26-03-2014, 04:29 PM
NTPC Ltd
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INTRODUCTION
India’s largest power company, NTPC was set up in 1975 to accelerate power
development in India. NTPC is emerging as a diversified power major with
presence in the entire value chain of the power generation business. Apart from
power generation, which is the mainstay of the company, NTPC has already
ventured into consultancy, power trading, ash utilization and coal mining. NTPC
ranked 317th in the ‘2009, Forbes Global 2000’ ranking of the World’s biggest
companies.
The total installed capacity of the company is 30, 144 MW (including JVs) with 15
coal based and 7 gas based stations, located across the country. In addition
under JVs, 3 stations are coal based & another station uses naptha/LNG as fuel.
By 2017, the power generation portfolio is expected to have a diversified fuel mix
with coal based capacity of around 53000 MW, 10000 MW through gas, 9000
MW through Hydro generation, about 2000 MW from nuclear sources and around
1000 MW from Renewable Energy Sources (RES). NTPC has adopted a multi-
pronged growth strategy which includes capacity addition through green field
projects, expansion of existing stations, joint ventures, subsidiaries and takeover
of stations.
National Capital Power Station Dadri
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.
The station's capacity allocation is mainly concentrated in northern region of India
. Spread over 2,465 acres , the station is situated on the Dadri -Dhaulana road
[10 kms. off Dadri G.T. road , and 12 kms. off the National Highway # 24] . The
route from New Delhi to NCPS is 60 kms. long and is about 25 kms. from
Ghaziabad
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.
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 .
INTERCONNECTING TRANSFORMER (ICT)
Power transformers are the backbone of the large grid. The power is generated
at the low voltage level and has to be carried to far away load centers. Typicallythe power is generated at the Pit heads i.e power source like coal, water. It is
uneconomical carry the bulk power at low voltage levels. Depending upon the
requirement the voltage level is stepped upto the transmission level i.e 220 or
400kV. At higher voltages the transmission losses are less. Similarly at the
remote end the voltage is stepped down the distribution level. To accomplish the
task
Power transformers are installed and act as bi-directional element in the system.
At NTPC Dadri this task is carried out by bank of Single Phase 400/220kV
Interconnecting transformers. Autotransformers are used when transformation
ratio is between 1 and 2 and above 315MVA, due to size and weight constraints
all the transformers are single phases. Three such single phase transformers are
installed three phases to make One bank of transformer.