HYDROELECTRIC POWER PLANT SALAL J & K

1. A Government of India enterprise)
PROJECT REPORT ON
ELECTRICAL ENGG(TRAIING) WITH RESPECT TO N.H.P.C
Submitted to CHANDIGARH University, Chandigarh
in partial fulfillment for the Award of the degree of
B.TECH(EEE)
(BECHLOR Of TECHNOLOGY)
Reporting to:
Mr. Jamil Akhtar ,
Pervesh Thakur,Dm(e&c
By:
Ajay Kumar Rana(358),
Aja Btech EEE
CGC GHARUAN MOHALI,

2. NHPC - AN OVERVIEW
•Set up in 1975 with an authorized capital of Rs. 200 Crores.
•Single largest organization for hydro power development in India in the central sector
•Capabilities to undertake all the activities from conceptualization to commissioning in relation to setting up of hydro
power projects
•Schedule ‘A’ Enterprise w.e.f. 15.5.1990.
•NHPC has been granted ISO 9001 Certificate for its quality system.
•Installed capacity : 2475 MW
•Projects constructed on Turnkey/deposit basis : 3
•Projects under O&M : 7
•Projects under construction : 11
•Projects under investigation : 20
•Projects under joint ventures : 4
•Projects under construction
•On turnkey/deposit basis : 2
SALAL AN OVERVIEW
State : Jammu & Kashmir
District : Reasi
Dam Site : Dhyangarh in Reasi
River : Chenab
Capacity : 6 X 115 MW
Annual Generation Target : 3100 MU
Rated Head : 94.5 m
Total Reservoir Capacity : 285 million Cumecs
Rockfill Dam : 1
Concrete Dam : 1
Penstocks : 6
Tail Race Tunnels : 2
Tariff Rate : 41.56 paise/unit

3. TECHNICAL FEATURES
• 118 m high, 630m long rockfill dam.
• 113 m high, 450 m long concrete dam
• 11 m dia, 2.46 km long tail race tunnel.
• 6 nos. Penstocks 5.23 m dia, 279 m long each.
• Sub-surface power house containing 6 units of 115 MW each.
Salal Hydroelectric Power Station Stage-I of 345 MW (115X3) and Stage-II of
345 MW (115X3) is constructed on river Chenab in the state of Jammu & Kashmir.
The project was conceived in 1920. The feasibility studies on the project commenced
in 1961 by the state government of J&K and construction was started in 1970 by
Central Hydroelectric Project Control Board under Ministry of Irrigation and Power. In
1978 construction of the projects was entrusted to NHPC on agency basis. After
completion of project, it was handed over to NHPC on ownership basis for Operation
and Maintenance. Stage-I of the project was commissioned in 1987. First unit of
Stage-II of the project was commissioned in 1993, second in 1994 and third in 1995.
At the peak of construction, about 12,000 personnel including contractors worked
around the clock to complete the project from 1970s to present day, under proper
guidance and maintenance of India's most successful company NHPC (NATIONAL
HYDROELECTRIC POWER CORPORATION. The project was taken by HCC and
various contractors.

5. GENERATOR
There are 3 Synchronous generators in stage-1 and 3 in stage -2.The synchronous generators are the
alternating generators whose rotor rotate at a a speed called synchronous speed. They run at this speed or
not at all.
They convert mechanical power into electrical power. Synchronous generators are usually of 3-phase
because of several advantages of three phase generation, transmission and distribution. It is also called
alternator. It mainly consists of two parts, a stator and a rotor.
1.GENERAL
•Manufacturer : BHEL
•Place of manufacture : Haridwar
•Type of design : Vertical suspension
•Applicable Standards : IS:4772-1968
2.Main data
•No. of phases : 3
•Rated P.F. : 0.9 lag
•Generator continuous rating at : 127.8 MVA
Rated frequency and voltage
•Generated rated voltage : 11 KV
•Rated Frequency : 50 Hz +5%
•No. of Poles : 32
•Rated Synchronous speed : 187.5 rpm
•Design runaway speed : 375 rpm
•Tolerance time of runaway speed : 2 min.
•Class of insulation for stator winding : F class
•Class of insulation for rotor winding : F class

6. 3.Efficiency
•At 100% continuous rated output (MVA) : 98%
•At 75% continuous rated output (MVA) : 97.7%
•At 50% continuous rated output (MVA) : 97%
4.Temperature
•Stator Winding : 60 C
•Rotor Winding : 75 C
•Max. temp at stator : 150 C
•Max temp at rotor : 120 C
5.Excitation Conditions
•Field Current : 1365 A
•Field Voltage : 243 V
•Max. permissible continuous field : 1600 A
current
•Main exciter rated capacity : 1500 A
•Main exciter rated voltage : 243 V
•Main exciter ceiling voltage ratio : 1.8
6.Stator
•Material : high quality si steel
•Insulation of laminations : Varnished
•Stator frame construction : fabricated

7. •No. of sectors : 4
•No. of slot : 456
•No. of pole : 32
•No. of slots per phase : 4.75
•Air gap : 25 mm
•No. of line terminals : 6
•No. of neutral terminals : 6
7.Generator Rotor
•Constructor of field poles : laminated
•Method of pole fixing : T-Heads
•Rotor rim Construction : punched steel segments
•Rotor spider construction : Fabricated
•Damper winding construction : cu, short circuited cage type
•OD of rotor : 7650 mm
•Type of collector ring brushes : carbon
•No. of slip rings : 2
8.Generator Shaft
•Material of the shaft : Steel forging
•OD : 1000mm
•Length : 7.9 m
•Dia of coupling flange : 1570 mm
•No. of coupling holes : 20

8. Transformer
1.General Stage I and Stage II
•Manufacturer CG and BHEL
•Design OFWF
•Applicable Standards IS2026

9. 4.Dimensions
Overall length 5.5m
Overall width 5.3m
Overall height
7.5m
2.Main data
•No. of phases : 1
•Rated power : 43.33 MVA
•Rated Frequency : 50 Hz
•Rated Voltage(No load)
HV side : 220/sqrt 3 KV
LV side : 11 KV
•Rated Line Current
HV side : 340.7 A
LV side : 3939.1 A
•Temperature Rise (oil) : 55 C
•Temperature rise (winding) : 65 C
•HV winding : star
•LV winding : delta
3.Losses
•Load losses at rated power, : 45 KW
frequency and at principal tapping,
referred to winding
•Core loss : 180 KW
•Total Loss : 185 KW

10. 6.HV neutral bushing
Type Oil communicating
Current rating
630 A
Voltage
36 Kv
7. bushings/bus duct termination
Current rating
3150 A
Voltage rating
17.5 KV
5.Transformer bushings
Manufacturer S&S Bushing ltd.
Type
Oil filled condenser
Current rating
800 A
Voltage rating
245 Kv

11. 2.Main data
Governor operating oil pressure
minimum 31Kg/cm2
maximum 40Kg/cm2
Rated 40Kg/cm2
Minimum wicket gate setting
Closing 10 sec
Opening 11 sec
Adjustmnt range in Governer opening and closing times
3 - 30 sec.
Sensitivity of governor to respond to minimumspeed change of rated
speed 0.02%
Governing system
1.General
Manufacturer
•Control Unit(Electro) : BHEL
•Hydraulic Unit(Hydraulic) : BHEL

12. Turbines
The turbine used at salal power plant was the Francis turbine.
Francis turbines are most widely used among water turbines and the development of the Francis
turbines in the last decade has opened up a large range of new application possibilities for this
type. These advances, motivated by a search for maximum profitability, have become possible
as the result of improved knowledge of the water flows in turbines and other hydraulic
phenomena.
A complete investigation and intensive research are carried out and efforts are put forth in the
improvement of turbine performance, the selection of suitable materials, and the construction
design in consideration of difficulties imposed by mechanical, manufacturing, and maintenance
factors at the design stage.
TOSHIBA is always making best efforts to design and manufacture highly efficient runners to
meet all requirements or Specifications. The runner is designed in consideration of various
parameters for computation by both theoretical analysis of internal flow and experimental
investigation by model tests. The runner is usually made of carbon steel castings and overlay
coating of stainless steel welding will be made on critical areas of cavitations if necessary. For
higher head machines, the runner is made of stainless steel castings. Especially 13%a Chrome
steel with enriched Nickel content becomes widely used for its excellent anti-cavitations
corrosion characteristics and mechanical strength.

13. The hydraulic research of the water passage through the spiral
case to stay vanes becomes very important in diminishing the losses of the
flow and the angle and the shape of stay vane cascades are carefully
designed. A new type of construction (parallel type) advantageous in
structural design is applied to all the stay rings. The spiral case is made of
steel plates for welded structures or high tensile strength steel plates.
TOSHIBA has used 60 or 80 kg/mm' high tensile strength steel plates for
spiral case shell plates of a big turbine or a high-head strength turbine. From
the view point of field welding, the spiral case shells are accurately cut out by
automatic gas-cutting machines, contributing to perfect field assembly even
without a temporary shop assembly check.

14. MAIN SHAFT
The main shaft for the turbine is made of high grade forged carbon steel. The
main shaft is connected to the generator shaft or the intermediate shaft by a
flange coupling. The shaft surface passing through the shaft seal is protected
with a stainless steel shaft sleeve to prevent the main shaft from wearing.
DRAFT TUBE LINER
The most commonly employed draft tube is of elbow type, in a
concrete structure, fixed with anchoring materials. Overall
configuration of the draft tube is thoroughly checked at Toshiba
Research Laboratory to ensure effective use of the head energy.
The draft tube liner, of welded construction, is made of steel plate
for general structure. If necessary due to theoretical and practical
reasons, a special air admission system is provided with a draft
tube liner to reduce water-pressure pulsation in the draft tube.

15. SPECIFICATION OF TURBINE AT SALAL POWER STATION
•Type Vertical
Shaft Francis
•Rated Speed : 187.5 RPM
•Rated Net Head : 94.5 m
•Minimum Head : 94.5 m
•Maximum Net Head : 102 m
•Rated Discharge : 137
Cumecs
•Turbine Rated Output
At rated head and rated discharge : 117.5 MW
Maximum Output of turbine at

16. Head > Maximum Head 123.5 MW
Optimum Efficiency of Turbine at
90% Part Load 92.5%
Maximum Runaway Speed 375 RPM
Specific Speed 229.2 m/KW
Direction of Rotation from Top Clock wise
Maximum Axial Hydraulic Thrust 382 Tonnes
Flywheel Effect of turbine
Rotating Parts 13000 Tonnes-m2
Total Thrust from turbine
Carried by Generator 382 Tonnes
Mass of Turbine rotating parts 52.4 Tonnes
Maximum permissible pressure rise 139 m (Max. water hammer)
Speed rise at 100% load throw off 55%
Pressure rise at 100% load throw off 35%

18. 220KV OUT DOOR SWITCHYARD:
Equipment in the switchyard
•Circuit breakers
•Isolators
•Current transformer
•Potential transformer
•Capacitive voltage transformer
• Lightening arrestor
•Bus Bar & conductor
•Earth switch
•Wave trap
•Insulators (post & Suspension)
•Control & power cables
•Clamps
•Fire fighting equipments

19. SINGLE LINE DIAGRAM OF 220 KV SWITCHYARD OF SALAL POWER STATION
Circuit Breaker
Isolator
C.T.
P.T.
L.A.
Capacitive Voltage Transformer
Earthing
UNIT#3UNIT#1 UNIT#2
BUS-A
BUS-B
UNIT#5UNIT#4 UNIT#6
BUS-A
BUS-A
P.T.
BUS-B
P.T.
K-2 J-2K-1 K-3 K-4 J-1
Wave Trap

20. 1.Circuit breakers
In this switchyard mainly two types of circuit breakers were used, one is SF6 and
another one is MOCB. SF6 breakers in Unit# 4,5,6 and outgoing feeders
Kishanpur # 2, Jammu #1,2. The MOCB is used in Unit # 1,2,3, Bus coupler and
Kishanpur # 1,3,4 feeders
SF6 CIRCUIT BREAKER
SF6 GAS: gas in pure state is inert, exhibits exceptional, thermal stability and
has excellent arc quenching property as well as exceptional high insulating
properties. It is one of most stable compounds, inert, non-flammable, and non-
toxic and odorless. The density of gas is about 5 times that of air and heat
dissipation in it is also much more than in air. At atmospheric pressure the
dielectric strength is about 2.4 times that of air and at 3Kg/cm2 it is same as that
of oil.
PHYSICAL PROPERTIES OF SF6 GAS
Molecular weight : 146.07
Melting point : - 50.7
Dielectric constant : 1.002 (at 760mm of Hg pressure)
CONSTRUCTION:
This is single-phase auto reclosing type circuit breaker. The three phases have
their own mechanism and air reservoir inter connected electrically and
pneumatically. Single pole of the breaker consisting of interrupting unit,
supporting unit and mechanism housing.
INTERRUPTING UNIT: The interrupter is a single-phase puffer type, which
consists of puffer cylinder and piston, stationary contact and its assembly. Over
conductors are connected to the upper and lower terminal pads.

21. OPENING OPERATION: opening is affected by pulling down the insulating rod, piston
rod, puffer cylinder, moving contact, moving arc contact and the nozzle. After some
contact wiping the stationary and moving arc contacts separate there by generating arc.
During down ward movement the gas pressure in puffer cylinder builds up and high-
pressure gas flows through nozzle and quenches the arc
CLOSING OPERATION: in closing operation insulating rod is pushed up and all the
parts move in reverse order of opening operation. Also sf6 is gas taken in to the puffer
cylinder.
SUPPORT UNIT ASSEMBLY: It consists of support porcelain and insulating pull rod,
this provides insulation between live parts and ground SF6 gas filled in containers in
interrupting and supporting unit at rated pressure.
AIR SYSTEM: Compressed air is required for opening operation of the breaker. It is
stored in inter connected chamber 70 Lt each which act as local source. This system is
provided with motor compressor unit. The capacity of compressor is 90 L/M. This
governor switch compressor system maintains the pressure between 14.5 to 15.5
Kg/cm2
PNEUMATIC OPERATING MECHANISM: The pneumatic operating mechanism
consists of opening piston, air cylinder, control valve, tripping coil& closing coil, latch,
trigger, closing spring, shock absorber and others.
OPENING OPERATION: The opening operation is affected by compressor air, when
opening signal energies trip coil, latch and cam are released by trip coil plunger and
control valve is open by spring which allows the compressed air, to push down the
piston of the pneumatic operating mechanism.
The movement of opening piston is
transmitted to the puffer cylinder through livers and rods and moving contacts of all all
three poles are pulled down together. The movement of opening piston

22. compresses the closing spring. At the final position of the opening operation the control valve
is closed by the linkage and the air in the cylinder is exhausted through the control valve to
the out side atmosphere. The piston is held in opening position against forcing of the closing
spring by holding latch.
CLOSING OPERATION: Closing operation made by the closing spring. When closing signal
energies the closing coil trigger and holding latch released by the closing coil plunger, and
closing spring closes the breaker.
SPECIFICATIONS
Rated voltage : 245 KV
Rated insulation level : 1050 KV (peak)
Rated frequency : 50 HZ
Rated normal current : 3150 A
Rated short circuit breaking current : 40 KA
Rated short circuit making current : 100 KA
Rated break time : 60 ms (3 cycles)
Rated short time current : 40 KA for 3 sec
Operating mechanism : spring closing, pneumatic tripping
Operating pressure(air)
:15 kg/cm2
SF6 gas pressure :6kg/cm2
Opening time : 30ms
Closing time : 100ms
Pole discrepancy : 3.3ms
Make : CGL

23. SF6 Circuit Breaker

24. MOCB (MINIMUM OIL CIRCUIT BREAKER)
220KV MOCB having two breaking units per pole, normally this can vary
between one and four, depending on the, rated voltage, insulation level and
short circuit current breaking capacity. The double breaking unit per pole is
connected together to form V shaped breaking unit.
The breaking units are mounted on post insulator, which constitute the
insulation of the pole to earth. Each [post insulator supports one double
breaking unit. The post insulator erected on a low concrete pedestal.
The breaking unit consists of an oil container with an arc control device of
cross blast type. The oil container consists of a porcelain tube reinforced with
a glass fiber tube on the inside, fixed contact mechanism housing cast in light
metal and gas tight top cap. The breaking unit is hermetically sealed and
pressurized with N2 gas. The top cap is, therefore fitted with a pressure
control valve. The circuit breaker is operated with a motor operated spring –
closing device of the type BLG. The operating device is connected with
mechanism of the breaking units via a pull rod system, link gears and
operating insulators.
The circuit is closed by operating device, which contains the closing
spring. When closing, the opening springs, which are tightly joined, to the
outer end of the rod system are charged. The opening catch in the operating
device keeps the CB in the closed position for opening all that is required is
to release the opening latch. Each breaking unit contains 53 lt.

25. MOCB SPECICATIONS:
Type : HLR 245/2502 E
Rated voltage :245 Kv
Impulse with stand voltage : 1050 Kv
Rated normal current : 2500A
Rated short time current : 40 KA
Breaking capacity : 40 KA
Rated making current :100KA
Gas pressure : 0.3 to 0.7
Mpa
Make : BHEL
MOCB Circuit Breaker

26. 2.Isolators
•Make : AMEI/WSI/BIMCO
•Type : Triple pole single circuit
Breaker
•Standard : IS9921
•Rated Continuous Current : 1600 A
•Rated voltage : 245 KV
•No of operations possible : 2500
•Rated short time current(1 sec) : 40 kA
•Clearance (Live and Ground) : 2300 mm
•Clearance(phase to phase) : 4500 mm
•Clearance(fixed contact and blades) : 2700 mm
3.Current transformer
Current transformers are instrument transformers to measure current in high circuit and for
protection purpose. The current transformer connected always in series with line. The CT s
installed in switchyard is oil filled hairpin type of 220kv. The hair pin arises out of fact that
the HV primary winding is of that shape, comprising a tube having graded insulation of oil
impregnated in which metal foils are inter posed at sutiblr intervals. The outer most of
these coils is connected to earth via an insulated terminal and link enabling dielectric loss
angle measurements be taken to check up the quality of insulation. This foil further acts as
earth shield between primary and secondary winding. The secondary winding with own
cores are mounted over the legs of hairpin. In this type of design up to 4 secondary cores
can be accommodated, an alternative design allowing accomadation forf ive secondaries.

27. Each unit is completely oil filled and sealed to ensure that the oil cannot come in
to contact the atmosphere and hermetically sealed with N2 gas at 0.35 kg/cm2
The flexible oil reservoir in the top housing above the high voltage terminal
chamber ensure this by preventing the creation of undue pressure or
depressions.
Unit side CTs having 4 core and outgoing feeder CTs having 5 core. Unit CTs
core 1 is for link line protection, core 2 is for LBB protection, core 3 is for Bus
differential main zone protection and core 4 is for metering, Bus differential
check zone protection. Ratio is 800/600/400/: 1.
The feeder side CTs core 1 is for main 1 distance protection and fault
locator, core 2 is for main 2 distance protection and disturbance recorder, core 3
is for Bus bar main zone protection, core 4 is for Bus bar check zone protection
and core 5 is for LBB protection and metering. CTs ratio is 800: 1, make BHEL
and CGL.

28. Current transformer
4.VOLTAGE TRANSFORMER
Voltage transformer is an instrument transformer for high voltage measurement and protection purpose. In
this switch yard, two types of voltage transformers are used. For Bus Bar potential transformer and for out
going feeders capacitive voltage transformer. The Bus bar voltage transformer having one primary and
two secondary winding. The primary winding is connected across phase and earth through neutral link.
The secondary winding is for measurement and another one is for disturbance recorder. The secondary
winding + ve terminal connected through 15a fuse and – ve earthed through neutral link. The PT is oil filled
with 300 lt.

29. SPECIFICATION:
Insulation level : 460/1050V
Primary volts : 127KV
Sec-wdg 1 : 63.5V
Burden : 500VA
Sec-wdg 2 : 63.5V
Burden :50 VA
Class : 5.0
Make : BHEL
5.CAPACITIVE VOLTAGE TRANSFORMER:
When the higher voltage of 110KV and above the electro magnetic design is a
costly item, and an economical is found in the capacitive voltage transformer. This
comprises a capacitor divider unit in which capacitors are connected in series
between line earths. A taping is made at convenient voltage (inter mediate voltage),
which is usually at 20/√3 or 12 KV. The secondary burden is connected to this
taping via a reactor and inter mediate transformer, the later being is electro
magnetic type. The reactor and transformer combined in one unit and oil filled,
hermetically sealed.
The CVT is using as a filter circuit for PLCC (Power line carrier
communication). The inductive reactance of combination is such as to balance the
capacitive reactance of the coupler at rated frequency i.e. there is a resonating
circuit. The primary and inter mediate voltage capacitors being housed in the
ceramic insulator and sealed to prevent air and moisture coming in to contact with
the insulation oil.

30. The HF terminal of CVT is for to send or receive high frequency
communication signal. the CVT and Wave trap and line impedeance combined form as a ∏
filter for PLCC.
SPECIFICATIONS:
Primary capacitance :4840 PF
Secondary capacitance : 48400 PF
HF capacitance :4400PF
Rated burden :100 VA
LIGHTENIG ARRESTER OR SURGE ARRESTER
Over voltages, which appear on electrical systems, are internal and external over voltages.
The internal over voltages are due to operation of circuit breaker when switching inductive or
capacitive loads, sudden earthing of one phase of system, disconnection of generator which
over speeds, sudden load removing etc. these over voltages rarely exceeds 3to 5 times of
normal voltage. External over voltages are caused by atmospheric discharges. These
voltages are cause considerable stress on insulation. The need to avoid breakdown of
primary insulation due to over voltages on the system, requires the CB, Transformer,post and
tension insulators and other apparatus have a with stand voltage level greater than the
protective levels of devices provided to give over voltage protection, e.g. surge diverters.
Diverters which provide these feature comprises one or more air gaps mounted in series with
non liner resistors, the function of air gap being to keep the circuit through the arrestor to
earth open under all normal power frequency to flash over and close the circuit when
abnormal voltages appear at the diverter terminal. In this

31. switchyard we used Zinc oxide non-linear gap less arrestor. Elpro make arresters
having 3 blocks each 66Kv, W.S. make having 4 arrester with 49.5 Kv voltage.
SPECIFICATIONS:
Make : ELPRO INSULATORS
Rated discharge current : 10 KA
Rating voltage : 66Kv
Make :W.S. INSULATORS
Rated discharge current :10 KA
Rated voltage :49.5 Kv

32. BUS BAR AND CONDUCTORS
Alternators are used in a power system where they are in parallel with many other
alternators. Bus Bar main function is to connect different alternators with common voltage
and frequency to deliver power. In this sub station double Bus system. , i.e. Bus A& Bus B .
Bus A and Bus B coupled through Bus coupler CB. Here three machines are connected in
one bus and another 3 machines are connected in another Bus. The out going feeders are
connected on Bus A and Bus B. Due to different loads on different feeders the buses are
not operating on split mode. The Bus conductor is twin tarantula (All Aluminium) conductor.
Each phase of bus having two conductors (bundle conductor).
Specifications:
No. Of strands: :37
Outer dia :36.67 mm
Conductor :AAC (tarantula)
The conductor from machine to Bus and Bus to out going feeder are zebra conductor.
SPECIFICATIONS:
•Conductor : ACSR (Aluminium conductor steel reinforced)
•Nominal size : Zebra
•Strands : 54 Al+ 7 steel (3.18 mm)
•Dia : 28.62 mm
•Area : 484. 480mm2

33. MAINTENANCE OF VARIOUS EQUIPMENTS IN SWITCHYARD
Maintenance of switchyard equipment is of two types:
1.Preventive maintenance.
2.Breakdown maintenance.
Preventive maintenance schedule is followed daily/monthly or yearly to avoid any outage
due to breakdown.
CB Monitoring & Maintenance:
1.Checking of SF6 gas pressure
2.Checking of air pressure
3.Drain water from air reservoir
4.Checking of looseness of compressor and motor mounting bolts and belt.
5.Oil level in crank case
Shutdown maintenance:
1.Cracks and contamination of porcelain clean with emery paper
2.Main terminal cleaning with emery paper
3.Tightness all external bolts
4.Rusting area painting
5.Stroke and contact wipe measurement
6.Setting check of gas density and air pressure switch, mesurement of dew point
7.Checking of opening and closing time etc
MOCB:
•Checking of leakage oil level
•Checking of oil leakage from grading capacitor

34. Shut down maintenance:
•B.D.V of oil
•Cleaning of breaker poles
•Checking of pole discrepancy relay
•Capacitance and tan delta measurement of grading capacitor
•Dynamic contact resistance and contact travel measurement
CURRENT TRANSFORMER:
1.Checking of oil leakage
2.Checking of any sparking at CT bushes
3.The rmovison scanning of CT
4.Cleaning and tightness CT primary bushing clamps and healthiness of bush
5.Checking of oil level and gas pressure
6.Capacitance and tan delta testing
CVT:
1.Checking of oil leakage
2.Thermo vision scanning of capacitance of stacks
3.Checking of any cracks
4.Capacitance and tan delta measurement
5.Testing of oil BDV
ISOLATORS AND EARTH SWITCH:
1.Maintenance of link gears
2.Cleaning of auxiliary contacts and greasing with silicon grease
3.Lubrication of operating mechanism
4.Alignment
5.Cleaning of support insulators and check for cracks
6.Contact resistance measure ment of isolator and earth switch

35. LIGHTENING ARRESTER:
1.Daily checking of surge counter and leakage counter
2.Cleaning of insulator
3.If required capacitance and tan delta tests
BUS BAR AND BUS INSULATOR:
1.Cleaning of insulators
2.Checking of insulators for cracks
3.Thermovison scanning of all clamps and joints
4.De weeding of switchyard
5.Checking of switchyard lights
WAVE TRAP:
1.Tightness and cleaning
2.General inspection and cleaning of tuning units
THERMO VISION SCANNING OF SWITCHYARD:
Thermo vision scanning of switchyard carrying out at the time of peak season for every
June and August. At every clamps and joints should be scanned through camera on peak
season
BUS BAR AND FEEDER PROTECTION
Bus bar protection works as back up protection to the connected generators & feeders .In
case of any fault on generator or feeder which was not cleared by its primary protection
scheme and the fault was being feed by other generators and feeders connected to same
bus to witch the faulty generator or feeder is connected, in this case bus bar protection work
as back up protection and thus trip all the generator and feeder connected to faulty portion
through this bus bar.