NTPC, the largest power Company in India, was setup in 1975 to accelerate power development in the country. NTPC has installed capacity of 29,394 MW. It has 15 coal based power stations (23,395 MW) & 7 gas based power stations (3,955 MW) 4 power stations in Joint Ventures (1,794 MW). The company has power generating facilities in all major regions of the country. It plans to be a 75,000 MW company by 2017.
Prime mover coupled to Alternator. Prime mover is driven by energy obtained from various sources such as burning of fuel, pressure of water, force of wind etc. Fig. Fundamental of generation of Electricity
A generating station which converts heat energy of coal combustion into electrical energy is known as a steam power station. Steam is produced in the boiler by utilizing the heat of coal combustion. The steam is then expanded in the steam turbine and is condensed in a condenser to be fed into the boiler again. The steam turbine drives the alternator which converts mechanical energy of the turbine into electrical energy.
a. Steam generating equipment b. Condenser c. Prime mover d. Electrical equipment Steam generating equipment includes : Boiler Superheater Economiser Air Pre-heate r
Boiler A boiler is closed vessel in which water is converted into steam by utilising the heat of coal combustion. Steam boilers are broadly classified into following two types: (a) Water tube boilers (b) Fire tube boilers In a water tube boiler, water flows through the tubes and the hot gases of combustion flow over these tubes. Water-tube boilers are used for high-pressure boilers Figure-water tube boiler
A device which removes last traces of moisture. It helps in reduction in requirement of steam quantity. steam being dry reduces the mechanical resistance of turbine. No corrosion at the turbine blades.
They are such devices which recover the heat from the flue gases on their way to chimney and raise the temperature of feed water. Air Pre-heaters recover the heat from the flue gases leaving the economiser and heat the incoming air required for combustion
Which condenses the steam at the exhaust of turbine. It creates a very low pressure at the exhaust of turbine, this helps in converting heat energy of steam into mechanical energy in the prime mover. The condensed steam can be used as feed water to the boiler.
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and converts it into mechanical energy. About 86% of all electric generation in the world is by use of steam turbines. It has almost completely replaced the reciprocating piston steam engine.
Turbo generator An turbo generator is coupled to a steam turbine and converts mechanical energy of the turbine into electrical energy. It may be hydrogen or air cooled. Rating of turbo generator is normally 200MW & 500MW. Transformers (a) main step-transformers, which steps-up generated voltage transmission of power (b) station transformers, general purpose (c) auxiliary transformers, which supply to individual unit- auxiliaries. Switchgear which locates fault on the system and isolate faulty part from healthy section. It contains circuit breakers, relays, switches and other control devices.
Source of coal = Jayant Mines (Madhya pradesh) Location of source = Near Singrauli (Madhya pradesh) Distance of source from plant = 5kms Type of coal = D grade Coal requirement = 25,000 MT/Day
CHP follows three coal paths: 1.Path A-from track hopper to bunkers 2.Path B-from track hopper to stockyard. 3.Path C-from stockyard to bunker. Path A-
Generally thermal power stations use coal mills or called coal firing system. Coal is reduced to fineness (-20mm). This fine powdered coal is called pulverized coal and is carried forward to the burner by air through pipes. MILLS
A natural result from the burning of fossil fuels, particularly coal, is the emission of flyash. Ash is mineral matter present in the fuel. For a pulverized coal unit, 60-80% of ash leaves with the flue gas. Electrostatic precipitator has series of collecting & emitting electrodes in a chamber. At the inlet of the chamber there are distributer screen. Hooper and flushing system form a base of chamber. Efficiency of ESP is approx. 99.8%
SWITCHYARD Switchyard is considered as the HEART of power plant. It is a junction, which carries the generated power to its destination. It is basically an open area where many different kind of outdoor equipments are located. eg: busbars, transformers, circuit breakers etc. Switch yards can be of 400KV, 132KV.