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SUMMER TRAINING AT
PANKI THERMAL POWER STATION
PTPSKANPUR
UPRVUNL
SUBMITTED BY: SUBMITTED TO:
SHAILENDRA PRATAP SINGH Mr. T.C.GUPTA
B.TECH, 3rd YEAR EXECUTIVE ENGINEER
MECHANICAL ENGINEERING MAINTENANCE AND
PLANNING DIVISON
(MPD)PTPS,KANPUR(U.P)
ROLL NO. : 1004540046
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HARCOURT BUTLER TECHNOLOGICAL INSTITUTE,
KANPUR-208002
ACKNOWLEDGEMENT
I am extremely thankful to the members of Panki Thermal Power Station
(PTPS), Kanpur for their kind support and co-operation during my 4 weeks
of training period.
I would like to acknowledge Mr. T.C.Gupta(Assistant Engineer,
Maintainance and Planning divison (MPD IV) for giving me this fortunate
chance to learn the various applications of mechanical engineering in reallife. I express my sincere gratitude towards him for his wonderful guidance
in the department and making me understand the various stages of thermal
power generation.I also express my respectful gratitude towards all other
engineers and technical staff at MPD for their help and guidance during my
training period.
Finally, I thank all those who have helped me in the success of my training
program. They have added a lot to my knowledge.
SHAILENDRA PRATAP SINGH
B.Tech 3rd year
Mechanical Engineering
HBTI Kanpur
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CERTIFICATE
It is certified that SHAILENDRA PRATAP SINGH, student of 3rd B.Tech
Mechanical Engineering H.B.T.I. Kanpur has worked on the Project on
PTPS Kanpur under my guidance and supervision. He has shown sincere
efforts and keen interest during preparation of this project report. My best
wishes are with him, his efforts and his future endeavours.
Mr. T.C.GUPTA
Assistant Engineer
MPD IV
PTPS Kanpur
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INDEX
S. NO. CONTENTS PAGE NO.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Acknowledgement
Index
Introduction
Organisational Set-up
Various divisions for effective working of PTPS
Water Treatment Plant
Boiler and Boiler auxiliaries system
Oil Handling Plant
Coal Handling Plant
Milling System
Coal firing system in the boiler furnace
Details of Boiler at PTPSSpecifications of the boiler
Steam generating units and auxiliaries
Technical specifications of the Milling Plant and
Fuel Firing System
2
4
6
8
11
13
15
15
16
17
19
2023
25
28
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15.
16.
17.
18.
19.
Turbine Maintenance Department (TMD)
Compounding of the steam turbines
Governing system of turbine
Turbine protection testing
Turbine oil pressure regulating system
Specifications of 110 MW Turbine
Important features of Turbine
Electronic instruments useful for the plant
Training in Electrical Maintenance Division (TMD)
Rating of Transformers of Unit 3 and Unit 4Current Transformer (CT)
Potential Transformer (PT)
Generator and Exciter
Introduction to Switch gears, Circuit Breakers and
Relays
Devices used for circuit breaking (making)
Fuse and Iron Clad Switches
Isolators
Circuit BreakersThermal Relays
Grid Substation
Wave Trap
Switch Yard
Tracks for Transformer
Control & Instrumentation Division
Various instruments of the C & I department
Turbo Supervisory equipments
Water Pollution Control
Air Pollution Control
Conclusion
30
31
31
31
32
33
34
34
35
3536
36
37
38
38
38
38
3942
43
44
44
44
45
45
46
4850
52
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INTRODUCTION
In India there is a very long chain of thermal power project including the
project in UP. Some of the power projects under Uttar Pradesh Rajya
Vidyut Utpadan Nigam Ltd. (UPRVUNL) are as follows:
S.No. Name of Power Project No. of Units Capacity(MW)
1 Harduaganj A 3 90
2 Harduaganj B 4 2103 Harduaganj C 3 230
4 Panki, Kanpur 2 210
5 Obra 8 550
6 Obra ext. 5 1000
7 Anpara 3 630
8 Anpara ext. 2 1000
9 Pariksha 2 220
Panki Thermal Power Station:
With the industrial development of Kanpur, a thermal power station was
established at the banks of river Ganga, in the year 1923, which was known
as Riverside Power House (RPH). In the year 1947, RPH was taken over
by the Government of UP under the name of Kanpur Electricity Supply
Administration (KESA). In 1962, RPH reached its maximum capacity of
100 MW leaving no scope of future development. Government of India
approved setting up of power station having capacity of 64 MW (2x32 MW).
The new plant was inaugurated on 17 Sep 1968 by the Prime Minister, Smt.Indira Gandhi.
In the year 1976, two units of 110 MW each were installed to meet the
increasing power demand. These units were inaugurated on 30 Jun 1976, by
the Chief Minister of UP, Mr. N.D.Tiwari.
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At present 2x32 MW units are not operating due to not having the suitable
Pollution control machinery. The Central government has commissioned a
210 MW unit at Panki Power Station.
At PTPS, 2x105 MW BHEL made coal fired turbo generating units are
presently in operation. These 105 MW machines were manufactured,
supplied and commissioned by M/s BHEL, during 1976-77 with features of
reheating and regenerative feed heating. The Steam Generator is balanced
draft, radiant, dry bottom, single drum, natural circulation, vertical water
tube type construction with skin casing and semi direct type of firing system.
Apart from the above 105 MW units, 2x32 MW Russia made turbo
generating units were also installed at PTPS in 1967-68, however these units
have become obsolete and permanently closed now after running for about
30 years.
Location:
PTPS is located in the West Kanpur in between Kalpi Road & the famous
Grand Trunk Road and is 16 km distant from the Kanpur Central Railway
Station. It is situated on the banks of lower Ganga canal and is connected
with the Panki railway station for the easy transportation of coal.
Availability of Raw Material at PTPS:
The main raw materials used in the plant are as follows:
Raw Material Source
Water Lower Ganga Canal
Coal Jharia Mines of Coal India Ltd., Bihar
Petroleum Products Indian Oil Corporation Ltd., Kanpur
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ORGANISATIONAL SET-UP
CHAIRMAN
DIRECTORS
GENERAL MANAGER
DGM (1) DGM (2) DGM (3) DGM (4)
Operation & Electrical Coal Handling Headquarters
Maintenance Stare & Civil
DGM(I)
Operation Group Maintenance Group
EE EE EE EE EE EE EEGP(A) GP(B) GB(C) GP(D) TMD BMD OPERATION
GENERAL
AE AE AE AE AE AEAE AE AE AE AE AE
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AE AE AE AE AE AE OG1 OG2
AE AE AE AE AE AE AE AE
AE AE
DGM (2) (ELECTRICAL)
Control & EMD EDD Central Purchase
Instrumentation Division
EE EE EE EE
AE AE AE AE AE AE AE AE AE AE AE AE AE AE
AE
DGM (3)
EE EE EE Transport Central
EFFI TRM Division Purchase Division Division
AE AE AE EE AE
AE AE
AE
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HQ
Store Division Power House Dispensary Civil Maintenance Division
AE AE AE AE AE AE
AE AE
ADMINISTRATIVE STRUCTURE OF PTPS
Employee of factory : GM
Circle officer : Superintending Engineer
Divisional officer : Executive Engineer
Sub-divisional officer : Assistant Engineer
Staff : Operators, Technicians & 4
th
class employee
The whole set up of management is known as a circle. The total number of
employees in PTPS is 1536.
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VARIOUS DIVISIONS FOR EFFICIENT WORKINGOF PTPS
Water Treatment Plant (WTP):
This division separates the physical and chemical impurities of water.
Coal Handling Division (CHD):
This division takes care of efficient supply of coal and oil fuel to the power
plant.
Boiler Maintenance Division (BMD):
This division looks after the efficient working and performance of boiler, its
mounting, its accessories, feed pump, milling system etc.
Turbine Maintenance Division (TMD):
This division looks after the efficient working of turbine and its accessories.
Electrical Maintenance Division (EMD):
This division takes care of the electrical networks and its elements in the
power station.
Control and Instrumentation Division (C & I):
This division takes care of various instruments fitted in the power plants for
controlling the generation of electricity.
Electrical Distributors Division:
This division looks after the distribution of produced electricity to the grid.
Civil Maintenance Division:This division looks after the construction and maintenance of various
structures in the power plant.
Operation General Division (OG 1):
This division takes care of the sanitation and cleaning etc of the power plant.
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Operation General Division (OG 2):
This division is responsible of the management of the power station. It deals
with the salaries of employees, recording and sending data related to the
performance of the power plant to the Head Office.
Store and Purchase Division:
This division deals with the storage and supply of various spare parts
requires in the power house along with their purchase.
Transportation Division:
This division looks after the transportation of coal.
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WATER TREATMENT PLANT
The water treatment plant is required as the water from canal cannot be
directly used in the boiler because it contains physical and chemical
impurities which have an adverse effect on plant operation. The turbidity of
this canal water is 80. The water used in the boiler is Demineralised water
(i.e. DM water).
Water from the canal is drawn by the pump house where large physical
impurities are operated by a screen having a net. This water is converted into
DM water in the following stages:
Flculator Plant:
In this plant the alum is added to water to precipitate dust particles in water.
Aluminium in alum neutralizes charge dust particles and dust particles
become very heavy and settle down. Bleaching powder and limestone is also
added to remove temporary hardness along with chlorine (liquid), which
removes bacteria and organic matter. Chlorine dosing is must during rainy
days. The process of sedimentation is applied to remove heavier particles.
Water is now stored in CST (Condensate Storage Tank).
Note: PAC (Poly Aluminium Chloride) is used instead of alum, when the
impurities in the canal water are more than a reasonable limit, especially
during the rainy season.
Clarifying Pump House:
It consists of five clarifying pumps, four service water pump and two
dividing pumps. Form the clarify pump house, the water goes to the
condenser and the sand filter.
Sand Filter:
These stages are put across the flow of water so as to remove other
suspended particles, if any. Now the turbidity of water is 2-3.
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Activated Carbon Filter:
This filter is employed for removal of bacteria and organic matter through
oxidation. It uses anthracite coal for filter. The turbidity of the water
obtained here is 1-2.
Cation exchanger:
At this stage, the ions (Ca, Mg, Fe) are absorbed by an ion exchange method
liberating H+ ions. HCl and resin (-ve) are principal ingredients of chemical
filters present here. Here the hardness of the water is removed.
Weak base anion exchanger:
Here the weak bases (acetic acid, carboxylic acid etc.) are absorbed by
carefully releasing OH- ions.
Degasser:
Here the gases like CO2, O2 and H2 are removed.
Strong base anion exchanger:
Here a resin is used which absorbs strong anions like SO 42-, Cl2-, phosphate
ion, silica etc. and releases OH-.
Mixed Bed Exchanger:
Here the remaining ions are extracted through both cation and anion resin.
The demineralised water is now ready which has the following
specifications:
Conductivity : 0.004 siemens/cm2
pH : 8.5-9
The desired pH in clear water is between 8.5 and 9. Phosphate dosing is
done at the end for this purpose. The total capacity of water treatment plant
is to provide 60 tonnes of water per hour.
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Low sulphur High stock oil (LSHS)
COAL HANDLING PLANT
A simple schematic diagram of the coal handling plant of PTPS is as shown.
The raw coal (bituminous coal) is brought to the power plant by the means
of railways. The wagon tripplers transfer it into the wagon triple hoppers
(WTH) which empties the coal from the wagons. The wagon capacity is
around 50-60 tonnes. From WTH the coal is transferred to the vibrators, it
separates the stone boulders from the coal from where it is then passed to the
conveyors. The length of the belt is 1000m and speed is approximately 7.2
km/hr.
The conveyor carries around 500 tonnes of coal per hour to crusher house
where the big pieces of coal are separated in a screen and sent to crusher
through conveyor from where the crushed pieces are transferred to other
conveyors. These are smaller particles of size ranging from 20 mm to 40 mm
or below. Then conveyor takes coal from where trippler transfer the coal to
raw coal bunker (RCB).
There are two suspension magnets present over conveyor just before crusher
house. These magnets remove any metallic impurities in the coal moving on
the conveyor belt.
The whole process described is valid when the coal brought by the trains
directly feed the RCB. When there is no train available then the coal comes
from the coal yard. The coal from the coal yard is dropped with the help of
bulldozers in the hopper from where it is transferred to the conveyors and
the process is repeated to carry the coal to the RCB.
When RCBs are full then the coal coming from the wagon trippler hopper,
after being crushed in the crusher house is transferred to conveyor which
carries it to the stacker that spreads the coal in the coal yard with the help of
boom conveyor. The boom conveyor can rotate 360 times on the stacker
which moves itself on a track laid over the length of the coal yard.
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Thus the coal gets stored in the coal yard, which can be used when the train
carrying coal are unavailable. In PTPS, more than one lakh tonnes of coal
can be stored in coal yard.
The coal handling plant also takes care of the storage purification and supply
of fuel oil, which is used for initial lighting up of the boiler furnace, and
generation of constant temperature in the furnace during normal operation.
Mode of operation in Coal Handling Plant:
1. Bunker filling operation: Coal flow from wagon trippler to boiler
house bunker
2. Reclaim operation: Coal flow from stockyard to boiler house bunker
3. Stacking: Coal flow from wagon trippler to stockyard
4. Bunker filling and reclaiming simultaneously
MILLING SYSTEM
A layout of the milling system at the PTPS is as shown in the figure. In a
thermal power plant pulverized coal is used for producing heat in the
furnace. This is because the burning of this state of coal takes place
completely and also there is lesser problem in ash handling. The coal pieces
of size 20 mm to 40 mm are taken from the RCB and through raw coal chainfeeder (RCF) their coal pieces are fed to the ball mills. In the ball mills, there
are steel balls of size 40, 50 and 60 mm and with a net weight of nearly 52
tonnes. These mills rotate about their axis and this makes the balls collide
with the coal pieces to break them into pulverized form.
Ball mills are provided with flue gases at about 300o C that helps drying the
coal and raises its temperature to about 85-90o C. There is a fan in the circuit
called as vapour fan, this fan solves three purposes:
It creates vacuum in the circuit so that the pulverised coal is sucked
out of ball mill with air.
If due to any reasons the supply of coal to the ball mill is broken and
flue gasses are continuously supplied then the temperature of the ball
mill will rise excessively high. To avoid this vapour fan thus
recirculates pulverized coal to the ball mill and so temperature of the
ball mill comes down.
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For cooling dry cold air is also supplied while recirculation. Cooling
is must because if the temperature becomes higher enough then the
coal can catch fire.
Micro particles of coal are directly sucked by the vapour fan with air andsupplied to the furnace chamber for combustion. The pulverised coal from
the ball mills is passed through a classifier that acts as a screen separating
out the bigger particles from the pulverized coal and returning them back to
the ball mill. From the classifiers the coal goes to the cyclone separators
where coal particles are separated from the air. The vapour fan pumps out
the air and the coal particles go to warm conveyor via turnicates. The warm
conveyor delivers the coal to be stored in pulverized coal bunker (PCB).
From PCB the coal goes to pulverized coal feeder that feeds the coal to the
furnace with the help of primary air fan (PAF). This fan takes air from
primary air heater and pushes the pulverized coal from all four corners of thechamber.
Secondary air fan (SAF) supplies hot air (taken from secondary air heater) to
the chamber for combusting the coal properly. Coal is supplied from the all
sides to have a uniform and complete combustion.
In PTPS there are three ball mills and four PCBs for each unit of 110 MW.
From ball mill A, coal can be directly given to PCB A and PCB B via
turnicates. Similarly from mill B to PCB B & PCB C and from mill Cto PCB C & PCB D. For any different combination of ball mill and from
those stated above, warm conveyor is used.
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COAL FIRING SYSTEM IN THE BOILER FURNACE
The steam generating unit has been designed for firing coal and oil at low
loads for stablisation. The fuel firing equipment is designed such that therated parameters would be reached when the fuel is fired. The burners are
located at corners of the furnace tangential to the imaginary circles, having
their centers co-axial with the center of the combustion chamber. At each
corner, there are nine compartments arranged as mentioned below.
There are four coal burner nozzles, three vapour burners and two oil burners
at each corner. The four coal nozzles are provided with air packets, which
flow around the coal fuel system. Each of the engine compartments is
provided with independent air dampers. All the adjustable tips are of
stainless steel to withstand high temperature.
Coal Bunkers:
Total bunkers : 16
Manufacturer : BHEL
Capacity : 3.65 ton/hr
Type : Tilting tangentially
Pulverised coal fired boiler:
With the increase in the size of the turbines, the boiler work also increases.They have to supply steam at a high temperature & pressure and in a bulk
quantity. In such type of the boiler coal is fired in pulverized form, which
has the following advantages:
1. Unlimited output capacity.
2. Even low grade coal can be burned.
3. Even very fine boiler output control is possible.
4. High efficiency.
5. Less possibility if unburned coal.
Fuel Oil System:
In the pulverized fuel fired oil boiler firing is used for safe and quick start up
of boiler ignition of pulverized coal and to bring stability to coal flame under
low output with eight flexible oil guns, two in each corner. The oil guns are
located at the top and bottom of secondary air nozzles and in between coal
nozzles. The oil guns are of pressure atomizing type.
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DETAILS OF BOILER AT PTPS
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A boiler is a closed vessel in which water under pressure is converted into
steam. It is one of the major components of a power plant. It is always
designed to transfer maximum amount of heat to the boiler water by all the
three modes of transformer: convection, conduction and radiation. Boilers
can be classified as water tube boiler and fire tube boiler.
a. Fire tube boiler:
In this type of boiler, products of combustion pass through tubes which
are surrounded by water. Depending on whether the tubes are horizontal
tube boilers they may be internally or externally fed. An internally fed boiler
has grate and combustion chamber enclosed including furnace. The grate is
separate and distinct from the boiler shell.
A fire tube boiler is simple, compact and rugged in construction. Its initial
cost is low. A vertical fire tube boiler occupies less floor space. However,
they are economical only for low pressure and therefore available in small
sizes having steam capacity of about 15,000 kg/hr.
b. Water tube boiler:
In this boiler, water flows inside the tubes and hot gases flow outside the
tube. The tubes are interconnected to common water channels and to steam
outlet. Water tube boilers are classified as vertical, horizontal and inclined.
The number of drums may be one or more. The circulation of water in the
boiler may be natural (due to difference in density between cold and hot
water) or forced through the action pumps. Forced circulation has the
advantages:
1. Lesser weight of boiler and cheaper foundation.
2. Lighter tubes.
3. Freedom from scaling problems.
4. Greater freedom in configuration of furnace, tubes etc.
5. Uniform heating of all parts.6. Better control of temperature.
7. Increased efficiency of boiler.
8. Quick response to load changes.
In view of all these modern boilers use forced circulation. However, forced
circulation means higher investment, more costly maintenance and increase
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in auxiliary power consumption. The unit is designed for minimum
continuous value of 375 tonnes/hr, at a pressure of 135 kg/sq. cm and a
temperature of 540o C. The reheat system steam flows at MCR. The feed
water temperature of the MCR is 240o C. The unit is balanced draft radiant
dry bolt on single drum, natural circulation, vertical tube type construction
with casing and a single reheat system.
The furnace is arranged for dry ash discharge and is filled with burners
located at the four pipes. Each corner burner is supplied with coal, vapour,
and oil filled secondary air components. The unit is provided with three ball
pipes and arranged to operate with intermediate coal power.
The steam super heaters consist of four stages which are ceiling, primary
S/H, platen and final super heaters. The ceiling terms the root of furnace and
horizontal pass and finishes as the rear wall of the second pass. The primarysuper heater is made up of horizontal bands located at the second pass while
the platens are located at furnace exits. The portion above the furnace too
encloses the super heaters. The control of super heater steam is achieved by
two stages of spray attempration which are located before the platen super
heater and the other located before the final super heater.
The re-heaters are in two stages. First and triplex heat exchanges located at
the second pass which absorbs heat from super heater a steam as well as
from flue gases. In the second stage exists re-heater located in the horizontal
pass as penitent tabular loop. Reheated steam temperature control valves and
the other emergency conditions by an attemprator located in the cold reheat
lines.
In order to ensure reliable and continuous operation ample soot blow
equipment is provided. There are start retractable steam soot blower
provided at the top of the furnace fully retractable steam soot blowers are
arranged for the horizontal re-heater and super heater in the rear pass. The
steam soot blowers are electrically operated.
SPECIFICATIONS OF THE BOILER
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Manufacturer : BHEL
Maximum continuous rating : 375 ton/hr
Maximum rating without stabilization : 240 ton/hr
Rated steam pressure at super heater outlet : 139 kg/sq. cm
Rated steam temperature at upper heater outlet : 540o C
Rated temperature of feed water at economizer inlet : 240o C
Rated steam flow through reheater : 324 ton/hr
Rated steam temperature at reheater inlet : 360o C
Efficiency of the boiler : 86 %
Design pressure of the boiler drum : 161 kg/sq. cm
Design pressure of the reheater : 42 kg/sq. cm
Motor for FD Fan:
Type : EL Motor
Rated output : 330 KWFull load current : 44 A
Induced Draft Fans (ID FANS):
It is a continuous type draft fan and its two units are used for each boiler.
The type is BHEL oxiall-430-2240. The induced draught fan does the
function of sucking the gas from the furnace, making the gas to flow through
the various heating surfaces & dust collecting equipment and sending the
gas out through the chimney with required velocity. The ID fan handles the
hot flue gases and sends the fly ash causing rapid erosion of impeller;
enough care is taken at the design stage to select the fan for the worst
condition.
Number : two per boiler
Capacity : 367200 m3/hr
Temperature of flue gases : 1215o C
Speed : 990 rpm
Motor for ID (Induced Draft) Fans:
Type : EL motor
Rated output : 440 KWFull load current : 127 A
Fan design ratings:
Capacity : 44.6x10 e-4 mm/hr
Total head developed : 410 mm
Maximum temperature of medium : 145o C
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Specific weight of medium : 863 Cp/cm
Fan speed : 990 rpm
Fan direction of rotation : clockwise
Blade type : laminated curved blade
Type of regulation : inlet valve regulation
Drive motor:
Manufacturer : MEEP, Haridwar
Frame size : 15-5-00-p
Design : Codena
Power:
Rated : 1000 KW
Actual power required : 740 KW
Rated voltage : 6600No. of phases : 3
Voltage & frequency:
Full load rpm : 990 rpm
Full load current : 104 A
Full load frequency : 94 %
Torque : 4.63
Frequency : 50 Hz
Terminal Connections:
Type : star
Number : 6
Note: The 6 leads taken out in the terminal box and connected on 4 brushes,
form a star.
STEAM GENERATING UNITS AND AUXILIARIES
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Supporting structure: It serves for arranging the suspending water wall
system, steam super heaters, re-heaters, economizers, air pre-heaters,
galleries insulation and sheet casing.
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Galleries and stairways: These provide access for maintenance like root
blowers, valve burners, dampers ant to various main & view holes.
Boiler drum and drum internals: Boiler drum is made of alloy steel plate
of thickness and has a diameter of 1800 mm. The drum is of fusion welded
on hemispherical dished ends. The function of the drum internals is to
reduce the dissolved solid content with the steam to a prescribed limit.
Rough mountings: These contents of access doors into the combustion
regions of super heater, economizers and air burners as well as observation
pots, explosion doors etc. The rough mountings are made of cast iron or are
of fabricated design.
Water walls: The combustion chamber is formed of water wall tubes onfour side diameters 60.3 mm set, at a pitch of 52 mm. In the corner where
the pulverized coal burners are located, the tubes are bent suitably to provide
opening for the sending of the tilting tangential burners.
Re-heaters: The steam re-heaters having a total surface area of 255.1 sq.
mm are made of pendant and horizontal tabular loops and are in two stages.
The first stage of horizontal tabular arrangements and the peripheral if
tabular is used. The steam for super heater flows through bigger tubes
outside diameter of 85 mm while the steam to be reheated flows outside the
tube through bigger tubes outside with a diameter of 70 mm. The super
heated steam from the triflux is drawn through three-way valve arranged in a
connecting pipe between the outlet of platen super heater and inlet of final
super heater. The second stage of super heater is suspended in the horizontal
pass of the boiler as pendant tabular loops. The reheater tubes are welded to
the inlet and exit heater.
Economiser:
The economizer with a heating surface of 4950 sq. cm made of steamless
tabular loops. The tubes of outside diameter of 32 mm are welded by meansof stubs to the inlet and outlet heater. The heater and horizontal loops rest on
supporting structure of second pass of the boiler with provision for free
expansion. The economizer blocks are arranged, with a second pass of the
heat recovery zone of the boiler so as to achieve recovery of heat in a very
common economic manner.
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inlet. The flue gases extraction ducting is made of alloy steel plate in view
of the fact that the hot gases will be around nozzles.
Soot Blower:
Below root in the furnace a top region the super-heater a reheater zone and
the economizer coils. Steam is used as the medium. The steam is tapped
from the pulled of the plate super-heater and the system includes are on the
reduction valves or safety valves. Four box type soot blowers at the trifler
reason and simple feed type root blower for economizers are also provided.
TECHNICAL SPECIFICATIONS OF THE MILLING
PLANT AND FUEL FIRING SYSTEM
Pulverising Mill:
Type : drum mill 800/575
Number of mills : three
Rated capacity : 20 tonnes/hr.
Type of drive : electric motor Speed : 990/990/171 and 170/175/170 rpm
Motor capacity : 6030 KW, 6.6 KV
Lubricating system:
Discharge pump : 22 l/min
Pressure of oil at pump : 80 psi
Quality of lubricated oil reqd. /mill : 350 l
Oil Cooler:Cooling water required : 7.5 com. /hr at 230o C
Raw Coal Feeder:
Type : chain feeder R600
No. of boiler : three
Type of drive : elect motor 7.5 KW
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Coal Burner:
Total no. of feeder : 16
Manufacturer : BHEL
Capacity : 3.65 ton/hr
Type : tilting tangentially
Oil Burners:
Number per boiler : 8 mm to tier
Type : manual with mechanized atomisation
Capacity : 800 kg/hr
Position of burner : at furnace corner
Cyclone Separator:
Type : SEA 1600/2Diameter of unit : 1600 mm
Efficiency : 82%
Vapour Fan:
Type : DL-1600-60
Type of inlet control : damper
No. of inlet : one
Runner : 1800 mm
Speed : 1480 rpm
Motor:
Manufacturer : BHEL, Haridwar
Type : DA 2014-64-67, TPEC
Rated output : 630 KW, 230 rpm
Rating : 6.6 KV, 3 phase, 50 Hz
Weight : 9.76 tonnes
Ball Mill:
Mill capacity : 28 tonnes/hr Mill current : 64-68 A
Coal consumption : 67 ton/hr for 110 MW
Coal consumption in KW/hr : 0.58 kg
Coal fineness : 200 mesh
Classifiers:
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Type : Raymond type 330, Raymond type 880
No. of per boilers : 3
Type of drive : electric motor, 7.5 KW (variable)
Method of control : Vane control
Range & efficiency : Adjustable
TURBINE MAINTENANCE DEPARTMENT (TMD)
The main works of this department are maintenance of turbine and look afterall the things related with turbine. The steam turbine has been used
predominantly as mover in all thermal power stations. It is not likely to be
replaced in the future. Turbines are mainly divided into three groups:
Impulsive turbines
Reaction turbines
Impulsive-reaction turbines
In both types of turbine, first the heat energy of the steam at high pressure is
converted into kinetic energy passing through the nozzles. The turbines areclassified as impulsive in impulsive turbinate steam coming at a very high
velocity through the fixed nozzle impinges on the blade fixed on the
periphery of the rotor. In the reaction turbine the high pressure steam boiler
is passed through the nozzle. When the steam comes out through these
nozzles, the velocity of steam increases relative to rotation and this resulting
force of steam on the nozzles give the rotating motion to the disc and shaft.
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The shaft rotates in opposite direction of steam jet. In an impulsive reaction
turbine the steam expands both in fixed and in moving blades continuously
as it passes over them. Therefore, the pressure drop occurs gradually and
continuously over both moving and fixed blades. For e.g. Parsons turbine.
COMPOUNDING OF THE STEAM TURBINES
If the entire pressure drop from boiler pressure to condenser pressure is
carried out in a single stage nozzle, then the velocity of the steam entering
into the turbine could be very high of the order of 1500 m/s. The turbine
rotor velocity (blade velocity) will be very high of the order of 3000 rpm as
it is directly proportional to the steam entering velocity. Such high rpm of
turbine is not useful for practical purpose and a reduction gear is necessary
between the turbine and external equipment (generator driven by theturbine). There is also a danger of structure failure of the blade due to
excessive centrifugal stresses. Therefore the velocity of the blades is limited
to 400 m/s. The velocity of the steam at the exit of the turbine is sufficiently
high when single stage blades are used. This gives a considerable loss of
kinetic energy (about 10-20 %). The compounding can solve the above
mentioned difficulties associated with the single stage turbine. The
combinations of the stages are known as compounding. There are three types
of compounding which are generally done.
a. Velocity compounding:
In this type of compounding there is only one set of nozzles and two
or more rows of moving blades. There is also a row of fixed blades in
between the moving blades. The function of the fixed blades is only to
direct the steam coming out from first moving row to the next moving
row without altering pressure and velocity of the steam. The heat
energy drop takes place only in the nozzle at the first stage and it
converts into kinetic energy. The kinetic energy of the steam gained in
the nozzles is successively used by rows of moving blades and finally
exhausted from the last row of the blades on the turbine rotor. Aturbine working on this principle is known as velocity compounded
impulse turbine. For e.g. Curtis turbine.
b. Pressure compounding:
A number of simple impulse turbine sets arranged in series is known
as pressure compounding. In this arrangement, the turbine is provided
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with one row of the fixed blades at the entry of each row of the fixed
blades, which work as nozzle. For e.g. Rateau turbine.
GOVERNING SYSTEM OF TURBINE
1. Speed range is 2850 rpm to 3360 rpm corresponding to primary oil
pressure of 2.17 to 2.99 atmosphere at oil temperature of 50o C (3000
rpm corresponds to 2.38 atm primary oil pressure.)
2. The non uniform changer (NUC) enables the exchanging of non
uniformity continuously in the range of 3.5 to 5 %.
3. Before start of increase of secondary oil pressure, safe oil pressure can
be achieved by limiter only when the main relay is in engaged
position.
4. During the starting of machine upto 2730 rpm, safe oil pressure isregulated by limiter.
5. When the turbine has taken over the regulation function, the limiter
works as by-pass valve on the secondary oil system.
TURBINE PROTECTION TESTING
The following protection parameters of turbine have to checked & recovered
in log book:
1. Primary oil pressure should be 3.05 kg/cm 2
2. Control gear pressure should be 7.00 kg/cm 2 (regulation oil pressure)
TURBINE OIL PRESSURE REGULATING SYSTEM
1. Reset the supply turbine.
2. Reduce the turbine oil from turbine local panel as described in T.G.set manual.
3. Further reduce the turbine oil pressure by procedure given above and
watch so that E.O.P. (A.C.) starts at 0.8 kg/cm2. Now further reduce
the pressure & water so that E.O.P. (D.C.) gets started automatically
at 0.7 kg/cm 2.
4. Mechanical shift tripping.
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5. Low vacuum tripping.
SPECIFICATIONS OF 105 MW TURBINE
Rated output at generator terminals : 110 MW
Rated speed : 3000 rpm
Rated steam pressure just before stop valve : 130 kg/sq. cm
Maximum steam pressure just before stop valve : 146 kg/sq. cm
Rated temperature just before stop valve : 540
Reheated steam pressure : 27.4 kg/sq. cm
Maximum steam pressure before MP casing : 36 kg/sq. cm
IMPORTANT FEATURES OF TURBINE
No. of regulated extractions : 8
No. of wheels in HP rotors : 2 row Curtis, 8 HP (impulse)
No. of wheels in MP rotors : 12 impulse
No. of wheels in LP rotors : 4 impulse of double flow design
No. of high pressure control valves : 4
No. of interceptor valves : 2Range of critical speed : 1200 to 2500
Weight of HP rotor : 5.5 Tonnes
Weight of MP rotor : 11 Tonnes
Weight of LP rotor : 24 Tonnes
Direction of rotation : Clockwise from front bearing stand
Material construction : special cast steel
HP MP outer casing : Casting of chromium vanadium steel
HP MP Inner casing : Casting of chromium vanadium
molybdenum carbon steel
ELECTRONIC INSTRUMENTS USEFUL FOR THE
PLANT
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The following instruments are found to be very useful for the power plant:
1. PR6422
2. PR6423
3. PR6424
4. CON 010
5. Conductivity Indicator Controller
6. pH-Redox Transmitter PP9041
7. Linear Displacement Transducers, PR9350 Series (LD 5000)
PR6422, PR6423, PR6424
Operation and construction:
The transducers belonging to the PR6422, PR6423, PR6424 series based on
the eddy currents measuring principle form together with the signal
converter CON 010 an oscillator circuit, whose amplitude of oscillation isdamped by the proximity of the metallic object w.r.t. face of the transducer.
The damping is proportional to the distance between the transducer coil and
the object.
The transducers are available for different static and dynamic measuring
ranges and with different dimensions. The transducers PR6422 and PR6423
are fitted with a 1m long cable. Transducer PR6424 is fitted with a 4m long
cable.
The zero point and gradient of the measuring s/n can be adjusted by means
of components located under a gas tight cover. The units are delivered fully
adjusted so that no onside calibration is required. The transducer is
connected via a self locking, water proof, plug connection. The power
supply and s/n o/p connections are via screw terminals.
Intrinsically safe operation is possible when zener barriers are used. The
units correspond to the relevant VDI, API and ISO standards.
Application:
These units are designed for use in many branches of industries and in
laboratories for measurement and supervision of small displacements and
vibration on ferromagnetic objects. Such various applications are:
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Monitoring distances between rotor parts
Monitoring vibration of mechanical elements
Monitoring deformation or bending of mechanical parts
Contact-less measurement of shaft eccentricity, vibration and small
displacements Transducers operate on the eddy current principle for static and
dynamic measurements
Transducers easy to mount and adjust
Compact design
This contact-less measuring principle as well as the small size, robust
construction and the resistance of the transducer to aggressive chemical
influences, make this system ideal for continuous supervision of all types of
rational machinery.
Measuring chains made up of displacements transducers, signal converter
and the additional electronic equipment belonging to the RMS700 system
moderately priced and maintenance free supervision of small shaft
displacements with respect to the shaft bearing or housing in two different
modes:
1. Radial, static displacement of the shaft and relative shaft vibration.
2. Axial, shaft displacement and relative expansion.
The following static and dynamic relative measurements are necessary for
supervision of the important mechanical parameters governing turbo-
machinery breakdown prevention.
a. Axial position of the shaft with respect to the housing.
b. Radial position of the shaft with respect to the housing.
c. Shaft vibration.
CON 010 (SIGNAL CONVERTER)
The signal converters contain the electronics necessary for energisation andsignal conversion, which is generally identical for all types. The signal
converter must be energized with 24 DC with +5 or -5%. The normal
deviation of the output voltage for the measuring range of connected
transducer is 4-20V. The converter is delivered together with the transducer
for which it was calibrated. Therefore, care must be taken that transducer
and system converter remain together.
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the equivalent conductivity of the fluid at the reference temperature of
25o C for different temperature of the fluid.
pH-REDOX TRANSMITTER PP9041
The Philips PP9041 is a pH-redox transmitter with a spam of 10 pH and with
zero settings at pH 0, pH 2 & pH 4. This allows the following measuring
ranges to be selected:
a. pH 0pH 10
b. pH 2pH 12
c. pH 4pH 14
Furthermore, eight mV ranges can be selected with a spam of 1000 mV,
output current ranges of 0-20 mV of 4-20 mV can be selected to use the
transmitter for the either electronic or pneumatic control to avoid earthingand/or interfacing problems, both electrode inputs are highly ohmic.
This allows the use of any electrode as a reference. The features of the
instrument make it very suitable for water treatment and pressure control
application.
TRAINING IN EMD
Panki Thermal power station has four units for generation. Each unit has a
separate transformer. Transformer rating depends on the generating capacity
of each unit. Units 3 and 4 generate power at 11 KV. Units 1 and 2 are
closed.
Rating of Transformers of Unit 3 and Unit 4
KVA H.V. 87500/12500
L.V. 87500/12500
No Load Volts H.V. 242000
L.V. 11000
Winding Temperature 30 degree c
Amperes H.V. 298
L.V. 656
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Phase H.V. 3
L.V. 3
Types of cooling ON/OFF
Frequency 50 Hz
Impedance Volts 12.15%
Vector group symbol Y d 1 1
Core winding weight 104000 kg
Weight of oil 34700 kg
Total weight 187000 kg
Oil 38550 litres
Oil circulation 2 x 1800 litres/min
Air circulation 24 x 50 m3/min
Type of circuit breaker O.F. (Oil Filter/ A.B.)
The ratings of major electrical equipments such as all transformers, for 110
MW units are as follows:
Power rating of generating transformer : 125 MVA
Power rating of unit auxiliary transformer (UAT) : 16 MVA
Voltage transformation ratio of generating transformer : 11/242 KV
Voltage transformation ratio of UAT : 11/6.6 KV
Voltage transformation ratio of reserve transformer : 132/6.6 KV
In PTPS, the generation of electrical power is done at 11 KV. The generated
power at this voltage goes to the bus bar through transformer which step-up
the voltage. Then power is ready for transmission and is fed into
transmission network.
After the generating transformer, the current transformer and the potential
transformer are located. After the CT and PT, two circuit breakers are
connected. One of the circuit breakers is manual while the other is
automatic. The automatic circuit breaker is air blast circuit breaker (ABCB).
When excessive current or over voltage or sudden dip in voltage occurs then
the circuit breaker disconnects the line.
CURRENT TRANSFORMER (C.T.)
At this substation a number of current transformers are used. These current
transformers are used with low ammeters to measure high current in high
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voltage A.C. circuit where it is not practical to connect instruments or
ammeters directly from high voltage lines. In addition to insulate the
instrument from high voltage it steps down the current in known ratio.
The current transformer has a primary coil of very few turns of thick wire
connected in series with the line whose current is to be measured. The
secondary consists of a large number of turns of thin wire and it is connected
across the ammeter terminals.
At required voltage the current transformer is of step-up type. But it is sure
that the current will be step down. Thus if the current transformer has
primary to secondary ratio of 100:5, then it step-ups the voltage 20 times
whereas it step-downs the current to 1/20 times of it.
POTENTIAL TRANSFORMER (P.T.)
The potential transformers are used to operate as voltmeters. The potential
coil of wattmeter and relays form high lines. The primary winding of the
potential transformer is connected across the line carrying the voltage to be
measured and the voltage circuit is connected across the secondary winding;
the design of a potential transformer is quite similar to that of a proper
transformer but the loading of a P.T. is always small. The potential
transformers are used to measure the high voltage. The potential transformer
is also used for operating the relays in control circuit.
For safety the secondary winding it is completely insulated from the high
voltage of primary side and grounded for boundary protection of the
operators.
Three types of cooling techniques are employed for the transformers. These
techniques are as follows:
a. Oil Natural Air Force
b. Oil Natural Air Natural
c. Oil Force Air Force
GENERATOR AND EXCITER
The electric generator is most important part of the power station. The
principal of electromagnetic induction is used to generate electric power
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with the help of synchronous generator. All modern type of AC generators
essentially consists of fixed starter and revolution rotor. An alternating e.m.f.
is induced when the shaft of the rotor is revolved with the help of a prime
mover.
The rotor provides the magnetic flux to the machine. The winding of three
generators may be connected either in delta or star arrangement. With star
arrangement two voltages can be obtained as the line voltage or as the phase
voltage. The neutral is connected to the earth and this helps in designing a
protective system in order to keep the temperature rise of various parts from
exceeding the respective maximum permissible values. Every generator
requires continuous cooling during its operation. The system cooling
adopted for the cooling purpose consists of a fan that circulates the air
through the alternator and the warm air is cooled by the water coolers before
being circulated again. This system gives good protection against fire inalternator due to restricted air supply. Carbon dioxide can also be easily
injected to extinguish the fire.
The exciter provides the direct current mended to excite the rotor field
magnets. The present on excitation must be absolutely reliable since their
failures will shutdown the alternators. The higher the total load and more the
lagging power factor, the greater excitation is required.
INTRODUCTION TO SWITCH GEARS, CIRCUIT
BREAKERS AND RELAYS
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Switch gear in a broad sense covers a wide range of equipments connected
with switching and protection. A circuit breaker is a switching (current
interrupting or making) device in switch gear. The basic requirements of
switching in power system practice are two fold:1. To permit apparatus and circuits to be conveniently put into or taken
out of service.
2. To permit appropriate and safe isolation of apparatus and circuits
automatically, in a pre-determined time period when they develop
faults.
DEVICES USED FOR CIRCUIT BREAKING (OR MAKING)
1. Fuse and Iron Clad SwitchesFuse is an over-current switch in the sense that when the current
exceeds a pre-assigned value in a circuit or device, it melts and causes
current interruption. The supply is restored only when a healthy one
replaces the damaged (melted) fuse in the line. To permit this without
any danger of shock to the operator, fuses are connected on the load
side of an iron clad switch.
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2. Isolators
An isolator is a switch connected after a circuit breaker. When a
circuit or a busbar is taken out of service by tripping the circuit
breaker, the isolator is then open circuited and the isolated line is
earthed through earth switch so that the trapped line charges are safely
conducted to ground.
These devices are used to break or isolate the circuit. They are
however, slower than circuit breakers in operation. They are used to
locate and rectify faults in circuit elements and therefore they relieve
the CB which may also be used for these operations. (However it is
not advisable to turn CB in off position for a long duration as this may
damage its springs.) In general, two isolators are put in circuit, one
each on both sides of CB, in order to facilitate repair of CB as well ascircuit isolation and repair. Air pressure for isolators at Panki thermal
power station is 16 kg/cm 2.
3. Circuit Breakers
Make or break both normal and abnormal currents.
Appropriately manage the high-energy arc associated with
current interruption.The problem has become more acute due
to interconnection of power stations resulting in very high fault
levels. Current interruption occurs only when it is called upon to do so
by the relay circuits.
In fact they are required to trip for a minimum of the internal
fault current and remain inoperative for a maximum of through
fault current.
Rapid and successive automatic breaking and making to aid
stable system operation.
3-pole and single pole auto-reclosing arrangement.
In addition to these breaking and making capabilities, a circuit breaker is
required to do so under the following typical conditions:
Short-circuit interruption
Interruption of small inductive currents
Capacitor switching
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Interruption of short-line fault
Asynchronous switching
Principles of circuit breaking
a.DC circuit breaking: effect of decreasing current and increasing arc
length.
b. AC circuit breaking: It is performed by several techniques which
are current-zero period, distortion of AC current wave by arc voltage
recovery and restriking voltages, single frequency and double
frequency transients, rate of rise of recovery voltage (RRRV), control
of RRRV, Resistance switching.
Current chopping-interruption of low magnetizing currents-Opening
resistors-capacitive current breaking-Switching of capacitor banks and
unloaded lines-Interrupting terminal faults and short-line faults.
Ratings of Circuit Breakers
Rated Voltage
Rated insulation
Rated FrequencyRated normal current
Rated short circuit breaking current
Rated short circuit making current
Rated opening sequence for auto-reclose CBs
Rated transient recovery voltage for terminal faults (Representation of
TRV by 4-parameters and 2-parameters)
CB interrupting time-its components in relation to fault clearing time
Single-pole auto-reclosing and its effects on system performance
Classification of Circuit Breakers
The circuit breakers are mainly classified as follows:
1. Air-break circuit breaker or miniature circuit breaker
2. Oil circuit breaker
3. Minimum oil circuit breaker
4. Air blast circuit breaker
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c. Oil Circuit Breaker:
In such CB, insulating oil is used as an arc quenching medium. The
contacts are opened under oil and arc is struck between them. The heat of the
arc evaporates the surrounding oil and dissociates its substantial volume of
gaseous hydrogen at high pressure. It has the advantage of better and
efficient arc quenching medium but on the negative side it involves risk of
fire.
d. SF6 CB:
In such circuit breakers SF6 gas is used as the arc quenching medium.
The SF6 is an electronegative gas and has a strong tendency to absorb free
electron. The contacts of the breakers are opened in a high pressure medium
of SF6 gas and arc is struck between them. The conducting free electrons in
the arc are rapidly captured by the gas to form relatively large, immobilenegative ions. This loss of conducting electrons in the arc quickly builds up
enough insulation strength to extinguish the arc. The SF6 CB has been found
to be very effective for high power and high voltage service.
The advantages of SF6 CBs are as follows:
1. Very short arcing time.
2. Can interrupt much larger current.
3. Noiseless operation.
4. No moisture problem.
5. No risk of fire.
6. Low maintenance cost.
The only disadvantage of SF6 CB is that SF6 is costly thereby increasing the
cost of CB.
Types of indoor switchgears:
a. Stationary Cubicle type
b. Draw-out or Truck type
c. SF6 filled switchgeard. Fuse-switch units
e. Flame proof or Explosion proof switchgear
f. Cellular type
g. Corridor switchboard
h. Mimic diagram board
i. Metal-clad switchgear
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j. Isolator and earthing switch-Vertical break isolator-Double break
isolator
THERMAL RELAYS
A thermal relay consists of a bimetallic strip which is heated by the means of
a heating coil that is supplied through a current transformer. An insulated
arm carrying contact is pivoted and is held in contact with the strip with the
help of a spring. The tension of spring can be varied by rotating the sector
shaped plate.
Under normal working conditions, the strip remains straight, but when the
strip is heated it bends and the tension of the spring is released thus the relay
contacts are closed which energises the trip circuit. The setting of relay can
be achieved by varying the tension of the spring. The construction ofbimetallic element consists of two nickel-alloyed strips and steel strips
welded together. These strips have high heat resistivity and are free from
thermal secondary effects and aging. Each of theses strips is subjected to an
artificial aging process and they are individually calibrated under currents.
These relays assume a temperature higher than the surrounding parts and
must have a short circuit capacity corresponding to the breaking capacity of
circuit breaker itself. This is achieved by using the heat resisting bimetal
material of suitable dimensions having large thermal time constant.
These over current tripping relays are used mostly for motor controls and
their heating elements are designed to withstand short time overload upto
seven times the full load current.
Only the smaller size of the indirect current heated bimetallic elements from
4A to 6.5A are used while 30A motor protective circuit breaker will call for
the additional fuses for the protection of winding along with relays. The
smallest thermal relays of 400A circuit breakers are short circuit proof upto
200 times their top current rating, i.e. upto 8 KA which is adequate.
Ratings of thermal relay are as follows:
With winding-temperature indication type R.B. form- H2AW74
Contact capacity for
(a) Cooker control 5A & 230V
(b) For all arms 0.2A & 125V (D.C.)
(c) For trip 0.2A & 125V (D.C.)
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Power supply 230V (A.C.)
Bushing Sec. Thermal Current Ratio VA Accuracy
A6 AS1 + AS2 -- -- --
B6 BS1 + BS2 400/1 60 5P20C6 CS1 + CS2 -- -- --
N N1S1 - N1S2 400/1 60 5P20
N N2S1 - N2S2 -- -- --
GRID SUBSTATION
The Panki grid substation has five buses at different voltage levels namely:
1. 220 KV bus
2. 132 KV bus3. 33 KV bus
4. 25 KV bus
5. 25 KV bus
Some of the power supplied by Panki thermal power station to the grid
substation is fed back for the purpose of operation of auxiliary components.
WAVE TRAP
This is used for communication by means of which, two grid substations
may communicate and receive messages.
SWITCHYARD
The air at high pressure required for ABCB is produced by the compressor.
There are two compressors for this purpose at PTPS. Both the compressors
are run by the diesel engines. This is to ensure that interruption of power
supply does not effect the operation of CB. The compressor maintains thepressure of air in main air tank. The compressor starts automatically when
pressure of air in main tank falls below 33 kg/cm 2 and stops automatically
when pressure in main tank has reached 40 kg/cm 2.
Each ABCB is provided with its own subsidiary air tank. This tank contains
air at pressure of 23 kg/cm 2 which is the operating pressure of the ABCB.
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The subsidiary tank ensures that sufficient air is available for ABCB
operation while its operation does not affect the main tank pressure.
Similarly, subsidiary tank of isolation contain air at pressure of 16 kg/cm 2.
Two sets of contact are provided for each phase of ABCB so that one of
these may operate if the other fails.
TRACKS FOR TRANSFORMER
Transformers are placed on the tracks (similar to railway tracks). This is
done to aid the transportation, loading, unloading and installation of
transformer. Using these tracks, transformer may be taken to the cranes
which then lift and place the transformer on the vehicle. Similarly, cranes
download these transformers which are then transported through the tracksto the site of installation.
CONTROL & INSTRUMENTATION DIVISION
This is the backbone of a thermal power plant. Various parameters in various
auxiliaries are controlled from here. The equipments are very sensitive and
can even pick up minute disturbances. Automatic control compares the
actual value of the plant output with the desired value, determined the
deviation and produces control signal which will reduce the deviation to zeroor a small value. The industrial automatic controllers that are employed in
the control and instrumentation section are as follows:
1. Two position or on-off controllers
2. Proportional controllers
3. integral controllers
4. Proportionally-integral controllers (PI)
5. Derivative controllers
6. Proportionally-integral-derivative controllers (PID)
Various instruments of the C&I department
1. Boiler Drum: There are numerous red and green lights in the control
room. The light continuously indicates the boiler drum steam and
water level. When the level goes in the danger region, on alarm is
activated.
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Since the rotor moves at a very high speed of about 2900 rpm to 3000 rpm,
due to impinging of steam at high temperature, the expansion of rotor takes
place. This is called eccentricity.
Bearing Temperature
Bearings are made of those metals, which melt at 100o C. Therefore
allowable temperature is 7.5o C. Platinum resistance thermometers are used.
The oil pressure is maintained at 35 kg/cm 2 at the header and a pressure of
15.8 kg/cm 2 at ball bearing.
WATER POLLUTION CONTROL
Main source of pollution in PTPS is polluted water that comes out. It is not
made to flow as such into nearby river. Rather it is first purified by effluent
treatment plant. Waste in the water us called sludge is collected in sludge,dyeing beds. From there it is taken away by trolleys once in a year. The
general working of plant is as follows-
Step-1
Polluted water comes for treatment through gate A of inlet drain. It is first
through screen. Before being collected in grease trap which is * feet deep,
big particles, polythene, rappers etc. have already been screened before
collection of water into oil and gases trap. Some dust and heavy parts and
oil, grease come in the upper parts which is sucked by oil and grease pump.
Oil is collected into drum from time to time this oil is sent to boiler for use.
Step-2
Water from oil and grease trap goes to a 17A deep chamber, here water
remains stand still for some time, heavy sludge, particles and impurities that
do not dissolve in water settles down. Water from here goes to aeration tank
through feed pumps.
Step-3
Aeration tanks are deep tank where oil is mined in water. There are 3aerators for this purpose. An aerator is basically a tabulator that is like a fan
and rotates in water. In this way oxygen is mixed in water. This is necessary
for the life of small bacteria that clear the water and makes it natural; 35 kg
lime and 15 kg urea are mined in water. They are used as water purifiers.
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Step-4
From aeration tank water comes to air fan tank. Motor is the center of
purifier which rotates at the speed of two rotations per hour. It amplifies due
to centripetal force created by the rotating sludge and by the particles which
move toward the centre of the tank.
Step-5
Pure water is discharged from the center i=of the air fan tank. Sludge pumps
from the center of air tank fan pit and send it into sludge drying beds. Water
vaporizes from this sludge beds and sludge remarks that are thrown away by
turn from time to time.
AIR POLLUTION CONTROL
Air pollution occurs due to ash present in the exhaust gas released from the
chimney of the power plant. Therefore, fly ash can almost effectively be
prevented from entering into atmosphere by employing electrostatic
precipitation technique.
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CONCLUSION
It was worth an educational experience to see the working of variousmechanical devices in practical, which I had just read about in books.
The process of knowing about the various stages of thermal power
generation (from coal) including the boiler & its auxiliaries, the steam
generating units & auxiliaries and the compounding, governing, protection
testing & regulation of turbines was a great experience.
Observing the practical implementation of the various mechanical devices
like boilers, turbines, pumps, compressors, fans and the electrical
equipments like current transformers, potential transformers, generators,exciters, switch gears, circuit breakers etc. added a lot to my knowledge.
To know about the various stages in a water treatment plant was a new
experience.
And lastly, I would like to mention about the team work, co-ordination and
time management which exists among the various departments of the unit.
This has really helped me to learn about the job skills.
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