3.
I wish to express my sincere gratitude to Shri- S.K.Banjara(C.E.)
PGTI ,CSPGCL for providing me an opportunity to do my vocational
training and project work in (D.S.P.M,TPS) korba, east.
I sincerely thank Mr . joshi sir (H.O.D of electrical engg.
department) Govt. polytechnic college for their guidance and
encouragement in carrying out this project work. I also wish to
express my gratitude to the officials and other staff members of
DSPM,TPS korba ,east who rendered there help during the period
of my project work.
Finally I express my thanks to my parents for supporting me while
I was able to complete this work successfully.
Submitted by:-
Ayushi
4.
5.
6.
7. introduction
to thermal power plant
Nowadays, Thermal power plant constitute
about 60 % of the total installed capacity in
the country. A Thermal power plant uses coal
and water to produce high pressure and high
temperature steam. The energy of this
steam is converted in to mechanical energy
due to rotation of turbine. Now mechanical
energy of turbine is converted into electrical
form with the help of alternators.
The functioning of every thermal power plant
is based on the following processes
Coal to steam
Steam to mechanical power
Power generation, transmission and
distribution.
15. The system which is used to remove the impurities
present in raw water is known as Water Treatment. Water
treatment is done to protect the boiler tubes from
corrosion and thus from damage.The final product of WT
plant is de-mineralized water (DM water). The water
treatment is sub-divided as:-
Pre-treatment
Post treatment
Pre-treatment- In the pre-treatment almost all visible
matters are separated from water. In practice, alum and
lime are used for quick sedimentation . The treatment
removes 90% of organic impurities and thus clarified
water is obtained.
Post treatment- This is about dissolved impurities which
are mostly salts of sodium, calcium and magnesium and
other elements.
After this process DM water is obtained which is stored
in DM water tanks and then supplied to boiler.
17. The heat of combustion of coal in the boiler is utilized
to convert water in to steam at high temperature and
pressure .The flue gases from boiler make their
journey through super heater, economizer, air-pre
heater .The boiler in the thermal power station
consists of the following equipments:-
Super heater:-super heater is used to remove the moisture
content from the steam. Super heater raises the
temperature of steam above 540 degree celcius .
Advantages of super heater-
1. Increases efficiency
2. Reduces corrosion of turbine blades
18. Economizer:-An economizer is essentially a feed water
heater and derives heat from the flue gases for this
purpose. The feed water is fed to the economizer
before supplying it to the boiler. The economizer
extracts a part of heat of flue gases to increase the
feed water temperature. Thus, saving on fuel
consumption to a large extent.
Air pre-heater:-An air pre-heater increases the temperature
of the air supplied for coal burning by deriving heat
from flue gases. The heat is transferred to the air fed
into the boiler for combustion and increases
efficiency.
19. They are used to separate the
ash particles from flue gases. In
this the flue gas is allowed into
the ESP, where there are several
metallic plates. when these gases
enter , a very high potential
difference is applied, which
causes gas particles to ionize
and stick to the plates, whereas
the ash particles fall down and
are collected in a hopper . The
flue gases is allowed to cool
down and is the released to the
chimney.
20. Turbine is the prime mover converting the energy of steam to the
rotation of turbine shaft which in turns rotates the rotor of generator.
In small generation unit (below 100MW) only single stage turbine is
used. But in large generation unit three stage turbine is used.
a. High pressure or (HP) turbine
b. Intermediate pressure or (IP) turbine
c. Low pressure or (LP) turbine
22. Electrical equipments in power plant
Power plant consists of variety of
electrical equipment.
Major electrical equipments are
Alternator, exciters, synchronizing
equipment, Circuit Breakers, current
and potential transformers, relays and
protection equipments, isolator,
lightening arresters, earthing
equipment, station transformer, battery
and motor for driving auxiliaries.
Transformer is the main equipment
used in the power station.
24. Transformer is a static device which
transfers AC electrical power from one
circuit to another without changing the
frequency but the voltage level is
changed.
Cooling OFB OB ON
MVA 130 90 65
KV no-load 230 H.V.
13.8 L.V.
Current (HV) 326.3 A 226 A 163 A
(LV) 5438.5 A 3765 A 2719 A
Phase 3
Frequency 50 Hz
Impedance voltage 12.56%
Vector symbol Yd11
Temperature rise Oil – 40 °C
Winding – 56 °C
The rating of 130 MVA Generator
Transformer
25. In electricity generation, an
electric generator or alternator
is a device that converts
mechanical energy into to
electrical energy.
Maximum KVA rating : 294100
KVA
Maximum KW rating
:250000KW
RPM (revolution/minute) : 3000 rpm
Rated stator voltage : 16.5 KV
Rated stator current : 10291
Amp
Rated power factor : 0.85 Lag
Excitation current :
Specification of Turbo generator
(2x250 MW unit)
26. switch yard
A switching substation, or switchyard, is a substation without
transformers that operates only at a single voltage level.
Switchyards, used mainly for connections and
interconnections, are essential for transmission, distribution,
collection, and controlling the flow of electricity.
The switchyard delivers power generated at the power plant to
the electrical grid.
Switchyards are generally classified by voltage level, circuit
breaker and bus arrangements. Switchyards are often located
directly adjacent to or near a power station.
28. Lightening arrestor
These are used to discharge
lightening over voltages and
switching over voltages to earth.
29. Circuit breaker
A circuit breaker is a mechanical device
used to open and close contact under
loading and un-loading conditions.
30. Relay
Relay is electro-mechanical device
which sense the excessive flow of
current and send signal to the circuit
breaker.
31. These are used to disconnect transmission
line under no load condition for safety,
isolation and maintenance.
32. Current transformer:- It is an instrument transformer
which is used to measure the current from high
voltage line with the use of normal ampere meter.
33. Potential transformer
Potential transformer:- It is an instrument
transformer which is used to measure the
high voltage from an ordinary low voltage
instrument.
34. The porcelain insulators
are used to support the bus-bar
from pole to ground. Current
rating of porcelain is above
2000Amp.
Bus-bar is a main bar or
conductor carrying an electric
current to which many
connections are to be made.
Material used for bus bar is
aluminium because it is high
corrosion resistance than
copper and lower cost. Bus-bar
are of 5 to 6 meter in length.
35. Control room
A control room is a room serving as a centre
where a large power equipment facilities or
services can be monitored and controlled.
