transformer Primary is delta connected and secondary is star connected. In addition to this to

take the load of water treatment plant system, clarified raw water etc. are taken by the case of

small transformer installed.

The H.P. & L.P. rotor are connected to the rigid compiling & they have a common

bearing. After passing through I.P. turbine, the steam enters the middle part of L.P. turbine is

connected by a semifinal coupling.

In L.P. turbine the steam flows in opposite paths having four stages in each path after

leaving L.P. turbine the exhaust steam conductors in the surface condenses welded directly to

the exhaust part of the L.P. turbine rotors of I.P. turbine & L.P. turbine are connected by a

semifinal coupling.

The boiler has been provided with primary air (two) & two forced draught fan for

supplying the required secondary air for the boiler, An E.S.P. has been provided with the air

heater & the I.D. fan for concocting the fine particles of fly ash. The boiler to equip with

three number of I.D. fans, one out of them reserving as standing by. These are located at the

outlets if, E.S.P.

3.6 Current Transformer:

Current transformer is used for monitoring the current for the purpose of measuring and

protection. They can be classified as dead tank inverter type. The dead tank current

transformer accommodates the secondary core inside the tank, which is at the ground

potential. The insulated primary passes through the porcelain and the tank and the terminals

into the top chamber. The primary used in such types of construction is of ‘U’ type. The

inserted secondary cores are insulated to the system voltage and hence inside the top chamber

which is at the line potential. Before commissioning of the current transformer the earthing of

the power terminal and base is essential, otherwise excessive high voltage appears at the

power factor terminals and leads to heavy spark. The secondary terminal of the core should


be short circuited and earthed which are not in use otherwise excessive high voltage will be

developed across the current transformer secondary. The current transformer should always

be in vertical position so that gas forming at the top does not enter the insulated part. The

current transformer actually steps down the current so that it can be measured by standard

measuring instrument. There are three current transformers in each feeder. The current

transformers are inserted into energy incoming and outgoing feeder from 220KV system for

measurement.

Figure. 3.2 Current Transformer

The current transformer is used with its primary winding connected in series with the line

carrying the current to be measured and therefore the primary current is not determined by

the load on the secondary of the current transformer. The primary consists of a very few turns

and there is no appreciable voltage across it. The secondary consists of a very large number

of turns. The ammeter or wattmeter current coil is connected directly across the secondary

terminals thus a current transformer operates its secondary nearly under short circuit

conditions. The secondary circuit is connected to ground in many cases.

Instrument transformers perform two important functions; they serve to extend the range

of the measuring instrument, much as the shunt or the multiplier extends the range of the dc

ammeter. They also serve to isolate the measuring instrument from the high voltage power

line. The primary winding of the current line transformer is connected directly to the load

circuit, while the secondary is open circuited. The voltage across the open terminal can be

very high (because of the step up ratio) and could easily break down the insulation between


the secondary windings. The secondary winding of a current transformer should therefore

always be short circuited or connected to a relay coil.

3.7 Potential Transformer:

A potential transformer (P.T.) is used to transform high voltage of power line to a lower

value, which is in the range of an AC voltmeter or the potential coil of an AC voltmeter.

Figure 3.3 Potential Transformer

CHAPTER 4


STEAM TURBINE & BOILER

4.1 Steam Turbine:

Turbine is machine in which a shaft is rotated steadily by impact or reaction of current or

stream of working substance (steam, air, water, gases etc.) upon blades of a wheel. It converts

the potential or kinetic energy of the working substance into mechanical power by virtue of

dynamic action of working substance. When the working substance is steam it is called the

steam turbine.

Figure 4.1 Steam Turbine In K.S.T.P.S.

4.1.1 Principal of Operation of Steam Turbine :

Working of the steam turbine depends wholly upon the dynamic action of steam. The

steam is caused to fall in pressure in a passage of nozzle: due to this fall in pressure a certain

amount of heat energy is converted into mechanical kinetic energy and the steam is set

moving with a greater velocity. The rapidly moving particles of steam, enter the moving part

of the turbine and here suffer a change in direction of motion which gives rose to change of

momentum and therefore to a force. This constitutes the driving force of the machine. The


processor of expansion and direction changing may occur once or a number of times in

succession and may be carried out with difference of detail. The passage of steam through

moving part of the commonly called the blade, may take place in such a manner that the

pressure at the outlet side of the blade is equal to that at the inlet inside. Such a turbine is

broadly termed as impulse turbine. On the other hand the pressure of the steam at outlet from

the moving blade may be less than that at the inlet side of the blades; the drop in pressure

suffered by the steam during its flow through the moving causes a further generation of

kinetic energy within the blades and adds to the propelling force which is applied to the

turbine rotor. Such a turbine is broadly termed as impulse reaction turbine.

The majority of the steam turbine have, therefore two important elements, or Sets of such

elements. These are :

The nozzle in which the system expands from high pressure end a state of comparative

rest to lower pressure end a status of comparatively rapid motion.

The blade or deflector, in which the steam particles changes its direction and hence its

momentum changes. The blades are attach to the rotating elements are attached to the

stationary part of the turbine which is usually termed.

The stator, casing or cylinder.

Although the fundamental principles on which all steam turbine operate the same, yet the

methods where by these principles carried into effect very end as a result, certain of turbine

have come into existence.

Simple impulse steam turbine.

The pressure compounded impulse turbine.

Simple velocity compounded impulse turbine

Pressure-velocity compounded turbine.

Pure reaction turbine

Impulse reaction turbine

AT KSTPS there are 2X110 MW, turbines installed for unit 1 & 2 and 3 210 MW

turbines installed for units 3, 4 & 5 one 195 MW turbine installed for unit 6.


Figure 4.2 Steam Turbine

Description of 210 MW Steam Turbine :

4.1.1 Steam Flow :

210 MW steam turbine is a tandem compound machine with HP, IP, LP parts are double

flow cylinders. The individual turbine rotors and generator rotor are rigidly coupled. The HP

Cylinder has a throttle control. Main steam is admitted before blending by two combined

main stop and control valves. The HP turbine exhaust (CRH) leading to reheat have two

swing check valves that prevent back flow of hot steam from reheated, into HP turbine. The

steam coming form reheated called HRH is passed to turbine via two combined stop and

control valves. The IP turbine exhausts directly goes to LP turbine by cross ground pipes.

4.1.2 HP Turbine :

The HP casing is a barrel type casing without axial joint. Because of its rotation

symmetry the barrel type casing constant in shape and leak proof during quick change in


temperature. The inner casing too is cylinder in shape as horizontal joint flange are relieved

by higher pressure arising outside and this can kept small. Due to this reason barrel type

casing especially suitable for quick start up and loading.

The HP turbine consists of 25 reaction stages. The moving and stationary blades are

inserted into appropriately shapes into inner casing and the shaft to reduce leakage losses at

blade tips.

4.1.3 IP Turbine :

The IP part to turbine is of double flow construction. The casing of IP turbine is split

horizontally and is of double shall construction. The double flow inner casing is supported

kinematically in the outer casing. The steam from HP turbine after reheating enters the inner

casing from above the below through two inlet nozzles. The center flow compensates the

axial thrust and prevent.

The HP and IP rotor are connected to the rigid completing & they have a common

bearing. After passing through I.P. turbine, the steam enters the middle part of L.P. turbine

through two cross pipes.

In L.P. turbine the steam flows in opposite paths having four stages in each path after

leaving L.P. turbine the exhaust steam conductors in the surfaces condenses welded directly

to the exhaust part of the L.P. turbine rotors of L.P. turbine & L.P. turbine are connected by a

semifinal coupling.

Steam inlet temperature affecting brackets, bearing etc. The arrangements of inner

confines high steam condition to admission branch of casing, while the joints of outer casing

is subjected only to lower pressure and temperature at the exhaust of inner casing. The

pressure in outer casing relieves the joint of inner casing so that this joint is to be sealed only

against resulting differential pressure.

The I.P. turbine consists of 20 reaction stages per flow. The moving and stationary blades

are inserted in appropriately shaped grooves in shaft and inner casing.

4.1.4 LP Turbine:

The casing of double flow type LP turbine is of three shall design. The shall are axially

split and have rigidly welded construction. The outer casing consists of the front and rear

walls, the lateral longitudinal support bearing and upper part.


The outer casing is supported by the ends of longitudinal beams on the base plates of

foundation. The double flow inner casing consist of outer shall and inner shall. The inner

shall is attached to outer shall with provision of free Super Thermal movement.

Steam admitted to LP turbine from IP turbine flows into the inner casing from both sides

through steam inlet nozzles.

4.2 Boiler:

The utility boilers are large capacity steam generators used purely for the electrical power

generation. In boiler beat energy is released from the combustion of fossils fuel and heat is

transferred to different fluids in the system and a part of its is lost or left out as unutilized. It

is therefore essential to study. The general principal of heat transfer for understanding the

design as well as the behavior of boiler different condition of operation.

4.2.1 Heat transfer modes :

There are three modes of heat transfer viz. conduction convection and radiation, one or

more of these modes for which heat source should be at higher temperature than the receiver

transfer heat energy hot surface to a heat recover.

4.2.2 Conduction:

It is the heat transfer from one part of body to another part of the same body or from body

to another physical contact without appreciable displacement of the particles of the body.

4.2.3 Convection:

It is the transfer of heat from one point to another within a fluid by mixing of one part

with another due to the movement of the fluid. When the movement of fluid is caused solely

by the differences in density resulting from temperature differences in density resulting from

temperature differences within fluid.

4.2.4 Radiation:

It is the transfer of heat energy from one body to another by electromagnetic waves which

can travel through vacuum when radiation impinges on a body. Some of the radian energy

will re-radiated, some of it will be transmitted through the body and remainder will be

absorbed.

4.2.5 Heat Transfer Surface Arrangement : There are three general kinds of

arrangements of heat transfer surfaces as the Relative flow of fluid in concern. They are


paralleled flow, counter flow and cross flow. In parallel flow both the fluids enter at the same

relative physical location with respect to heat transfer surface. Resulting rapid rise in

temperature. In counter flow, the two fluids enter at opposite ends of the heat transfer surface

and flow in opposite direction over the surface resulting sudden rise in temperature. In cross

flow the flow paths of the two fluids are perpendicular to each other resulting gradual rise in

temperature.

4.2.6 Heat Transfer Sections :

The various heat transfer section of a boiler can be grouped as follows :-

4.2.6.1 Furnace :

The furnace design influenced by the fuel, surface, plain area (13.86 X 10.59) volumetric

(5470 m3) and burner clearance. The major fuels used in the steam generation are coal, oil and

gas. Super heater and reheater.

The location of super heater and reheater is almost standard based on the past experience.

Typical arrangement of super heater and re-heater is indicated in the elevation drawing.

4.2.6.2 Economizer :

This is also convection heat transfer section located in relatively cooler gas temperature

zone and preheats the water entering the drum. The inlet temperature should not be less than

140° C from the low temperature corrosion point of view. The outlet temperature should be

35-45° C lower than the saturation point to avoid the streaming tendency in the economizers.

4.2.6.3 Air Heaters :

The technical developments of the air pre-heater provide regenerative type air heaters.

The air temperature required for drying the case of coal fired boiler decided the size of the air

heaters.

4.2.6.4 Material Selection for Heat Transfer Surfaces :

The selections of the heat transfer surfaces are being on the basis of the temperature of

themed metal temperature as well as the outer surface temperature complete water wall

system is provided with only carbon steel where as super heater ad re-heat are provided with

whereas grades of ASTM specification.

4.2.7 Circulation System :In natural circular system, water delivered to steam

generator from feed header which are at a temperature well below the saturation value


corresponding to that pressure. Entering the economizer, it heated to much greater the

saturation temperature from economizer the water enter the drum and thus joins the

circulations system through down covering water wall tubes. In water wall tubes a part of the

water is converted to steam due to boiler and the mixture flows back to drum on the basis of

the thermo siphon principal. In the drum, the steam is separated out through the steam heater

when the steam temperature becomes high and pressure up to 150 Kg. Steam is allowed to

enter the turbine to convert potential energy to kinetic energy.

4.2.8 General Description :

Boilers are tangentially fired, balance draft, natural circulation, radiant type, dry bottom

with direct fired pulverized coal from bowl mills. They are designed for burning low grade

coal with high ash content. Oil burners are located between coal burners for flame

stabilization. Pulverized coal is directly fed from the coal mills to the burners at the four

corners of the furnace through coal pipes. The pulverized fuel pipes from the mills to the

bunkers are provided with basalt lined bends to reduce erosion and to improve the life of

these pipes.

For the last stage of heat recoveries there are two regenerative air heater of trisector type.

The air heater has separate section for heating the primary air (required for the pulverize) &

the section secondary air (required for the combustion process.)

The fuel preparation section consists of primary for number bowl mill arranged for

pressurized operation. Each mill has its own raw coal feeder. The pulverized coal from each

mill is carried through pipes to the burner to the for carried through pipes to the burners to the

four corners of furnace arranged for tilting tangentially arranged for firing. The burners

wind-box section is located in four corner of the furnace. Owing to poor grade of coal there is

a high percentage of mill rejects. The mill rejects are conveyed in a sluice way to an under-

ground tank. From this tank the mixture is taken to an overhead hydro-bin where water is

decanted and the mill reject are disposed off by trucking. ESP with collection efficiency of

99.8% have been provided to reduce environmental pollution and to minimize induce draft

fan wear. A multi-flue reinforced concrete stack with two internal flues has been provided.

Two boiler feed pumps each of 100% capacity are driven by AC motor through hyd.

Coupling with scoop tube arrangement for regulating feed water pressure for each unit.

The air required for combustion is supplied by two forced draft fans. Due to anticipated

high abrasion of ID fans impellers. Three ID fans each of 60% capacity have been provided


one ID fan to serve as stand by Four ensuring safe operation of boilers, furnace safe guard

supervisory system (FSSS) of combustion engineering USA designed has been installed.

This equipment systematically feed fuel to furnace as per load requirement.

The UV flame scanners installed at two elevation in each of the four corners of the

furnace, scan the flame conditions and in case of unsafe working conditions but out fuel and

trip the boiler and consequently the turbine. Turbine- boiler interlocks safe guarding the

boiler against possibility furnace explosion owing to flame failure.

Facilities have been provided to simultaneously unload and transfer 10 light oil and 40

heavy oil tankers to the designated tanks. Oil preheating arrangement is provide on the tanks

floors for the heavy oil tanks.


CHAPTER 5

COOLING SYSTEM

5.1 General Cooling:

In KSTPS hydrogen cooling system is used for generator cooling. Hydrogen is used for

cooling medium primarily because of its superior cooling properties and its low density.

Thermal conductivity of hydrogen is 153.7 times of air. It has also higher transfer coefficient.

Its ability to transfer heat is about 50% better than air. Density of hydrogen is approximately

¼ of the air density at a given temperature and pressure. This reduces the wind age losses in a

high speed machine like turbo generator. Increasing the hydrogen pressure within the

machine improves its capacity to absorb and remove hear. Relative cooling properties of air

and hydrogen are given below:

1) Elimination of fire risk since hydrogen will not support combustion.

2) Reduce machine maintenance because of a gas tight enclosure

3) Corona discharge is not harmful to insulation since oxidation is not possible.

To overcome the serious possibilities of hydrogen explosion within the machine and to

ensure the safety operation the purity of hydrogen in the generator casing must be maintained

as high as possible. The purity of hydrogen should be 98% or above but not below. In case

hydrogen purity drops below 98% an alarm is provided.

5.2 Hydrogen Dryers:

Two types of dryers are provided to absorb the moisture in the hydrogen in the generator.

Moisture in this gas is absorbed by the silica gel. The saturation of silica gel is indicated by

its change from blue to pink. Heating reactivates the silica gel.

5.3 Hydrogen Filing system:

The filing system is carried out in two system steps:

Scavenging the air by carbon dioxide.

Expelling the carbon dioxide with hydrogen.

Before filling hydrogen to a pressure of two atmospheres in the machine, it is necessary to

store:


At least 18 cylinders of 20 Kg of carbon dioxide each i.e. 360 Kg of carbon

dioxide.

48 cylinders of hydrogen

The electric power generators require current excited magnets for its field system respond

quickly to excitation current requirement. When a fast acting regulator excitation system

response it is mainly dependent on an exciter given. Exciter given from the transformer and is

then rectified.

5.4 Function of Excitation System:

The main function of excitation system is to supply required excitation current at the rated

load condition of turbo generator. It should be able to adjust field current of the generator

either by normal control or automatic control, so that for all operation between no load and

rater load the terminal voltage at the system machine is maintained at its value.

Figure 5.1 Block Dig. Of Excitation System


5.5 Types of Excitation System:

There have been many developments in the excitation system designs. The modern

excitation system developed presently on BHEL made turbo generators:-

Conventional DC excitation system

Brushes excitation system

Static excitation system

5.5.1 Static Excitation system:

In KSTPS there is static excitation system. It consists of the following parts:-

- Rectifier system

- Six number of thyristors converters.

- An automatic voltage regulator (AVR)

- Field suppression equipment

- Field fishing equipment

5.5.2 General Arrangements:

In the static excitation system the power requires for the excitation of generator are

tapped from 11KV bus bar through a step down rectifier transformer. After rectification in

thermistor converter by adjusting the field flashing system facilities initial built up of

generator voltage from the static AC or DC supply.

5.5.3 Advantages of Static Excitation System:

very fast response

Extremely reliable in view of static components

Low maintenance cost

High efficiency


Fast field suppression through field and discharge resistance as well as through

Thermistor bridge feeding the generator field.

5.6 Operation:-After bringing the speed to operating speed say 3000 Rpm. The voltage

is slowly built up with the help of excitation system. This action is taken for synchronizing

the generator with grid.

5.6.1 Synchronizing:

For synchronizing the generator to the grid system five conditions of equality have to be

satisfied are:

1) Voltage

2) Frequency

3) Phase displacement

4) Phase sequence

5) Wave form

Waveform and phase sequence of the generator are determined at the design and

commissioning stages but voltage, frequency and phase displacement have to be set up by the

operator during each connection of synchronizing the generator.

5.6.2 Machine connected on Infinite Bus:

While connecting and separating a machine in parallel with the grid we will have two

conditions:

1) Any increase in the power input to generator increase its phase of electrical load.

2) Any increase in the excitation of generator increases its phase of reactive load.

5.7 Fans:

A fan can be defined as a volumetric machine, which like pumps moves quantities of air

or gas from one place to another. In doing this it overcomes resistance to flow by supplying

the fluid will the energy necessary for contained motion. The following fans are used in

boiler house:

5.7.1 Forced Draft Fan (F.D. fan) :To take air from the atmosphere at ambient

temperature to supply all the combustion air can either be sized to overcome all the boiler

loss or just put the air in the furnace, Speed varies between 600 to 1500 rpm.


5.7.2 Induced Draft Fan (I.D. fan) :

Used only in balanced draft units to suck the gases out of the furnace and through them into

the stack. Handles fly ash laden gases at temperature of 125 to 200 degree centigrade. Speed

seldom exceeds 1000 rpm.

5.7.3 Primary Air Fan (P.A. fans) or Exhauster fan :

Used for pulverized system. Primary air has got two-function viz. drying the coal and

transportation into the furnace. Usually sized for 1500 rpm due to high pressure.

5.8 Technical – Data:

(A) Generators:

Type TGP 23406012 H

Rating : Continuous

Apparent Output : 137, 500 KVA

Active Output : 110,000 KW

Power Factor : 0.8 (Lagging)

Rated Voltage : 11000 VI 5%

Rated Current : 7220 amp

Rated Speed : 3000 rpm

Critical Speed : 3000 rpm

Frequency : 50 Hz

Phase Connection : Double Star

No. of terminals : 6

Main Dig. Of Slip ring : 420 mm

Max. O/P with Hy. Cooler : 9692.50 KVA

Max. O/P with Air Cooling : 68,750 KVA

Max. O/P of Rated Voltage and


Zero P.F. (lagging) : 50,000 KVA

Max. O/P of Sudden Shoots CPT

Current Including D.C. Component : 9.2 A

Internal Voltage Regulation : 39%

Shoot CPT Ratio : 0.5

(B) Hydrogen cooler:

No. of cooling Elements : 6

Cooling Medium : Water, H2 at 2Atm

Dissipated Losses : 1500 KW

Quantity of H2 : 30 meter cube/sec

Quantity of Water : 250-m3 cube/sec

Cooling Water Temp. : 34 degree Centigrade

Cooling cold H2 Temp : 40 degree centigrade

Flow Resistance (H2 Side) : 12mm of peak

Inherent Voltage Regulation : 39%

Max. Capacity : 50,000 KVA

Short C14 Ratio : Hc-WII-BS/C46

(C) Generator Brushes:

Number: 42

Size: 25*32


CHAPTER 6

WATER TREATMENT PLANT

The principal problem in high-pressure boiler is to control corrosion and steam

quality.Internal corrosion costs power station corers of rupees in repair without strict control

impurities in steam also form deposit over turbine blades and nozzles. The impurities present

in water solid materials are:

1. Un-dissolved and suspended solid minerals,Dissolved slats and minerals,Dissolved

gases and other minerals (oil, acid etc.)

2. Turbidity &Sediment,Silica, Micro Biological, Sodium & Potassium Salt, Dissolved

Sales Minerals

3. Gas (Oxygen, Carbon-Di-Oxide).

Figure 6.1 Chlorical Water Treatment Plant


6.1 D.M. Plant:

In this plant process water is fed from all these dissolved salts.This plant consists

exchanger and mixed bed exchanger. The filter water to DM plant through 250 dia. Headers

from where a heater top off has been taken to softening plant. Two filtered water booster

pumps are provided on filtered water line for meeting the pressure requirement in DM Plant.

Sodium Sulphate solution of required strength is dosed into different filtered water by mean

of dosing pump to neutralize chlorine prior to activate carbon filter. When water passed an

activated carbon filter will remove residual chlorine from water. Provision is made for back

Washing the activated carbon filter. When pressure drop across filter exceeds a

prescribedlimit from the activated carbon filter the works acid cation unit. The deception

water the weak scrubbed out of water by upward counter flow of low pr. Air flow through

Degasified lower and degassed water is pumped to strong base exchanger (anion

exchanger).Arrangement for dosing ammonia solution into de-mineralized water after mixed

bed unit has been provided 9+1 correction before water is taken in decondensate transfer pump

the DM water to unit condenser as make up.

The softening plant is plant designed to produce 100M3 of the softened water per stream.

It is used for bearing cooling.

6.2 C.W.Plant:

Circulating water pump house has pumps for condensing the steam for condenser. Five

pumps are used for condensing Unit No. 1 & 2 and after condensing this water is discharged

back into the water.

Each pump has capacity of 8275 M3 / Hr, and develops pressure about 1.94

Kg./Cm2.Three seal water pump are used for sealing circulating water pump shaft at pr. 4.5

Kg./cm2.Two pumps for unit 1 & 2 with on stand by is used for supplying raw water to

clarified chemical dosing is tone between and chlorified water is taken through main line.

From main line water passes through filter bed to filter the water. Chlorfied water is pumped

to 42 m elevation by two pumps of capacity 270 M3/ Inch at discharge pressure of 6.9

Kg./Cm2. At 42 M elevation the water is stored in tan k and used for cooling the oil coolers

and returned back to river. Oil coolers are situated on ground and there is no. of tress for each

unit.


Figure 6.2 Water Treatment Plant

6.3 B.C.W. Pump House :

Filter water after demineralization is used for bearing cooling from BCW pump house

after passing through strainer and heat exchanger it enter at 30-32° C and leave exchanger

quantity is stored in sumps of BCW Pump House. From here the water is pumped to CW

pump By TWS (Traveling water screens) pumps are run by motors of 90 KW and has a

capacity of 240 Cum/hr/pump at pressure of 5 kg/cm2.

BCW here stand for water used for cooling oil the bearing. In CW pump house water is

discharged from nozzle and impinged for traveling water screens for cleaning it.

6.4 Condensate System:

A typical condensate system consists of the following :

Condenser (including hot – well)

Condensate pumps

Air extraction system

Gland coolers and L.P. heater

Deaerator

6.4.1 Condensor :

The functions of condensor are :


To provide lowest economic heat rejection temperature for the steam. Thus saving on

steam required per unit of electricity. Also convert exhaust steam to water for reuse thus

saving on feed water requirement. Dearation of make up water introduce in the condensor.

And to from a convenient point for introducing makes up water.

6.4.2 Type of Condensor :

6.4.2.1 Direct Contact Type (Jet Condensor):

In this type condensation of steam takes place by directly mixing exhaust steam and

cooling water. Requirement of cooling water is much is much less here compare to surface

type. But cooling water quality should be equal to condensate quality.

6.4.2.2 Surface Condenser :

This type is generally used for modern steam turbine installation. Condensations of

exhaust steam takes place on the outer surface of the tubes. Which are cooled by water

flowing inside them.

6.4.3 Condensate Extraction Pumps :

Condensate extraction pumps are normally multistage, vertical, centrifugal pumps. They

are generally required to operate on minimum net positive suction head (NPSH). The

condensate pumps operate on few inches of suction submergence. A ven line connects the hot

well, from where the condensate pumps the suction with the condenser. This equalizes the

vapour pressure of condenser and hot well. No of stages in the pump is determined by the

discharges pressure required for the condensate cycle. In 120 MW unit. Three condensate

pumps, each having 50% capacity, are provided for pumping the condensate to deaerator.

Condensate water is also used for :

Sealing of glands of valves operating under vacuum.

Temperature control of L.P. by pass steam.

Falling siphons of main ejectors and 15 meter syphone of drain expander.

Actuating the forced closing non-return waves of turbine steam extraction lines.

Operation of group protection device for by passing H.P. heaters.

For cooling steam dumped through steam throw off device.


6.4.4 Air Extraction System :

Air extraction system is needed to extract air and other non condensable gases from the

condenser for maintaining vacuum. Amount of air to be extracted from condenser during start

up is quite large land the extraction should be done as rapidly as possible so as to allow the

turbine to be started.

Under normal operating conditions quantity of air to be extracted is lower; it consists of

air leakage in to the condenser via flanges and glands and also of very little non condensable

gases present in steam.

To guard against excessive water vapour extraction along with air, the space beneath the

air extraction baffles has been provided with its own cooling tubes in order to condense as

much water vapour as possible and thus preventing its removal from condenser.

6.5 Low Pressure Heater :

The heater is of horizontal surface type consisting of two halves, each half has been

located inside the upper part of each condenser. The two halves have been installed in

parallel. The steam to both is supplied from the same extraction point.

The housing for the heater is fabricated from M.S. plates with suitable steam inlet and drain

connections. The tube plate is of mild steel and is secured to the water box and housing by

means of studs land nuts. ‘U’ shaped tubes have been used to ensure independent expansion

of tubes and the shell. They are of solid drawn admiralty brass, 19 mm external dia, 1 mm

and 0.75 mm thick and are expanded by rolling into the tube plate at facilities drawl for tube

replacement, and maintenance. Partitions mild steel plates have been provided for supporting

the tubes at intermediate points and effective distribution of heat load in all the zones of

heater.

6.6 Gland Cooler :

Gland cooler has been designed to condensate the leaks off steam from intermediate

chambers of land earthing of HP & IP turbines.

The construction of this cooler is identical with low pressure heater No. 2, 3 & 4. The

main condensate flows through the tubes in four paths before leaving the cooler.

The deal off steam enters the shell through a pipe and flow over the tube nest. The

participation wall installed in the tube system lead to zigzag flow of steam over the tube nest.

Condensate of leak off steam referred as drain trickles down the tubes and is taken out from


the lower portion of the shell by automatic level control valve, installed on the tubes on is

taken out from the lower portion of the shell by automatic level control valve, installed on the

drain line.

6.7 Dearator :

The pressure of certain gases like Oxygen, carbon dioxide and ammonia dissolved in

water is harmful because of their corrosive attack on metals, particularly at elevated,

temperature. Thus in modern high pressure high pressure boiler, to prevent internal

corrosion, the feed water should be free, as far as practicable, of all dissolved gases,

especially oxygen,. This is achieved by embodying into the freed system a dearating unit.

Figure 6.3 Dearator


CHAPTER 7

COAL HANDLING PLANT

It cam be called the heart of super thermal power plant because it provided the fuel for

combustion in boiler. The coal is brought to the KSTPS through rails there are fourteens

tracks in all for transportation of coal through rails. The main coal sources for KSTPS are

SECL (South eastern coalfields Limited), ECL (Eastern coalfield limited) and BCCL (Bharat

Coking coal limited) .Everyday 3 to 4 trains of coal are unloaded at KSTPS. Each train

consists of 58 wagons and each wagon consists of 50 tones of coal. The approximate per day

consumption at KSTPS is about 1400 metric tones. The coal is firstly unloaded from wagon

by wagon triples then crushed by crushers and magnetic pulley and pulverized to be

transformed to the boiler. The whole transportation of coal is through conveyor belt operated

3-induction motor.The coal handling plant can broadly be divided into three sections :

Wagon Unloading System.

Crushing System.

Conveying System

7.1Wagon Unloading System :

Figure 7.1 Incoming Coal At K.S.T.P.S.


7.1.1 Wagon Tripler:

It unloads the coal from wagon to hopper. The hopper, which is made of Iron, is in the

form of net so that coal pieces of only equal to and less than 200 mm. Size passes through it.

The workers with the help of hammers break the bigger ones. From the hopper coal pieces

fall on the vibrator.It is a mechanical system having two rollers each at its ends. The rollers

roll with the help of a rope moving on pulley operated by a slip ring induction motor with

specification :

Rated output : 71 KW

Rated Voltage : 415 V.

Rated Current : 14.22 Amp.

Rated Speed : 975 rpm.

No. of phases : 3

Frequency : 50 Hz.

The four rollers place themselves respectively behind the first and the last pair of wheels

of the wagon,. When the motor operates the rollers roll in forward direction moving the

wagon towards the “Wagon Table”. On the wagon table a limit is specified in which wagon

to be has kept otherwise the triple would not be achieved.

7.2 Coal Handling Plant:

In the coal handling plant a mass haling yard has been provided to receive the coal trains

& unloading them. The wagons are positioned on the wagon tippler with the help of wagon

handling gear. Two wagon tipplers remain standing by having a capacity to handle 12 box

wagons per hour. Coal from wagon tippler is discharged into tw3o underground hoppers is

transferred by the two belt feeders to either of the conveyors of 675 tons per hour capacity

either of the conveyors to take coal directly to the crusher house.

7.3 Crushing System:

7.3.1 Crusher House:

It consists of crushers, which are used to crush the coal to 20-mm size. There are mainly

two types of crushers working in KSTPS :-

Primary Crushers i.e. i) Rail crushers or ii) Rotary breaker


Secondary Crushers i.e. Ring granulators

7.3.1.1 Primary Crushers :

Primary Crushers are provided in only CHP stage 3 system, which breaking of coal in

CHP stage I & Stage 2 system is done at wagon triple hopper jail up to the size (-) 250 mm.

7.3.1.2 Secondary Crusher :

Basically there are three ways to reduce material size: impact attrition, shearing and

compression. Most of the crushes employ a combination of three crushing methods. Ring

granulators crush by compressing accompanied by impact and shearing. The unique feature

of this granulator is the minimum power required for tone for this type of material to be

crushed compared to that of other type of crushers.

7.3.1.3 Construction & Operation :

Secondary crushers are ring type granulators crushing at the rat of 550 TPH / 750 TPH for

input size of 250 mm. And output of 20 mm. The crusher is coupled with motor and gearbox

by fluid coupling.

Main part of granulator like break plates, cages, crushing rings and other internal parts are

made of tough manganese (Mn) Steel.

The rotor consists of four rows of crushing rings each set having 20 Nos. of toothed rings

and 18 Nos. of plain rings. In CHP stage 1 & 2 having 64 Nos. of ring hammers. These rows

are hung on a pair of suspension shaft mounted on rotor discs. Crushers of this type employ

the centrifugal of swinging rings stroking the coal to produce the crushing action. The coal is

admitted at the top and the rings stroke the coal downward. The coal discharges through

grating at the bottom. The spacing of the bar determines the maximum size of the finished

product.

7.4 Conveying System :

7.4.1 Stacker Re-claimer:

The stacker re-claimer unit can stack the material on to the pipe or reclaim the stack filed

material and fed on to the main line conveyor. While stacking material is being fed from the

main line conveyor via tripler unit and vibrating feeder on the intermediate conveyor which

feds the boom conveyor of the stacker cum re-claimer. During reclaiming the material


discharged on to the boom conveyor by the bucket fitted to the bucket wheel body and boom

conveyor feeds the material on the main line conveyor running in the reverse direction.

Conveyor Belt Specification of Stacker/Re-claimer :

Belt width : 1400 mm.

Speed : 2.2 m/second

Schedule of Motor : All 3-f induction motors

Bucket wheel Motor : 90 KW

Boom conveyor Motor : 70 KW

Intermediate conveyor Motor : 90 KW

Boom housing Motor : 22 KW

Slewing Assembly : 10 KW

Travel Motor : 7.5 KW

Vibrating Feeder : 2x6 KW

Total installed Power. : 360 KW

Convey or Specification : 1) 1350 tones per hour

Capacity 2) 750 tones per hours

No of conveyor : 38

Horizontal length : 28 meters

Angle of induction : As per conveyor profile drg.

Lift (M) (approx.) : Variable to suit the system

Belt width : 1400 mm.

7.5 Plow Feeders:

This structure is erected to serve the purpose of storage. Under ground machines are

installed known as plow feeder machines.

These machines collect the coal from conveyor and drop it to the other from one

conveyor with the help of jaws and this coal is taken to huge erected structure from where the

coal falls to the ground. Jali chutes are used to prevent dust.


CHAPTER 8

ASH HANDLING PLANT:

This plant can be divided into 3 sub plants as follows :-

Fuel and Ash Plant.

Air and Gas Plant

Ash Disposal and & Dust Collection Plant.

8.1 Fuel and Ash plant :

Coal is used as combustion material in KSTPS, In order to get an efficient utilization of

coal mills. The Pulverization also increases the overall efficiency and flexibility of boilers.

However for light up and with stand static load, oil burners and also used. Ash produced as

the result of combustion of local is connected and removed by ash handling plant. Ash

handling plant in KSTPS consists of specially designed bottom ash and fly ash in electro

static precipitator and air pre-heaters hoppers.

8.2 Air & Gas Plant :

Air from atmosphere is supplied to combustion chamber of boiler through out the action

of forced draft fan. In KSTPS there are two FD fan and three ID fans available for draft

system per unit. The air before being supplied to the boiler passes through pre-heater where

the fuel gases heat it. The are heating of primary air causes improved and intensified

combustion of coal.

The fuel gases formed due to combustion of coal first passes round the boiler tubes and

then it passes through the super heater and then through economizer. In re-heater the

temperature of the steam (CRH) coming from the HP turbines heated with increasing the

number of steps of re-heater the efficiency of cycle also increases. In economizer the heat of

fuel gases raises the temperature of feed water. Finally the fuel gases after passing through

the Electro-static precipitator is exhausted through chimney.

8.3 Ash Disposal & Dust collection Plant:

KSTPS has dry bottom furnace. Ash Handling consists of especially designed bottom and

fly ash system for two-path boiler. The system for both units is identical and following

description is applied to both the units the water compounded bottom ash hopper receives the


bottom ash from the furnace from where it is stores and discharged through the clinker

grinder. Two slurry pumps are provided which is common to both units & used to make

slurry and further transportation to ash dyke through pipeline.

Dry free fly ash is collected in two number of 31 fly ash hoppers, which are handled by

two independent fly ash system. The ash is removed from fly ash hoppers in dry state are

carried to the collecting equipment where it is mixed with water and resulting slurry sump is

discharged.

8.4 Controller :

Now a day microprocessor based intelligent controllers are used to regulate the power fed

to the HVR. The controls the firing/ignition angle of the thrysters connected in parallel mode.

Input out waves of the controller and HVR are also shown above, which clearly indicates that

average power fed to ESP field can be controlled by variation of the firing angle of thyristers.

The output of controller with respect to time is also controlled by microprocessor, so that

ESP operation is smooth and efficient. The chars is as shown :

As can be seen in the event of spark between electrodes the output of controller is reduced

to zero for few millisecond for quenching the spark. Controller also takes place care of fault

in KVR and gives a trapping and non-trapping alarm as per the nature of fault.

8.5 High Voltage Rectifier Transformer :

HVR receives the regulated supply from controller. It steps up to high voltage rectifier.

The D.C. supply is fed to E.S.P. field through its negative bushing. The positive bushing so

connected to earth through small resistance, which forms a current, feed back circuit. A very

high resistance column is also connected with negative bushing. It forms the voltage feed

back circuit. These two feedbacks are used in the controller for indication and control

purpose.

8.6 Electrostatic Precipitator:

Mechanical precipitations consist of number of primary cells having vanes to impart the

ash particles & course ash particles fall into the primary hoppers.

The ESP, consists of a large in which have No. of collecting electrodes. In it dust particles

are charged and stick to the electrodes.


8.7 E.S.P. Field:

The field consists of emitting and collecting electrodes structure, which are totally

isolated from each other and hanging with the top roof of field. The emitting is also isolated

from the roof through the support insulators, which are supporting the emitting electrode

frame works, and also the supply to these electrodes is fed through support insulators. The

collecting electrodes are of the shape of flat plates. By several similar plates which the

emitting electrodes are of the shape of spring. Strong on the emitting framework with the help

of hooks in both the ends.

The ash depositing on these electrodes is rapped down by separate wrapping mechanism

happens at the bottom of the field. From these hoppers ash is evacuate by ash handling

system and dispose to the disposal area. The wrapping system is automatically controlled

with the help of the programmable metal controller ash especially during rainy season.

The heating effect helps the dry ash to flow freely during evacuation. Heaters are

controlled with the help of thermostat.


CHAPTER 9

CONTROL ROOM

9.1 Main Control Room:

There is one unit controls from which two adjacement unit of 110 MW each can be

controlled. In addition are local panels at the boiler, turbo sets and boiler feed pumps. The

operation of unit is basically controlled from unit control room.

The operation of various rents and chain are done locally as per requirement. The unit

control room has a set of parameters panel for indicating or recording parameter of boilers or

turbo sets.

Figure 9.1 Control Room

The parameters recorded in control room included per pr. and temp. of line steam, reheat

steam, feed water, fuel oil flow and mill outlet temp. Mill differential turbine speed, control

valve operation turbine shaft, axial shaft, back pressure in condenser, metal temperature etc.

There is data logger to ensure accurate lagging of essential data.

The VCB also control panel for one generator and contains exciter synchronizing

arrangement. The unit control room also houses most of electronic regulator, recorders and

other devices in near side of room.


The scheme of control and instruction is provided to control the parameters and safe

operation of equipment. Automatically control is provided for combustion for feed water

regulation and reheat temp. The combustion control is designed to inlet maintain the desired

steam pressure at turbine only variation thereof utilized to very fuel to the boiler w.r.t. steam

pressure. Ratio steam flow maintained automatically.

The feed water regulation is based on impulses from drum level, feed water flow to boiler

and steam flow for the boiler.Super heated temp. Counted with feed water spray. The furnace

draft control of draft fan. The boiler oil system is provided with itself control for ignition

control and also provided with safety interlock to prevent operation under low oil pressure

and temperature.

CP 1.

1. FAN CONTROL DESK :

Induced draft fan (3 Nos.) at full load and 2 Induce Draft fans Run.

Forced draft fan (2 Nos.)

Primary Air fan (3 Nos.) at full load.

2. Furnace Pressure (- 5 to 10 wel).

Primary Air Header Pressure (750-800 mm. Level wel.)

3. FO

Wind box pressure or wind box differential pressure.

CP. II

Fuel Control Desk :

Coal, oil flow.

Oil Pressure.

Temp. of mill (inlet & outlet)

Flow of air

Differential pressure of mill

CP. III

Steam & Water Desk :


Drum Level Control

Flow of steam & Water.

Pressure of Steam & Water

Temp. of Steam & Water

CP. V

Generator Control Panel :

Voltage Current MVAR.

Stator Rotor Temp.

For Stator Cooling (a) H2 Pressure. (b) H2O Pressure.

9.2 PROTECTION:

1. Field Protection

2. Pole Slipping

3. Plane Overload Protection

4. Inter-turn Fault

5. Negative Phase Sequence protection

6. Reverse Power Protection

7. Forward Power Protection

8. Under Frequency & Over Frequency Protection

9. Generator Voltage Protection

9.2.1 General Protection :

It is most important electrical equipment of many generating station. Tripping of even a

generating unit may cause overloading of associated machines and even to system un-

stability. The basic function of protection applied to generator is to reduce voltage to

minimum by rapid discrimination clearance to faults. Unlike other apparatus the opening of

C.B. to isolate faulty generator is not sufficient to prevent future damage. Since generator

would continue to supply power to stator winding fault, until its excitation is suppressed. It is,

therefore, necessary to open field stop fuel supply to prime mover & in some case breaking

also.


CHAPTER 10

AUXILIARY SUPPLY FOR THERMAL POWER STATION

Electrical supply system for auxiliaries is the most important part of a thermal power

plant. The failure of even comparatively small equipment could result in the station losing

load or being put out of commission. So reliability of the station can be no better than the

reliability of its auxiliaries. The degree of reliability should be considered in relation to the

financial risk of forced outages or damages to the plant. It is therefore essential:

To use the most suitable equipment available.

To understand the functions of various components clearly in order to make an intelligent

choice of the equipment to be installed.

To select the best and reliable method of supplying power to auxiliaries and the

components.

To design the system carefully as it involves selection of voltages and rating of

switchgear and motors.

To use simple layout with minimum number of inter connections as it gives reliability and

flexibility operation.

10.1 Type of Auxiliaries:

The auxiliaries can be broadly classified as:

Boiler Auxiliaries such as draft fans, pulverize mills fuel and ash handling facilities, feed

pumps etc.

Turbo-generator and condenser auxiliaries such as circulating water pumps, condensate

pumps, seal and lube oil pumps, stator water pumps etc.

10.1.1 Service Auxiliaries:

These are common auxiliaries associated with one or more units. Their loss would not

affect the out put of the station until after considerable time interval.

Theelectrical supply to auxiliaries is, therefore, arranged according to the important of

auxiliaries, when unit ratings were smaller auxiliary supply was drawn from a common bus.


With increase in unit ratings, such a system is not practicable because of the very high

currents and fault levels associated with it.

It is a universal practice to adopt the “Unit System”. In this one boiler one turbine and one

step up transformer with auxiliary transformer (connected to the generator terminals) operate

as a unit. It has become a normal practice in India to adopt the unit system. In this system the

generator, transformer and unit aux. Transformer (one or two) are considered as a unit, as

these are switched to the power system altogether as a unit. These types of units are bussed

only on the high voltage side of the step up transformer. Elimination of a very high current

low voltage generator breaker has brought in considerable savings in cost.

The transformer is connected to a power system (grid) to which the generating unit is to

feed power. Such transformers are sufficient for more than one unit. When a local distribution

system has to be established, it is economical to provide a tertiary on the station transformers

for start up supply. But this is not healthy practice. It is better to have separate station

transformer.

While giving supply to auxiliaries it is ensured that unit auxiliaries are supplied from the

unit transformer and the service auxiliaries for the station transformer. Each unit has an

entirely separate and failure of one unit does not affect any of the other. This method of

dividing the unit and service auxiliaries gives greater.

Common auxiliaries comprising compressors, overhead cranes water treatment plant

equipment, service pumps, fire lighting elevator, lighting etc.

With the present trends of increase in MW ratings and use of higher steam temperature

and pressure for the generation units installed, the size of the auxiliaries have increased and

also they have assumed a greater importance requiring careful study of the various aspects

affecting their own performance and thereby the performance of the unit. The complexity of

the problem can be imagined from the fact that the range of drive for the auxiliaries various

controlled, fuse protection single phase fractional horse power motor to 5000 HP or above for

boiler feed pumps motors with sophisticated control and projection scheme.

10.1.2 Auxiliary Load:

The overall auxiliary power can be reasonably estimated if the following details are

available:

1. Unit rating


2. Heat cycle pressure and maximum flow of steam

3. Type of boilers.

4. Type and treatment of fuel

5. Circulating and reed water arrangement

6. Generator cooling system.

It has been estimated that for a coal fired units. Auxiliaries should consume about 6% to

8% of the gross unit rating. Out of this boiler feed pumps. Boiler fans, circulating water

pumps and pulverize mills themselves constituting 70% of the total auxiliaries load.

10.2 Source of Supply:

As regard source is concerned the auxiliaries are divided into two main groups.

10.2.1 Unit Auxiliaries:

These are associated with the running of a unit, whose loss would an immediate reduction

in unit out put reliability to the unit auxiliaries because disturbance and faults on the less

important service auxiliaries are not reflected on the unit auxiliaries.

Though the changes of total of power are quite remote but still it cannot be ruled out. It is

essential to provide standby power to ensure continuity to essential power load such as

bearing gear, emergency lubricating and seal oil pumps etc. For this diesel engine for

emergency power are provided:

10.2.1.1 Method of Operation:

To start up unit a supply is taken from the grid via the station board to the unit board, the

unit has circuit breaks being open. When the generator has been brought up to normal speed,

it is synchronized with the main transmission bus and loaded to about 10% of the rating. The

units supply and station board supply is then disconnected form the unit boards, leaving unit

auxiliaries supplied from the unit board.

10.2.1.2 Selection of Unit Auxiliaries:

The total KVA capacity of unit auxiliaries transformer required can be determined by

assuming 0.85 power factor and 0.9 efficiency for total, auxiliaries motor load. It is safe and

desirable to provide about 20% excess capacity than calculated one to provide of

miscellaneous auxiliaries and possible increase in auxiliary load.


With higher unit ratings and higher steam condition the auxiliary power required also

increased and limitation imposed by the switchgear voltages available dictate the maximum

size of unit auxiliary transformer connected to the generator. Such as arrangement normally

provides separate bus sections fed by the separate auxiliary transformer with bus section

breakers. In selecting a unit auxiliary transformer care has to be taken that the percentage

impedances of the transformer for the proposed unit should satisfy the following conflicting

requirements.

The maximum short circuit currents on auxiliary bus should be limited to the maximum

switchgear rating available.

The maximum permissible voltage dip while starting the largest single auxiliary motor,

usually boiler feed pumps, shall remain within acceptable limits.

Any reduction in unit auxiliary transformer impedance to reduce voltage dip results in

increase in switchgear duty and vice versa. The maximum voltage dip, which can be

permitted on starting the largest motor, is normally limited to 15to 20%. If the voltage dip is

higher than the permissible limits, the transformer impedance has to be reduced, the

consequent increase in short circuit duty may require the use of higher rated switchgear.

Therefore, to create balance between these two conflicting conditions for larger units, it

becomes imperative to use more than one unit auxiliary transformer or to increase the service

voltage. The OFF or ON load taps or +/- 5% are provided to cater to the operational

requirements.

10.2.2 Station Transformer:

As already discussed above, the station transformer is required to feed power to the

auxiliaries during start up. This transformer is normally rated to the initial no-load auxiliary

load of the unit. In typical cases, this load is of the order to 60% of the load at full generating

capacity. But in large stations where more than one unit is operating, the station transformer

should have sufficient capacity to start two units at a time. It is also provided with on load tap

changers to cater to the fluctuating voltage of the grid.

10.2.3 Motor:

The rating of auxiliary drives is determined by the unit raring and the steam conditions.

The boiler feed pumps is the largest single auxiliary load and it’s rating as a percentage of

unit rating increase with steam pressure. The electric motor drive is still the preferred method


for unit ratings up to at least 300 MW. The 500 MW unit prefect steam turbine driven

B.F.P.s., still at least one B.F.P. is driven by electric motor for start up of the unit.

The motor of each drives has to be matched with the driven equipment as regards H.P.

Speed, starting torque, inertia of driven load and enclosure. In most cases, the normal design

of squirrel cage induction motor is found to be acceptable. Since the boiler feed pump

requires the largest motor drive in a steam station. To keep this within limits, it may be

necessary to limit the starting current to 4-5 times instead of the normal valued of the order

6/1/2 times. It is necessary to specify that all motors will satisfactory meet their full load with

maximum dip in the bus voltages. It is also desirable to have motor capable of starting up and

accelerating their lads to full speed with low bus voltage


CHAPTER 11

SWITCH GEAR:

Switch gear is one, which makes or breaks an electrical circuit. Problem encountered in

erection losing and commissioning of switch gear and various precaution to be taken in

operating and maintenance of switch gear.

The switch gear used at KSTPS is indoor type :

They may be classified in the following groups :

Stationary cubical type: In this switch gear the component occupy fixed position.

Draw out type or Truck type: In this type of switch ear the circuit is installed on a switch that

can be pulled to provide insulation.

Compound filled or SF6 Filled type: In this type of switch gear the endorser is filled with SF6

gas.

Flux proof or explosion proof type.

Flux switch units and rings mains

Circular Type: In this switch gear, brick wall or R.C.C. slabs separate the units.

Corridor switch gear : A switchboard on which device are mounted on two opposite side

separated by accessible by corridor

11.1 Mimic Diagram Board:

A switch gear on which the mimic diagram of the main is reproduced.

11.2 Metal glad Type:

In this type of switch gear the components are arranged in separated comported with

vertical endorser intended to the earthed.

The switch gear components are arranged in separate compartments with metal endorser

intended to be earthed. The switch gear which is used in KSTPS is draw out or truck type

indoor switch gear.

Draw out type switch gear: In this switch gear the circuit breaker and some other

components are mounted with durable carriage. For insulation after opening the circuit


breaker it is lowered mechanically by manual gear. There after the carriage is pulled out. The

main components of the draw out indoor switch gear are given below.

11.3 Switching Insulators :

They are capable of :

Interrupting transformer magnetizing current.

Interrupting line charging currents

Load transformer switching

The main applications is in connection with feed or bank transformer feeders, this makes

it possible to switch out one transformer while the other one is still on the load.

Circuit Breakers: A circuit breaker is a device that can make or break circulation load and

even a fault.

It is heavy duty equipment mainly utilize protection of various circuit and separation at

load. The circuit breakers in the switch gear are installed on a movable truck. It is tripled by a

relay or by a manual signal. The circuit breaker, which used in switch gear now a days are

minimum oil circuit, air circuit breaker, vacuum circuit breaker and other type are also used

in switch gears. The required form of circuit breakers is that it should be capable to :

Carry continuously minimum current of the system at the time of insulation.

Make and break circuit under the normal working conditions.

Earth Switches: Earth switches are connected between line conductor earth, normally it is

open when line is disconnected the earthing is closed to as to discharge he voltage trapped on

line for high voltage. The capacitance between line and earth is discharge to high voltage so

for maintenance work, these voltages are discharged to earth the earthing switch. The

switches are mounted on line forms of insulators.

11.4 Bus Bars:

Bus bars are defined as conductor to which several incoming and outgoing lines are

connecting. These are essential components of switchgear. These are made up of copper or

aluminum. The type and design of bus bars depends upon rated current (normal) and short

circuit capacity. The bus bars are connected in bus bar chamber.


They are fitted on insulation primary. The insulation is provided by cast openly resin

fitting. In KSTPS, these are two types of indoor switchgear :

6.6 KV or high tension

415 KV or low tension

220 KV System:

Two 220 KV bus bars have been provided in switchgear and me interconnected through a

bus bar coupler. Each of the two 110 MW generator is connected to this system through a

step up generator transformer of 125 MVA 24011 KV star-delta type. Four line feeders are

taken from 220 KV switch yard, two to SAKATPURA G.S.S and two to HEERAPURA,

JAIPUR G.S.S Each of he four line feeders have been provided with a bioscillator, which is

come connected across line breaker isolators. This feature provides total shutdown of a line

breaker of a line without interrupting of flow in the line.

This is achieved by closing the bus coupler between the 220 KV bushes and putting the

line feeders, whose breakers requires maintenance of any bus through by insulation and all

other line feeders whose breakers is by passed is than transformed to bus coupler breaker. A

brief description or electrical equipments of 220 KV system is as follows :

11.5 Circuit Breakers :

Each of the generator, transformer, station transformer, line feeders and bus coupler

provided with circuit breakers either minimum oil breakers (YCB) BHEL make of vacuum

circuit breakers, which are rated for 245 W< 2500 A and 13400 MVA circuit breakers are

used to break the circuit either in load conditions or in no load conditions.

11.6 Isolators :

All the isolators are provided in 200 KY switchyard are motor operated, triple pole

double breakers type and are rated for 245 KW and 1250.

The four isolators are provided with each switch. They are used for supporting time

conductor bus bars.

11.7 Current Transformers:

All the 200 V current transformers provided for measuring and protection are BHEL

make single phase oil fitted nitrogen sealed single phase. The current transformers have been

provided at the rated one per phase.


11.8 Potential Transformer:

Each of the two 220 KV is provided with three potential transformer core for each phase

of BHEL made. These are single phase oil filled, outdoor, nitrogen cooled electromagnetic

type potential transformer having two secondary winding and selected for 220/13 V 110/13

KY. One secondary winding has an output 01 500 VA and accuracy class of 0.5 and is used

for melting. Other secondary winding has an output of 220 VA and accuracy class of 3.0 and

is used for protection.

11.9 Lighting Arrestor:

For protection against lighting each of the line feeders, generator, transformer and station

transformer has been provided with three lighting arrestor in number (one after each phase).

All the lighting arrestors are two phase outdoor type and are rated 193 KV. Three are

manufactured by W.S. Insulators of India Ltd.

11.10 Earthing Isolators:

If we have to do some work on the line, first we earth the line through the earthing

isolator for discharging the line capacitor and then work out.

11.11 Capacitor Voltage Transformer:

Each of the four line feeders is provided with three capacitor voltage transformer. They

all are single phase, W.S. Insulators of India Ltd. Make and have two winding in secondary

slick. The capacitor voltage transformers are rated for 220 / KV / 110 / V / 100 / V.

11.12 Switch Yard:

11.12.1 220 KV System:

Two 220 KV bus bars have been provided in switch yard and are interconnected through

a bus coupler. Each of the two 110 MW generator is connected to this system through a step

up of 125 MVA 240/ 11 KV yard generator transformer. There are two step down

transformer each feeding 6.6 KV system (Station Switchyard) viz. BS-IB.


Figure 11.1 Switch Yard At K.S.T.P.S.

Each station transformer has two windings one secondary side and is rated for 50/25/20

mva. 270/7/7.2 KVA four feeders take off from 220 switch yard, two to SKATPURA, GSS

and other to HEERAPURA, Jaipur GSS. Each of four feeders is provided with bypass

isolators, which is connected across line breaker, and breaker isolator. By closing bus coupler

between 220 KV buses and putting line feeders whose breaker required maintenance of any

one bus through by pass isolators and all other line feeders whose breaker is by passed is then

transformer to bus coupler breaker.


RESULT& CONCLUSION

I have undergone a training of one month at KSTPS in which i have studied about the

generation of electricity through a steam power plant. I have acquired all the necessary details

regarding the generation.

The training of one month was successfully coupled &pretly good knowledge regarding

generation of electricity.

This one month was one of the most knowledge gaining month of my engineering

career.

Power plants play major role in development of any country and all the technocrats, who

gives their efforts to make these plants best are supposed to give optimal output in their

concerned task and as we are also going to become electrical engineers, so we should know

how our learned theoretical concepts converts into practically possible things. Practical

exposure to the plant like K.S.T.P.S. has proved to be most beneficial in making us

practically aware besides the theoretical knowledge. It provided an opportunity for encounter

with such huge machines like wagon tippler, 110 MW & 210 MW turbines and generators.

The architecture of the power plant, the way various units are linked and the way working of

whole plant is controlled make the student realize that engineering is not just learning the

structured description and working of various machines, but the greater part is of planning

proper management. It also provides an opportunities to learn how technology used at proper

place and time can cave a lot of labour e.g. wagon tippler (CHP).

But there are few factors that require special mention. Training is not carried out into its tree

sprit. It is recommended that there should be some project specially meant for students where

presence of authorities should be ensured. There should be strict monitoring of the

performance of students and system of grading be improved on the basis of work done.

However training has proved to be quite fruitful. It has allowed an opportunity to get an

exposure of the practical implementation to theoretical fundamentals.


REFERENCES

1. B.R. Gupta / A Text Book of Electrical Technology Vol. II / Chapter 32/ Transformer/

Page No. 1116-1120.

2. www.google.com/ images/ boiler.jpg.

3. www.ieee.com/electricalengineering/inductionmotors.html

4. B.R. Gupta / A Text Book of Electrical Technology Vol. II / Chapter 34/ Induction

Motor/ Page No.1245-1248.

5. www.mapsofindia.com/kota/industries/super-thermal-power-plant.html

6. www.energymanagertraining.com/power_plants/ThermalPowerPlants.html

7. www.sciencedaily.com/ thermal power

8. Sunil S. Rao / Switch Gear Protection and Power Systems / Chapter 33/

Protection of Generators/ Page No. 826-830


http://www.sciencedaily.com/

http://www.energymanagertraining.com/power_plants/ThermalPowerPlants.htm

http://WWW.GOOGLE.COM/

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