Industrial Training at NTPC Anta Gas Power Plant

Presentation on Industrial Training AtNTPC,Anta

Gas power Plant Presented by:-

Dulara Sharma

EE-2 0602080

April 9, 2023

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Topics to be covered:-

•Introduction•Gas turbine•Generator•combined cycle process•Waste heat recovery boiler(WHRB)•Steam turbine•Generator & Transformer protection• Switchyard•Power evacuation

IntroductionNTPC Ltd.•NTPC Limited is the largest power

generating company of India. •A public sector company, it was

incorporated in the year 1975 to accelerate power development in the country as a wholly owned company of the Government of India.

• the installed capacity of NTPC is30,644 MW .

IntroductionNTPC Ltd.Through its•15 coal based (24,395 MW), •7 gas based (3,955 MW) •4 Joint Venture Projects (2,294 MW). •NTPC's share on 31 Mar 2008 in the total

installed capacity of the country was 19.1% and it contributed 28.50% of the total power generation of the country during 2008-09.

NTPC ANTA Anta Gas Based Combined Cycle Power Project is not only the first Gas Power Plant of NTPC but is also the beginning of an era of state of art Combined Cycle Power Plants in the country.

BRIEF DISCRIPTION

• Established in : 1989• Type of station :Gas based combined cycle• Location : Anta in Baran district of Rajasthan• Total land : 390.75 acres.• Fuel : Natural Gas, Naphtha• Fuel source : By GAIL through HBJ Pipe line• Water source : KOTA RIGHT MAIN CANAL• Gas Turbine Output : 3 X 88.71 MW• Steam Turbine Output : 153.20 MW• Net plant Output : 419.33MW• Reservoir : 10 Million m3 , for One Month• Beneficiary States : Rajasthan, Delhi, Haryana, Panjab, UP, J & K,

Union Territory of Chandighar.

Units Configuration

GT1B 88.71 ST1C 153.2

GT1C 88.71

Total Station Capacity 419 MW

Total capacity

=419.33 MW

GT1A 88.71

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Gas Turbine is a heat engine

The Process Includes

• Compression :▫ of working medium (air) taken

from atmosphere in a compressor.

• Combustion▫ Increase of working medium

temperature by constant pressure ignition of fuel in combustion chamber.

• Expansion ▫ of the product of combustion

in a turbine.

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Start-up of the GT • Start-up of the GT is driven with the help of

starting equipment which runs the generator as a motor with speed increasing from 0to 600rpm. At this speed a pilot flame is ignited in the combustion chamber, fuel (gas/naphtha) enters and combustion takes place.

• The speed increases further both with the help of generator motoring and the combustion of fuel up to about 2000 rpm. At this speed starting equipment is switched off and only the generator is made ready for synchronization with the grid. After synchronizations, the turbine load increases up to base load with more and more fuel entering the combustion chamber.

Applications of Gas Turbine

• Conventional applications are Simple cycle operation.  Combined cycle operation.

• Electric utility companies use gas turbine predominantly in simple cycle and combined cycle applications.

• Combined cycle operation is much efficient than open cycle operation.

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Advantages of gas turbine w.r.t steam turbine are:

1. They can be started and loaded quickly.

2. Less maintenance and simple design.

3. They have lower installation cost.

4. GT plant involve less metal and material.

5. They don’t require enormous water for cooling.

6. They are more compact. 10

Air Fuel

Exhaust gas

Steam Turbine

Steam

G

G

Combined Cycle Power PlantWHRB

15%

100%

33%

16%

36%

Gas Turbine

Input

Condensor

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Generator Generator is three phases, two pole air cooled machine.

The mechanical energy generated by turbine is converted to electrical energy by the generator and appear in the stator winding in the form of current and voltage. This balances the torque of the gas turbine.

It lead the magnetic flux, and carries the field winding, the generator is self excited. The power required for the excitation is taken from the generator terminals and fed to the field winding through the excitation transformer and the thyristor- controlled rectifier units.

Gas GeneratorSalient Features

1. Generator Type : Non Salient Pole

Synchronous generator

2. No. of phases : 3

3. No. of poles : 2

4. Stator winding : star

5. Insulation class : F class

6. Rated apparent power : 135MVA

7. Rated voltage : 10.5 KV

8. Rated current : 7423 A

9. Full load efficiency : 98.38%

10. Type of cooling : Air cooled

Steam GeneratorSalient Features

1. Generator Type : Non Salient Pole

Synchronous generator

2. No. of phases : 3

3. No. of poles : 2

4. Stator winding : star

5. Insulation class : F

6. Nominal apparent power : 160 MVA

7. Nominal voltage : 15.75 KV

8. Full load efficiency : 98.38%

10. Cooling

a) Stator : Air cooled by fans

b) Rotor : Axial cooling

Waste Heat Recovery Boiler• Anta Combined cycle power plant also known as Waste

Heat Recovery Boilers (WHRB) plant, which are of non-fired, dual pressure and forced circulation type. The boiler has two different water/steam cycle known as high-pressure system and low-pressure system.

Components of WHRB The main components of the WHRB can be divided into

following categories:• LP Economizer• LP Drum & Evaporator• LP Super-heater• HP Economizer• HP Drum & Evaporator

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LP Economizer

• In economizer the flue gas heats up the feed water.

• After the economizer the feed water enters the LP evaporator and then to LP drum boiler.

LP Super-Heater

The steam, leaving at the top of the LP-drum flows through the flue gas heated super heater, where it reaches the end temperature of about 212°C.

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HP BOILER PARTS

• HP Economizer The HP economizer coils are in two part one part is just

below the LP economizer and other part is below LP super heater and both the coils are connected in series

• HP Boiler Drum & Evaporator The feed water in the HP-boiler drum is pumped through

the evaporator by means of 2 x 100 % HP circulation pumps.

• HP Super-Heater The HP super heater consists of two parts with a spray

attemperator between them. This configuration allows the temperature control of the super heated steam.

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Condensate Pre-Heater

• The main condensate is pumped by condensate extraction pumps (CEPs) to the feed water tank.

• Before entering the feed water tank the condensate is passed through the condensate pre-heaters, which are situated at the tail end of the WHRBs and heated by the flue gas to achieve the highest cycle efficiency.

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Cooling tower

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GENERATOR TRANSFORMER The generator is connected to this transformers by means of

isolated bus ducts. This transformer is used to step up the generating voltage of 15.75 KV to grid voltage.

Specification of Generator Transformer :

Rated power 160 MVA

Voltage (HV) 230 KV

Voltage (LV) 15.75 KV

Current (HV) 728 A

Current (LV) 10.6 KA

Phases 3

Frequency 50 Hz

Ambient oil temp. 500 C

Ambient winding temp. 55 0 C

Unit Auxiliary Transformer (UAT) Specification of three winding UAT :

Rated power 6300 MVA Rated voltage no load HV 15.75 KV

Rated voltage no load LV side 2.55 KV and 0.433 KV

Rated current HV side 230.9 A

Rated current LV side 1143 A and 1667 A

Frequency 50 Hz

Transformer protections

• Transformer Differential protection.•Three phase over current protection. •Earth fault relay•Restricted earth fault relay•Buchholz relay

Generator Protections

•Generator Differential Protection•Generator Stator earth fault protection

•Generator rotor earth fault protection

Switchyard and transmission equipment•Transformer•Isolators•Circuit breakers•Earth switches•Wave trap•Lightning arrestor•Current transformer •Potential transformer•Bus bars

Bus Switching Schemes

Bus

Coupler

6 Transmission lines

Transfer Bus

Main Bus-1Main Bus-2

Double main and Transfer bus scheme

ADVANTAGES OF GAS BASED PLANTS

HIGH THERMAL EFFICIENCY

LOW WATER REQUIREMENTS

ENVIRONMENT FRIENDLINESS

FAST START - UP

LOW INSTALATION COST

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POWER EVACUATION FROM NTPC ANTA There are total six 220 kv transmission

lines for evacuation of power generated at Anta.

• two lines for Bhilwara, • two lines for Jaipur and • one line for Kota and • one line for Rawatbhata power plant

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