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A
PROJECT REPORT ON
NTPC LIMITED
KANTI,(MUZAFFARPUR),BIHAR
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CHAPTER 1
INTRODUCTION
Kanti bijlee utpadan nigam limited (Muzaffarpur thermal power station) is a joint venture o
National thermal power corporation (N.T.P.C) and Bihar State Electricity Board (B.S.E.B). It is
situated in Muzaffarpur district of bihar across National highway.
It has a installed capacity of 220 MW (2 X 110 MW).Another two units of 2 X 195 MW is
proposed and the work is already started. The coal required for power generation comes from
raniganj and mugma.The source of water is old bagmati river and canal. The ash as a result of
combustion of coal is deposited at ash dike across the river.
1.1) INTRODUCTION TO THERMAL POWER PLANT
FIG-1 THERMAL POWER PLANT
A thermal power plant is a power plant in which the prime mover is steam driven. Water is heated,
turns in to steam and spins a steam turbine which drives an electrical generator.
After it passes through the turbine, the steam is condensed in a condenser; this is known as
Rankine cycle .such power stations are most usually constructed on a very large scale and designed
for continuous operation.
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Reciprocating steam engines have been used for mechanical power sources since the 18 th century
with notable improvements being made by James watt. The very first commercial central electrical
generating stations in New York and London in 1882 also used reciprocating steam engines. By
the 1920s any central station larger than a few thousands kilowatt would use a turbine prime
mover.
1.2) EFFICIENCY
The efficiency of a conventional thermal power station ,considered as energy produced at the plant
bus bars compared with the heating value of the fuel consumed ,is typically 33% to 48% efficient.
1.3) COMPONENTS OF A TYPICAL THERMAL POWER PLANT
1 .Cooling tower 15.Coal pulverizer
2. Cooling water pump 16.Boiler steam drum
3. Three phase transmission line 17. Bottom ash hopper
4. Step up transformer 18. Superheater
5. Electrical generator 19. Forced draught fan.
6. Boiler feedwater pump 20. Reheater
7. Low pressure steam turbine 21. Economiser
8. Surface condenser 22. Air preheater
9. Intermediate pressure steam turbine 23. Precipitator
10. Steam control valve 24. Induced Draught fan
11. High pressure steam turbine 25. Ash dike
12. Feed water heater
13 .Coal conveyor (Reference 1)
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CHAPTER 2
FUEL & FUEL HANDLING SPECIFICATIONS
The fuel (coal) used at MTPS comes from two sourses, that are Raniganj and Mugma.The grade of
coal is BCD.
Type of fuel = Pulverized coal, heavy oil & L.D.O.
Number of mills = 06
Type of mills = Pressurized type bowl mill.
Number of P.A fan= 02
Number of F.D fan= 02
Number of I.D fan = 03 (1 standby) (Reference
2.1) Fuel preparation system: In coal-fired power stations, the raw feed coal is brought through
railway wagons to the coal storage area. Wagon triplers are used to empty the rail wagons and coal
from here are directly sent to coal conveyer units from where coal is to be forwarded to crusher
house for pulverization and from there further forwarded to coal bunkers beside the boiler through
conveyer belts. Manual coal feeding is carried out through crane.
FIG-2 WAGON TRIPLER
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Conveyer belt arrangement is accompanied by pull cord switch which operates at 16A & 440 V
A.C. It urgently stops the conveyer belt system in case of fault. A number of pull cord switch is
connected in series.
A suspended magnet (16 KVA Electromagnetic separators) is lifted above conveyer belts to attract
metal pieces from the coal passing above the conveyer belts.
FIG-3 CONVEYOR BELTS
2.2) CRUSHER HOUSE: From the hopper coal reaches to surge hopper through conveyer belts
and from there it get divided in two parts called as vibrating screen 1 and vibrating screen 2. From
there fine particles bypass to number three belt and large pieces of coal goes to the crusher. Shaft
of the crusher is connected to foot coupling drive (FCUI) drive which contains oil at 45 degree
empty. More speed of FCUI drive more speed of crusher so, more crushing of coal. From here
pulverized coal fall on conveyer belt arrangement as shown in figure.
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FIG-4 PULVERIZER
Inside the crusher house there is an induction motor to move the conveyer belts over the rollers.
The specifications of the induction motor are as follows:
Power = 100 KW
Volts = 415
Rpm = 1480
Amperes = 169
Phase = 3
Frequency = 50 Hz
Horse power = 133 (Reference 1 & 2)
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CHAPTER 3
GENERATION OF STEAM
3.1) BOILER:
Type of boiler- single drum, tangential firing & reheat type.
A boiler is a closed vessel in which water or other fluid is heated. The heated or vaporized fluid
exits the boiler for use in various processes or heating applications.
The pressure vessel in a boiler is usually made of steel, stainless steel or wrought iron. Copper was
often used for fireboxes (particularly for steam locomotives), because of its better therma
conductivity; however, in recent times, the high price of copper often makes this an uneconomic
choice and cheaper substitutes (such as steel) are used instead.
3.2) BOILER FITTINGS AND ACCESSORIES:
Safety valve: It is used to relieve pressure and prevent possible explosion of a boiler.
Water level indicators: They show the operator the level of fluid in boiler, also known as a sight
glass, water gauge or water column is provided.
Bottom blow down valves: They provide a means for removing solid particulates that condense
and lay on the bottom of a boiler. As the name implies, this valve is usually located directly on the
bottom of the boiler, and is occasionally opened to use the pressure in the boiler to push these
particulates out.
Continuous blow down valves: This allows a small quantity of water to escape continuously. Its
purpose is to prevent the water in the boiler becoming saturated with dissolved salts. Saturation
will lead to foaming and cause water droplets to be carried over with steam, a condition known as
priming.
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Low water cutoff: It is a mechanical means (usually a float switch) that is used to turn off the
burner or shut off fuel to the boiler to prevent it from running once the water goes below a certain
point ,thus preventing boiler from rupture on account of dry firing.
Surface blow down line: It provides a means for removing foam or other light weight non-
condensable substances that tend to flow on top of the water inside the boiler.
Circulating pump: It is designed to circulate water back to the boiler after it has expelled some of
its heat.
Feed water check valve or clack valve: A no return stop valve in the feed water line. This may be
fitted to the side of the boiler, just below the water level or to the top of the boiler. A top mounted
check valve is called a top feed and is intended to reduce the nuisance of lime scale. It doesnt
prevent lime scale formation but causes it to be precipitated in a powdery form which is easily
washed out of the boiler.
Chemical injection line: A connection to add chemicals for controlling feed water pH.
3.3) STEAM GENERATION: After the coal reaches bunkers which are at a height of 53m above
the ground ,coal reaches bunkers through conveyer belts. The bottom of the bunker is coupled to
motor which extracts coal from bunker.
At a height of 15m from the ground there is coal mill or pulverizer. Below the pulverizer there is a
bowl like structure which is movable and a roller is placed at the top of the bowl like structure
which crushes the coal and pulverized coal comes out of the bowl by virtue of centrifugal force.
Now this pulverized coal is brought to the boiler through primary air fan.
There are four mills and corresponding to each mill there is six elevations (A,B,C,D,E,F) and for
each mill the pulverized coal is brought by primary air fan is fed to boiler through six elevations as
given corresponding to each mill.
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Inside the boiler pulverized coal is now fed and there are water walls in the boiler which gets
heated on account of combustion of coal & hence steam is generated.
The generated steam reaches the boiler drum which is above the boiler and it is maintained at
constant pressure such that high temperature steam comes out of the drum. The steam generated
which is not suitably heated is again sent to boiler for further heating where there is ring header (a
small area of heating), inside boiler & steam after getting heated reaches boiler drum due to
density difference & comes out of it.
Air path: External fans are provided to give sufficient air for combustion. The forced draught fan
takes air from the atmosphere and, first warming it in the air preheater for better combustion
injects it via the air nozzles on the furnace wall.
The induced draught fan assists the FD fan by drawing out combustible gases from the furnace
maintaining a slightly negative pressure in to avoid backfiring through any opening. At the furnace
outlet and before the furnace gases are handled by the ID fan, fine dust carried by outlet gases is
removed to avoid atmospheric pollution. This is an environmental limitation prescribed by law
and additionally minimizes erosion of the ID fan.
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CHAPTER 4
COOLING TOWERS
Cooling towers are heat removal devices used to transfer process waste heat to the atmosphere.
FIG-5 COOLING TOWER
Cooling towers may either use the evaporation of water to remove process heat and cool the
working fluid or rely solely on air to cool the working fluid .
Common applications include cooling the circulating water used in power plants and achieve
cooling. The towers vary in size from small roof top units to very large hyperboloid structure that
can be up to 200 meters tall and 100 meters in diameter, or rectangular structures that can be over
40 meters tall and 80 meters long. Smaller towers are normally factory built, while larger ones are
constructed on site.
4.1) D.M. PLANT: The water is treated in this portion such that it is free of all the mineral
impurities. Hence the name demineralization plant. Thus the water becomes fit for further use in
the boiler drum with high value of steam formation and least damage to the turbine. This leads to
the increases life of the boiler and an improvement in efficiency.
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4.2) BOILER FEED PUMP: It is a specific type of pump used to pump feed water in to a steam
boiler. The water may be freshly supplied or returning condensate produced as a result of th
condensation of the steam produced by the boiler. These pumps are normally high pressure units
that use suction from a condensate return system and can be of the centrifugal pump type or
positive displacement type.
4.3) CONDENSER: The surface condenser is a shell and tube heat exchanger in which cooling
water is circulated through the tubes. The exhaust steam from the low pressure turbine enter the
shell where it is cooled and converted to water by flowing over the tubes as shown in the adjacent
diagram. Such condensers use steam ejectors or rotary motor-driven exhausters for continuous
removal of air and gases from the steam side to maintain vacuum.
FIG-6 CONDENSER (Reference 5)
For best efficiency, the temperature in the condenser must be kept as low as practical in order to
achieve lowest possible pressure in the condensing steam. The condenser generally uses either
circulating cooling water from a cooling tower to reject waste heat to the atmosphere, or once
through water from a river, lake or ocean.
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CHAPTER 5
ASH HANDLING
Coal burnt in the boiler produces a large amount of ash, out of these only 20% of ash settles at the
bottom of the boiler and through ash slurry pumps these are sent to ash dike across river bagmati.
Still 80% of the ash is now with the flue gases. The pressure maintained with in the boiler is
negative on account of the reason that-
(a.) Flue gases can be ejected from the boiler easily.
(b.) A cylindrical flame is required in boiler.
(c.) To ensure that there is no backfiring through any of the nozzles.
After the flue gases are ejected from the boiler flue gases passes through superheater, reheater &
economizer. The flue gases coming out of economizer has a temperature of 275-325 degree
Celsius before it enters air preheater. After coming out of the air preheater flue gases get divided in
to two paths-
(a.) First accompanied by induced draught fan.
(b.) Path leading to electrostatic precipitator (E.S.P).
Electrostatic precipitator: Electrostatic precipitator consists of pair of seven plates in which of a
pair first plate is negatively charged and second is positively charged & as a result field is created
The ash get deposited on the positive plate of the pair of seven plates on all the seven pair of plates
and by continuous hammering , it is removed from the plates and from here it is deposited at ash
dike across river by the use of slurry pumps.
The flue gases consist of carbon dioxide, nitrogen di oxide and sulphur dioxide. Induced draught
fan extract these gases and forward it to chimney from where it is exhausted. The flue gases
coming out of the chimney has a temperature of at least 120 degree Celsius.
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CHAPTER 6
TURBINE: SPECIFICATIONS & OPERATION
Type of turbine: Reheat type
Number of cycles: 3(HP, IP, LP)
Temperature of hp turbine inlet: 535 degree Celsius
Pressure at hp turbine inlet: 130 atm
Temperature at IP turbine inlet: 535 degree Celsius
Turbine speed: 3000 rpm
Condenser vacuum pressure: 0.1 kg/cm^2 (Reference 1)
FIG-7 TURBINE
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6.1) INTRODUCTION:
A steam turbine is a mechanical device that extracts thermal energy from pressurized steam, and
converts it in to useful mechanical work.
It has almost completely replaced the reciprocating piston steam engine (invented by Thomas
Newcomen and greatly improved by James watt) primarily because of its greater therma
efficiency and high power to weight ratio. Because the turbine generates rotary motion, it is
particularly suited to be used to drive an electrical generator about 80% of all electric generation
in the world is by the use of steam turbines. The steam turbine is a form of heat engine that derives
much of its improvement in thermodynamic efficiency through the use of multiple stages in the
expansion of the steam, which results in a closer approach to the ideal reversible process.
6.2) OPERATION OF TURBINE IN UNIT:
There are three stages of operation:
(a.) High pressure (H.P)
(b.) Intermediate pressure (I.P)
(c.) Low pressure (L.P)
The three stages of expansion of the steam is used because of the large shaft length. In the first
stage the high pressure steam from the output of the boiler is given to the first turbine unit .The
steam expands on the blades in this stage and sent to the next stage and so on.
NOTE: A special operation motor is mounted on the shaft of the turbine in order to keep it rotating
even in non-generating condition. This is done in order to keep the coupled shaft of the turbine and
the alternator from bending.
From superheater steam divided in two parts, left and right then after they pass through oil
operated control valve. When the pressure of the oil increase up to suitable level plunger above
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rises and steam enters the HP turbine. To increase oil pressure we have arrangement in contro
room and manual arrangement near HP turbine which when rotated in anti clockwise direction
increases the pressure of oil and plunger rises.
Control valves start opening at 0.7 and get fully opened at 1.5 units of pressure.
After passing through HP turbine steam again enters boiler and after getting heated it enters the I.P
turbine through valves present on left and right positions of the turbine.
Another valve present on I.P turbine that is low pressure control valve (L.P.C.L) that is on the
adjacent positions.
L.P.C.L valves starts opening at a pressure of 0.5 units and get fully opened at pressure of 1 unit of
pressure. Steam then enters low pressure turbine, having definite arrangement, when steam enter
inside it gas expands and this in turn rotates the blades of the turbine. The L.P turbine is coupled to
generator which produces electricity.
Three phase supply is obtained from the stator of the generator through hexagonal pipes which is
connected to generating transformer.
FIG-8 GENERATING TRANSFORMER
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CHAPTER 7
GENERATION UNIT/ALTERNATOR
The generation unit consists of the following sub-parts:
(a.) Turbine assembly
(b.) Alternator
(c.) Excitation Transformer.
FIG-8 GENERATOR
7.1) GENERATOR RATING/SPECIFICATIONS:
MW Rating = 110MW
MVA Rating = 137.5 MVA
KV Rating =11KV (+/- 5 %)
Frequency = 50 Hz
Power Factor = 0.8 lagging (Reference 1)
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7.2) ALTERNATOR:
An alternator is an electromechanical device that converts mechanical energy to electrical energy
in the form of alternating current.
Most alternators use a rotating magnetic field but linear alternators are occasionally used. In
principle, any AC electrical generator can be called an alternator, but usually the word refers to
small rotating machines driven by automotive and other internal combustion engines. Alternators
in power stations driven by steam turbines are called turbo-alternators.
Basic principle:
Alternators generate electricity using the same principle as DC generators, namely, when the
magnetic field around a conductor changes, a current is induced in the conductor. Typically, a
rotating magnet, called the rotor turns within a stationary set of conductors wound in coils on an
iron core, called the stator. The field cuts across the conductors, generating an induced emf
(electromotive force), as the mechanical input causes the rotor to turn.
The rotating magnetic field induces an AC voltage in the stator windings. Often there are three sets
of stator windings, physically offset so that the rotating magnetic field produces a three
phase current, displaced by one-third of a period with respect to each other.
The rotors magnetic field may be produced by induction (as in a "brush-less" alternator), by
permanent magnets (as in very small machines), or by a rotor winding energized with direct
current through slip rings and brushes. The rotors magnetic field may even be provided by
stationary field winding, with moving poles in the rotor. Automotive alternators invariably use a
rotor winding, which allows control of the alternators generated voltage by varying the current in
the rotor field winding. Permanent magnet machines avoid the loss due to magnetizing current in
the rotor, but are restricted in size, owing to the cost of the magnet material. Since the permanent
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magnet field is constant, the terminal voltage varies directly with the speed of the generator
Brushless AC generators are usually larger machines than those used in automotive applications.
An automatic voltage control device controls the field current to keep output voltage constant. If
the output voltage from the stationary armature coils drops due to an increase in demand, more
current is fed into the rotating field coils through the Automatic Voltage Regulator or AVR.
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CHAPTER 8
TRANSFORMERS
A transformer is a device that transfers power from one circuit to another through inductively
coupled electrical conductors.
FIG-10 TRANSFORMER
A transformer is a device that transfers electrical energy from one circuit to another
through inductively coupled conductorsthe transformer's coils. A varying current in the first or
primary winding creates a varying magnetic flux in the transformer's core and thus
varying magnetic field through the secondary winding this varying magnetic field induces a
varying electromotive force (EMF), or "voltage", in the secondary winding. This effect is
called mutual induction.
If a load is connected to the secondary, an electric current will flow in the secondary winding and
electrical energy will be transferred from the primary circuit through the transformer to the load. In
an ideal transformer, the induced voltage in the secondary winding (Vs) is in proportion to the
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primary voltage (Vp), and is given by the ratio of the number of turns in the secondary (Ns) to the
number of turns in the primary (Np) as follows:
By appropriate selection of the ratio of turns, a transformer thus allows an alternating curren
(AC) voltage to be "stepped up" by making Ns greater than Np, or "stepped down" by
making Ns less than Np.
In the vast majority of transformers, the windings are coils wound around a ferromagnetic
core, air-core transformers being a notable exception.
Transformers range in size from a thumbnail-sized coupling transformer hidden inside a
stage microphone to huge units weighing hundreds of tons used to interconnect portions of power
grids. All operate with the same basic principles, although the range of designs is wide. While new
technologies have eliminated the need for transformers in some electronic circuits, transformers
are still found in nearly all electronic devices designed for household ("mains") voltage
Transformers are essential for high-voltage electric power transmission, which makes long
distance transmission economically practical.
8.1) Basic principle: The transformer is based on two principles: first, that an electric current can
produce a magnetic field (electromagnetism), and, second that a changing magnetic field within a
coil of wire induces a voltage across the ends of the coil (electromagnetic induction). Changing the
current in the primary coil changes the magnetic flux that is developed. The changing magnetic
flux induces a voltage in the secondary coil.
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FIG-11 WINDING OF TRANSFORMER
An ideal transformer is shown in the adjacent figure. Current passing through the primary coil
creates a magnetic field. The primary and secondary coils are wrapped around a core of very
high magnetic permeability, such as iron, so that most of the magnetic flux passes through both the
primary and secondary coils.
Induction law
The voltage induced across the secondary coil may be calculated from Faraday's law of induction
which states that:
where Vs is the instantaneous voltage, Ns is the number of turns in the secondary coil and is
the magnetic flux through one turn of the coil. If the turns of the coil are oriented perpendicular to
the magnetic field lines, the flux is the product of the magnetic flux density and the area A through
which it cuts. The area is constant, being equal to the cross-sectional area of the transformer core,
whereas the magnetic field varies with time according to the excitation of the primary. Since the
same magnetic flux passes through both the primary and secondary coils in an idea
transformer, the instantaneous voltage across the primary winding equals
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Taking the ratio of the two equations forVs and Vp gives the basic equation for stepping up or
stepping down the voltage
Np/Ns is known as the Turns ratio, and is the primary functional characteristic of any transformer
In the case of step-up transformers, this may sometimes be stated as the reciprocal, Ns/Np. Turns
ratio is commonly expressed as an irreducible fraction or ratio: for example, a transformer with
primary and secondary windings of, respectively, 100 and 150 turns is said to have a turns ratio of
2:3 rather than 0.667 or 100:150. (Reference 4)
8.2) TRANSFORMER RATINGS:
(a.) Generating transformer (G.T):-
Manufactured by BHEL Bhopal
Three phase
Oil Temperature rise: 50 degree c
Winding Temperature rise: 55 to 60 degree c
Type of cooling: oil cooled
MVA Rating: 140 MVA
KV Rating: 230/11 KV
Frequency: 50 HZ
(b.) Station Transformer (S.T):-
Manufactured by BHEL Bhopal.
Three phase
Oil Temperature rise: 50 degree c
Winding Temperature rise: 55 degree c
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Type of cooling: Oil cooled
MVA Rating: 31.5 MVA
KV rating: 220/6.6KV
Frequency: 50 HZ
(c.) Unit Auxiliary Transformer:-
Manufactured by BHEL Bhopal
Three phase
Oil Temperature rise: 50 degree c
Winding Temperature rise: 55 to 60 degree c
Type of cooling: Oil cooled
MVA Rating: 20 MVA
KV Rating: 11/7 KV
Total number of transformers = 13
Station service transformer = 02
Sub-Station service transformer= 02
Cooling tower transformer = 02
Coal handling transformer = 02
Ash handling transformer = 02
Electrostatic pressurizer = 03 (Reference 1)
Use of various transformers in the plant depending on their ratings is as following:-
Generating transformer is used for the purpose of stepping up the voltage to 220 KV bus bar in
order for high voltage transmission, to reduce the line losses.
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Station transformer has the ratings as specified above and used as the unit which receives the
power from the incoming bus and gives it to the plant switchgear in order to provide power for the
initial start up and operation of each unit in order for it to start generating and transmitting power.
Another use of station transformer is to supply power to the various auxiliary equipment when the
plant has none of its unit in generating mode.
Unit auxiliary transformer is used only when the unit is generating. As explained earlier the station
transformer supplies power for the initial start up, but as the plant starts to generate power thi
auxiliary transformer is a 11/7 KV transformer.
Tappings are taken out of the generator feeding ducts which are given to the UAT and it supplies
power for the operation of the auxiliary equipments. At this point of time the station transformer
stops to operate and the plant becomes self sustaining.
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CHAPTER 9
POWER GRID
After the generation is done the 110 MW of power needs to be transmitted and distributed to the
various load centres. Since electrical power cannot be stored at one place it needs to be supplied to
the required areas as developed.
The station transformer is used to step up the 11KV generated voltage in to 220 KV transmitting
voltage. This is done because it has its own benefits of reduction in losses and improvement in the
transmission efficiency. There is a requirement of various protection gears in order for safe and
continuous operation. This is where the isolators and circuit breakers come in to play.
The grid present in the KBUNL has a switchyard which can receive and transmit power at two
values of voltages that are 220 KV and 132 KV. This can be better understood by the single line
diagram as shown for the 220 KV switchyard. Now we need to discuss the various parts of the
switchyard in detail.
9.1) THE 220 KV SWITCHYARD:
The switch yard consists of three buses:
(a.) Main bus 1
(b.)Main bus 2
(c.) Bypass bus
The three buses are installed in a manner such that the main bus 1 and 2 are used for either
receiving or sending power from station transformer 1 and 2 respectively. The purpose of the
bypass bus is just like a back up or a standby bus which operates only when there is a problem in
any one of the bus.
Since unit number 1 is under maintenance at the present moment hence only the main bus 2 is
charged and operational.
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9.2) SINGLE LINE DIAGRAM OF 220 KV SWITCHYARD
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)
9.3) OPERATION:
To understand the operation we need to go step by step with the single line diagram, Here we are
considering the unit 2 and hence that the GT 2 is operating. The generating transformer 2 steps up
the voltage to the value of 220 KV. Then it is taken to the bus but first there are two more
equipments attached in between. First is a CCVT used for the purpose of synchronization and then
a CT/PT is connected in series in order to measure that the appropriate amount of values of current
and voltage are passing through. After that comes the operation of the isolators.
9.4) THE 132KV SWITCHYARD:
The 132 KV switchyard has the same exact components as the 220 KV line leaving aside the fact
that it has a different operating voltage. For the operation at this voltage there needs to be a
stepping down of the voltage. This is done by an INTER BUS TRANSFORMER (IBT).
INTER BUS TRANSFORMER: The inter bus transformers are three winding transformers that
can do both jobs of stepping up or stepping down for the transmission at a different value. The IBT
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in KBUNL plant are used for the purpose of transforming the voltage from 220/132 KV. The
transformer specifications are as follows:
Manufactured by BHEL Bhopal.
Three phase, Three Winding.
Oil Temperature Rise 50 degree c
Winding Temperature rise 55 to 60 degree c.
Type of cooling-Oil cooled
MVA rating = HV LV TV
100 50 30 MVA
KV rating = 220 132 33 KV
Frequency = 50 HZ (Reference 1)
CHAPTER 10
COMPONENTS IN SWITCHYARD
10.1) CURRENT TRANSFORMERS: The current transformers are used for the instrumentation
and protection. It consists of a single winding in secondary. The direction of current in the C.T is
opposite to the direction of current in the supply.
FIG-12 CURRENT & POTENTIAL TRANSFORMERS
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10.2) POTENTIAL TRANSFORMERS: The potential transformers as the name suggests are
used for measuring the values by the use of stepping down the power and hence used for protection
and instrumentation.
10.3) WAVE TRAP: The wave traps are basically used for communication purposes. This is done
by increasing the usual operating frequency from 50 Hz to 50 MHz.
FIG-13 WAVE TRAP
Hence as the lines travel between the plant and the load centres, a direct communication can be
established between the various grids without the use of regular telephone lines.
10.4) SURGE ARRESTERS: Surge arresters are employed at every step in the switch yard in
order to protect the equipment from lightening strokes.
Specifications are as follows:
Max. Voltage= 216 KV
Max. Current= 10 A
10.5) LINE TOWERS: The line supports used for transmission are called as transmission tower
The two types of tower that we found in KBUNL plant were:
(a.) SINGLE LINE TOWERS for 132 KV line
(b.) DOUBLE LINE TOWERS for 220 KV line
10.6) LINE ISOLATORS: It usually works on no load condition and separates a circuit from the
rest of the healthy part for either fault clearance or maintenance.
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FIG-14 ISOLATORS
Types of lines isolators used are:
(1.) S&S made, double break,1250 A (220 KV bus)
(2.) S&S made, double break,800 A (132 KV bus)
10.7) CIRCUIT BREAKERS: They are used for operation on no load conditions and hence trip
the circuit in any case of failure. These are of oil, vaccum & SF6 operated.
FIG-15 CIRCUIT BREAKER
Specifications are given as under:
(1.) Siemens type 3AS2, 245 KV, 2000 A
SF6 type, for 220 KV bus.
(3.) Siemens type 3AS2, 145 KV , 1600 A
SF6 type for 132 KV bus. (Reference 1 & 6)
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10.8) GUARD RING: It is basically a bunch of round wire used for safety purpose of humans and
animals. It also avoids accidents and failure of line.
10.9). INSULATORS: The insulators used in KBUNL plant are of three types:
(a.) PIN INSULATORS (up to 33 KV)
(b.) STRAIN INSULATORS (up to 11 KV)
(C.) SUSPENSION INSULATORS (each disc designed for low voltage up to 11 KV).
CHAPTER 11
LOAD CENTRES
11.1) LOAD CENTRES UNDER 220 KV LINE:
(a.) Darbhanga 1
(b.) Darbhanga 2
(c.) Gopalganj 1
(d.) Gcpalganj 2
(e.) Kafen 1
(f.) Kafen 2
11.2) LOAD CENTRES UNDER 132 KV LINE:
(a.) Motihari
(b.) Muzaffarpur 1
(c.) Muzaffarpur 2
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(d.) Samastipur 1
(e.) Samastipur 2
NOTE: According to the agreement with the power grid corporation of India limited the KBUNL
can draw power from the Kafen power grid when it requires power initially for generation
purposes. The total power distributed by KBUNL is 180 MW and as it has a generation capacity of
110 MW presently hence it is allowed to draw power from the Kafen grid to fulfill power
requirements.
CHAPTER 12
GRID CONTROL ROOM
The control room, in case of remote control, houses all the necessary measuring instruments for
each panel or alternator and feeder, synchronizing gear, protective gear, automatic voltage
regulator, communication arrangement etc. A separate battery room and a motor-generator set or a
rectifier is also installed for supplying to make and trip circuit of switchgear. In case of outdoor
switch gear normally compressed air is used for operation.
.
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FIG-16 CONTROL ROOM
The supply and receiving of power as well as the health of various transformers and automatic
control of the equipment is done from this place. A monitoring engineer is specially placed there to
take the various readings of power meters to the load centers.
CONCLUSION
I hope this project would provide some knowledge and at the same time would be entertaining
national thermal power plant in Kanti, Muzaffarpur gives the insight of the real instruments used
There are many instruments like transformer, CT, PT, CVT, relay , bus bars, insulator, isolators
control room etc. What is the various problem seen in thermal plant while handling this
instruments
To get insight of the switch yard, control room how things operate, how things manage all is
learned there. Practical training as a whole proved to be extremely informative and experience
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building and the things learnt at it would definitely help a lot in snapping the future ahead a better
way.
REFERENCES
1. Manual of NTPC Kanti.
2. B. R. Gupta, (2008) Generation of Electrical energy Eurasia Publishing House (Pvt.) Ltd
page 109.
3. http://en.wikipedia.org/wiki/Alternator
4. http://en.wikipedia.org/wiki/Transformer
5. http://www.google.co.in/imgres?
imgurl=http://www.osha.gov/SLTC/etools/electric_power/images/condenser
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6. http://www.mvcircuitbreaker.com/pro.asp?id=145&Cid=109
7. Power System Protection and SwitchGear:- B. Ravindranath & M.Chandra, New Age
International (P) Limited Publication, Third Edition (2005), Pg No. (100-150)
8. www.wikipedia.org/wiki/insulators