Report Ntpc p

8/6/2019 Report Ntpc p

1/29

NATIONAL THERMAL POWER CORPORATION

LIMITED

PROJECT REPORT ON

ELECTRICAL POWER

GENERATION, TRANSMISSION &

PROTECTION

SU

BMITTED BY:


2/29

AMIT

TRIPATHI

MNNIT,A

LLAHABAD

ACKNOWLEDGEMENT

I express my sincere gratitude to NTPC for giving me the opportunity of

undertaking summer training of 42 days at BTPS. I thank all technicians,

foreman and executives for explaining the practical aspects of theoretical

knowledge that I have acquired from my college. I take the opportunity to

thanks the various labs in charges for taking pain in demonstrating the

internal circuitry of various instruments.

I specially thank

Mr. M.S. Chabbra,

Mr. Anil Sharma,

Mr. Yogeshwarchand

for their kind support and encouragement at every point of training

without which this training would not have been successful.

AUTHOR


3/29

CERITIFICATE

This is to certify that Mr. Amit Tripathi, student of Electrical

Engineering, Motilal Nehru National Institude Of Technology, Allahabad

has successfully completed vocational training at National Thermal Power

Corporation (NTPC), Badarpur, New Delhi for a period of six weeks from23-05-2011 to 02-07-2011.

He has completed whole training as per project report submitted by him.

Training Incharge

(BTPS New Delhi)


4/29

INTRODUCTION

National Thermal Power Corporation L.T.D.(N.T.P.C.) is the company,

which is working at Badarpur Thermal Power Station, which is situated in

New Delhi in India.

N.T.P.C. is the largest thermal power generation company of India. It was

incorporated in the year 1975 with the objective of planning, promoting

and organising an integrated development of thermal power in the

country.

N.T.P.C. is the public limited company wholly owned by the government

of India. It has power generating capacity in all the four major regions of

the country.

Badarpur Thermal Power Station

Approved capacity 705

MW installed

Location

New Delhi

Coal sourceJharia coal field


5/29

Water

Agra canal

Beneficiary state

Delhi

Unit size 3

X 95 MW

2

X 210 MW

ELECTRICAL MAINTAINANCE DIVISION I

The EMD I at BTPS is in charge of the switchgears, LT motors, HT motors

etc. The training however was restricted to the above three areas only.

COAL HANDLING PLANT -


6/29


7/29

ESP is meant for air pollution control. The working of ESP is based on

CORONA DISCHARGE. An electrostatic

precipitator (ESP) or electrostatic air cleaner is a particulate collection

device that removes particles from a flowing gas (such as air) using the

force of an induced electrostatic charge. Electrostatic precipitators are

highly efficient filtration devices that minimally impede the flow of gases

through the device, and can easily remove fine particulate matter such as

dust and smoke from the air stream. In contrast to wet scrubbers which

apply energy directly to the flowing fluid medium, an ESP applies energy

only to the particulate matter being collected and therefore is very

efficient in its consumption of energy (in the form of electricity).

SWITCHGEARS -

Switchgear is a switching/ interrupting device used in connection with

generation, transmission, distribution and conversion of electric power for

controlling, metering protecting and regulating devices. It is a

combination of electrical disconnects fuses and/or circuit breakers used to

isolate electrical equipment. Switchgear is used both to de-energizeequipment to allow work to be done and to clear faults downstream.

These are located in substations on both the high and low voltage sides of

the large power transformers. One of the basic functions of switchgear is

protection, which is interruption of short-circuit and overload fault

currents while maintaining service to unaffected circuits. Switchgear also

provides isolation of circuits from power supplies. Switchgear also is used

to enhance system availability by allowing more than one source to feeda load.

The various types of switchgears are -


8/29

1.Isolator Switch - It is a part of an electrical circuit whichelectrically isolates the circuit that is continually powered. It breaks

the electrical circuit when the circuit is to be switched in no load.

These are normally used in various circuits for the purpose of

isolating a certain portion when required for maintenance etc.. The

most common isolator is the rotating centre post type in which each

phase has three insulator posts, with the outer post carrying fixed

contacts and connections while the centre post having the contact

arm which is arranged to move through 90 degrees on its axis.

However in some cases two post design is used wherein earth fault

carries a half length contact arm linked together with the ability to

rotate through 90 degrees in opposite directions. The design was

introduced so as to economise on insulation but has been found to

occupy a greater area than the three post type and necessitates

making the break structure extremely rigid to avoid deflection of

insulation under load. The modern trend is again to return back to

the three post type. It has been possible to reduce the isolator size

by limiting the moving contact blade to move a fully open position of

70 degrees to the axis of 3 phases of isolator instead of 90 degrees

but last 20 degrees of movement is used to rotate the moving

contact in its own axis, while the full diameter of the contact is

presented to the fixed contact fingers so that necessary contact

pressure is achieved. The concept of using that last 20 degrees of

movement of the rotating centre post to turn the moving contacts

through this angle about their own axis enables very high contact

pressure to be achieved without the need for a very powerful

operating mechanism.

2. Load Break Switch - An electric switch in a circuit with severalhundred thousand volts, designed to carry a large amount of current

without overheating the open position, having enough insulation to

isolate the circuit in closed position, and equipped with arc interrupters to

interrupt the load current.

3. Earth Switches Devices which are used normally to earth a

particular system, to avoid any accidents which may happen due toinduction on account of live adjoining circuit. These equipments do not

handle any appreciable current at all. Apart from this equipment, there

are a no. of relays etc. which are used in the switchgear.


9/29

Circuit Breakers - A circuit breaker is an automatically-operatedelectrical switch designed to protect an electrical circuit from damage

caused by overload or short circuit. Unlike a fuse, which operates once

and then has to be replaced, a circuit breaker can be reset (either

manually or automatically) to resume normal operation. Circuit breakersare made in varying sizes, from small devices that protect an individual

household appliance up to large switchgear designed to protect high

voltage circuits feeding an entire city. The circuit breaker must detect a

fault condition like overload current etc.

Once a fault is detected, contacts within the circuit breaker must open to

interrupt the circuit; some mechanically stored energy within the breaker

is used to separate the contacts, although some of the energy required

may be obtained from the fault current itself. The stored energy may be

in the form of springs or compressed air.

The circuit breaker contacts must carry the load current without

excessive heating, and must also withstand the heat of the arc produced

when interrupting the circuit. Contacts are made of copper or copper

alloys, silver alloys, and other materials. Service life of the contacts is

limited by the erosion due to interrupting the arc. When a current is

interrupted, an arc is generated - this arc must be contained, cooled, andextinguished in a controlled way, so that the gap between the contacts

can again withstand the voltage in the circuit. Different circuit breakers

use vacuum, air, insulating gas, or oil as the medium in which the arc

forms. Different techniques are used to extinguish the arc including:

Lengthening of the arc

Intensive cooling (in jet chambers)

Division into partial arcs

Zero point quenching

Connecting capacitors in parallel with contacts in DC circuits

Finally, once the fault condition has been cleared, the contacts must

again be closed to restore power to the interrupted circuit. Depending on

the method of extinguishing the arc, the high voltage circuit breakers canbe classified as:


10/29

1. SF6 Circuit Breaker -The SF6 circuit breaker installed at BTPS isHPA by ABB as per standard IEC56. HPA is a medium-voltage circuit

breaker using SF6 gas as the insulation and breaking medium. Its design

is compact and space-saving. The breaker is also available in a version

with synchronised making for maximum damping of transients for

different applications. The HPA breaker works according to the puffer

principle, implying that when breaking, the gas is compressed between a

fixed plunger and a moving cylinder and then blown on to the arc

between the fixed and moving arc contacts. When the breaker is closed,

the current flows via the main contacts and the cylinder. When a tripping

impulse is given, the cylinder moves downwards, whereupon the upper

main contact opens and the current commutes over to the arc contact. At

the same time, the gas in the cylinder is compressed. When the nozzle

has left the arc contact, the compressed gas is blown along the arc and

cools it. The breaking process is completed as the current passes through

zero.

SF6 (sulphur hexafluoride) gas possesses a unique combination of

properties that makes it extremely suitable for use in circuit breakers.

SF6 gas has insulation strength some three times higher than that of air

at an overpressure of 2 bar, which is even higher than that of transformer

oil.

SF6 gas properties

High insulation strength

Excellent ability to quench arcs
http://en.wikipedia.org/wiki/File:Gas_circuit_breaker_operation_1.jpg


11/29

Chemically stable

Non-toxic

Non-flammable

Another SF6 breaker used at BTPS is Voltas SF6 circuit breaker.

ABB SF6 Circuit Breaker

Circuit breaker HPA

Standard IEC 56

Rated voltage 12 kV

Insulation level 28/75 kV

Rated frequency 50 Hz

Breaking current 40 kA

Rated current 1600 A

Making capacity 110 kA

Rated short time current 40 kA/3s

Weight 185 kg

Auxiliary voltage

Closing coil

Opening coil

220 V DC

220 V DC

Motor 220 V DCSF6 pressure at 20C 2-2.5 Bar (.2-.25 MPa)

SF6 gas per pole 0.25 kg

Voltas SF6 circuit breaker

Rated Current 1250 ARated Voltage 9.2 KV

Frequency 50 Hz

Breaking Capacity 40 KA symmetrical

43.45 KA asymmetrical

Short time current 40 KA 3s

SF6 gas pressure 2.5 bar

2. Minimum Oil Circuit Breaker (MOCB) -The MOCB at BTPS isKirloskar HKH 1/1000C.


12/29

In minimum oil circuit breakers the arc extinction takes place in

insulating housing enclosed in ceramic enclosures. The medium used is

dielectric oil and the breaking capacity is 3.6 - 145 KV.

In the bulk oil breakers, the oil serves as both arcs extinguishing medium

and main insulation. The minimum oil breakers were developed to

reduce the oil volume only to amount needed for extinguishing of the arc about 10% of the bulk- oil amount. The interrupter containers of the

minimum oil breakers are made of insulating material and are insulated

from the ground. This is usually referred to as live tank construction. For

high voltages (above 132 kV), the interrupters are arranged in series.

MOCB Kirloskar

Type HKH 12/1000C

Rated Voltage 6.6 KV

Normal Current 1250 A

Frequency 50 Hz

Breaking Capacity 34.7 KA symmetrical

34.7 KA asymmetrical

360 MVA symmetrical

Operating Coils CC 220 V/DC

FC 220 V/DC

3. Air Circuit Breaker -The air type circuit breaker at BTPS is TataMerlin & Gerin Ltd.

Air Circuit Breaker (Tata Merlin & Gerin Ltd.)

Rated Voltage 6.6 KV

Rated Current 630 A

Auxiliary Circuit 220 V/DC


13/29

4. Vacuum Circuit Breaker -By Jyoti Ltd., Vacuum circuit breakershave minimal arcing (as there is nothing to ionize other than the contact

material), so the arc quenches when it is stretched a very small amount

(


14/29

Vacuum circuit breaker

Relays -

A relay is an electrical switch that opens and closes under the control of

another electrical circuit. In the original form, the switch is operated by an

electromagnet to open or close one or many sets of contacts. When a

current flows through the coil, the resulting magnetic field attracts anarmature that is mechanically linked to a moving contact. The movement

either makes or breaks a connection with a fixed contact. When the

current to the coil is switched off, the armature is returned by a force

approximately half as strong as the magnetic force to its relaxed position.

Usually this is a spring, but gravity is also used commonly in industrial

motor starters. Most relays are manufactured to operate quickly. In a low

voltage application, this is to reduce noise. In a high voltage or high

current application, this is to reduce arcing.


15/29

Since relays are switches, the terminology applied to switches is also

applied to relays. A relay will switch one or more poles, each of whose

contacts can be thrown by energizing the coil in one of three ways:

Normally-open (NO) contacts connect the circuit when therelay is activated; the circuit is disconnected when the relay is

inactive. It is also called a Form A contact or "make" contact.

Normally-closed (NC) contacts disconnect the circuit when therelay is activated; the circuit is connected when the relay is inactive.

It is also called a Form B contact or "break" contact.

Change-over, or double-throw, contacts control two circuits:one normally-open contact and one normally-closed contact with a

common terminal. It is also called a Form C contact or "transfer"

contact. If this type of contact utilizesmake before break"

functionality, then it is called a Form D contact. The relay was used

as:

Master Trip Relay (MTR)

Flag Relay

Closed Position Relay (CPR)

Trip Position Relay (TPR)

Unit Trip Relay (UTR)

Unit Signal Relay (USR)

MOTORS


16/29

The AC induction motor is a rotating electric machine designed to

operate from a three-phase source of alternating voltage. The stator

is a classic three phase stator with the winding displaced by 120.

The most common type of induction motor has a squirrel cage rotor.

3 Phase Squirrel Cage Induction Motor - A squirrel cage rotoris the rotating part often used in an AC induction motor. An electric

motor with a squirrel cage rotor is sometimes called a squirrel cage

motor. In overall shape it is a cylinder mounted on a shaft. Internally it

contains longitudinal conductive bars of aluminium or copper set into

grooves and connected together at both ends by shorting rings forming

a cage-like shape.

Specifications:

Frequency 50 Hz

Voltage 6600 V

Current 23.5 A

Efficiency 91.8%

Rpm 1430

Power factor 0.85

Weight 410 kg
http://en.wikipedia.org/wiki/Induction_motorhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Electric_motorhttp://en.wikipedia.org/wiki/Induction_motor


17/29

Design-

60 slots Double Layered

Each slot has 2 coils, no. Of slots vary as 36, 48, 60, and 90

Speed = 1430 rpm

Poles = 4

Speed = 120*f/poles

Poles = 4 poles/phase

Slots per phase = 60/3 = 20

Slots/pole = 20/4 = 5

Coil pitch = 1 to 11

1 phase has 4 poles.

Motor Starting

The methods employed in starting a motor are extremely varied, being

dependent on the system, type, starting repetition and environment etc.

Probably the simplest and the most common method is to connect the

supply directly to the motor allow it to accelerate normally to its running

speed. This method is referred to as Direct On Line (DOL) starting.

DOL Starting

The choice of this method depends on number of conditions. If for

example, the load has high inertia, then DOL will not be ideal because the

prolonged starting current could be six times the normal running current.

This in turn (assuming the switch used can carry this large current) would

put an excessive drain on the supply system. In fact, for large horse

power motors the supply authorities do not allow DOL starting.

DOL starting is however used extensively in modern power stations one

reason being that it is less expensive than others. Excessive current

surge is more tolerable in power stations than on consumer premises.

DOL Starters


18/29

The simplest electric motor drive consists of a squirrel cage motor

switched direct on line and an associated automatic motor starter

consists of basically a contactor to connect the motor to supply and an

overload relay to prevent over heating of the motor.

Star Delta Starter

This method involves starting motor from rest, with the stator windings

connected in star configuration. In this condition, the effective voltage

across each winding is 1/3 of the line voltage or 59%. The current and

torque are reduced to 33% of the values obtained if the motor was

started as DOL. After a period of acceleration, the supply is removed from

the motor and by suitable switching process the windings are connected

in the delta configuration. Before the motor has chance to decelerate, the

supply is re-established with full voltage across each winding. Some

deceleration does takes place in practice and mechanical shock is

introduced to the drive on reconnection at full voltage. This would not be

practical on large units but can be accepted on many small and medium

drives.

ELECTRICAL MAINTAINANCE DEPARTMENT

II

TRANSFORMER


19/29

A transformer is a constant frequency static device comprising

coils coupled through a magnetic medium connecting two ports at

different voltage levels (in general) in an electrical system allowing

the interchange of electric energy between the two ports in either

direction via magnetic field.

A transformer in its simplest form consists of two insulated windings

interlinked by a common or mutual magnetic field established in a core.

When one of the windings is termed as primary, it is connected to a

alternating voltage source, an alternating flux is produced in the core

depending upon the primary voltage, number of turns and frequency. The

mutual flux links the other winding called the secondary. A voltage is

induced in the secondary of the same frequency as primary but its

magnitude depends on the number of turns of secondary.

Types of Transformers -

Step up

Isolation

Step down

Major transformers in the power station

Generator transformer

The generator is connected to this transformer by means of

isolated bus-ducts . this transformer is used to step-up the

generating voltage of about 15 KV to the grid voltage .It is


20/29

generally provided with OFB cooling and is oil immersed .Off circuit

taps on the high voltage side are also present. The transformer has

elaborate cooling system consisting of a number of oil pumps and

cooling fans apart from various accessories discussed later.

Unit Auxiliary transformer

UAT draws its input from the Main bus duct connecting the

generating transformer. Total KVA capacity UAT required can be

determined by using 0.85 p.f. and 0.9 efficiency for the total

auxiliary motor load.

It is usually safe and desired to provide 20% excess capacity then

calculated to provide for miscellaneous auxiliaries and possible

increase in the auxiliary load.

For large units it has become necessary to use more than one UAT.

Such arrangement normally provide separate bus section fed by

separate auxiliary transformer, with bus section breaker while

selecting one thing is to be taken care of is that the percent

impedence of the transformer for the proposed unit should satisfy

the following conditions.

Maximum short circuit current on the auxiliary bus should be

limited within the maximum switchgear rating available.

Maximum permissible voltage dip while starting the largest single

auxiliary motor usually boiler feed pump should remain within

acceptable limit.

Maximum voltage drop permitted on starting largest motor isabout 15-20% . if the voltage drop is higher than the permissible

limits, then transformer impedence has to be reduced ,the

consequent increase in the short circuit current duty may require

the use of higher rated switchgear. Thus to create balance for

larger units, it becomes imperative to use more than one UAT.

Station Transformer


21/29

It is needed to feed the auxiliaries during the start-ups. These are

usually rated for the initial auxiliary load requirements of the unit.

Typically this load is of the order of 60% of the load of the full

generating capacity. But in the large stations where more than one

units are operating, the station transformer should have sufficient

capacity to start two units at the same time. It is also provided with

on load tap changer to cater to fluctuating voltage of the grid.

Construction

Transformer consists of the following parts-

Core and winding

Conservator

Breather

Buchholzbox

Marshalling box

Cooling system

Core and winding

Two types of arrangements are provided

Core type

Shell type

In the core type, the winding is wound around the two legs of the

rectangular magnetic core, while in the shell type the winding are

wound on the central leg of a three legged core.

Conservator

It is the small tank placed on the top of the main tank. It maintainsthe level of oil in the transformer. If the oil level falls more air

comes in conservator through the breather which is nothing but


22/29

silica gel. And if the level of the oil rises the air pumped out to

maintain the pressure. The level of the oil can be monitored by an

indicator on the surface of the conservator. This arrangement also

ensures that surface area of the transformer oil exposed to the

atmosphere is limited so as to prevent fast oxidation and

consequent deterioration of insulating properties of the oil.

Breather

A breather is provided to prevent the contamination of the

transformer oil in the conservator by the moisture present in the

air entering the conservator. Outside air is drawn into the

conservator through the breather every time the transformer cools

down. The breather is filled with material like anhydrous calcium

chloride or silica gel, which has the property of absorbing all water

vapour contained in the air passing through it there by making the

air quite dry. After sometime the calcium chloride or the silica gel

gets saturated with moisture completely and can no longer absorb

moisture. It is thereby very important to replace when it turns pink

in colour. The old silica gel can be reconditioned and used again by

heating up to 150-200 C.

Marshalling box

It is a sort of local control box which houses control for cooling fans

and pumps. There is an oil temperature indicator and winding

temperature as well.

PRV / Explosion vent

Explosion vent: In case of a severe fault in the transformer, the

internal pressure may build up to a very high level. This may result

in an explosion of the tank. To avoid such contingency a relief vent

is provided with a Bakelite diaphragm at the top, which breaks and

relieves the pressure in case of excessive pressure building up.

Pressure relief valve: It also releases excess pressure by opening apressure valve and then closes automatically.


23/29

Cooling Systems:

It consists of the following:

Radiator

Fans

Pumps

The assembly circulates oil in the transformer, which provides insulation

as well as cooling along with the air.

Application Important tasks performed by the transformer are:-

1. Changing current and voltage levels in electrical power systems.

2. Matching source load impedance for maximum transfer in controland electronic circuitry.

3. Electrical isolation

Transformers are used extensively on ac power systems. They make

possible power generation at most desirable and economical transmission

level (10-20 KV). Power transmission voltage (220-1000 KV) and power

utilization at most convenient distribution voltage (230-415 V).

The input to main transformer is through ducts at generated level of

voltage. Output is at 220 KV and connected to infinite Bus Bar through

brushes (insulators).

SWITCHYARD


24/29

It consists of:

Two buses (operation) at 220 kV level and one by-pass back up also at

220 kV.

Air blast circuit breakers

Isolators

Current transformers

Potential transformers

Feeders

Bus coupler

Bus -

Odd numbered bus is connected to generating unit by convention. This is

also considered keeping in mind the fact that every bus has a separate

set of protection unit for reliability.

Thus, bus no. 1 is connected to unit no. 1 and bus no. 2 is connected to

unit no. 2.

Distribution is done through the feeders. The buses operate at 220 kV

voltage levels. The output of the main transformer is coupled and joined

to the bus 1 and 2.

By pass bus

This bus is a back up bus which comes handy when any of the buses

become faulty, when any operating bus has a fault. The bypass bus is

brought into the circuit and then the faulty line is removed, thereby,

restoring the healthy power line.

Air blast circuit breaker


25/29

The ABCB has air at pressure of about 32kg/cm2. It isolates the circuit

when the current in the circuit exceeds certain limit. It operates in

milliseconds and works on no load

Isolator

It operates off load and is mechanical in nature. If any part of the circuit is

to be isolated to work on it during the off load condition, only the circuit is

isolated using isolator. The essential difference between a circuit breaker

and isolator is the presence of quenching such as air or oil in the circuit

breaker. An isolator cannot be used in on load condition because an arc is

formed which may touch the earth thus converting it into a line fault.

Current and Potential TransformerThese are primarily used to measure high current and voltage (of order of

KA and KV).

CVT-Capacitor Voltage Transformer

These are also used for measuring voltage but have higher accuracy than

PTs.

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

systems to step-down extra high voltage signals and provide low

voltage 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 theinstrumentation or protective relay.
http://en.wikipedia.org/wiki/File:Cvt.png


26/29

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. 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.

Rating-220KV/110V

Feeders -

The following are feeders:

IP Extension 1&2

Okhla 1&2

Mehrauli 1&2

Badarpur 1&2

Noida

Alwar

By Pass Feeder

Bus Coupler -

Buses are coupled using the bus coupler. The main function of the bus

coupler is separate the supply from two sources. It helps to shut fault

supply.


27/29

GENERATOR

The two main parts of a generator or motor can be described in either

mechanical or electrical terms

Mechanical:

Rotor: The rotating part of an alternator, generator, dynamo or motor.

Stator: The stationary part of an alternator, generator, dynamo or motor.

Electrical:

Armature:The power-producing component of an alternator,

generator, dynamo or motor. In a generator, alternator, or dynamo the

armature windings generate the electrical current. The armature can

be on either the rotor or the stator.

Field:The magnetic field component of an alternator, generator,

dynamo or motor. The magnetic field of the dynamo or alternator can

be provided by either electromagnets or permanent magnets mounted

on either the rotor or the stator.

Because power transferred into the field circuit is much less than in the

armature circuit, AC generators nearly always have the field winding on

the rotor and the stator as the armature winding. Only a small amount of

field current must be transferred to the moving rotor, using slip rings.

Direct current machines necessarily have the commutator on the rotating

shaft, so the armature winding is on the rotor of the machine.


28/29

Excitation-

An electric generator or electric motor that uses field coils rather

than permanent magnets will require a current flow to be present inthe field coils for the device to be able to work. If the field coils are not

powered, the rotor in a generator can spin without producing any

usable electrical energy, while the rotor of a motor may not spin at all.

Very large power station generators often utilize a separate smaller

generator to excite the field coils of the larger.

In the event of a severe widespread power

outage where islanding of power stations has occurred, the stations

may need to perform a black start to excite the fields of their largest

generators, in order to restore customer power service.

Given below are the specifications of the 210 MW unit turbo

generator:

GENERATOR 210 MW

Max. Constant kVA rating 247000

Max constant kW rating 210000

Rated terminal voltage 15.75 kvRated power factor 0.85 pf

Rated speed 3000 rpm

Phase connection Double star

Stator volts 15750

Stator amps 9050

Rotor volts 310

Rotor amps 2600

TURBO GENERATOR 100 MW

Make BHEL

Speed 3000 rpm

Capacity(kva) 117500

Power factor 0.85 lagging

Power 100 MW

Frequency 50 Hz

Stator current 6475 amp

Excitation 280 vGas pressure 2.5 kg/cm2


29/29

ROTOR COOLING

Hydrogen pressure 4.5 kg/cm2

Purity 97%

Gas volume 66 cubic meter

STATOR COOLING

Water pressure 3.5 kg/cm2

Quantity of water 130 m3/hr

Report Ntpc p

Documents