NTPC UNCHAHAAR

8/6/2019 NTPC UNCHAHAAR

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NTPC

PROJECT REPORT

Summer Training

PROJE CT REPORT

ON

FEROZE GANDHI UNCHAHARTHERMAL POWER STATION

Reporting Officer:

Mr. Bimal Shah

(HR-EDC)

FGUTPS, UNCHAHAR

Submitte

d by:


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...........

.....

B.Tech(FINAL YEAR)

Contents

1. Introduction of NTPC

2. Introduction about Project

3. Production of Electicity

4. Principal of Steam Power Plant

5. H.T.Switch gear

6. L.T.Switch gear

7. Generators and Transformers

8. D.C. System

9. Switch Yard

10. Coal Handling Plant

11. Coal Handling Plant Power Distribution


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Driven by its vision to lead, it has charted out an ambitious growth plan of

becoming a 40,000 MW plus company by 2012.

Following are the other important highlights of 2008-09:

1. Total Income of Rs.455, 000 million.

2. Net profit in excess of Rs.78, 274 million

3. A dividend payment of Rs.126, 865 million to the Govt. of India.

Received highest credit rating AAA by CRISIL and LAAA by ICRA for domestic

bond and international rating for Eurobond.

INTRODUCTION ABOUT PROJECT


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The Unchahar Thermal Power Plant located about 125kms from Lucknow. It is

nearly 80kms from Allahabad. The nearest railway station is Unchahar. The

project lies in the Raibareilly District in U.P.Water source for this plant is Sarda

Sahayak Canal. The climate conditions are quite favourable with greenery all

around.The installed capacity is 5 X 210 MW.

The Uttar Pradesh Vidyut Utpandan Nigam Limited started this project in 1981.

This was fully owned by the UP Government. Our late Prime Minister Smt. Indira

Gandhi laid down the foundation stone on 27TH June 1981. The project was

started with an installed capacity of 420MW (2*210).

Faced with financial crunch of its affairs, the Nigam was not able to operate the

plan continuously at optimum capacity. Resulting in loss of generation the UPSEB

was not able to pay charges to NTPC for energy bought. Then it was decided to

sell of the project to NTPC to augment and continue generation of electricity at

full level and commence actives the expansion project in the interest of power

development.

The governor promulgate Uttar Pradesh Vidyut Utpadan Nigam Limited

(Acquisition and transfer of Undertaking) act. Consideration worth Rs.925 Crore

was decided for takeover.

PLF in 1990-91 was 5.5% and at the time of take-over in 1992-93, it was around

20%. NTPC is managing the project well and the result is PLF of 54.9% in 1992-

93, 68% in 1993-94 and more there after. In the year 2000-2001 it has achieved

85.5%. PLF in March 2009 is highest at 100.03%.

It supplies the produced electricity to region of Uttar Pradesh. The project is a

coal-based thermal power project and the main constituents for production is

coal, oil and water.

The NTPC has total installed capacity of 30, 144 Mega Watts and has the goal to

reach the capacity of 40000 Mega Watts. Today it has project at the following

places: -

1. Northern region station

1. Singrauli (5*2000+2*500) Mega Watts.

2. Rihand (2*500) Mega Watts.

3. Unchahar (5*210) Mega Watts.


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4. Tanda (4*110) Mega Watts.

2. Southern region station

1. Ramagundem (3*200+3*500) Mega Watts.

2. Kayamkulam (2*155GT+1*120St) Mega Watts.

3. Western region station

1. Korba (3*200+3*500) Mega Watts.

2. Vindhyanehal (6*210+2*500) Mega watts.

3. Kawas (4*106 GT+2*105 ST) Mega Watts.

4. Eastern region station

1. Farakka (3*200+2*500) Mega Watts.

2. Kahalgaon (4*210) Mega Watts.

3. Takher (4*60+2*110) Mega Watts.

5. Nation capital region station

1. Dadri coal (4*210) Mega Watts.

2. Auta (3*88 GT+1*149 St) Mega Watts.

3. Auraiya (4*110 GT+2*106 ST) Mega Watts.

4. Faridabad (2*143 GT+1*144 ST) Mega Watts.


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PRODUCTION OF ELECTRICITY

The means and steps involved in the production of electricity in a coal-fired

power station are described below.

The coal, brought to the station by train or other means, travels from the coal

handling plant by conveyer belt to the coal bunkers, from where it is fed to the

pulverizing mills which grinds it as fine as face powder. The finely powdered

coal mixed with pre-heated air is then blown into the boiler by fan called

Primary Air Fan where it burns, more like a gas than as a solid in convectional

domestic or industrial grate, with additional amount of air called secondary air

supplied by Forced Draft Fan. As the coal has been grounded so finely the

resultant ash is also a fine powder. Some of this ash binds together to form

lumps which fall into the ash pits at the bottom of the furnace. The waterquenched ash from the bottom of the furnace is conveyed to pits for subsequent

disposal or sale. Most of ash, still in fine particles form is carried out of the boiler

to the precipitators as dust, where it is trapped by electrodes charged with

high voltage electricity. The dust is then conveyed by water to disposal areas or


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to bunkers for sale while the cleaned flue gases pass on through ID Fan to be

discharged up the chimney.

Meanwhile the heat released from the coal has been absorbed by the many

kilometres of tubing which line the boiler walls. Inside the tubes is the boiler

feed water which is transformed by the heat into the steam at high pressure

and temperature. The steam super-heated in further tubes (Super Heater)

passes to the turbine where it is discharged through the nozzles on the turbine

blades. Just the energy of the wind turns the sail of the wind-mill, so the energy

of the steam, striking the blades, makes the turbine rotate.

Coupled to the end of the turbine is the rotor of the generator a large

cylindrical magnet, so that when the turbine rotates the rotor turns with it. The

rotor is housed inside the stator having heavy coils of copper bars in which

electricity is produced through the movement of the magnetic field created by

the rotor. The electricity passes from the stator winding to the step-up

transformer which increases its voltage so that it can be transmitted efficientlyover the power lines of the grid.

The steam which has given up its heat energy is changed back into water in the

condenser so that it is ready for re-use. The condenser contains many

kilometres of tubing through which the colder is constantly pumped. The steam

passing around the tubes looses the heat and is rapidly changed back to water.

But the two lots of water (i.e. boiler feed water & cooling water) must NEVER

MIX. The cooling water is drawn from the river, but the boiler feed water must be

absolutely pure, far purer than the water we drink, if it is not to damage the

boiler tubes. Chemistry at the power station is largely the chemistry of water.

To condense the large quantities of steam, huge and continuous volume of

cooling water is essential. In most of the power stations 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 the water out to the cooling towers.

The cooling towers are simply concrete shells acting as huge chimneys

creating a draught (natural/mechanically assisted by fans) of air. The water is

sprayed out at the top of towers and as it falls into the pond beneath it is cooled

by the upward draught of air. The cold water in the pond is then circulated by

pumps to the condensers. Inevitably, however, some of the water is drawn

upwards as vapours by the draught and it is this which forms the familiar whiteclouds which emerge from the towers seen sometimes.

Why bother to change steam from the turbine back into water if it has to be

heated up again immediately? The answer lies in the law of physics which states

that the boiling point of water is related to pressure. The lower the pressure, the

lower the temperature at which water boils. The turbine designer want as low

boiling point of water as possible because he can only utilize the energy of the

steam when the steam changes back into water he can get NO more work out

of it. So a condenser is built, which by rapidly changing the steam back into

water creates a vacuum. This vacuum results in a much lower boiling pointwhich, in turns, means he can continue getting work out of the steam well below

100 degree Celsius at which it would normally change into water.


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Principle of the Steam Power Plant

The working principle of a steam plant is based upon the

Rankine cycle. Generally steam is taken as the working medium

due to its ability to be stable and that its readily stable. The

flow of steam in the plant can be very easily be understood by

the flow diagram of the plant. A graph plotted between the

temperature and the entropy would indicate the technical

details of the working by the rankine cycle. The entropy of a

system can be understood as an index of degradation of

energy.


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PLANT FLOW DIAGRAM

H.T.SWITCH GEAR


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OPERATIONG VOLTAGE - 6.6KV

For low voltage circuits fuses may be used to isolate the faulty circuit. For

voltage higher than 3.3 kV isolation is achieved by circuit breaker.

Requirement of circuit breaker:

1. After occurrence of fault the switchgears must isolate the faulty circuit as

quickly as possible i.e. keeping the delay to minimum.

2. It should not operate when an over current flows under healthy condition.

Basic principal of operation of circuit breaker:

Circuit breaker consists of a fix contact and sliding contact into which movesa moving contact. The end of moving contact it attached to a handle that can

be manually operated or may operate automatically with the help of

mechanism that has a trip coil energized by secondary of CT. Under normal

condition the secondary of CT is not energized sufficiently to trip the coil but

under false condition the coil is energized fully to operate the trip coil and the

circuit breaker is operated.

1. MOCB (Minimum oil circuit breaker)

2. SF6 (Sulphur hexafluoride circuit breaker)

Here oil and SF6 are used to quench the arc.


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L.T SWITCH GEAR

OPERATING VOLTAGE- 415VOLT

TYPES OF CIRCUIT BREAKER: - Air break circuit breaker

Air brake circuit breaker:

The arc interruption process of air- based circuit breaker is based on the natural

deionization of gases by cooling action. The arc is resilient and can be stretched,

and has a resistance, which can be increased both by length and confinement.

Hence the arc resistance is increased by stretching the arc and as the resistance

increases to higher value, the short circuit current drops to zero and arc is

extinguished.

Reducing the phase difference between the system voltage and the short circuit

current assure that when the are current is interrupt at its zero value, the

recovery voltage has very low value at its not allowed to reach 2-3 times the

value of the system peak voltage, a phenomenon that occurs in most cases,

when arc current is interrupted at low power factor.


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GENERATORS AND TRANSFORMERS

INTRODUCTION-

The auxiliaries in a plant can be divided into two

categories-

1. URGENT AUXILIARIES- the urgent auxiliaries are those, which are

associated with running of unit.

2. SERVICE AUXILIARIES- the service auxiliaries are those whose loss would

not affect output.

GENERATOR

SPECIFICATIONS-

TURBO GENERATOR (gen1, gen2)

KVA 247000

Pf 0.85

Volts of stator 15750

Amperes of stator 9050

Volts of rotor 310

Amperes of rotor 2600

Rpm 3000

Hz 50

Phase 3

Connection YY

Coolant Water (stator)& hydrogen (rotor)


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Gas pressure 3.5kg/cm-sq.

Insulation class B

EXCITATION SYSTEM-

1. STATIC EXCITATION SYSTEM-The generators in stage -1(u-1&u-2) have

this excitation system. Static excitation system has slip ring and carbon

brush arrangement. It consists of step down transformer, converter and

AVR (automatic voltage regulator).

2. BRUSHLESS EXCITATION SYSTEM The generators in stage -2(U-3, U-

4& &U- 5) have this excitation system. It has two exciters, one is main

exciter and other is pilot exciter.

GENERATOR PROTECTION-

1. STATOR PROTECTION- The neutral of star connected winding is

connected to primary of neutral grounding transformer, so that earth fault

current is limited by over voltage relay.

2. DIFFERENTIAL PROTECTION- In case of phase-to-phase fault

generator is protected by longitudinal differential relay.


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3. ROTOR PROTECTION- Rotor winding may be damaged by earth faults

or open circuits. The field is biased by a dc voltage, which causes current

to flow through the relay for an earth fault anywhere on the field system.

4. OVER SPEED PROTECTION Mechanically over speed device that is

usually in the form of centrifugally operated rings mounted on the rotor

shaft, which fly out and close the stop valves if the speed of the set

increase more than 10%.

5. OVER VOLTAGE PROTECTION It is provided with an over voltage

relay. The relay is usually induction pattern. The relay open the main

circuit break and the field switch if the over voltage persists.

6. SEAL OIL SYSTEM Hydrogen in the generator is under veryhigh pressure. There is a possibility of this hydrogen to come out of gaps,

which is very hazardous. So, seal oil is used to seal the gaps so that

hydrogen doesnt come out.

7. LUBRICATION OIL SYSTEM Turbine lubrication-oil system seeks

to provide proper lubrication of turbo generator bearings and operation of

barring gear. Pumps are used to circulate lubrication-oil inside thegenerator. The oil of the lubrication and the governing system is cooled in

the oil coolers. The cooling medium for these coolers is circulating water.


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TRANSFORMER

TYPE PF TRANSFORMERS

1. GENRATOR TRANSFORMER: -- This is a step up transformer. This supply

gets its primary supply from generator and its secondary supplies the

switchyard from where it is transmitted to grid. This transformer is oil

cooled. The primary of this transformer is connected in star. The

secondary is connected in delta. These are four in number.

2. STATION TRANSFORMER: -- This transformer has almost the same

rating as the generator transformer. Its primary is connected in delta and

secondary in star. It is a step down transformer. These are 4 in number.

3. UNIT AUXILIARY TRANSFORMER: -- This is a step down transformer.

The primary receives from generator and secondary supplies a 6.6 KV bus.

This is oil cooled. These are 8 in number.

4. NEUTRAL GROUNDED TRANSFORMER: -- This transformer is

connected with supply coming out of UAT in stage-2. This is used toground the excess voltage if occurs in the secondary of UAT in spite of

rated voltage.


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SPECIFICATIONS

Generator transformer (GT-1 & GT-2)

KV 15.75/242

MVA 250

Phase 3

Hz 50

Connections Y-D 11

Type of cooling OFAF/ONAF/ONAN

Rated HV and IV (MVA) 250/150/100

Rated LV (MVA) 250/150/100

No Load Voltage HV (KV) 242

No Load Voltage IV (KV)

No Load Voltage LV (KV) 15.75

Line current HV (Amps) 597.14/358.29/238.86

Line current IV (Amps)

Line current LV (Amps) 9175.15/5505.09/3670.66

Temp rise coil oC 50

Temp rise winding oC 55

Neural grounded transformer (NGT)


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KVA 1150

Phase 3

Hz 50

Type of cooling ONAF/ONAN

No load voltage HV (volts) 6600

No load voltage LV (volts) 250

Line current HV (Amps) 105.9

Line current LV (Amps) 2655.8

Temp rise oil oC 50

Temp rise winding 55

Potential Transformer

KVA 1000

Phase 3

Hz 50

Type of Cooling ONAN

No Load Voltage HV (volts) 6600

No Load Voltage LV (volts) 433

Line Current HV (Amps) 87.53

Line Current LV (Amps) 133.5

Temp rise oil

o

C 50Temp rise winding oC 55


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D.C SYSTEM

INTRODUCTION:

DC system is generally used for control and protection operation, as AC supply is

not fully dependable. To maintain constant supply in case of power failure we

use DC supply.

DC system consists of a battery charger. These are the mode of energy storage.

CHARGING EQUIPMENTS:

The battery charging equipment comprises of trickle charger, quick charger, battery panel, main

distribution board and switch control and signaling board.

CHARGING EQUATION:

In battery PbO2 used as positive plate and Pb as negative plate.

1. DISCHARGING PROCESS

2. CHARGING PROCESS

BATTERY CHARGER:

Battery charger normally operates in two modes.

1. Float charging: It is constant voltage mode and works as a trickle charger.

2. Boost charging: It is constant current mode and works as a quick charger.

TRICKLE CHARGER:


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This charger is fed from three-phase ac supply and gives a dc-stabilized output at rated full load

current. The variation of the dc output voltage is limited to +/- 1% for 0 to 100% load variation and

simultaneously ac voltage variation of +/- 10% of frequency variation of +/- 5% from 50 Hz.

The rectification is obtained through full bridge controlled silicon rectifier. Stack comprising of these

SCR and three diode with the surge suppression RC network connected across each SCR and diode.

SWITCH YARD

As we know that electrical energy cant be stored like cells, so what we generateshould be consumed instantaneously. But as the load is not constants therefore

we generate electricity according to need i.e. the generation depends upon load.

The yard is the places from where the electricity is send outside. It has both

outdoor and indoor equipments.

SINGLE LINE DIAGRAM OF 220KV SWITCH YARD-


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OUTDOOR EQUIPMENTS

1. BUS BAR

2. LIGHTENING ARRESTER

3. WAVE TRAP

4. BREAKER

5. CAPACITOR VOLTAGE TRANSFORMER

6. CORONA RING

7. EARTHING ROD

8. CURRENT TRANSFORMER

9. POTENTIAL TRANSFORMER

10. LIGHTENING MASK

11. LIGHTENING MOOSE


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INDOOR EQUIPMENTS

1. RELAYS

2. CONTROL PANELS

CIRCUIT BREAKER:

The code for circuit breaker is 52. An electric power system needs some form of switchgear

in order to operate it safely & efficiently under both normal and abnormal conditions.

Circuit breaker is an arrangement by which we can break the circuit or flow of

current. A circuit breaker in station serves the same purpose as switch but it has

many added and complex features. The basic construction of any circuit breaker

requires the separation of contact in an insulating fluid that servers two

functions:

1. It extinguishes the arc drawn between the contacts when circuit breaker

opens.

2. It provides adequate insulation between the contacts and from each

contact to earth.

The insulating fluids commonly used in circuit breakers are:

1. Compressed air

2. Oil which produces hydrogen for arc excitation.

3. Ultra high vacuum

4. Sulphur hexafluorides

The Specifications of the circuit breaker used are:


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MAKE CROMPTON GREAVES LTD.

TYPE AIR BLAST CIRCUITREAKERRATED VOLTAGE 245 KV

RATED LIGHTING IMPULSE

WITHSTAND VOLTAGE 1050 KV

RATED SHORT CIRCUIT BREAKING

CURRENT

25 - 40KA

RATED FREQUENCY 50HZ

RATED NORMAL CURRENT 2000 A TO 4000 A

RATED CLOSING VOLTAGE 220 V DC

RATED OPENING VOLTAGE 220 V DC

LIGHTING ARRESTER:

It saves the transformer and reactor from over voltage and over currents. We

have to use the lightning arrester both in primary and secondary of transformer

and in reactors.

A meter is provided which indicates the surface leakage and internal grading

current of arrester.

1. Green arrester is healthy

2. Red arrester is defective.

In case of red we first de-energize the arrester and then do the operation.

AIR BREAK EARTHING SWITCH:

The code of earthling switch is 5, 6, 7.The work of this equipment comes into

picture when we want to shut down the supply for maintenance purpose. This

help to neutralize the system from induced voltage from extra high voltage.

This induced power is up to 2KV in case of 400 KV lines.


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The specification of earthling switch is:

MAKE S & S POWER

TYPE MADRAS

VOLTAGE 245 KV

CURRENT 10 KA

MOTOR VOLT (AC) 415 VOLTS

CONTROL VOLT (DC) 220 VOLTS

BUS BAR:

Bus bars generally are of high conductive aluminum conforming to IS-5082 or

copper of adequate cross section .Bus bar located in air insulated enclosures

& segregated from all other components .Bus bar is preferably cover with

polyurethane.

1. Current Transformer (CT):

A current transformer is a type of instrument transformer designed to provide a

current in its secondary winding proportional to the alternating current flowing in

its primary

.

Current Transformer Diagram

Application:


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1. They are commonly used in metering and protective relaying in the electrical power

industry where they facilitate the safe measurement of large currents, often in the

presence of high voltages.

2. The current transformer safely isolates measurement and control circuitry from the

high voltages typically present on the circuit being measured.

3. Current transformers are used extensively for measuring current and monitoring the

operation of the power grid. The CT is typically described by its current ratio from

primary to secondary. Often, multiple CTs are installed as a "stack" for various uses

(for example, protection devices and revenue metering may use separate CTs).

Similarly potential transformers are used for measuring voltage and monitoring the

operation of the power grid.

4. Capacitive Voltage Transformer (CVT):

A capacitor voltage transformer (CVT) is a transformer used in power systems

to step-down extra high voltage signals and provide lowvoltage signals either for

measurement or to operate a protective relay. In its most basic form the device

consists of three parts: two capacitors across which the voltage signal is split, an

inductive element used to tune the device to the supply frequency and a

transformer used to isolate and further step-down the voltage for the

instrumentation or protective relay as shown in figure below.

The device has at least four terminals, a high-voltage terminal for connection to

the high voltage signal, a ground terminal and at least one set of secondary

terminals for connection to the instrumentation or protective relay. CVTs are

typically single-phase devices used for measuring voltages in excess of one

hundred kilovolts where the use of voltage transformers would be uneconomical.


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In practice the first capacitor, C1, is often replaced by a stack of capacitors

connected in series.This results in a large voltage drop across the stack of

capacitors that replaced the first capacitor and a comparatively small voltage

drop across the second capacitor C2, and hence the secondary terminals.

The total number of bays is 22. Out of which we have 3 spare bays.

Bay 1 250 MVA 15.75/242 kV Generator transformer 1

Bay 2 Spare 40 MVA 220/7.1 kV Station Transformer- 3

Bay 3 40 MVA 220/7.1 KV Station Transformer - 1


Bay 6 250 MVA 15.75/242 KV Generator Transformer -2

Bay 7 220 Kv (Chin hut) Luck now Feeder - 1

Bay 8 220 KV Luck now Feeder -2

Bay 9 Bus couplets 220 KV

Bay 10 220 KV Fateful Feeder - 1

Bay 11 220 KV Fateful Feeder - 2

Bay 12 220 KV by Pass Breaker

Bay 13 210 MW Generators -3


Bay 16 210 Mw Generators - 3

Bay 17 220 KV Transfer Bus Coupler- 2

Bay 19 220 KV Kanpur Feeders - 1





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COAL HANDLING PLANT

Introduction: -

NTPC Unchahar gets its coal supply mainly from Bihar. Now coal is also coming

from Australia, as coal produced in India is of low grade and ash content is more.

The coal being filled in the wagons of the rail reaches plant. The purpose of this

plant is to convey the coal to the bunker in the size not larger than 20mm.It

handles and transports the coal to the bunker from the wagons by passing

through various conveyors, transfer points, crusher houses, etc.

Type of coal: -

BCCL costs Rs.4/kg

CCl cost Rs.6/kg

Type of unloading the coal: -

1. Manual Unloading: - Previously, manpower was used for unloading

the wagons. But it was very time consuming and more workers were required

for the job to be done.

2. Box in (using wagon tippler for unloading): - This method is

still used in stage -1of NTPC Unchahar. For this method, Indian Railway grants

10 hours for unloading the 58 wagons. In this method, Wagons are separated

and tippled by using wagon tippler. The Beetle Feeder is used to move the

wagon on wagon tippler. The coal from the wagons gets accumulated in The

Track Hopper. At this time; the size of the coal is approximately 300mm.

3. BOBR: - This method is used in used in stage -2 of NTPC Unchahar. Indian

Railway grants only 2.5 hours for Unloading 58 BOBR wagons. This is an

advanced technology in which we use the compressor system.


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In Bottom Open Bottom Release (BOBR) technology the wagons are opened

from side. Pressure is applied by the compressor to open the bottom gates of

the wagon so that the coal gets released over the track hopper and wagon

get unloaded quickly.

Various equipment used in CHP: -

1. WAGON TIPPLER: - The wagon tippler is a most important device in

thermal power project.

The Wagon tippler turns back the wagon at 135-degree angle and the

structure of the wagon tippler is to be very heavy. Upper side of the wagon is

fixed with the many angles for supporting the wagon. When the wagon is

fixed on the Platform then whole platform is turned back and the coal fall

down in the wagon tippler hopper. The unloading time of the Rack is 6hours.

Here the type of the rack is Box C / Box N type.

A- WTH, B-VF, C- BC, D- DS are the parts of the wagon tippler.

1. Wagon Tippler Hopper: - The Wagon tippler Hoper is a part of the

wagon tippler where the coal is stored from the wagon tippler. The size of

the coal here is less than 300mm.

2. Vibrating Feeder: - The vibrating feeder is used for falling the coal

on the conveyer through Wagon tippler Hoper. Before Wagon tipplerHoper and Vibrating Feeder the gate is providing to control the flow of the

coal.

3. Beetle Charger: - The Beetle charger is a traveling device that is

used to carry the wagon on the wagon tippler platform.

4. Dust Suppuration: - Dust Suppuration is a useful device. When

the wagon are tippling then the dust is mixed in the air and that area

becomes very dusty then Dust Suppuration operates and water flows

through its points and the dust settles down. It is an automatic device.


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.

2. PADDLE FEEDER: - They have been installed on conveyors below the

manual unloading track hopper. There are 6 nos. of paddle feeders, 3 on

each conveyer. 3 Paddle Feeders of each conveyer move to and fro within a

limiting range. The rotating part of the paddle feeder is called as plough

wheel. Plough wheel has 6 blades. By the rotation of the plough wheel, the

coal of the track hopper gets accumulated between the blades and is

discharged on the conveyor below it. The main components of paddle feeder

are:

1. Plough wheel-It is the rotating part consists of 6 blades. It is attached

with the rotor of 3-phase slip ring induction motor.

2. Reduction gear box- It is installed to control the speed of plough

wheel.

3. End limit switch (left or right)-It provides the limiting motion of the

paddle feeders.

4. Anti-collision switch- It provides the prevention from collision between

two paddle feeders.

5. Interlock system-It is provided for safety purpose. By this, the conveyor

belt moves first then paddle feeder starts.

3. VIBRATING FEEDER: - They have been installed below the trackhoppers of wagon tippler. The coal is accumulated over the vibrating feeder

so by giving vibrations to the vibrating feeder we discharge the coal from

track hopper to the conveyors. Their main purpose is to provide uniform

feeding on the conveyors. The vibrating feeders consist of a tray to which

vibrator body is fixed on the rear end.

4. TRANSFER POINTS: - Transfer Point is provided with flap gate andConveyer. In transfer Point the coal is transferred from one conveyer to other

conveyer.


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1. Flap Gate: - The flap Gate is a two-way device. It consists of two

gates. Both gates cannot operate together. By help of the flap Gate, we

change the way of coal that fall down on the conveyer.

2. Conveyers: - The Conveyer Belt is a moving device. It travels on itsplatforms. The shape of the conveyer belt is to be flat but on the platforms

it is to be in curve shape. The coal falls down the conveyer and goes to the

primary Crusher House Platforms. The capacity of conveyer in Stage I is

800MT/ hr. & in Stage II is 1200MT / hr.

Many protecting device provide to the Conveyer---

a -Zero Speed Switch, b -Pull Cord Switch, c - Belt Sway Switch

1. Zero Speed Switch: - The Zero Speed Switch prevents the Conveyer

from over load run. When the conveyer is over loaded, the speed of the

conveyer is reduced and Zero Speed Switch is operated and stops the

conveyer. This device is provided at Head End of the Conveyer. The Zero

Speed Switch is a Centrifugal Switch.

2. Pull cord Switch: - This is a manual protecting device. When the

Worker sees any mistake like big stone or any dangerous fault, pulls this

cord. The Pull Cord Switch is to be operated, and the Conveyer stops.

3. Belt Sway Switch: - The Belt Sway Switch also protects the

conveyer. This device is provided on both side of the conveyer. When the

conveyer leaves its way the switch is operated and the conveyer stops.

This is also an automatic protecting device.

.

5. PRIMARY CRUSHER (ROTARY BREAKER): - In Primary Crusher House,

the coal breaks in Rotary Breaker. Here the coal comes from the Transfer

point; breaks here and the stone fall down to a separate place. Coal is

converted from 300mm to 150mm size.

Part of the Primary Crusher House a- Rotary Breaker b- Belt Feeder

1. ROTARY BREAKER: - The Rotary Breaker has a rotating mechanism.

It is rotated on the shaft. The coal come from the conveyer through the

Flap Gate falls down into the rotary breaker. The rotary breaker is to be


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rotated and coal moves up and down and collides and hence breaks. The

Rotary Breaker is H.T. 170KW 6.6KV Motor

2. BELT FEEDER: - The Belt Feeder is a small size of the conveyer. It is

used for feeding the coal to the conveyer through Flap Gate.

6. SECONDARY CRUSHER (RING GRANULATOR): - In Secondary crusher

House first the magnetic part separate from the coal and then feed to the

Secondary Crusher. This Crusher breaks the coal in 20mm size and coal is

sent to the Flap Gate and then feeded to the conveyer. The Secondary

crusher is hammer type. H.T. motor are used for breaking of the coal.

Specifications are 700KW 6.6KVMotor.

7. CROSS BELT MAGNETIC SEPRATORS: - They will remove the ferrous

particles, which passes along with the coal. It consists of electromagnet

around which a belt is moving. It is suspended from top, perpendicular to the

conveyor belt at certain height. Whenever any iron particle passes below the

CBMS, it is attracted by the magnet and stick to the cross belt below it. The

CBMS capacity is of 50kg.

8. METAL DETECTOR: - The purpose of installation is to detect any

metallic piece passing through the conveyor. Whenever the pieces pass

below the search coil of the metal detector, it gives the trip command to the

conveyor. Simultaneously, sand bag marker will fall on the conveyor belt so

that the metal can be searched easily and removed.

9. STACKER/RECLAIMER: - It is a very important device. The whole

Structure of it is called Super Structure. It stacks the excessive coal and

reclaims the coal on its requirement. It is a two-way device. It consists of

following main parts.

1. Stacker: - The Stack is a position (1). When the rack comes, the

excessive coal is send to the stacker through the conveyer from

Secondary Crusher house. The coals are stacked at the Secondary Crusher

Coal Heap. The coal falls down from the stacker through Boom Conveyer.

2. Reclaimer: - The Reclaimer is position (2). When the rack is not

coming and there is a shortage of coal, then reclaiming is to be started


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and the coal is lifted from the Secondary Crush Coal Heap and feeded to

the bunker.

3. Boom Conveyer: - The Boom conveyer is a Bi-directional conveyer.

It moves clockwise & anticlockwise direction. In stacking position, it ismoving in clockwise direction and in the reclaiming position its moving in

anticlockwise direction. They are provided with Center Chute and End

Chute on the both end.

4. Boom hoist: - The Boom hoist is a link of the Super Structure. The

hoist is moved up and down. For controlling the up & down position, limit

switch is provided.

5. Slew drive: - The Slew Drive moves at 180-degree. When the coal is

stored on both the side of the track of travel, then the Slew Drive moves

and lifts or fall the coal from Boom Conveyer. For control the rotation of

Slew Drive, the limit switch is provided.

6. Bucket wheel: - The Bucket Wheel is used when there is a requirement

of the coal. It is a rotary device. It is always rotated in anticlockwise. In the

Reclaiming position, the Center Chute is to be up and End Chute of theBoom Conveyer is fixed on the conveyer. The Bucket Wheel rotates; when

the Bucket of the wheel is full with coal and the wheel is rotated the coal

fall down on the Boom conveyer and the coal is send to the Super

Structure.

7. Travel: - It is a slip ring induction motor driven system. The Super

Structure moves on it. The normal speed of the Travel is 10 meter /

minute. It moves on its track from one end to other end.

10. TRANSFER TOWER: - Here the coal is send to the Tipper. Transfer

Tower is provided with a coal sampler.

11. TIPPER: - The Tipper is a three-way device to feed the coal in

Bunker. It is moveable device. It is move on its track.

12. BUNKER: - Here the coal is collected from the tipper and stored. The

capacity of the bunker for Stage-I is 4800MT & Stage-II is 8700MT


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COAL HANDLING PLANT POWER DISTRIBUTION SYSTEM

STAGE-1

S.NO DRIVE

(CONVEYOR)

RATINGS (KW) TYPE-F.L

MCC-1

1 CON1/A/B/C/D 75 NR-3 134A

2 CON2A/B (P) 125 BKR 228A

3 CON2A/B (S) 75 NR-3 143A

4 CON10A/B 125 BKR 228A

5 P/F 1-6 LCC SF-2 100A

6 PLOUGH WHEEL 22 NR-34A

7 LONG TRAVEL 5.5 RV-11A

8 PCRD 2.2 NR-5A

9 SPEED CONTROL 0.25 RV-0.6

10 B/F-1, (PCH) 22 NR-2,37A

MCC-2

11 B/F-2 (PCH) 22 NR-2 37A

12 SUSPENDED MAG. SF-1 63A

13 LIGHTING BOARD SF-3 250A

14 DE-1 (SCH) FSU-2 250A

15 MAG.SEP.(SCR) SF-2 63A

16 VIB.SCREEN-1,

2(SCH)

37 NR-3 64A

17 CON-3A/B 160 BKR 269

18 CON-4A/B 55 NR-3 96A

19 B/F-4 (SCH) 22 NR-2 37A

MCC-3


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20 CBMS-3 TP-8 63A

21 TT-1 63A

22 DE-4(BUNKER) 63A

23 DE-3(BUNKER) 250A

24 CON5A/B 110 BKR 195A

25 CON6A/B 125 BKR 228

26 CON7A/B 90 159A

27 CON8A/B(P) 160 BKR 269

28 CON8A/B(S) 75 BKR 134

29 CON9A/B 90 159A

30 CON12 125 BKR 228A

31 BEETLE CHARGER

1,2

55 RV-98A

32 BAGOB TRIPLER-

1,2

71 RV-126A

33 VIB.FEEDERS

1,2,3,4

SF-63A

STAGE 2


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Equipment KW

Conv14 2*95

Conv15 2*140

Conv16 2*115

Conv17 65

Conv18 160

Conv19 115

Conv20 315

Conv21 140

Conv22 140

Conv23 2*110

Conv24 110

Conv25 110

Conv26 2*115

R.B 160

Crusher 450


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STAGE-2

S.No. Drive (conveyor) Ratings (KW) Type-F.L

1 CON14A/B 2*95 161

2 CON15A/B 2*140 237

3 CON16A/B 2*115 195

4 CON17A/B 65 115

5 CON18A/B 160 269

6 CON19A/B 115 195

7 CON20A/B (HT) 315 34

8 CON21A/B 140 237

9 CON22 140 237

10 CON23 2*110 182

11 CON24A/B 110 182

12 CON25A/B 110 182

13 CON26 2*115 195

14 R.B 160 269

15 CRUSHER (HT) 450 54

16 BELT FEEDER (SCH)

1,2

18.5 35

17 BELT FEEDER (PCH)

4,5

25 47

18 PADDLE FEEDER

7,8,9,10

45 80

19 S/R-2 BOOM

CONVEYOR

75 127

20 S/R-2 BUCKET

WHEEL

75 127

21 S/R-2

SLEW/TRAVEL

MOTOR 7.5(DC)

22 VGF 1,2,3,4 37 65

23 SWP 1A/B 115 195


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24 SWP 2A/B 32

25 SUMP-PUMP 15

TERMS FULL FORM

CBMS Cross belt magnetic

separator

ILMS Inline magnetic separator

PF Paddle feeder

TT Transfer tower

TP Transfer point

MD Metal detector

SM Suspended magnet

RB Rotary breaker

VGF Vibro grizzly feed

RPG Rack and pinion get

CR Crusher rotary

RH Reclaim hopper

VS Vibrating screen

BF Belt feeder

FG Flap gate

TC Telescopic chute

WT Wagon tippler

PH Pent house

PCH Primary crusher house

SCH Secondary crusher house

S/R Stacker/Reclaimer

CO Conveyor

CHP Coal handling plant

TH Track hopper

MCC Motor control center

LCS Local control switch


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PCS Pull card switch

BSS Belt swag switch

ZSS Zero speed switch

VF Vibrating feeder

VF. Vibrating fan

SOME IMPORTANT FACTS

Coal handling plant area 200acrs

Length of conveyor stage-1 13km

Length of conveyor stage-2 13.5km

M.U.T.H coal capacity stage -1 2800 M.T

New track hopper coal capacity stage

-2

5400M.T

Primary yard coal capacity stage -1 2.5 lac M.T

Secondary yard coal capacity stage -1 1.5 lac M.T

Secondary yard coal capacity stage-2 1.8 lac M.T

Bunker capacity stage -1 400*12=4800 M.T

Bunker capacity stage-2 730*12=8760 M.T

Coal used in 24 hrs(4 unit) 12000 M.T

Total plant area 970acrs

Total township area 280acrs

Coal import CCI, BCCL

Water source Sharda and dalmau canal

Power line (220kv) Uncr-Lko(2 lines), Uncr-Fatehpur(2

lines), Uncr-Kanpur(4 lines)

Power export Delhi, Punjab, Rajesthan, UP, Haryana,

Chandigarh, J & K, HP


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DEMINERAL (DM) PLANT

INTRODUCTION: --

Water is required in plant for many purposes like for formation of steam, for

removal of ash, for safety during fire, etc. But the water required for the

formation of steam should be perfectly devoid of minerals because if minerals

are present in the steam and the steam strike the blades of the turbine, then due

to being high in pressure it produces scars or holes on the turbine blades.

PURIFICATION OF WATER: -

Water is purified in DM plant through a chain of processes as under: --

1. Carbon filter Water taken from the river is first sent to the

carbon filter for the removal of carbon contents in the water.

2. Strong acid cation exchanger After passing through the carbon

filter, water is sent to the strong acid cation exchanger, which is filled with

the concentrated HCL. The acid produces anions, which get combined with

the cations present in the water.

3. Strong base anion exchanger After that the water is sent to the

strong base anion exchanger, which is filled with the concentrated

NaOH.The base produces cations, which get combined with the anionspresent in the water.

4. Mixed bed exchanger And then water is sent to the chamber of mixed

bed exchanger where the remaining ions are removed. This is the last

stage of purification.

COAL, WATER & STEAM CYCLES


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COAL CYCLE

C.H.P Plant Bunker R.C Feeder Pulverization millBoiler section

1. R.C Feeder: It is an induction motor driven device, which

determine the Quantity of coal enter in the pulverize mill.

2. Pulverization mill: Pulverization means exposing a large surface area

to the action of oxygen .Two Types of mill are used in the plant.

1. Ball mail: A ball mill operates normallyunder

suction. A large drum partly filled with steel balls, is used in this mill .The

drum is rotated slowly while coal is fed in to it .The ball pulverize the coal

by crushing. This type of mill is used in stage-1.

2. Contact mail: This mill uses impact principle. All

the grinding elements and the primary air fan are mounted on a single

shaft. The flow of air carries coal to the primary stage where it is reduced

to a fine granular state by impact with a series of hammers. This type ofmill is used in stage-2.

WATER CYCLE

D.M Plant Hot well C.E.P Pump Low Pressure Heater

1, 2, 3 Derater Boiler Feed Pump High PressureHeater 5, 6 Feed Regulating station Economizer

Boiler Drum.

1. DERATER:


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1. Feed strong tank of water

2. To produce sufficient pressure before feeding to B.F.D.

3. Filter the harmful chemicals.

2. FEED REGULATING STATIONS:

1. Control the quantity of water in to boiler drum.

3. ECONOMISER:

2. Flux gases coming out of the boilers carry lot of heat. An economizer

extracts a part of this heat from the flue gases and uses it for heating the

feed water.

4. DRAFTS SYSTEM:

3. In forced draft system the fan is installed near the base of the boiler

furnace. This fan forces air through the furnace, economizer, air preheater

and chimney.

4. In an induced draft system, the fan is installed near the base of Chimney.

STEAM CYCLE


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Boiler Drum Ring Header Boiler Drum (Steam chamber) Super

Heater H.P Turbine Repeater I.P Turbine L.P Turbine

condenser

1. BOILER: Boiler drum consists two chambers water chamber, steam

chamber. Before Entering in super heater the steam is going in to boiler

drum, where the boiler drum filtered the moisture and stored in to water

chamber.

2. SUPER HEATER: The function of super heater is to remove the lasttraces of moisture from the saturated steam leaving the tube boiler. The

temperature is approx.530 oC.

3. TURBINE: Steam turbine converts the heat energy in to mechanical

energy and drives the alternator. The velocity attained during expansions

depends on initial and final heat content of the steam. Turbine having

number of stages in which the pressure drops takes place.

Conclusion


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On completion of my vocational training at Feroze Gandhi

Unchahar Thermal Power Project, Unchahar I have come to

know about how the very necessity of our lives nowadays i.e.,

electricity is generated. What all processes are needed to

generate and run the plant on a 24x7 basis.

NTPC Unchahar is one the plants in India to be under

highest load factor for the maximum duration of time and that

to operating at highest plant efficiencies. This plant is an

example in terms of working efficiency and management of

resources to all other thermal plants in our country. The

operating plf of the NTPC as compared to the rest of country is

the highest with 87.54% the highest since its inception.

The training gave me an opportunity to clear my concepts from

practical point of view with the availability of machinery of such

large rating.


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Acknowledgements

Everything that happens in the world is an out come of interaction of various

factor, some ofwhich are favourable while other not. Always for a desired result,

the number of favourable factors is more. This work is NO exception to this fact. I

acknowledge that Ive been fortunate enough to get the support, mentally and

physically in everything that I do.

First of all I would like to thank Shri Munish Jauhari, Honourable DGM

(EMD),NTPC Unchahar who led the entire team of FGUTP for functioning of

each department in a modernized and techno-commercial atmosphere to make

the project touch such peaking performance.

I would give our special thanks to Mr. Bimal Shah (HR-EDC) and Mr.A.K.Singh (Sr

Engg), for giving his very kind permission to undergo the training programme

under the able guidance of NTPC engineers. We would thank Mr .M V Sathe

(Supdt Engg.), Mr. K.K.Singh (HT Switchgear),Mr.K.M.Gupta(HT

Switchgear),Mr.J.K.Sahu (LT Switchgear), Mr.H.Mukherjee (Motor Maintenance),

Mr.Rakesh(Supdt.,Switchyard) & Mr.Verma(CHP) under whose able guidance I

completed my training. All these people were of immense importance regardingthe knowledge and supports for the well furnished equipments. Special gratitude

towards Mr.Ranjeet Prasad Singh who provided us the best moral support which I

was in need for.

I greatly acknowledge the help and the mental strength provided by our entire

family for encouraging me and providing me knowledge & guidance related with

every deptt. of NTPC, FGTUP.

At last I conclude by thanking all the employees of NTPC, FGTUP (both executives

& workers) who helped me in making our training a boon for me.

Mayur

Btech Final Year, Electrical Engineering

Motilal Nehru National Institute of Technology,Allahabad.


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NTPC UNCHAHAAR

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