1. Dr. NARLA TATA RAO
THERMAL POWER
STATION
POWER PLANT FAMILIARIZATION -2016
INDUSTRIAL IN-PLANT TRAINING REPORT
COURSE CO-ORDINATOR
MR. GOPI KRISHNA
SUBMITTED BY: BATCH-8

2. ACKNOWLEDGEMENT
We wish to extend our profund and sincere thanks to VTPS management as
without their support, this training have been a distinct dream.
We also acknowledged to the corporationauthority of Vijayawada Thermal Power
Station for their permission to visit the plant and their support. Specially we are
very much thankful to the All-chief engineers for all detailed information they
have provided about the working and other components of the power plants.

3. INDEX
SERIAL
NO.
NAME OF CHAPTERS
1. Abstract
2. Introduction
3. Purposeof visit
4. Details of TPS
5. Block Diagram of TPS
6. Working of VTPS
7. Equipments required in VTPS
8. Generator
9. Transformer
10. Switchyard
11. Control Room
12. Cooling
13. Advantages &disadvantages
14. Conclusion
15. Reference

4. ABSTRACT
Thermal Power
A thermal power station is a power plant in which heat energy is
converted to electric power. Water is heated, turns into steam and
spins a steam turbine which drives a generator. After it passes through
the turbine, the steam is condensed and recycled to where it was
heated; this is known as a Rankine cycle.There are different types of
thermal power plant in India based on fuel used to generate the steam
such as coal, gas, diesel, etc. About 75% of electricity consumed in India
is generated by thermal power plants.
Coal
More than 51% of India’s commercial energy demand is met through the
country’s vast and massive coal reserves. A coal based thermal power
plant converts the chemical energy of coal into electrical energy. This is
done by raising steam in boiler, expanding it through turbine and
coupling the turbines to generators which converts mechanical energy
into three phase AC electrical energy.

5. Introduction
 Andhra Pradesh Power Generation Corporation Limited is power
generating organization in Andhra Pradesh. It undertakes
operation and maintenance of the power plants and also setting
up new power projects alongside upgrading the project's
capacity..
 The total installed capacity of APGENCO, after the formation of
TSGenCo is 4559.6 MW comprising 2810 MW Thermal, 1747.6
MW Hydro and 2 MW Wind power stations. The Power Plants of
APGENCO include thermal, hydel and wind based plants.
 The performance of APGenCo thermal power stations in terms of
reliability, availability and maintainability is one of the best in
India.
A] Thermal projects
Dr Narla Tata Rao Thermal RayalaseemaThermal PowerStation
PowerStation

6. 2] Hydel projects
Srisailamdam Tungabhadradam
Sr. No. Project InstalledCapacity (MW) Total (MW)
1 Chettipeta Mini Hydel 2 x 0.5 1
2 Donkarayi PH 1 x 25 25
3 Hampi Dam PH 4 x 9
(AP Share – 28.8)
28.8
4 Lower Sileru PH 4 x 115 460
Sl.
No.
Project Capacity
(installed / under construction)
(MW)
Total (installed)
(MW)
1 Dr. Narla Tata Rao
TPS
6×210 + 1×500 (Stage IV) 1760
2 Rayalaseema TPP 5×210 + 1×600 (Stage IV, Unit-6
under construction)
1050
Overall capacity 3410.00 2810.00

7. Sr. No. Project InstalledCapacity (MW) Total (MW)
5 Machkund PH 3 x 17 + 3 x 23
(AP Share – 84)
84
6 Nagarjuna Sagar RCPH 3 x 30 90
7 Penna Ahobilam PH 2 x 10 20
8 Srisailam RBPH 7 x 110 770
9 Tungabhadra Dam PH 4 x 9
(AP Share – 28.8)
28.8
10 Upper Sileru PH 4 x 60 240
Overall capacity 1747.6
3] Non-conventionalunits
Sl. No. Project Inst.Capacity
(MW)
Total
(MW)
1 Ramagiri Wind Mills 10 x 0.2 2.0
Overall capacity 2.0

8. Dr. Narla Tata Rao Thermal Power Station is also known Vijayawada
Thermal Power Plant. It was developed under 4 stages, with the project
cost of Rs 193 Crores and Rs 511 Crores respectively. Again with an
investment of RS 840 Crores 2 units were commissioned under III Stage.
The seventh unit of 500 MW was commissioned in 2009. The station
stood first in country during 94-95, 95-96, 96-97, 97-98 and 2001-02 by
achieving the highest plant load factor. The station has received many
prestigious awards from various organizations.
Purpose of Visit
The main reason to visit the power plant was to understand and get
complete knowledge about practical overview of energy generation
plant. Since we are to study the theoretical working and details about
various thermal plants in our syllabus, this visit helped us to correlate
between the various equipments and parameters used in actual power
generation technique with the one given in books.

9. WORKING OF THERMAL POWER PLANT
The thermal power station converts heat energy of coal into electrical
energy. The coal handling plant supplies coal to the boiler. The ash
formed in the boiler is disposed of by ash handling plant. Air is taken
from atmosphere by primary and forced draft fans and thus air is heated
in preheated before fed to the boiler. The flue gases pass through the re-
heater, superheater, and economizer, air preheater and electrostatic
precipitator before being discharged to the atmosphere through chimney.
The boiler vaporizes water into wet steam which is further heated in
super heater and fed to the high pressure turbine. After expanding the
steam is reheated again in the boiler and fed to the intermediate pressure
turbine. The exhaust steam from low pressure turbine is condensed by
condenser as shown in fig and condensate along with the makeup water
is passed through economizer before being fed to the boiler. In this way
electrical energy is produced by rotating turbine using steam which is
coupled to the alternator of required rating.
UNITS in Dr. NTTPS
The total installed capacity of VTPS is 1760 MW. This TPS consist of 6
units of 210MW and 1 unit of 500MW. It is having reserved unit of one
500MW which is commissioned in 2016 but not yet in working. We
have visited and given all the information about these 6 units of
210MW. Some comparisons of parameters between 500MW and
210MW details were also given to us. As soon as we entered there this
we noticed the greenery of campus as around 1, 34,000 trees were
planted during erection of this plant.

10. Coal handling Plant (CHP)
In a coal based thermal power plant, the initial process in the power
generation is “Coal Handling”.
Plant was designed for bituminous coal (70% from Talcher mines and
30% is imported from Singapore and Indonesia). Bituminous is second
best, hardest form of coal. Such coals may contain ash, moisture and
volatile material, and hence there is a need for pulverisation. The firing
systems also differ for different grades of coal.
The huge amount of coal is usually supplied through railways. A railway
siding line is taken into the power station and the coal is delivered in the
storage yard. The coal is unloaded from the point of delivery by means
of wagon tippler. It is rack and pinion type. The motor used for tippling
is a slip ring induction motor. The coal is taken from the unloading site
to bunker by belt conveyors.
The transfer points or junction towers are used to transfer coal to the
next belt.
The belt further elevates the coal to the transfer point and it reaches the
crusher through belt. In the crusher a high-speed 3- phase induction
motor is used to crush the coal to a size of 20mm so as to be suitable for
milling system. Coal rises from crusher house and reaches the bunker by
passing through transfer point.
1. Pulveriser: Pulverization is a mechanical process for grinding of
different types of material. For example, they are used to pulverize
coal for combustion in steam generating furnaces of thermal power
plants. There are various types of mills such as ball and Tube mills,
Ring and ball mills, demolition. The pulveriser reduces the coal
size to 74 micron which is then sent to the boiler through the
secondary air.
2. Dryers: They are used in order to remove moisture from coal

11. mainly wetted during transport. As the presence of moisture will
result in fall in efficiency due to incomplete combustion and also
result in CO emission.
3. Magnetic separators: Coal which is brought may contain iron
particles. This iron particle may result in wear and tear. The iron
particles may include bolts, nuts wire fish plates, etc so this is
unwanted and removed with the help of magnetic separators which
are usually placed above the conveyer belts.
Stacker-Reclaimer

12. Boiler
The water-tube boiler is about 65 feet tall. Its walls are made of a web of
high pressure steel tubes.
Pulverized coal is air-blown into the furnace through burners located at
the four corners and it is ignited to rapidly burn, forming a large fireball
at the centre(tangential firing). The thermal radiation of the fireball heats
the water that circulates through the boiler tubes near the boiler
perimeter. As the water in the boiler circulates it absorbs heat and
changes into wet steam. It is separated from the water inside a drum at
the top of the furnace by turbo separators. The saturated steam is
introduced into superheater that hangs in the hottest part of the flue
gases as they exit the furnace. Here the steam is superheated to 540 °C
to prepare it for the turbine.
Boiler auxiliaries are used to increase the efficiency of its working. They
are-
A] Economizer: It is located in the boiler. It is there to improve the
efficiency of boiler by extracting heat from flue gases to heat water and
send it to the boiler drum.
Advantages of economizer include:
1. Fuel economy: - Used to save fuel and to increase efficiency of
boiler plant.
2. As the feed water is pre heated in the economizer and enter boiler
tube at elevated temperature, it reduces thermal stresses.
3. Optimum usage of heat of the flue gases.
B] Superheater: It super heats the wet steam from the drum to dry
super-saturated steam which then drives the HP turbine.

13. Advantages:
1. Increases the efficiency
2. Protects the turbine blades from corrosion.
3. Optimum usage of heat from flue gases.
C] Re-heater: it reheats the steam from the HP turbine before sending
it to the IP turbine.
Advantages:
1. Increases the efficiency
2. Protects the turbine blades from corrosion.
3. Optimum usage of heat from flue gases.
ECONOMISER

14. Steam Turbine
The turbine generator consists of a series of steam turbines
interconnected to each other and a generator on a common shaft. There
is a high pressure turbine at one end, followed by an intermediate
pressure turbine, a low pressure turbine, and the generator. As steam
moves through the system and loses pressure and thermal energy it
expands in volume, requiring increasing diameter and longer blades at
each succeeding stage to extract the remaining energy. It is so heavy that
it must be kept turning slowly even when shut down (at 3 rpm) so that
the shaft will not bend even slightly and become unbalanced. This is so
important that it is one of only six functions of blackout emergency
power batteries on site. Other functions are emergency lighting,
communication, station alarms, generator hydrogen seal system, and
turbo-generator lube oil.
Superheated steam from the boiler is delivered to the high pressure
turbine where it falls in pressure to 39kg/sq.cm and to 320 °C in
temperature through the stage. It exits cold reheat lines and passes back
into the boiler where the steam is reheated in special re-heater tubes
back to 1,000 °F (540 °C). The hot reheat steam is conducted to the
intermediate pressure turbine where it falls in both temperature and
pressure and exits directly to the long-bladed low pressure turbines and
finally exits to the condenser.
Condenser
The condenser condenses the steam from the exhaust of the turbine into
liquid to allow it to be pumped. If the condenser can be made cooler, the
pressure of the exhaust steam is reduced and efficiency of the cycle
increases. The function of condenser is
1. To provide lowest economic heat rejection temperature for steam.

15. 2. To convert exhaust steam to water for reserve thus saving on feed
water requirements.
3. To introduce make up water.
The heat absorbed by the circulating cooling water in the condenser
tubes must also be removed to maintain the ability of the water to cool
as it circulates. This is done by pumping the warm water from the
condenser that reduce the temperature of the water by evaporation, by
about 11 to 17 °C (20 to 30 °F)—expelling waste heat to the atmosphere.
1] Ejectors: From the condenser the water then goes to the main air
ejector through the condensate extraction pump to extract non
condensing gases. Then the water is then sent to the low pressure heaters
which are 2 in number and is then sent to deaerator.
2] Deaerator: Its function is to remove dissolved non-condensable gases
and to heat boiler feed water.
3] Boiler Feed Pump: It is provided for pumping feed water to
economiser. There is also a feed water storage tank to store the water
when not needed

16. Generator
The generator voltage for modern utility-connected generators ranges
from 11 kV in smaller units to 22 kV in larger units. The generator high-
voltage leads are normally large aluminium channels because of their
high current as compared to the cables used in smaller machines. They
are enclosed in well-grounded aluminium bus ducts and are supported
on suitable insulators. The generator high-voltage leads are connected to
step-up transformers for connecting to a high-voltage electrical
substation (usually in the range of 115 kV to 765 kV) for further
transmission by the local power grid.
The necessary protection and metering devices are included for the high-
voltage leads. Thus, the steam turbine generator and the transformer
form one unit. Smaller units may share a common generator step-up
transformer with individual circuit breakers to connect the generators to
a common bus.
GENERATORAUXILARIES: The generator in the 210 MW generates a
voltage of 15.75kV of which the auxiliaries in the plant take about 6.6
kV through the unit auxiliary transformers.
There is also a station transformer which takes power from the grid
directly in case of emergencies. The station transformers are designed to
be able to withstand the entire unit auxiliary’s requirements.

17. Ash handling plant
Slag and ash falling from the furnace are temporarily stored in the
bottom ash silo. They are then sent to the ash pond using a hydro ejector.
Alternatively, they are sent back to the bottom ash silo to be recycled
after going through a submerged drag chain conveyor or dry ash
extraction conveyor.
 Bottom Ash Hopper System utilizing Hydro-ejector’s
 Dry Ash Extraction System.
For the Fly Ash Handling for power plants, pneumatic conveyor system
have world-widely been applied (ESP, Bag Filter, Etc.). The fly ash
handling system transports the ashes pneumatically with the compressed
air from blower or air compressor through it.
Ash Disposal System: The bottom ash, coarse ash and fly ash lead to the
common slurry sump. Wet ash can be used by cement industries and
extra wet ash is disposed in ash ponds which on filling are converted
into parks.
Control Room
The control room, in case of remote control, houses all the necessary
measuring instructions for each panel or alternator and feeder,
synchronizing gear, protective gear, automatic voltage regulator,
communication arrangement etc.
Types of Control panel
 Fuel gas panel
 Combustion Panel

18.  Primary Air and coal panel
 Steam panel(boiler)
 Feed Water panel
 Condensate & cooling water panel
 Turbo-supervisory panel
Switch yard
EHV Substation at VTPS:
1) 220 kV Switchyard
2) A) 220 /132 kV SS; B)132 kV SS
3) 400 kV Switchyard
The 220 kV switchgear comprises of the following equipment:.
1) C.T’s and P.T’s
2) ISOLATOR
3) CIRCUIT BREAKER
4) LIGHTNING ARRESTOR
5) CVT
6) Wave trap (included in PLCC)
7) BUS BARS
8) Bus coupler
Tasks of the switchyard:
 Protection of transmission system
 Controlling the exchange of power
 Maintain the system frequency within targeted limits
 Determination of power transfer through transmission lines
 Fault analysis and subsequent improvements
 Communication

19. SWITCHYARD
Advantages and Disadvantages of thermal power
stations:
Advantages:
1. Economical for low initial cost other than any generating plant.
2. Land required less than hydro power plant.
3. Since coal is main fuel and its cost is quite cheap than petrol or
diesel so generation cost is economical.
4. These are having easier maintenance.
5. Thermal power plant can be installed in any location where
transportation and bulk of water are available.
Disadvantages:
1. The running cost for a thermal power station is comparatively
high due to fuel maintenance etc.

20. 2. Large amount of smoke causes air pollution. The thermal power
station is responsible for global warming.
3. Overall efficiency of thermal power plant is low like 30%.
Conclusion:
After visiting this power station I came to know about the practical
generation process of electrical energy. I understood the function of
various components in thermal power station, there importance, there
arrangements and precaution to be used for the safety in the power
plants. This experience gave us good exposure to the industries- tied
branches of engineering. This visit to VTPS was an exciting experience,
since the hard work of APGENCO and mutual cooperation of their staff
and workers is really appreciable. I would like to thank our staff
members for arranging this quality visit.
REFERENCES:
1. www.apgenco.gov.in
2. Google, Wikipedia
3. Course material on Power plant familiarization-
APGenCo