NTPC Kayamkulam Training Report
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Transcript of NTPC Kayamkulam Training Report
June 2011
Jyothish Kumar C G Jostin John Fedreral Institute Of Science & Technology,Angamaly,Kerala
Summer Training Report- NTPC, Kayamkulam
ACKNOWLEDGEMENT
We thank Mrs. Sreekumari Radhakrishnan for allowing us to
undergo summer training at NTPC Kayamkulam and all of the HR
team of the Institute for their continued guidance. We also wish to
convey our warm regards to Mr. Manu George Thomas,
Mr.Ashil Thomas & Mr. Dinesh K V for providing us with all the
knowledge database that we needed for this report.
We also thank Mr. M G K Pillai for providing us this wonderful
opportunity to work with the NTPC family.
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.Today NTPC
contributes more than 1/ 4th of the total power generation in
India.
NTPC KAYAMKULAM
BRIEF DISCRIPTION
• Established in : 1998
• Project Name : Rajiv Gandhi Combined Cycle Power Project
(RGCCPP)
• Type of station : Gas based combined cycle
• Approved Invetment : Rs. 1189.94 crore
• Location : Choolatheruvu in Alappuzha district of Kerala
• Fuel : Naphtha
• Fuel source : BPCL
• Water source : Achankovil river
• Gas Turbine Output : 2 X 115 MW
• Steam Turbine Output : 1 X 120 MW
• Net plant Output : 350 MW
• Beneficiary States : Kerala & Tamil Nadu (with consent of Kerala)
Introduction To Gas Power Plants
The development of the sector in the country, since independence has been predominantly through the State Electricity Boards. In order to supplement the effects of the states in accelerating power development and to promote power development on a regional basis to enable the optimum utilisation of energy resources, the Government of India decided to take up a programme of establishment of large hydro and thermal power stations in the central sector on a regional basis. With this in view, the Government set up the National Thermal Power Corporation Ltd., in November 1975 with the objective of planning, construction, commissioning, operation and maintenance of Super Thermal and Gas Based Power projects in the country.
The power plant consists of gas turbine generating units waste heat recovery boilers, steam turbo generator, auxilliary electrical and mechanical equipments. The power generated at this power station is fed over 220 KV AC transmission system and is distributed to substations at Kundara and Pallam.
The function of a gas turbine in a combined cycle power plant is to drive a generator which produce electricity and to provide input heat for the steam cycle. Power for driving the compressor
is also derived from gas turbine.
Combined Cycle to improve efficiency
Combined Cycle power plant integrates two power conversion cycles namely. Brayton Cycle (Gas Turbines) and Rankin Cycle (Conventional steam power plant) with the principal objective of increasing overall plant efficiency.
In the above two cycles gas turbine exhaust is at a temperature of 500–550 0C and in Rankine Cycle heat is required to generate steam at the temperature of 500-550 0C. so, why not use the gas-turbine exhaust to generate steam in the Rankine cycle and save the fuel required to heat the water ? Combined Cycle does just the same.
The efficiency of Gas Turbine cycle alone is 30% and the efficiency of Rankine Cycle is 35%. The overall efficiency of combined cycle comes to 48%.
Black Start System To start a gas turbine in the event of AC-power failure an emergency black start system is provided. It also helps in safe closing down of the gas turbine and its auxiliaries following a ‘trip’ in the event of grid collapse. The black start system consists of a separate diesel engine or a gas turbine driven synchronous generator connected to station switch gear bus. It
can be operated manually from local or remote and also it automatically comes into operation following a black out condition. Capacity of the black start unit should be such that it can supply the total auxiliary power required to start a gas turbine from standstill condition.RGCCPP is provided with diesel generator set for the duty.
How Does A Combined-Cycle Power Plant Work?
Air Inlet
The amount of air needed for combustion is drawn though
the large air inlet section where it is cleaned, cooled and
controlled, in order to reduce noise.
Turbine-Generators:
The air then enters the gas turbine where it is compressed,
mixed with fuel Naptha and ignited, which causes it to
expand. The pressure created from the expansion spins the
turbine blades, which are attached to a shaft and a
generator, creating electricity.
Each gas turbine produces 115 megawatts (MW) of
electricity.
Heat Recovery Steam Generator
(HRSG)
The hot ehaust gas exits the turbine at about 550 degree
Celsius and then passes through the Heat Recovery Steam
Generator (HRSG).
In the HRSG, there are tubes filled with demineralised
water. The hot exhaust gas coming from the turbines passes
through these tubes, which act like a radiator, boiling the
water inside the tubes, and turning that water into steam.
The gas then exits the power plant through the exhaust
stack at a much cooler 100 degree Celsius, after having
given up most of its heat to the steam process.
This steam is fed to the steam turbine through large pipes.
Steam Turbine
The steam turbine is capable of producing up to 120 MW.
It is located on top of the condenser, across from the
cooling tower.
Steam enters the turbine with temperatures as high as 550
degree Celsius and pressure as strong as 2,200 pounds per
square inch. The pressure of the steam is used to spin
turbine blades which is coupled to a generator, producing
additional electricity, about 120 MW per HRSG unit.
After the steam is spent in the turbine process, the residual
steam leaves the turbine at low pressure and low heat,
about 100 degree Celsius. This exhaust steam passes into a
condenser, to be turned back into water.
By using this “combined-cycle” process, two gas turbines
and one steam turbine, we can produce a total of about 350
MW of electricity.
Transmission of Generated Power
Onto the Grid
The Gas Turbine and Steam Turbine generators produce
power at 10.5 kV.
The transformers take the generated 10.5 kV and
“transform” them to 220 kV, which is the required voltage
needed for transmission to the nearby tower that sends
power to the substation.
A small amount of generation is directed to “Auxiliary
transformers” which “transform” the generated voltage to a
6.6 kV, so that it may be used by the plant to power its own
pumps, fans, and motors.
Gas Insulated Switchyard(GIS)
The most salient feature of NTPC Kayamkulam is the GIS,
which is the 1st of its kind in India.
GIS is extremely compact compared to other conventional
switchyards.
Unlike conventional switchyards here the insulation
between three phase lines(R,Y,B) in each busbar is
provided by SF6 which is a highly inert gas.
From each transformer, the power passes underground into
the switchyard.The power from all of the generators comes
together there, where it is measured, metered and directed
onto the grid.
Condenser and Cooling Tower
The purpose of the condenser is to turn low energy steam
back into pure water for use in the Heat Recovery Steam
Generator.
The purpose of the cooling tower is to cool the circulating
water that passes through the condenser. It consists of 8
cells with large fans on top, inside the cone-like stacks, and
a basin of water underneath.
The cool basin water absorbs all of the heat from the
residual steam after being exhausted from the steam
turbine and it is then piped back to the top of the cooling
tower.
As the cool water drops into the basin, hot wet air goes
out of the stacks. Normally, hot moist air mixes with cooler
dry air, and typically a water vapor plume can be formed.
DeMineralising Plant
By gravity pipe
Reservoir
River Achankovil
Muttam makeup-water Pump House
Raw-water Pump House
Stilling chamberChlorine + lime
ClarifierCoagulated alum & PAC
Clarified water storage tank
Pure water
Domestic purpose , DM-Plant
Cooling tower makeup pump
Gravity sand, filter-bed
Potable water to colony, plant and DM-feeder
Filtered water storage tank
DeMineralising Plant
It is the plant where the purified water to condenser is demineralised. Demineralisation is done to prevent the rusting of condensing chamber and its pipes. It has the following five stages:
Actuated Carbon Filter (ACF) Strong Acid-Cation exchange bed (SAC) Degasser tower Strong Base Anion exchange bed Mixed Bed Unit (MBU)
Passing through these five stages, purified water is demineralised and fed to the condenser.
CONCLUSION
In today’s society electricity is a prerequisite. Being electrical engineering students, studying about its generation has been our necessity.
The past six days in NTPC gave us an opportunity to explore the dimensions of power generation, with the proper guidance of the qualified and skilled employees of NTPC.
The knowledge we gained from this training would be highly beneficial in our further studies and career.