introduction ntpc ltd

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 don’t require enormous water for cooling. They are more compact. Combined Cycle Power Plant Generator

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8/8/2019 Introduction NTPC Ltd

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8/8/2019 Introduction NTPC Ltd

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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 thestator 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 theexcitation is taken from the generator terminals and fed to the field winding through the excitation transformer andthe 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 WHRBThe 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 PARTSHP 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 circulationpumps.

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 aresituated 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 noload HV 15.75 KV Rated voltage no load LV side 2.55 KV and 0.433 KV Rated current HV side 230.9 A Ratedcurrent LV side 1143 A and 1667 A Frequency 50 HzTransformer protectionsTransformer Differential protection.Three phase over current protection.Earth fault relayRestricted earth fault relayBuchholz relay

Generator ProtectionsGenerator Differential ProtectionGenerator Stator earth fault protectionGenerator rotor earth fault protection

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Switchyard and transmission equipmentTransformer IsolatorsCircuit breakersEarth switchesWave trapLightning arrestor Current transformer

Potential transformer Bus bars

Bus Switching SchemesADVANTAGES OF GAS BASED PLANTSHIGH THERMAL EFFICIENCYLOW WATER REQUIREMENTSENVIRONMENT FRIENDLINESSFAST START - UP

LOW INSTALATION COSTPOWER EVACUATION FROM NTPC ANTAThere are total six 220 kv transmission lines for evacuation of power generated at Anta.two lines for Bhilwara,two lines for Jaipur andone line for Kota andone line for Rawatbhata power plant

Reference: http://www.seminarprojects.com/Thread-industrial-training-at-ntpc-anta-gas-power-plant-full-report#ixzz0v6451isv

http://www.seminarprojects.com/Thread-industrial-training-at-ntpc-anta-gas-power-plant-full-report#ixzz0v6451isv