12-11-2012, 01:48 PM
INDUSTRIAL TRAINING REPORT ON NTPC DADRI THERMAL POWER PLANT
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Overview of NTPC
NTPC was set up in the central sector in the 1975 in response to widening demand & supply gap with the main objective of planning, promoting & organizing an integrated development to thermal power in India. Ever since its inception, NTPC has never looked back and the corporation is treading steps of success one after the other. The only PSU to have achieved excellent rating in respect of MOU targets signed with Govt. of India each year. NTPC is poised to become a 40,000 MW gint corporation by the end of XI plan i.e. 2012 AD. Lighting up one fourth of the nation, NTPC has an installed capacity of 19,291 MW from its commitment to provide quality power; all the operating stations of NTPC located in the National Capital Region & western have acquired ISO 9002 certification. The service groups like Engineering, Contracts, materials and operation Services have also bagged the ISO 9001 certification. NTPC Dadri, Ramagundam, Vindhyachal and Korba station have also bagged ISO 14001 certification.Today NTPC contributes more than 3 / 5th of the total power generation in India.
NTPC Limited is the largest thermal 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. NTPC ranked 317th in the ‘2009, Forbes Global 2000’ ranking of the world’s biggest companies. Within a span of 34 years , NTPC has emerged as a truly national power company, with power generating facilities in all the major regions of the country. With a current generating Capacity of 30,644 MW, NTPC has embarked on plans to become a 75,000 MW company by 2017. Apart from power generation from coal and gas, it has also diversified into hydro power, coal mining, power equipment manufacturing, oil and gas exploration, consultancy in the area of power plant constructions and power generation, power trading and distribution in the form of joint ventures with various other entities in India and abroad.
Station At Glance
NTPC dadri is model project of NTPC . also it tit the best project of NTPC also known as NCPS ( National capital power station ). Situated 60 kms away from Delhi in the District of gautam budh Nagar, Uttar Pradesh. The station has an installed capacity of 1669 MW of power – 840 MW from Coal based units and 829 MW Gas Based Station . the station is excelling in performance ever since it’s commercial operation . consistently in receipts of meritorious projectivity awards, the coal based units of the station stood first in the country in terms of PLF for the financial year 1999 – 2000 by generating an all time national high PLF of 96.12 % with the most modern O & M Practices. NTPC – Dadri is committed to generated clean and green Power. The Station also houses the first HVDC station of the country (GEP project) in association with centre for power efficiency and Environment protection (CENEEP) – NTPC & USAUID. The station has bagged ISO 14001 & ISO 9002 certification during the financial year 1999 – 2000, certified by Agency of International repute M/s DNV Netherlands M/s DNV Germany respectively.
DADRI THERMAL POWER STATION
The National Capital Power Station [NCPS] has the distinction of being the country's only three in one project ; consisting of Stage-I 840 MW; Stage-II 490MW ( and 490 MW under construction) of coal based units , 829 MW gas based modules , and a 1,500 MW H.V.D.C. converter station {under the operational control of P.G.C.I.L. since October '93}. The stage-II (490MW*2) coal based units are scheduled in 2010 to meet the common wealth games power requirement. The commercial operation of Stage-II Unit-V 490 MW has been declared w.e.f 31.01.2010. Also work for Stage-II UNIT-VI 490MW is under full swings. Besides the station has the largest switchyard in the country with a power handling capacity of 4,500 MW
The station has the unique distinction of having Asia's first 100 percent dry ash extraction with transit ash storage silos and final storage place converted to an green ash mound . An Ash Technology park has also been set up to demonstrate the uses of ash which has become the point of attraction for the visitors.
National Capital Power Station - Coal
The coal-based station mainly meets power requirements of the National Capital Region [NCR] , and the northern grid . With the World Bank funding component , the capital cost of the units is Rs. 16.69 billion . There are four 210 MW coal based units. The units have a coal-fired boiler and a steam turbine each . The boiler design is also suitable for 100% operations with heavy furnace oil firing . For this , three storage tanks , each of capacity 15,000 kL , enough for 10 days continuous oil firing requirements have been provided for the boilers .
Coal Source:
The coal is transported from the Piparwar block of mines of the North Karanpura Coalfields of Bihar , over a distance of about 1,200 kms. , by the Indian Railways bottom discharge , and Box 'N' type of wagons . The coal requirements for the four units is 15,000 M.T. each day , 3.67 million tonnes annually . The station has its' own 14 kms. Long rail track from the Dadri Railway Station , to the site , and a 6 km in-plant track , on electric traction.
National Capital Power Station - Gas
The gas-based station at N.C.P.S. is the country's largest . It has two modules; each module consists of two gas turbines of 130.19 MW each with one waste heat recovery boiler and one steam turbine of 154.51 MW capacity . The power from this plant is allocated to Uttar Pradesh , and also to Delhi , Punjab , Jammu and Kashmir , Haryana , Himachal Pradesh and Rajasthan . The cost of gas based modules is Rs. 9.75 billion , which includes a German K.f. W. funding . The modules are fully commissioned . Gas turbines generate power at an efficiency of about 32% only , and to utilize the rest of this energy , a combined cycle system is adopted . The waste heat from the gas turbine exhaust is routed through the waste heat recovery boiler , and the steam thus generated is utilized in a conventional steam turbine to generate additional power . By this , the overall efficiency of fuel heat utilization reaches to about 48% .
Gas Source:
The source of fuel for this plant is the reserves of South Bassein fields in South Tapi and mid Tapi delta in the Arabian Sea . The natural gas from South Bassein off shore fields is transported through a submarine pipeline to Hazira onshore terminal and then through the 1,700 kms. Long Hazira-Bijapur pipeline via Shahjanpur and Babrala , to the project . For the 829 MW project , the requirement is 3.00 million cubic meters per day (yearly average). It would be worthwhile to note that within a short span of less than 7 years , both the coal and gas based power cycle units/modules have been commissioned in a project . Both the projects have diverse modern technologies , with the latest process controls .
HVDC
This is a technological accomplishment in power by NTPC . Commissioned in December '90 , the system is the first commercial long distance HVDC link in India , and also the largest in Asia . The basic objective of the HVDC link is to transmit the power generated at the RhSTPP efficiently to the northern region , with significant reduction in transmission losses . It consists of two converter stations - one located at Rihand (RhSTPP) acting as a rectifier , and the other at Vidyutnagar (NCPP) as an inverter , involving a distance of about 900 kms. . These stations are connected by a +/- 500 kV HVDC line for transmission of 1,500 MW power from Rihand to Vidyutnagar .
The description of some of the components above is as follows:
Cooling towers-
Cooling towers are eveporative coolers used for cooling water. Cooling tower use evaporation of water to reject heat from processes such as cooling the circulaing water used in oil refineries, chemical plants, power plants, etc. The tower vary in size from small roof – top units to very large hyperboloid structures that can be upto 200 meters tall and 100 meters in diameter, or rectangular structure that can be over 40 meters tall and 80 meters long. Smaller towers are normally factory built while larger ones are constructed on site. The primary use of large, industrial cooling tower system is to remove the heat absorbed in the circulating water system used in power plants, petroleum refineries, petrochemical and chemical plants, natural gas processing plants and other industrial facilities.
Three phase transmission line-
Three phase electric power is a common method of electric power transmission. It is a type of polyphase system mainly used for power motors and many other devices. In a three phase system, three circuits reach their instantaneous peak values at different times. Taking one conductor as reference, the other two conductor are delayed in time by one-third and two-third of cycle of the electrical current. This delay between phases has the effect of giving constant power over each cycle of the current and also makes it impossible to produce a rotating magnetic field in an electric motor. At the power station, an electric generator converts mechanical power into a set of electric currents one from each electromagnetic coil or winding of the generator. The currents are sinusoidal functions of time, all at the same frequency but offset in time to give different phases. In a three phase system, the phases are spaced equally giving a phase separation of one-third of one cycle. Generators output at a voltage that ranges from hundreds of volts to 30,000 volts. At the power station. Transformers step-up this voltage for suitable transmission. After numerous further conversions in the transmission and distribution network, the power is finally transformed to standard mains voltage i.e. the household voltage. The power may already have been split into single phase at this point or it may be still three phase. Where the step-down is three phase. The output of the transformer is usually star connected with the standard mains voltage being the phase neutral voltage.
Electrical generator-
An electrical generator is a device that coverts mechanical energy to electrical energy, using electromagnetic induction whereas electrical energy is converted to mechanical energy with the help of electric motor. The source of mechanical energy may be a reciprocating turbine steam engine. Turbines are made in variety of sizes ranging from small 1 hp(0.75 kW) used as mechanical drives for pumps, compressors and other shaft driven equipment to 2,000,000 hp(1,500,000 kW) turbines used to generate electricity.
Boiler Feed Pump-
A Boiler Feed Pump is a specific type of pump used to pump water into steam boiler. These pumps are normally high pressure units that use suction from a condensate return system and can be of centrifugal pump type or positive displacement type. Construction and Operation feed water pumps range in size upto many horsepower and the electric motor is usually separated from the pump body by some form of mechanical coupling. Large industrial condensate pumps may also serve as the feed water pump. In either case, to force water into the boiler, the pump must generate sufficient pressure to overcome the steam pressure developed by the boiler. This is usually accomplished through the use of centrifugal pump.