1. INDEX
About company
Evolution of NTPC
Generation Growth
Introduction
Unit overview
Various cycle
Switchyard
Circuit Breaker
Lightening Arrestor
Generator and Protection
Transformer
Boiler
ESP
Coal Handling and Its Parts
Advantages of Coal Handling
Conclusion
2. NTPC-FGUTTP
MAY 2012-13
ABOUT THE COMPANY
Corporate Vision:
“A world class integrated power major,
powering India’s growth, with increasing
global presence”
Core Values:
B-Business Ethics
C-Customer Focus
O-Organizational & Professional pride
M-Mutual Respect and Trust
I- Innovation & Speed
T-Total quality for Excellence
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. At present, Government
of India holds 89.5% of the total equity shares
of the company and the balance 10.5% is
3. EVOLUTION OF NTPC
1975
NTPC was set up in 1975 with 100% ownership
by the Government of India. In the last 30
years, NTPC has grown into the largest power
utility in India.
1997
In 1997, Government of India granted NTPC
status of “Navratna’ being one of the nine
jewels of India, enhancing the powers to the
Board of Directors.
2004
NTPC became a listed company with majority
Government ownership of 89.5%. NTPC
becomes third largest by Market Capitalisation
of listed companies
2010
NTPC Ltd. Has granted of Maharatna status by
Govt. of India. NTPC Ltd. Has been ranked 7th
5. INTRODUCTION
A)Location
Located on Lucknow Allahabad state highway
35 Km from Raebareli
80 Km from Allahabad
120 Km from Lucknow
B)Installed Capacity
Stage I = 2 X 210 MW
Stage II = 2 X 210 MW
Stage III = 210 MW
C)Production Input
Coal Source
Central Coal fields Ltd. ( CCL)
Bharat Cooking Coal Ltd. (BCCL)
Water Source
Sharada Sahayak Canal (main)
Dalmau Pump Canal ( from river Ganga)
6. INTRODUCTION:-
D)Requirements
Coal – 140 tonnes / hr / unit
Water – 700 tonnes/ hr / unit
E)Cost of Generation
Rs. 2.40 / Kwh
F)Environmental Aspects
Water Pollution- Effluents from
thermal discharges from
condenser, wastes from coal
handling plant, service areas, oil,
DM plant, sanitary waste and
effluents from ash pond will be
neutralized before being
discharged.
Air Pollution- Particulate emission
will be limited to 150 mg/Nm3 by
installing high efficiency ESPs.
8. VARIOUS CYCLE
i. Coal Cycle
C.H.P Plant → Bunker →R.C
Feeder → pulverize mill→ Boiler
section
ii. Water Cycle
D.M. Plant → Hot Well → C.E.P.
Pump → Low Pressure heater
1,2,3→Derater → Boiler Feed
pump → High pressure Heater 5,6
→ Feed Regulating station
Economizer → Boiler Drum.
iii. Steam Cycle
Boiler drums → Ring Header →
Boiler Drum (Steam chamber) →
Super Heater → H.P. Turbine →
Reheater → I. P. Turbine → L.P.
Turbine
9. SWITCHYARD
The switch yard is the places from where
the electricity is send outside. We know
that electrical energy can’t be stored like
cells, so what we generate should be
consumed instantaneously. But as the
load is not constants therefore we
generate electricity according to need i.e.
the generation depends upon load. It has
both outdoor and indoor equipments.
Outdoor Equipments
Bus Bar
Lightening Arrester
Wave Trap
Breaker
Capacitor Voltage Transformer
Earthing Rod
Current Transformer
Potential Transformer
Isolators
PLCC
Indoor Equipments
Relays
Control
10. CIRCUIT
BREAKER Circuit breaker is an arrangement by
which we can break the circuit or flow of
current. A circuit breaker in station serves
the same purpose as switch but it has
many added and complex features. The
basic construction of any circuit breaker
requires the separation of contact in an
insulating fluid that servers two functions:
It extinguishes the arc drawn between the
contacts when circuit breaker opens.
It provides adequate insulation between
the contacts and from each contact to
earth.
The insulating fluids commonly used in
circuit breakers are:
Compressed air
Oil which produces hydrogen for arc
excitation.
Vacuum
Sulphur hexafluoride (SF6 )
There are two makes of Circuit Breakers
used at NTPC Unchahar switchyard:
SF6 Circuit Breaker – manufactured by
ALSTOM
Gas Circuit Breaker – manufactured by
12. LIGHTENING ARRESTOR
• It saves the transformer and reactor
from over voltage and over currents. We
have to use the lightning arrester both in
primary and secondary of transformer and
in reactor
Green – arrester is healthy
Red – arrester is defective
13. GENERATOR
The transformation of mechanical energy into
electrical energy is carried out by the generator.
The generator also called the alternator is
based upon the principle of electromagnetic
induction. This is a doubly excited system and
the field is excited from dc supply whereas the
output received from the alternator is ac
MAIN COMPONENT:-
1)ROTOR AND ROTOR WNDG
2)STATOR,FRAME,CORE,WNDG
Excitation System
Static Excitation System-The generators in
stage -1(u-1&u-2) have this excitation system.
Static excitation system has slip ring and
carbon brush arrangement. It consists of step
down transformer, converter and AVR
(automatic voltage regulator).
Brushless Excitation System –The
generators in stage -2(U-3, U-4& &U- 5) have
this excitation system. It has two exciters, one
is main exciter and other is pilot exciter.
14. GENERATOR
PROTECTION:- Stator Protection- The neutral of star
connected winding is connected to primary of
neutral grounding transformer, so that earth
fault current :
GENERATOR COOLING:-
Water as well as hydrogen cooling is present
in stage-I turbo generators with following
specification
Rotor cooling: Hydrogen gas pressure: 3.5
Kg/cm2, Purity: 98%
Stator cooling: Water pressure: 3.5 Kg/cm2,
Rate of flow of water: 130 m3/hr
Stage-II & III:
Only hydrogen cooling is used for both
stator and rotor cooling.
Rotor cooling: Hydrogen Stator cooling:
Hydrogen gas pressure: 2.0 Kg/cm2, Purity:
RotorProtection-Rotor winding may be
damaged by earth faults or open circuits. The
field is biased by a dc voltage, which causes
current to flow through the relay for an earth fault
anywhere on the field system
15. TRANSFORMER
The transformer is a device that transfers electrical
energy from one electrical circuit to another
through the medium of magnetic field and without
the change of frequency. It is an electromagnetic
energy conversion device, since the energy
received by the primary is first converted to
magnetic and is then reconverted to electrical
energy in the secondary
ACCESSORIES:-
1)CONSEVATOR
2)BREATHER
3)BUSHING
4)RELAY
5)TAP CHANGER
COOLING:-
Simple Cooling
Natural cooling by atmospheric circulation, without
any special devices. The transformer core and
coils are open all round to the air. This method is
confined to very small units at a few kV at low
voltages
Mixed Cooling
with alternative additional air-blast cooling.
16. MAIN TRANSFORMER:-
Generator Transformer: -- This is a
step up transformer. This supply gets
its primary supply from generator and
its secondary supplies the switchyard
from where it is transmitted to grid.
This transformer is oil cooled. The
primary of this transformer is
connected in star. The secondary is
connected in delta. These are five in
number.
Station Transformer: --This
transformer has almost the same
rating as the generator transformer.
Its primary is connected in delta and
secondary in star. It is a step down
transformer. These are 4 in number.
Unit Auxiliary Transformer: -- This is
a step down transformer. The primary
receives from generator and
secondary supplies a 6.6 KV bus.
This is oil cooled. These are 10 in
number.
Neutral Grounded Transformer: --
This transformer is connected with
supply coming out of UAT in stage-2.
This is used to ground the excess
voltage if occurs in the secondary of
17. BOILER
The boiler used at FGUTPP is the water tube boiler
type in which, water circulates in tubes surrounded by
fire. Hence it takes up heat and gets converted into
steam. The steam then rises up and gets collected
inside the boiler drum. The boiler is made up of carbon
steel. The temperature of steam that comes out of the
boiler is around 530 deg Celsius and its pressure is
120kg/cm2.
Soot blowers are basically pipe like structures that go
inside the furnace and the boiler for efficient on load
cleaning. Cleaning is done by the superheated steam
which is tapped from the super heater for the purpose
of soot blowing. The pressure is reduced to 31kg/cm2
at 330 deg Celsius by means of reducing valve. We
mainly have three types of soot blowers:
long retraceable soot blower
wall blower
air Reheater
Before sending this steam to the turbine, the steam is
again superheated and then its temperature is around
580deg Celsius
19. ESP:-
The ash content in the Indian coal is of the order
of 30 to 40 %. When coal is fired in the boiler,
ashes are liberated and about 80% of ash is
carried along with the flue gases. If this ash is
allowed to flow in the atmosphere, it will cause air
pollution and lead to health troubles. Therefore it is
necessary to precipitate the dust from the flue
gases and this work is done by the electrostatic
precipitator.
Working principle
The principle upon which an electrostatic
precipitator works is that dust laden gases are
passed into a chamber where the individual
particles of dust are given an electric charge by
absorption of free ions from a high voltage DC
ionising field. Electric forces cause a stream of
ions to pass from the discharge electrodes
(emitting) to the collecting electrodes and the
particles of ash in the gas are deflected out of the
gas stream into the collecting surfaces where they
are retained by electrical attraction. They are
removed by an intermittent blow usually referred to
as RAPPING
21. COAL HANDLING:-
Introduction
NTPC Unchahar gets its coal supply mainly from
Bihar. Now coal is also coming from Australia, as
coal produced in India is of low grade and ash
content is more. The coal being filled in the
wagons of the rail reaches plant. The purpose of
this plant is to convey the coal to the bunker in
the size not larger than 20mm.It handles and
transports the coal to the bunker from the
wagons by passing through various conveyors,
transfer points, crusher houses, etc.
BCCL costs Rs.4/kg
CCI cost Rs.6/kg
Properties of Coal
Calorific value: the heat evolved when unit
amount of coal is burned.
Gross calorific value: the heat evolved when all
the products of combustion are cooled to the
atmospheric temperature.
Net calorific value: it is the value obtained when
GCV is subtracted by sensible and latent heat of
water in the products of combustion.
Grindablity: it is the ease with which the coal
can be ground to fine sizes. It is measured on the
hard grove scale. Coal used here has a
Grindablity index of 55.
22. COAL HANDLING:-
Coal analysis
It is done in two ways:
Proximate analysis: it gives the behaviour of coal when
heated.
Ultimate analysis: it tells the elementary composition of
coal. It is useful in determining the air required for
combustion and in finding the weight of combustion
products
Different methods of unloading the coal
Manual Unloading: - Previously, manpower was used for
unloading the wagons.
But it was very time consuming and more workers were
required for the job to be done.
2. Box in (using wagon tippler for unloading): - This
method is still used in stage-1 of NTPC Unchahar. For
this method, Indian Railway grants 10 hours for unloading
the 58 wagons. In this method, Wagons are separated and
tippled by using wagon tippler. The Beetle Feeder is used to
move the wagon on wagon tippler. The coal from the
wagons gets accumulated in The Track Hopper. At this time;
the size of the coal is approximately 300mm.
3. BOBR: - This method is used in used in stage -2
and stage-3 of NTPC Unchahar. Indian Railway grants only
2.5 hours for Unloading 58 BOBR wagons. This is an
advanced technology in which we use the compressor
system. In Bottom Open Bottom Release (BOBR)
technology the wagons are opened from side. Pressure is
applied by the compressor to open the bottom gates of the
wagon so that the coal gets released over the track hopper
and wagon get unloaded quickly.
23. PARTS OF CHP:-
Marshalling Yard: it consist of railway tracks
provided to receive the loaded trains, to unload
them and to put them back in formation without
interference between loaded and empty racks.
Wagon Tripler: The wagon Tripler is a most
important device in thermal power Project
Paddle Feeder: - They have been installed on
conveyors below the manual unloading track
hopper. There are 6 nos. of paddle feeders, 3 on
each conveyer. 3 Paddle Feeders of each
conveyer move to and fro within a limiting range.
Vibrating Feeder: - They have been installed
below the track hoppers of wagon tippler. The
coal is accumulated over the vibrating feeder so
by giving vibrations to the vibrating feeder we
discharge the coal from track hopper to the
conveyors.
Transfer Points: - Transfer Point is provided
with flap gate and Conveyer. In transfer Point the
coal is transferred from one conveyer to other
conveyer.
Flap Gate: - The flap Gate is a two-way device. It
consists of two gates. Both gates cannot operate
together. By help of the flap Gate, we change the
way of coal that fall down on the conveyer
24. CHP:-
Conveyers: - The Conveyer Belt is a moving
device. It travels on its platforms. The shape of the
conveyer belt is to be flat but on the platforms it is
to be in curve shape. The coal falls down the
conveyer and goes to the primary Crusher House
Platforms. The capacity of conveyer in Stage – I is
800MT/ hr. & in Stage –II is 1200MT / hr.
•Primary crusher (rotary breaker): - In Primary Crusher
House, the coal breaks in Rotary Breaker. Here the coal comes
from the Transfer point; breaks here and the stone fall down to a
separate place. Coal is converted from 300mm to 150mm size.
•Secondary Crusher (Ring Granulator): - In Secondary
crusher House first the magnetic part separate from the
coal and then feed to the Secondary Crusher. This
Crusher breaks the coal in 20mm size and coal is sent to
the Flap Gate and then feeded to the conveyer.
25. CHP:-
Coal handling
•Magnetic separator: - They will remove the ferrous
particles, which passes along with the coal. It consists of
electromagnet around which a belt is moving. It is
suspended from top, perpendicular to the conveyor belt at
certain height. Whenever any iron particle passes below
the CBMS, it is attracted by the magnet and stick to the
cross belt below it. The CBMS capacity is of 50kg.
•Metal Detector: - The purpose of installation is to detect
any metallic piece passing through the conveyor.
Whenever the pieces pass below the search coil of the
metal detector, it gives the trip command to the conveyor.
Simultaneously, sand bag marker will fall on the
conveyor belt so that the metal can be searched easily and
removed.
Stacker/Reclaimer: - It is a very important device. The
whole Structure of it is called Super Structure. It stacks
the excessive coal and reclaims the coal on its
requirement
26. CHP:-
Advantages:
It can operate at full load
capacity in bad weather.
It is productive at all times as no
return journey is to be
performed.
DISADVANTAGE:
The only drawback is that it is
expensive
27. CONCLUSION:-
NTPC Unchahar is one the
plants in India to be under
highest load factor for the
maximum duration of time and
that to operating at highest plant
efficiencies. This plant is an
example in terms of working
efficiency and management of
resources to all other thermal
plants in our country. The
operating plf of the NTPC as
compared to the rest of country
is the highest with 87.54% the
highest since its inception.
The training gave me an
opportunity to clear my concepts
from practical point of view with
the availability of machinery of
diverse ratings.