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TRAINING REPORT
ON
“GENERATION OF ELECTRICITY”
KALISINDH THERMAL POWER PLANT
Under Guidance of
MR. S.P. MEENA
1
Assistant personnel officer (katpp, RVUNL, JHALAWAR)
ACKNOWLOWEDGMENT
I am gratefully indebted to my management for the many opportunities given to me for
doing this project work. I am profoundly grateful to Mr. MANOJ MITTAL (HOD, ME) in Gecj
College.
I am come out of impression and knowledge, which has been given to me by the
supervision, guidance and valuable suggestion from all the faculty members during the
completely academic session.
I also want to thanks Mr. S.P. MEENA assistant personnel officer katpp, RVUNL,
JHALAWAR for allowing me for the practical training in the plant.
I would also like to pay thanks to all the staff of electrical section for their kind support.
RAKESH KUMAR
B. TECH, 4TH YEAR
7TH SEM, ME
2
CERTIFICATE
This is to certify that Industrial Training report presented by “RAKESH KUMAR” student of
4th year B.TECH. in "MECHANICAL ENGINEERING" is the bonfire presentation of his work
done by him under my supervision and guidance. They have submitted this project report
towards partial fulfillment for the award of degree of Bachelor of technology of GECJ during
the academic year (2014-2015). It’s further certified that this work has not been submitted
elsewhere for the award of any other degree or diploma.
MR. MANOJ MITTAL
(HOD, ME, GECJ)
Date:-.................
Place:-Jhalawar
3
CHAPTER-1
Chapter name:- page no:-
1.1 INTRODUCTION TO THERMAL POWER PLANT.....9
1.2 WORKING PRINCIPLE..................................................10
1.3 COMPONENTS OF POWER PLANT............................11
1.4 PLANT LAYOUT..............................................................12
CHAPTER-2
2.1 DESCRIPTION OF COMPONENTS..............................13
2.1 (a) BOILER.........................................................................13
2.1 (b) BOILER AUXILLARY................................................17
2.1 (c) BOILER MOUNTING.................................................18
2.1 (d) TURBINE..................................................................18-20
CHAPTER-3
3.1 GENERATOR................................................................21-23
3.2 TRANSFORMER...........................................................24-26
4
CHAPTER-4
4.1 SWITCHYARD..............................................................27-29
4.1(a) CIRCUIT BREAKER...................................................27
4.1(b) ISOLATOR....................................................................28
4.1(c) LIGHTNING ARRESTER...........................................28
4.1(d) EARTHING ISOLATOR.............................................29
4.2 SWITCHSER…………………………………….……29-30
CHAPTER-5
CONTROL ROOM PANEL................................................31
CHAPTER-6
WATER TREATMENT PLANT......................................32-35
CHAPTER-7
7.1 COAL HANDLING PLANT.......................................36-39
7.2 ASH HANDLING PLAT..................................................39
5
CHAPTER-8
COOLING TOWER.............................................................40
CHAPTER-9
EFFICIENCY.......................................................................41
CHAPTER-10
CONCLUSION....................................................................42
REFERENCE.......................................................................43
6
LIST OF FIGURE:-
FIGURE NO TOPIC NAME PAGE NO
1. Kalisindh thermal power plant................................... 9
2. Rankine cycle................................................................ 10
3. Plant layout..................................................................... 12
4. General Boiler................................................................ 13
5. Boiler in kalisindh......................................................... 14
6. Turbine stages............................................................... 20
7. Turbine in kalisindh....................................................... 20
8. Generator in kalisindh.................................................... 21
9. Transformer in kalisindh............................................... 26
10. Circuit breaker............................................................... 27
11. Circuit isolator ................................................................ 28
12. Water treatment plant .................................................. 35
13. Cooling tower ................................................................ 40
7
LIST OF TABLES:-
TABLE NO NAME OF TOPIC PAGE NO
1. Water tube boiler.............................................. 15
2. Generator specification for unit 1 and 2.......... 22, 23
3. Diesel generator set............................................ 23
4. Wagon trippler................................................... 37
5. Chrusher Machine……………………………… 37
.
8
CHAPTER-1
1.1 INTRODUCTION TO KALISINDH THERMAL POWER PLANT
The site of kalisindh thermal power plant is located in Nimoda, Undal, Motipura, Singharia and Devri villages of tehsil Jhalarapatan, dist-jhalawar, Rajasthan. The proposed capacity of coal based thermal power project is 2x600=1200 MW. The project site is about 12km from Jhalawar and NH-12.it is 2km from state highway no 19 and 8km from Ramganj Mandi-Bhopal broad gauge rail line.
This power plant is included by the govt. Of Rajasthan in 11 th five year plan. The cost for this power plant is 7723 crores proposed by govt and this power plant is constructed with the help of BGR Company Chennai
FIG-1 KALISINDH THERMAL POWER PLAN
9
1.2 WORKING PRINCIPLE OF THERMAL POWER PLANT
Thermal power plant works on the principle of Rankine cycle. The Rankine cycle is a model that is used to predict the performance of steam turbine systems. The Rankine cycle is an idealized thermodynamic cycle of a heat engine that converts heat into mechanical work. The heat is supplied externally to a closed loop, which usually uses water as the working fluid.
Fig.2 RANKINE CYCLE
Water is heated turns into steam and spins a steam turbine which drives an electric generator after it passes through the turbine ,the steam is condensed in a condenser and recycled to where it was heated ;this is known as rankine cycle.
10
1.3 COMPONENTS OF KALISINDH THERMAL POWER PLANT
• Boiler
• Super heater
• Turbine
• Condenser
• Alternator
• Cooling tower
• Circulating water pump
• Feed water pump
• Coal handling tank
• Ash handling tank
• Ash storage tank
• Coal storage tank
• Economiser
• Air preheater
• Induced draught fan
• Forced draught fan
• Chimney
• Transformer
• Water treatment tank
• Condensate extraction pump
• Exciter
11
ENERGY CONVERSION PROCESS IN THERMAL POWER PLANT
Fig.3 PLANT LAYOUT OF KALISINDH POWER PLANT
12
CHAPTER-2
2.1 DESCRIPTIONS OF COMPONENTS:-
2.1 (a) Boiler
A boiler is a closed vessel type tank in which coal coming from crusher mill (powder type 25mm size) is burnt with the help of igniter. The heat emitted from burning coal is used to raise the temperature of water. These water is converted into steam under high pressure which rotated the turbine .A boiler is always designed to absorb maximum amount of heat released in process of combustion. So boiler is also called steam generator. It is one of the major components of thermal power plant. The transfer of heat from boiler to raise the temperature of steam is done by three methods i.e.by conduction, convection and radiation.
The process of heating a liquid until reaches its gaseous state is called evaporation. Boiler are tangentially fired, balance draft ,natural circulation, radiant type, dry bottom with high ash content.oil burners are located between coal burners for flame stabilisation. Pulverized coal is directly fed from coal mills
Fig-4 GENERAL BOILER:-
13
FIG-5. BOILER IN KALISINDH THERMAL POWER PLANT
14
In simple way, boiler is a device used for producing steam. There are two types of boiler (depending upon tube content):
• Fire tube boiler
• Water tube boiler
Here, boiler used is of water type. In the boiler, heat energy transfer takes place through tube walls and drum. The gases lose their heat to water in the boiler or superheated. The escape heat is used to heat the water through economizer.
ID and FD fans are used to produce artificial draught. The fuel oil is used to ignite the boiler and pulverized coal is lifted from the coal mills by PA fans.
WATER TUBE BOILER USED IN KaTPP WITH 97M HIGHT
Various motors use in boiler are different rating and parameters 32KW ,15KW ,11KW ,& 3.3KW
Parameter in 15KW motor
TABLE-1 WATER TUBE BOILER:-
Manufacturing CQ.GEAR BOX LTD.CHINA
Motor rating 15 KW
Speed 970 r.p.m
Rated voltage 416 V
Rated current 28.4 A
Impedance voltage 80.0 %
Oil weight 20 Kg
Core winding weight 224 Kg
Total weight 600 Kg
Temp rise 50-55 deg cel.
Combustion takes place at a temperature of (1300-1700) degree centigrade depending on coal grade. Particle resistance time in boiler is typically 2 to 5 seconds, and the particles’ must be enough for complete combustion to have taken place during this time.
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HOW IT WORK-
The concept of burning coal that has been pulverized into a fine powder so that if the coal is made fine enough, it will burn almost and efficiently as gas. The feeding rate of coal according to boiler demand and amount of air available for drying and transporting the pulverized coal is controlled by control room. Pieces of coal are crushed between balls or cylindrical rollers that move between two tracks or “races”. The raw coal is then fed into the pulveriser along with air heated to about 650-degree fareheight from the boiler. As the coal is crushed by the rolling action, the hot air dries it and blows the usable fine coal powder out to be used as fuel. The powder coal from the pulveriser is directly blown to a burner in the boiler.
The boiler system comprises of-
• Feed water system
• Steam system
• Fuel system
1.Feed water system:
It provides water to the boiler and regulate feed according to demand.
2.Steam system:-
It collects and controls the steam produced in the boiler steam are directed through a piping system to a point of use. steam pressure is regulated using valves and checked with pressure gauges.
3.Fuel system:-
Fuel system includes all equipments used to provide fuel to generate the necessary heat for higher boiler efficiency feed water is preheated by economiser using the waste heat in the flue gases.
2.1(b) BOILER AUXILIARIES-Efficiency of a system is of most concerned. Thus it is very important to maintain a system as efficient as possible. So Boiler auxiliaries help in improving boiler’s efficiency. Following are the important auxiliaries used
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ECONOMISER: Its purpose is to preheat feed water before it is introduced into boiler drum by recovering heat from flue gases leaving the furnace. Economiser is located in the boiler near gas pass below the rear horizontal super heater.
AIR PREHEATER: air preheater is employed to recover the heat from the flue gases leaving the economiser and are used to heat the incoming air for combustion. This raises the temperature of the furnace gases, improves the combustion rates and efficiency and lowers the stack (chimney) temperature, thus improving the overall efficiency of the boiler. cooling of flue gases by 20%raises the plant efficiency by 1%.
In kalisindh thermal power plant, regenerative type of preheater is used. The rotor is placed in a drum, which is fixed on an electrical shaft rotating at a speed of 2 to 4 rpm. As the rotor rotates the flue gases, are pass through alternatively gas and air zone. The rotor elements are heated by flue gases in their zone and transfer the heat to air when they are in air zone.
SUPER HEATER: It increase the temperature of steam to super heated region. A super heater is a device, which removes the last traces of moisture from the saturated steam leaving the boiler tubes and also increases its temperature above the saturation temperature. The steam is superheated to the highest economical temperature not only to increases the efficiency but also to have following advantages.
• Reduction in requirement of steam quantity for a given output of energy owing to its high internal energy reduces the turbine size.
• Superheated steam being dry, turbine blades remain dry so the mechanical resistance to the flow of steam over them is small resulting in high efficiency.
• No corrosion and pitting at the turbine blades occur owing to dryness of steam.
REHEATER: It is used for heat addition and increase the temperature of steam coming from high pressure turbine to 540 deg. Reheater are provided to raise the temperature of the steam from which part of energy has already been extracted by HP turbine. this is done so that the steam remains dry as far as possible through the last stage of the turbine. A reheater can also be convection, radiation or combination of both.
FANS: They handle the supply of air and the pressure of furnace.
2.1(c) BOILER MOUNTINGS-These are used for the safe operation of boiler. Some example of mountings used are water level indicator in drum, furnace temperature probe, reheat release valve, pressure gauges indicating steam pressure etc.
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2.1(d) STEAM TURBINE
Turbine is an m/c in which a shaft is rotated steadily by the impact of reaction of steam of working substance upon blades of a wheel. It converts the potential energy or heat energy of the working substance into mechanical energy. When working substance is steam, it is called ‘Steam Turbine’
In the steam turbine, the pressure of the steam is utilized to overcome external resistance and the dynamic action of the steam is negligibly small.
PRINCIPLE Working of the steam turbine depends wholly upon the dynamic action of steam. The steam is caused to fall with pressure in a passage of nozzle, due to this fall in pressure, a whole amount of heat energy is converted into mechanical energy & steam is set moving with the reactor velocity. The rapidly moving particle of steam enter the moving part of turbine and here suffers a change in the direction of motion which gives rise to change of momentum and therefore to a force. This constitutes a driving force to a turbine.
The passage of them/through the moving part of the turbine commonly called the blade, may take place in such a manner that the pressure at the outlet sides of the blade is equal to that of the inlet side. Such a turbine is broadly termed as outlet turbine or Impulse type.
On the other hand, the pressure of the steam at outlet from the moving blade may be less than that at type inlet side of the blade. The drop of pressure suffered by the steam during its flow through the moving blades causes a further generation of kinetic energy within the blades and adds to the propelling force, which is applied to the turbine rotor, such a turbine is broadly termed as Reaction Turbine. Here in Kalisindh Thermal Power Project N600-16.7/587/537,Re-Het,Three Casing, Four Exhaust, Tandem Compound Condenser Type Turbine Used.
The turbine is of tandem compound design with separate High Pressure (HP), Intermediate Pressure (IP) and Low Pressure (LP) cylinders. The HP turbine is of Single Flow type while IP and LP turbines are of Double Flow type .The turbine is condensing type with single reheat. It is engineered on reaction principle with throttle governing. The stages are arranged in HP, IP AND LP turbines driving alternating current full capacity turbo generator.
The readily designed HP, IP and LP turbines are combined and sized to required power output, steam parameters and cycle configuration to give most economical turbine set. The design and constructional feature have proved their reliability in service and ensure trouble free
operation over long operating periods and at the same time ensuring high thermal efficiencies.
18
HP TURBINE:-
The hp casing is a barrel type casing without axial joint. Because of its rotation symmetry the barrel type casing remain constant in shape and leak proof during quick change in temperature. The inner casing tool is cylinder in shape as horizontal joint flange are relieved by higher pressure arising outside and this can kept small. Due to this reasion barrel type casing are speially suitable for quick start up and loading. The hp turbine consists of 25 reactions stages. The moving and stationary blades are inserted int appropriately shapes into inner casing and the shaft to redue leakage losses at blade tips.
IP TURBINE:-
the IP part of turbine is of double flow construction. The double flow inner casing is supported kinematically in the outer casing. The steam from HP turbine after reheating enters the inner casing from above and below through two inlet nozzles.The centre flows compensate the axial thrust and prevent steam inlet temperature affecting brackets, bearing etc. the arrangement of inner casing confines high steam inlet condition admission branch of casing, while the joints of outer casing is subjeted only to lower pressure and temperature at the exhaust of inner casing. The pressure in outer casing relieves the joint of inner casing so that this joint is to be sealed only against resulting differential pressure.
The IP turbine consists of 20 reactions stages per flow the moving and stationary blades are inserted in appropriately shaped grooves in shaft and inner casing.
LP TURBINE:-
The casing of double flow type LP turbine is of three shell design. The shells are axially split and have rigidly welded construction. The outer casing consist of the front and rear walls, the lateral longitudinal support bearing and upper part.
The outer casing is supported by the ends of longitudinal beams on the base plates of foundation. The double flow inner casing consist of outer shell and inner shell the inner shell is attached to outer shell with provision of free thermal movement. Steam admitted to LP turbine from IP turbine flows into the inner casing from both sides through steam inlet nozzles.
19
FIG:-6 TURBINE STAGES
FIG-7 TURBINE IN KALISINDH PLANT
20
CHAPTER-3
3.1 GENERATOR:-
Generator is the important part of thermal power plant. It is a device, which convert the mechanical energy into electrical energy. Generator is driven by coupled steam turbine at a speed of 3000 r.p.m. Due to rotation at high speed it get heat. Therefore, there is cooling construction enclosing the winding core of the generator so that during the operation is being in normal temperature.
In KaTPP , Each of the 2 units have been provided with 3-phase turbo generator rated output 706MVA, 18.525KA, 22KV, 0.85 lagging p. f. , 984 rpm and 50 cycles/sec .The generator has closed loop of hydrogen gas system for cooling of the stator and rotor at a pressure of 4.5kg/sq-cm(g)
Each generator has terminal led out of its casing and a star point is formed by sorting the neutral side terminals by a sorting bar. The neutral is grounded by a 1-phase 11000/220v, neutral grounding transformer, whose secondary coil is laminated by laminated strip with mechanical ventilating holes, is connected across a 650v, class 0.4 ohm, 50 kw neutral grounding resistors and relays for protection of generator against stator earth faults and stator in turns fault.
FIG-8. GENERATOR IN KALISINDH PLANT
21
TABLE-2 GENERATOR SPECIFICATION FOR UNIT I AND II:-
Make CQ GEARBOX China
Type QFSN
Apparent output 706 MVA
Active output 600 MW
Power factor 0.85 lagging
Rated voltage 22 KV
Rated current 18525 Amp
Rated speed 3000 r.p.m
Frequency 50 Hz
Phase connections Double gen.star
Cooling mode H20-H2-H2
Rated H2 pressure 4.5 Kg/sq-cm
Terminal in generator 6
TABLE -3 DIESEL GENERATOR SET:-
It is used to emergency purpose to supply auxiliary system of power plant.3 Set Diesel generator are use in which one is standby. Parameters of generator are as
Make BY STAMFOARD MAHARASTRA INDIA
Rating 1900 KVA
Speed 1500 R.P.M
Rated Current 2643.37 A
Rated Temp 40 Deg cell
AMPS 3.6 A
22
DESCRIPTION OF THE GENERATOR PARTS:-
• STATOR BODY:-
Armature of a generator formed of laminations having slots on its inner periphery to accommodate armature conductor and is known as stator. The stator body is totally enclosed gas tight fabricated structure suitably internally to rigidity. The function of stator frame is to contain and support the stator core winding, hydrogen coolers and path for distribution of cooling hydrogen through the generator.
• STATOR CORE:-
The rotating magnetic field flow with the core in order to reduce the magnetizing current (eddy current) losses in the active portion of the stator core due to rotation of field structure in between the stator the entire core is built up of thin laminations.
• STATOR WINDING:-
The stator has 3-phase double layer, short pitched and bar type of winding having two parallel paths. Each slot accommodates two bars. The upper and lower bars are displaced from each other by one winding pitch and connected at their ends to form coil groups. Each bar consists of solid as well as hollow conductor with cooling water passing through the later alternator.
• ROTOR:-
The field structure is the largest and heaviest component of generator and is called the rotor. The rotor houses the static excitation winding and the exciting current is supplied to the rotor through the slip rings and brushes. The rotor shaft is a single piece forging the longitudinal slot for inserting the field winding. The slots are distributed over the circumference so that two field solid poles are obtained.
Negative sequence relay is used for the protection of generator.
23
3.2 TRANSFORMER
Transformer is a static device which is used to change the voltage level keeping the power and frequency same. In the power plant transformer is one of the most important equipment. The transformer works on the principle of Faraday’s laws of Electromagnetic induction. This process is completed in two process first the A.C applied is converted into magnetic flux then this flux linked with secondary winding giving as of desired value depending on the no. Of turns in primary and secondary winding.
Whenever we apply alternating current to an electric coil, there will be an alternating flux surrounding that coil. Now if we bring another coil near the first one, there will be an alternating flux linkage with that second coil. As the flux is alternating, there will be obviously a rate of change in flux linkage with respect to time in the second coil. Naturally, emf will be induced in it as per Faraday's law of electromagnetic induction. This is the most basic concept of the theory of transformer.
The winding, which takes electrical HYPERLINK "http://www.electrical4u.com/electric-power-single-and-three-phase/" HYPERLINK "http://www.electrical4u.com/electric-power-single-and-three-phase/"power from the source, is generally known as primary winding of transformer. Here in our above example it is first winding.Transformer is made of following components:-
• Core• Winding• On load tape changer• Tank• Bushing• Auxiliary equipment• Insulating oil• Cooling system
The winding, which gives the desired output voltage due to mutual induction in the transformer, is commonly known as secondary winding of transformer. Here in our example it is second winding.
24
The above mentioned form of transformer is theoretically possible but not practically, because in open air very tiny portion of the flux of the first winding will link with second; so the current that flows through the closed circuit of later, will be so small in amount that it will be difficult to measure.The rate of change of flux linkage depends upon the amount of linked flux with the second winding. So, it is desired to be linked to almost all flux of primary winding to the secondary winding. This is effectively and efficiently done by placing one low reluctance path common to both of the winding. This low reluctance path is core of transformer, through which maximum number of flux produced by the primary is passed through and linked with the secondary winding. This is the most basic theory of transformer.
Main Constructional Parts of TransformerThe three main parts of a transformer are,
• Primary Winding of transformer - which produces magnetic flux when it is connected to electrical source.
• Magnetic Core of transformer - the magnetic flux produced by the primary winding, that will pass through this low reluctance path linked with secondary winding and create a closed magnetic circuit.
• Secondary Winding of transformer - the flux, produced by primary winding, passes through the core, will link with the secondary winding. This winding also wounds on the same core and gives the desired
In kalisindh, there are various transformers for various purposes. They are:-
• Generating transformer(GT)
• Unit transformer(UT)
• Unit auxiliary transformer(UAT)
• Unit service transformer
• Unit Station transformer
• Current transformer
• Potential transformer
• GENERATING TRANSFORMER(GT):- In kalisindh thermal power plant 3 single phase generating transformer
installed for each phase in single unit. Output of generator has step up to 400KV by generating transformer. In kalisindh power plant 150/200/250MVA, 22.98/22KV,generating transformers are used.
25
• UNIT TRANSFORMER(UT):- Unit transformer are installed to fed supply to HT switchgear. There are two 80MVA transformer installed near GT which are fed through main busducts coming from generator and fed to the HT switchgear. After step down this supply upto 11 kv HT switchgear used to supply on the measure axuliary of the plant like BFP,CWP,ID ,FD,PA fans etc. The unit transformer is used to HT switchgear and it supply voltage 22/11KV to UAT and different motors in boiler. UT is rated for 48/64/80MVA,22/11.6/11.6KV, dyn11yn11 type winding. This permit to voltage down upto 11KV it have 2 radiator.
UNIT AUXILIARY TRANSFORMER(UAT):- Each unit has two unit auxiliary transformers. When the unit starts generating electricity these transformer are energized and then supplies power to the auxiliaries. Before starting of the, UAT bus is connected to the station bus. Auxiliaries of one unit take about 20MW of power. UATis connected between the generator and the GT. A tapping is taken from the power coming from the generator to the GT. UAT relieves GT from extra load of about 20MW which is to be supplied to the auxiliaries via GT and ST thus increasing the efficiency. It is step down transformer,which steps down the voltage from 16.5 KV to 6.9 KV . The rating of UAT is 20 MVA. UAT bus supplies only those auxiliaries, which are not necessary to be energized in case of sudden tripping of generator.
UNIT SERVICE TRANSFORMER:- It is also a 66 KV /415 V transformers which is used to supply the auxiliaries connected to the the unit secondary switchgear bus.
UNIT STATION TRANSFORMER:- It is a step down transformer ,which is connected to the station bus. It steps down the voltage from 6.6 KV to .433 KV . it is used to supply the voltage au
FIG-9 TRANSFORMER IN KALISINDH POWER PLANT:-
26
CHAPTER-4
4.1 SWITCHYARD:-The 400KV and 220KV switchyard have conventional two buses arrangement with a bus-coupled breaker. Both the generator transformer and line feeder taking off from switchyard can be taken to any of the two buses, similarly two station transformer can be fed from any two buses. Each of these line feeders has been provided with bypass isolators connected across line isolator and breaker isolator to facilitate the maintenance of line breaker. Each 400KV and 220KV lines have provision of local break up protection. All the breaker of the connected zone and bus coupler, breaker will trip in event of fault in that zone.
Each of the two bus bars has one P.T. one for each phase connected to it. Potential transformer are make in CROMPTON LTD. Each time line feeders has three no. cores for each phase capacitor voltage transformer. For metering and protection are multicored single line phase, oil filled, nitrogen sealed and are provided at rate of one per phase. Electrical equipment at 400KV and 220KV system is as follows:-
• Circuit breaker
• Isolator
• Current transformer
• Potential transformer
• Lightning arrester
• Earthing arrester
• Capacitor voltage transformer
• Inter connected transformer
4.1(a) CIRCUIT BREAKER:-A circuit breaker is a piece of equipment, which can make or break a circuit manually or by remote control under normal condition. Break a circuit automatically under fault condition.
27
FIG-10 CIRCUIT BREAKER:-4.1(b) ISOLATERS:-It is essentially a knife switch and is designed to open a circuit under no loads. Its main purpose is to isolate one portion of the circuit from the other and is not intended to be opened while current is flowing in the line. Such switches are generally used on both sides of the circuit breakers in order that repairs and replacement of circuit breakers can be made without any danger. They should never be opened until the circuit breaker in the same circuit has been opened and should always be closed before the circuit breaker is closed. It is also called no load breaker
FIG-11 CIRCUIT ISOLATOR:-
4.1(c) LIGHTNING ARRESTER:-An electrical discharge between cloud and earth is known as lightning.
28
A lightning arrester or a surge diverter is a protective device, which conducts the high voltage surge on the power system to the ground.
4.1(d) EARTHING ISOLATORS:-
The term ‘ Earthlings’ means connecting of the non-current carrying parts equipment or the neutral point of the supply system to the general mass of earth in such a manner that all times an immediate discharge of electrical energy takes place without danger. An earthling’s isolator is a value of capacitance. This can be charged up to the voltage. Earthling’s isolator is used to discharge the line capacitance and work on it.
4.2 SWITCHGEAR:-The apparatus used for switching, controlling and protecting the electrical circuits and equipments are as known SWITCHGEAR.
Switchgear is one, which makes or breaks electric circuit.
The main components of switchgear are as follows:-
• Bus-bars
• Isolating switches
• Current transformer
• Potential transformer
• Circuit breaker
• Relays
• Inter locking arrangement
BUS-BARS:-Bus bars are defined as the conductor to which several incoming and outgoing lines are connected. They are essentially component of switchgear. They are made up of cu and al. the bus bars are enclosed in bus chamber. In kalisindh, thermal power plant two types of indoor switchgear are used.
11KV and 3.3KV or high tension
3.415 Or low tension
ISOLATING SWITCHING:-
They are capable of interrupting the transformer magnetizing current, Interrupting line charging current, interrupting load transformer switching.
CIRCUIT BREAKER:-
29
They are capable of breaking the circuit on faults. It is heavy duty equipments mainly utilized for protection of various circuits and separation of load.
The circuit breaker uses on a relay or by manual signal. The circuit breakers, which are used in switchgear, are VCB type.
• EARTHED SWITCHES:-
Earthed switches are connected between line conductor and earth. Normally it is open when line is disconnected. The earthing switched is closed to discharge the voltage trapped on line for high voltage and so the capacitor between line and earth is charged to high voltage.
• INTER-LOCKING:-
The following type of inter-locking are provided
The circuit breaker must be in open position before it is lowered in this position.
The breaker can be closed only raising the final plug in position.
The circuit breaker can be closed before raising plug in position.
Inter-locking between isolator, earthlings switches and circuit breakers are provided.
• RELAYS:-
A relay is a device that detects the fault and initiates the operation of the circuit breaker to isolate the defective element from the rest of the system.
30
CHAPTER-5
CONTROL ROOM PANEL:-Various measurements can be taken at the control room simultaneously. The relays used in kalisindh thermal power plant are as follows:-
FAN CONTROL DESK:-
Induced draft fan at full load.
Forced draft fan at full load.
Primary air fan at full load.
PRESSURE CONTROL DESK:-
Furnace pressure (5-10 mm hg)
Primary air header pressure (750-800 mm hg)
FUEL CONTROL DESK:-
Coal oil flow
Oil pressure
Temperature of mill
Flow of air
Drum level control, flow of steam water
Pressure of steam and water
Temperature of steam and water
TURBINE DESK:-
Pressure control, load mode control
Speed control
Ejector, control valves, stops valves and deviators.
GENERATOR CONTROL PANEL:-
Voltage, current, MVAR
Stator, rotor temperature
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Stator cooling
CHAPTER-6
WATER TREATMENT PLANT:-To protect boiler from corrosion water treatment is necessary.
WATER:
•The purest available from water vapor in atmosphere as rain ,show or produced by melting or ice.
•This H2O reaching ground different type of gases from atmosphere like N2, and lesser extent carbon dioxide.
•Apart this H2o travels to various place and catches various organic matter suspended solid (macro size sand, rite, slit etc.).
•Colloidal micro size particles (0-100nm).
•Dissolved forms alkaline salts, neutral salts and organic matter
•Alkaline salts are mainly bicarbonates rarely carbonates and hydrates of Ca, Mg and Na
•Neutral salts are sulphate chlorides, Nitrates of Ca, Mg and Na.
WATER CONDITIONING IN THERMAL POWER PLANTS FOR PROCESS AND BOILER USEVarious water qualities inside thermal power plant
•Cooling Water (BCW, ACW)
•Boiler water
•Consumptive water
H2O TREATMENT:
•Pre-treatment of raw H2O
•Filter H2O for softening and DM Plant
•DM H2O for Boiler
H2O TREATMENT WHY?:•To avoid formation
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•To avoid corrosion•To control microbiological growthThe purpose of H2O treatment programmed is to provide real exchanger surface that are intact and free of deposits, so that designed specification are met at KSTPS. Suspended and soluble H2O impurities are removed with the help of PAC (Poly Aluminum Chloride) while treatment of organic impurities are removed with the help of raw H2O and circulating cooling H2O is being carried out with the help of liquid chlorine
CLARIFICATION:
•Remove all types of solid and large particle sediments oil, natural organic matter, color etc.
Consist of four steps:
•Coagulation-Flocculation
•Screening
•Sedimentation
•Filtration
•Medium screening (Spacing 10 – 40 mm)
•Coarse screening (Spacing > 40 mm)
•Coagulation – Flocculation removes suspended solids and colloidal particles
•Screening protect downstream units form, easily separable objects
ION EXCHANGE:•Resins-acidic/basic radicals with ions fixed on them, exchanged with ions present in H2O.
•Theoretically removes 100% of salts, organics, viruses or bacteria.
•2 types of resins-
Gel type (micro porous) micro porous or loosely cross-linked type
3 system of resign beds:
Strong acid cation + strong base anion.
Strong acid cation + weak base anion + strong base anion.
Mixed bed Deionization.
Ion exchange plant softens, removes heavy metals, and produces demineralised H2O.
Various cooling water system: WA
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•Once through cooling water system.
•Open recirculation cooling system.
D.M.PLANT:
Dissolved solids present in water are removed in DM Plant by ION exchange process and for this, ION exchange Resins are used.
ION EXCHANGE RESINS: ION Exchange Resins are synthetic organic polymers. Most commonly used resins are gel type polymerize resins. Acrylic-resins/macro porous/micro porous resins are now available in market.
CATION EXCHANGE RESINS:Cation Exchange Resins are nothing but acid and can be simply represented us:
R-H+, where R is resin matrix, completely insoluble in water and only H+ is mobile in water.
Cation resins are of two type. Strong Acids Cation Exchange Resins (SAC) and Weak Acid Cation Exchange Resins (WAC).
SAC:When the functional group attached to resins matrix is strong acid group. It is called Sac resins.
SAC can split all the salts and their performance is not influenced by pH of water. Operational exchange capacity and regeneration efficiency of SAC is less than WAC.
WAC:
When the attached functional group is of weak acid is called WAC resin.
WAC can only split weak electrolyte (Carbonate and Bicarbonate).
It performs better with high pH water and with lower pH water its performance decreases and when pH falls below 4 actually regeneration take place.
ANION EXCHANGE RESINS:Anion resins can be simply represented by R+ and OH- and is nothing but an alkali / base. OH- is only mobile in water.
Anion Exchange resins is two types. Strong base anion resins (SBA) and Weak base anion resins (WBA).
SBA:
When the functional group is strong, base it is called SBA resins. SBA performance is not influenced by water pH and it can exchange with both strong and weak acids.
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WBA:
When the functional group attached with a weak base it is called WBA resins. WBA performs better at low pH and increased pH decreased its performance. When pH is more than 11, actually regeneration takes place.
Operational capacity and regeneration efficiency of WBA is higher than SBA. WBA can only react with strong acids.
PRINCIPLE OF DEIONISATION:
All impurities expect dissolved solids are removed in pre-treatment plant.
Only dissolved solids are removed in D.M. Plant.
Dissolved solids in water dissociates into ions (as water is polar solvent and it is dissolved in electro-valet compound.
Positive charged ions are called cations and Negative charged ions are termed as anions.
In normal river water most common salts presented are calcium, magnesium and sodium salts, associated with corresponding equivalent ions like Cl-, SO4- etc.
If above water passes through a cation exchanger, all cations are exchanged with H+ of cation exchanger resins.
Similarly all cations are exchanged and retained by resins and ultimate product will be corresponding acids. PH drops around 3.5 and it becomes soft.The above water when passed through an anion exchanger, all anions exchanged with OH- of SBA resins and equivalent of water is produced.Similarly all acids are convertible to H2O. It appears that by passing water-containing salts through a cation and anion exchange resins all-isolable salts can be removed.
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FIG-12 WATER TREATMENT PLANT:-CHAPTER-7
7.1 COAL HANDLING PLANT:-Thermal power plant is based on steam produced on the expanse of heat energy produced on combustion of fuel. Coal is categorized as follows depending upon fixed carbon, volatile matter and moisture content:
Anthracite having 86% fixed carbon
Bituminous having 46 to 86% fixed carbon
Lignite having 30% fixed carbon and
Peat having 5 to 10% fixed carbon
Coal from mines is transported to CHP in railway wagons. It is unloaded in track hoppers. Each project requires transportation of large quantity of coal mines to the power station site. Each project is established near coal mine which meets the coal requirements for the span of its entire operational life. For the purpose each plant has Merry Go-Round (MGR) rail transportation system. The loading operation of the coal rake takes place while it is moving under the silo at a present speed of 0.8 Km/hr. the loading time for each wagon is one minute. For unloading of coal from the wagons, an underground track hopper is provided at the power station.
The term coal handling plant means to store and to handle the coal, which is transported by the train, and convey to the bunkers with the help of belt conveyers. Through the bunkers, coal is transferred to the coal mill and drifted to the furnace. The coal handling plant includes wagon tippler, conveyer belt, crusher house, and stacker & reclaimed, bunkers & coal mill.
COAL SUPPLY IN KaTPP-Ministry of coal, Govt. of India has allotted Paras east and Kanta
basin coal blocks to RVUN in Chhattisgarh state.
2.2 STAGES OF COAL HANDLING PLANT
• WAGON TIPPLER-The term Wagon Tippler contains two words WAGON & TIPPLER .Wagon means the compartment of train which is just like a container which is used to carry the coal from mines to generating stations & the word Tippler means a machine, which is used to unload the wagon into the hopper. Hopper is just like a vessel, which is made of concrete, & it is covered with a thick iron net on its top. Here big size coal pieces are hammered by the labors to dispose it into the hopper.
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TABLE-4 WAGON TIPPLER:-
Capacity 90 tonnes
Types of Tipplers 1.Weighing type,2.Non weighing type
Angle of Tip 30 ‘to35’
Wire Ropes 1.Hoisting Ropes, 2.Counter Weight Ropes
Drive unit Motor 37.3 KW
Operating Cycle 10 wagons/Hour on 1 wagon Tippler
Time consume for one cycle 6 minutes
• FEEDER- It is used to control the supply of crushed coal to the mill depending upon load condition. It is installed under wagon tippler and hopper. In KaTPP there are 4 unbalanced Motor Vibrating Feeder installed in unit 1st.
• CHRUSHER/RING GRANULATOR-In ring granulator the material is fed in to the crushing chamber and is crushed by the rind hammers with impact and rolling action across the feed, with concentrated pressure. This cracks the coal producing a granulator product with a minimum of fines up to 20 mm square.
TABLE-5 CHRUSHER MACHINE:-
Capacity 500 Tonnes/hr
Machine Weight 30 Tonnes(approx.)
Max Feed Rate 500 Tonnes/hr
Rotor Speed 720 r.p.m
Motor 550 H.P
Volts 606 Kv
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Phase 3 Phase motor
• CONVEYORS-Conveyor belt is used to send the coal from coal storage yard and used to send crushed coal from store to mill bunkers. The carrying capacity of conveyors belt is 750 tonnes/hrs that are installed in KaTPP.
Conveyor belt used in coal handling plant (CHP) are of 2 types
• 5 ply x1000 mm width with 5 mm rubber top side and 5 mm rubber bottom side.
Total thickness of belt:-17 to 18 mm
Power:-1000KN/m2
• 4 Ply x1000 mm width with 5mm rubber top side and 5 mm rubber bottom side.
Total thickness of belt:-17mm
Power:-800KN/m2
Cold joint are used in joining the conveyor, conveyor belts run with the help of electric motor, gearbox, fluid coupling geared coupling are installed at head of all conveyors.
• PARTS OF CONVEYORS:
• Flap Gate-it provides under coal transfer chutes for replacements of crusher/conveyors.
• Deflector Plate-Deflector plates are installed in the chutes coming on conveyors to keep the coal direction in the centre of the conveyors.
• Skirt board and Skirt rubber-These are provided on tail end chutes to avoid spillages of coal from Conveyors.
• Stone picker-Stone picker pick the stones from the running belt manually.
• Metal Detector-Electromagnets are providing on conveyors to avoid and to save crusher parts and entry of iron pieces in crusher. It also stops the entry of iron pieces in coalbunker to save damage of coal mills.
• Guide Idlers-These idlers help to train/guide the conveyors.
• Return Idlers-These idlers carries the conveyors belts in return side.
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• R.T.I (Return Training Idler)-These idlers are provided on return side to guide the conveyors.
• Impact Idler-These Rubber idlers are provided under chutes through which coal falls on conveyors.
• Carrying Idlers-These are installed to run the conveyor.
BUNKERS-Bunkers are fabricated to store the coal before sending to coal mills. Coal is fed in the bunkers with the help of tripper trolleys installed at 37 m height for unit 1st and 2nd.These are 20 bunkers for unit 1st and 2nd.
Capacity of a bunker=500 tonne/bunker.
ASH HANDLING PLANT:-The ash produced on the combustion of coal is collected by ESP. This ash is now required to dispose off. This purpose of ash disposal is solved by Ash Handling Plant (AHP). There are two types of ash handling process undertaken by AHP.
• Dry Ash System
• Ash Slurry System
DRY ASH SYSTEM- Dry ash is required in cement factories as it can be directly added to cement. Hence, the dry ash collected in the ESP hopper is directly disposed to silos using pressure pumps. The dry ash from these silos is transported to the required destination.
ASH SLURRY SYSTEM- Ash from boiler is transported to ash dump areas by means of sluicing type hydraulic system, which consists of two types of system-
• Bottom Ash System
• Ash Water System
BOTTOM ASH SYSTEM- In this system, the ash slag discharged from the furnace is collected in water-impounded scraper installed below bottom ash hopper. The ash collected is transported to clinkers by chain conveyors. The clinker grinders churn ash, which is then mixed with water to form slurry.
ASH WATER SYSTEM-In this system, the ash collected in ESP hopper is passed to flushing system. Here low pressure water is applied through nozzle directing tangentially to the section of pipe to create turbulence and proper mixing of ash with water to form slurry. Slurry formed in above processes is transported to ash slurry sump. Here extra water is added to slurry if required and then is pumped to the dump area.
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FLY ASH SYSTEM-Even, though ESP is very efficient, there is still some ash, about 0.2%, left in flue gases. It is disposed to the atmosphere along with flue gases through chimney.
CHAPTER -8
COOLING TOWER:- It is a structure of height 202 m (tallest in the world) designed to cool the water (coming from condenser) by natural draught. The cross sectional area is less at the centre just to create low pressure so that ate air can lift up due to natural draught and can carry heat from spherical drops. The upper portion is also diverging for increasing the efficiency of cooling tower. Hence, it is named as natural draught cooling tower.
In KaTPP two natural draught cooling towers (2 NDCT) is present with height 202 m each for each unit.
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FIG-13 COOLING TOWER:-
CHAPTER-9
EFFICIENCY:-Efficiency is defined as the ratio of output to input. Efficiency of any thermal power plant can be divided into four parts-
• Cycle Efficiency
• Boiler Efficiency
• Generator Efficiency
• Turbine Efficiency
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Efficiency of thermal power plant is defined as in the term of overall efficiency
i.e. overall efficiency = cycle x boiler x generator x turbine efficiency
CYCLE EFFICIENCY- Cycle efficiency is defined as the ration of energy available for conversion in work to the heat supplied to the boiler.
BOILER EFFICIENCY- Efficiency of boiler depends upon the following factors:
• Dry flue gas loss: Increase by excess air in boiler.
• Wet flue gas loss: Moisture in coal.
• Moisture in combustion loss: Hydrogen loss.
GENERATOR EFFICIENCY- Efficiency of generator is about 98% also its efficiency depends upon:
• Copper and iron loss
• Windage losses
TURBINE EFFICIENCY-It means the efficiency of steam turbine in converting the heat energy made available in the cycle into actual mechanical work.
CHAPTER-10
CONCLUSION:-This is my first practical training in which I learned lot of things and seen lot of huge machine like Turbine, Boiler, Generator, cooling tower and many other things.
The architecture of the power plant, the way various units are linked and the way working of whole plant is controlled make the student realize that engineering is not just learning the structure description and working of various machine but the great part is of planning proper and management.
I think training has essential for any student. It has allowed an opportunity to get an exposure of the practical implementation to theoretical fundamentals.
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REFERENCE
• www.rvunl.com
• www.googleindia.com
• Generation of electrical power By B. R. Gupta, S CHAND PUBLICATION
• IEEE site
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