29-03-2010, 09:41 PM
Presentation on Industrial Training at NTPC Anta Gas power Plant
Presented by:-
Dulara Sharma
Nand kishor
Topics to be covered:-
Introduction
Gas turbine
Generator
combined cycle process
Waste heat recovery boiler(WHRB)
Steam turbine
Generator & Transformer protection
Switchyard
Power evacuation
Introduction NTPC 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 .
Introduction NTPC 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.
Units Configuration
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.
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.
Advantages of gas turbine w.r.t steam turbine are:
They can be started and loaded quickly.
Less maintenance and simple design.
They have lower installation cost.
GT plant involve less metal and material.
They donâ„¢t require enormous water for cooling.
They are more compact.
Combined Cycle Power Plant
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.
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
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.
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.
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.
Cooling tower
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 ÂÂ
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
ADVANTAGES OF GAS BASED PLANTS
HIGH THERMAL EFFICIENCY
LOW WATER REQUIREMENTS
ENVIRONMENT FRIENDLINESS
FAST START - UP
LOW INSTALATION COST
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
