one word ans
TRANSCRIPT
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ONE WARDE ANSWERS
Normal size of Control room building is 40 *30mts
Normal area required for the S/S is 800 * 600mts
D G set Capacity for substation is 250 KVA
Substation Land level must be 300 mm above the Ground level (HFL)Space required for one bay 75 *27mts
Substation bearing capacity is more than 10 ton / m^2
Width of single and double line road is 3.75mts and 7.0mts
Height of boundary wall is 2.5 mts-3.5mts
Width of bay is 27mts
Gantry height of 400 kV is 15mts + 8.5mtspeak
Gantry height of 220kv is 10mts +5.5 mts peak
Gantry to gantry 21mts
Distance between bays 21mts
400kv ph: -ph clearance 7mts22 0kv ph-ph clearance 4mts
Clearance in S/S 400kv 220kv
Ph to earth 3.5m
Ph to ph 7m 4.5m
Bus to Bus 10m
Bus Bar height 8m
Bus Bar ph to ph 7m
Bus Bar size 4 inch IPS
Creep age distance of 400kv AC bushing is 10500mmDia of earth mat rod is 40mm (400, 220kv)
Dia of earth mat rod is 32mm (132kv)
Earth flat size is 75 *12mm
Earth mat should buried 600mm below the ground level
Station Earth resistance max 0.5 ohms
Height of the lightning mask is 47mts spike length is 3mts
Switching impulse is 250 microsecond / 250 m sec.
Leakage of (GIS) SF6 of each compartment should be less than 1%.
Mineral insulating oil-type-paraffinic
Transformer oil must have minimum Flash point 140Conservator air cell is made forNitral rubber
In ICT internal fault is make due to over heating and sudden switching surge
NGR is Petersonl oil
MVAR flow should not from one voltage level to the other voltage level
TSE - thyristor switching capacitors
TCR thyrestor controlled reactors
VTS Voltage Transformer Supervision
RLDC is doing only central sector scheduling ,
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A B T : Availability Based Tariff
: S R Introduced 01.01.03
A B T :- A B T has been so so effective in improving the Grid Discipline and operation.
It is heartening to note that Commercial and Economic forces even in India shows that
results can be obtained from Sensible and relatively simple measures .
RELIABILITY
1. Two 220v Battery set
2. Two 48v Battery set
3. Main 1 , Main 2 protection
4. One and Half Breaker System
5. Bus 1 ,and Bus 2
6. Shunt Reactor
7. 400/220 kv Auto Transformer
8. Fault Locator
Objectives of grid managements system frequency, voltage, loading, security system
reliability, Grid discipline merit order of breakdown.
EVENT LOGGER To record the event in the system
FAULT LOCATER To measured the fault distance in the line
DISTURBANCE RECORDER To record the disturbance in the system
To identify voltage current of pre or post conditionHaving 8 Analog channel and 16 Digital channel
BUS BAR protection In time of un balancing current or voltage the bus bar
protection is Operated
LBB or BFR Any fault condition Breaker trip command via 186 (trip
relay) . Breaker failure relay simultaneously command
LBB relay.186 . will not operate the breaker. after 200 ml
sec LBB operate. At . the time BUSBAR section dead
TAN DELTA Indication of quality and healthiness of the insulation in
the
(Test purpose) bushing or Equipments (0.007 at 20c
CIRCUITE BREAKER It is ON load device. Contact resistance end to end 150 .
. micro ohms Switching automatic interruption
P I R ( 400 ohms ) Are reduce the switching surge over voltage
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to close 8 to 10 mille seconds before the main contact
GRADING CAPACITOR Uniform voltage distribution on service
S F- 6 Very ideal for Arc quenching 6kg/cm^2
It is electro negative and 5 times heavier than air
ISOLATOR Disconnect under no load condition for safety insulation and
Maintenance work, center brake type, con.resistance max 300 ohms
EARTH SWITCH -To discharge the voltage on dead line. To earth contact resistance
300 micro ohms
C V T * Stepping down the voltage ,monitoring for metering, protection and
control
*They consist of coupling capacitor Made from di-electric impregnatedpaper
* Coupling capacitors are used for the PLCC
C V T use To measured the voltage Inputs to Relays / protection For of PLCC
C T Step down the current for measurement, controls, and protection.
Having 5 cores
L A High voltage surge to ground without affect to substation equipments1 Gapped L A, 2 Gapless L A Rated voltage 360kv,CGL 390KV
. Made for Zinc Oxide conductor
SURGE ARRESTER Diverting the high voltage surges to earth and protect the
insulation
Surge Monitor unit In between the LA and Earth
WAVE TRAP Trapping Carrier frequency
Wave trap are providing between the line and power station
Is a inductive device, to avoid carrier frequency entering thsubstation
Only allowed power frequency
LCR 20 to 2000kz Carrier Frequency
SHUNT REACTOR : -Will control the dynamic over voltage
To compensate shunt capacitance of T/L either switched or un
. switched
Control over voltage under abnormal conditions of system
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Take care of switching transients
SHUNT REACTOR Rated power 50 MVAR (Mega Volt Reactive VAR)
Gapped core construction, gapped core between air gaps are
. . molded in
Epoxy resin to prevent movement between individual
lamination
Core segments are radial laminated configuration, to prevent
. fringing flux
Five limbed core construction has been adopted
Tan delta 0.00158, Capacitance 44680,
IR value 1000 M ohms
N G R To limit the earth fault current it is connected neutral point of
S.R
Established Current to trap at the Neutral Point of the N G R
I R value primary to earth is 900m ohm
Tan delta value 0.00310,capacitance 310 pf (Pico farode)
S I L Surge impedance load to limit theTL at reactive VAR absorbed
. by Line equals the capacitive VAR supplied by the line
LIGHTNING MASK Lightning mask protect the substation area covered in 30
Height 45 mts Spike 3 mts
BLOCKING OF
AUTO RECLOSE LBB, Reactor protection, over voltage, Bus bar protection, .
. Z2 to, Z3 of distance protection circuit breaker problem, carrier
fail, . receipt of direct trip
R T U Remote terminal unit-Analog (parameter) &Digital(equipment) . . . .
. Datas From RTU is transmitted to the nearest sub LDC Trough
PLCC
HVDC Two different Generating station or to link with Asynchronous
link
System Hydro + Thermal
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Types of filter in HVDC: -
. 1. Single frequency tuned filter,
. 2nd order broad bond damped filter
3rd order broad bond damped filter, C type broad bond damped
filter
Corona ring To make electrical field around the live part uniform resulting
in electrical stress on insulators and hardware
Arcing horn Divert the arc under flash over away from insulator string
Frantic effect In TL receiving end voltage is higher than sending end voltage,
due
.. to the capacitive effect of line at lightly loaded on no load case
Objectives of Grid
Management : System frequency, System voltage, Line loading
System security, System reliability, Grid discipline, Merit order
of b
Advantages of
Fiber Optic Cable : -Small size, flexibility, easy of handling, Immunity to
Electromagnet . Interference,High bandwidth as the frequency, cross talks between Cables is .
. . . impossible ,
Unaffected lightning and electric shock, .
. Immunity To nuclear radiation,
No frequency clearance is required, not easy to Tap, Direct
digital . transmission is possible
Touch potential The potential difference between two points. one on the ground
other
Which can simultaneously touch by either end.Step potential
The potential difference between two points on ground surface. .
. Which Can be simultaneously touched by feet
Metal spread reason provide highly resistively for working person
Minimize hazards of Reptiles
To avoid surface area for muddy, and water storage
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Communication advantage :- Highly reliable, Continuously availability,
Less capital cost, less maintenance
POWER FACTOR Power factor is the ratio of resistive current to that of total
current
COS Q =Ir / It
COUBLING CAPACITOR For carrier communication
SHUNT CAPACITOR Power factor improvement during low voltage and low
power . fact
STATIC - V A R Step less variation of shunt compensation
DISSIPATION FACTOR Dissipation Factor is the ratio of resistive current to that
of . capacitive Current following in insulation materials.Tan Q = Ir / Ic
SURGE ARRESTER Diverting the high voltage surges to earth and protect the
insulation
RANZA Ranza is firstGeneration of Numerical relay, it is
accuracy memory
In the last event
( Z ) Impedance V / I P 10
FA1 B1
L +2
F- fault , L Line length , P monitor digital reading
Synchronous motor Power factor improved by the Synchronous motor
Synchronous admissible for 400kv +or 10%
Metering Accuracy + or 0.5
Energy Meter Calibration Error Limit + or - 0.25
Line loss 2%
Meter error 1%
PPM Parts Per Millennium 1/1000000 =0.000001
P S I Power Grid Safety instruction
P S I 02 Demarcation of work and testing Areas in substation
SEM-Special Energy Meter Electronic Energy Meter with 10 days backup 15
minutes reading
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ABT-Availability Based Tariff Grid Discipline start at Jan-2003
Modem Computer messages through the another computer to the way of modem
Minimum Ground earth mat resistance should be less then 0.5 ohms
Earth mat has been layed at a depth of600 mm from ground
Wave Trap Induction is 0.5 M H
Coupling capacitor capacity 4400pf or 8800pfImpedance matching of line and HF filter is close by coupling device
MVAR generated by 400kv line is 0.55 MVAR/km
Capacity of tertiary winding is 105MVA ( 3rd Harmonic )
Impedance of shunt Reactor approx 3200 ohms
SF6 Due point should be less then -15
SF 6 Arc quenching medium at a low and Auto pneumatically controlled
pressure
In 400kv switching surge without PIR is 4.6pu and with PIR is 2.3 Pu
Breaker main contact material is silver coated copper
Duty cycle of 400kv Breaker is O-0.3 CO (sec) 3 minute CNow a day up to 210 km P40, PIR is required
Pole Discrepancy not more than 3.33 ms
Between Two pole breaks should be less than 2.5ms
Breaker impulse withstand 1425 + 245 kvp
Rated breaking current 40KA
Rated making current peak 100KA
Voltage distribution 4%
Operating rod of CB is made ofpolytetra fluro ethylene (PTFE)
Operating rod of ABB CB is 200 mm, CGL-270MMCircuit Breaker (400kv) closing time maximum 150ms
Circuit Breaker (220kv) closing time maximum 200ms
Circuit Breaker (400kv) Tripping time maximum 25ms
Circuit Breaker (220kv) Tripping time maximum 35ms
250 km PIR not necessary
Bus Isolator All the Inter locks linked dont bypass
The maximum fault level in 400kv System 40 kA / 1 sec
The Dead Time of 400kv system is 0.3sec (300ms)
Normal Rating current of400kv Equipment 2000 / 3150 AThe charging reactive power for100km is about 120 MVAR
Contact resistance of interrupter is 50 75 micro ohm
Value of breaker grading capacitor is 500 PF
LA non linear (zin.o) resistor is using when voltage increase resistance is decrease
Silicon grease is applied on the busing to avoid flash over due to deposit old dust,
other . Particles
Value of PIR is 400 ohms (8 to 10 mille sec- before close the main contact)
Maximum value of contact rsistance of breaker is 150 micro ohms (75 +75)
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In 400kv BIL (lightning impulse) is 1425 kvp, Switching impulse 1050kvp
Surge impedance loading for 420 kv system is 550 MW
Power Frequency with stand voltage 630kv rms
Switching impulse level for 400kv equipment 1050kv peak
Insulation level of Transformer1300kv
Insulation level of Breaker and other Equipment 1425kvpLighting with standing capacity 1550kvp
Condition monitoring of transformers DGA, C+TAN DELTA, FRA, Exciting
magnetization, Current test, IR value, Ratio test, winding resistance
Basic impedance level in 400kv is 1425kvp
Switching impedance in 400kv is1050kvp
Lightning impulse with stand voltage 1550 kv peak
Transformer Bushing insulation level 1050kv peak
Power frequency 630kv rms
Rating of surge arrestor in 400kv is 390 kV for 10 sec
NGR is petersonl oilPower line impedance is 0.3-0.4 ohm /km
Normal flux density transformer is less than< 1.2 web
Accuracy of fault locator is 3%
Operating time of bus bar protection is 1 cycle
Conservator air cell is made forneutral rubber
Transformer oil has minimum flash point 140 dig.
Transformer oil is mainly used for1-insulation , 2-coolent.
Transformer oil - Paraffinic and Nephthenic.
Transformer oil is undergoes Electrical and Thermal Stresses insideTransformer oil In case of problem in the transformer, Insulating Oil gets de-
composed . and various gases like Hydrogen , Hydro carbon are
Generated and Solid . Insulation Generate Co,& Co2
Transformer Bushing for 400kv 245kv
Rated current 1250 A
Insulation level 1050 kvp
Power frequency 460
Value of the damping resistance in CVTis 13 ohms and 23 ohms
EHV grade transformer oil having minimum BDV 60kv with 2.5mm electrode gape
Line matching unit is part of the PLCC equipmentPIR are reduce the switching surge over voltage
Breaker puffer pressure is 17 kg /cm
Normal life of on transformer is 25years
Condition monitoring of C B: --DCRM, Breaker timings, Capacitance&Tan delta of
grading
Capacitors,Due point of SF6 gas
PIR closing is 8 to 10 mille sec
In ICT-OLTC tap changer is change in voltage; 1.25 % of voltage 17 steps
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Auto Transformer Tapping - +10% tapping HV
Transformer Territory winding for suppressing the Third Harmonic
PRD pressure 10 psi alarm (Pound per square inch)
Normal insulating oil drum capacity 209 lit
Before filling oil in transformer underthe vacuum pressure
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NGR rated power 3.0 MVAR
NGR System voltage 145kv class
NGR Rated Impedance 561 ohms
NGR HV bushing 145kv
NGR Neutral bushing 36kv
NGR To Limit the Earth Fault currentCapacitance 310 PF,Tan delta 0.00310,I.R value Primary to Earth 900M.ohms
Nuclear power station will trip at a frequency of51.5 Hz
N G RTan delta 0.00310, Capacitance 310 PF
Conservator Bladder Material Mitrile Rubber
C V T-Each stag 132 kV
C V T-Rated secondary voltage 110 V 3
Brea down voltage (KV) 60 KV for 2.5mm gap
Water content PPM = 30 PPM
Short time thermal current 40 KA/ 1Sec
Dynamic peak current 100 KAC T un used secondary core (terminals) should be short
C T secondary winding resistance minimum (500v megger) 50 M ohms
Dew point limit of SF6 IN -35 at normal -26 during O&M.
Dissipation Factor = Reactive current (To detect weakness in HV insulation)
Capacitive current
Dissipation Factor - Ratio of resistive current to that of Capacitive current
Tan Delta = Ir / Ic (Ir-resistive current) (Ic-capacitive current)Power factor = COS 0 = Ir / It
Power factor - The Ratio of Resistive current that of Total current
Tan Delta should not be more than 0.007 at 20c
OPGW- Maintenance-SRLDC, NRLDC, ULDC, CC-Engineering , CC-OS
Size of Copper Earth
95 sq mm copper main Earth
35 sq mm copper Additional Earth
Safety Clearance Ladder & Stick
400kv 3.1 meters
230kv 2.4 meters
MVAR = Active power
Reactive power
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VRM Voltage Recording Meter
FRM Frequency Recording Meter
P P M Parts per millennium 1 / 1000000 =0.000001
Availability calculation
Total NO of Lines in operation 40
Total NO of Days in month (January) 31days
Total NO of Hours in a Day 24 hours
Total Actual Time = No of line X No of days X No of Hours
Total Outage Attributable to Power Grid Include AMP + Fault tripping + Mal
operation + Breakdown (71.63hrs)
Percentage of Availability -% of ABT = Total Actual Time Outages X 100Total Actual Time
UST Ungrounded Specimen Test
GST Grounded Specimen Test
Generally measured using sharing bridge (or) Ratio Arm Bridge
Thalcher Kolar Line length is 1400 Commissioning on 14.12.03
A C PLANT Chennai, Selam centralized compressor capacity 50 tone each
Trichy 3.75 tone x 2 9 (Freon gas-R 22 ,R 12 )
O&M Expenses 1% on capital cost
SOS As and When Required
Voltage Control
400 kv system 360---400---420
220kv system 200---220---245
Frequency Control 49.0 Hz---50.5 Hz
Gateway of Telecom 3 places ,Mumbai ,Channai ,Kochi
R L D C has 5 centers. E-W-Mumbai, N-Delhi ,S-Bangalur, NE-Shillong
Grid code: -Standard List of Element Outage Categories
PUNCOM :-Every 10 second DATA updated
Microwave Tower :- Receive and Repeated station
SCADA :- Supervisory Control And Data Acquisition
OPGC :- Optic fiber Geopical Cabling
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Kudankulam Atomic Power station:- Aim AT 2000mw by Russian collaboration
Each Reactor consist of 1000 MW
:-Thrunelveli,Udumelpet,Kochi,Edaman,Thruvandr
um
If the Neutral is not Grounded1. The Capacitance current in the healthy phase increases to V3 Times the normal
value
2. The Capacitance current in the faulty phase become 3 times the normal value
3. Healthy feeders are taken to Line to Line
Need for Grounding the Neutral is
1. Protective scheme can be used to disconnect the fault
2. Arching Ground is eliminated
FIRE FIGHTING PUMP HOUSE
Jacky pump ,Compressor Auto start and Auto stop
Hydrant pump , Emulsifier pump Auto start and Manual stop
FFP house water storage tankcapacity 300M^3
Storage tank capacity 450 M^3Hydropnematic tank capacity 18 M^3
Hydrant points must be at a distance of 60Mts
Diesel Engine - Kirlosker Cummins
Rated - BHP 155 / 2100rpm
Pump Capacity - 410 m^3 / hour (Becon)
Emulsifier pump B&C/L make
- Delta Star connection ,132 kw / 180 HP, 213 A ,2960rpm
Becon make - BHP 410 m^3 / hourHydrant pump B&C / L make
- Delta connection ,37 kw / 50 HP, 63 A ,2920rpm
Becon make - BHP 80 m^3 / hour
Jockey pump - B&C / L make
- Delta connection ,11 kw / 15 HP, 20 A ,2900rpm
Becon make - BHP 32 m^3 / hour
Compressor - Star connection 1.5kw / 2 HP , 3.4 A 1405rpm
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Non-Return Valve KOLES 250mm inlet
Hydrant point - 16 points having
Co2 - 15 nos
Dry Chemical Powder (DCP) 40 nos
Heat detector (Quartozoid bulb) burst at above 79c
A C PLANT
Freon gas F22 Grade
Compressor oil grade Freezol 68
USV Un loading Solenoid Valve
A C Plant Compressor 3.5 ton
LIGHTNINIG ARRESTER
To safe yard Equipment for Lightning Surges
Incase of High Voltage Resistance will decrease
Gapped L AGapless LA Silver Carbide
Mare ELPRO
Ratting Current 10 KA
Ratting Voltage 360 KV
Maximum Spark Voltage 870 kv / 1.25 micro sec
Maximum Spark Voltage 1125 kv / 1.25 micro sec
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CIRCUIT BREAKER Automatic Switching during normal or abnormal condition
1 Breaker System Three Breaker used in Two Feeder
Advantage 1 Fault one Breaker or Bus or Line will not Interruption to the System
2 Addition of Circuits to the System is possible.
Grading Capacitors : Uniform voltage Distribution on service
P I R : 400 ohms before closing 8 to 10 mille second from Main contacts
Hydraulic operated : N2 Gas Accumulator is used for
Arc Interruption : 1 High Resistance
2 Current Zero Resistance
CB Annual maintenance
Timing test pole to pole difference 3.5 msGrading Capacitor Tan delta (UST)
I R value 5kv megger
Insulation Resistance 500v megger
Operating Times
Static Contact Resistance
Dynamic Contact Resistance Measurement (DCRM)
Tan delta & Capacitance of Grading Capacitance
Due point of SF6
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DCRM Dynamic Contact Resistance Measurementtest
- Current , Resistance ,Traveling speed
- Open , Close , Close open time
- Set Amplitude 36 for opening
- In this test identify Main Contact if any damage- Current inject 100 A
- 400KV breaker 2000 micro ohms set
- sampling speed set 10kilo cycle
- check for stroke length of CB
- check for over travel or over shut
- check for default travel
- check for Travel measurement
- check for Velocity measurement
- velocity = Distance
- Time
Operating rod ABB 200mm
Operating rod CGL 270mm
Pole Discrepancy Test difference 2.5 ms
Trip coil 1 , Trip coil 2 15 to 20 ohm
Difference between Main contact and PIR contactDucter value (contact Resistance)
Dew point test (-35) press two time for purging and test last value
ABB SF 6 Circuit Breaker
Breaker has supporting insulators,PIR , main contact, Grading Capacitors.
Operating pressure - Fully Pneumatic system
Pressure maintain 31.5 kg /cm 2
Closing time 100 to 120ms
Tripping time 18 to 22ms
SF-6 General Lock out 5.6 barSF-6 Alarm 5.8 bar
SF-6 Operating Pressure 7.5 / bar 20 c
PIR Pre Insertion Resistance 400 ohms ,it is contact 8 to 10 ms before the main contact
Grading Capacitors 500 Uniformly distributed the voltage operation
Due point (SF-6) -27
Duty cycle O 0.3sec CO
ABB Closing & Tripping coil Resistance 15 to 20 ohms
Trip & Closing coil - 15 to 20 ohms
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Breaker Contact Resistance 150 micro ohms end to end
Operating Rod - 200mm
63A 27.6 - Annunciation
63T - Trip
63C - Close63S - Start and Stop
P D - Pole Discrepancy
Pressure setting AIR Pressure SF 6 Pressure
Dynamic Contact Resistance Three Years Once
Tan delta & Capacitance Three Years Once
In ABB Breaker occur problem in Trichy
Magnetic ventle fail, Drive mechanism Oring fail , actuated ring damage
220 KV BREAKER
TCO - 50 ms
TOC - 200 ms
ABB -35
BHEL -36
CGL -35 NGEL -36
BHEL BREAKER
Accumulator oil Aero shell fluid 4 / 21 lit
Operating Electro magnetic, Hydraulic pressure
Hydraulic pressure 32.5 normal
ON 31.3
OFF 32.5
Air Lock out 30.5
Closing lock out 27.3General Lock out 25.3
SF6 6.0Kg / cm2
Opening time
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Opening coil 80 ohms
Opening Pneumatic
Closing Spring system
CGL BREAKER
Opening pneumatic pressureClosing spring system
Operating pressure 15.5 kg / cm2
SF-6 Pressure 6.0 kg / cm2
Operating time < 20 milli sec.
Closing time
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WT
= =
LMU
BT
PLCC
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BATTERY
Momenting current withstands the long period. Used for protection, PLCC, Auxiliary
supplies, triping & closing coil supplies Emergency lighting
Safety Materials Apron , Gaggle , Fresh water arrangement
Soda Solution Purpose for Neutralization of Acid
Acid proof Black paint coated
Acid proof Floor Tails
Acid and De Mineralized water marked and keep it separate .
. room
CELLS
Station Batteries are Led Acid Cells
No of positive plates ( Anode ) = X
No of Negative plates( Cathode) = X+1
Charged plates Positive ( Anode ) Brown
Negative plates Negative( Cathode) Gray
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Charging is Electrolysis.
Discharging is Galanism
Electrolysis Electrolysis is the conversion of Electric energy in to
chemical . Energy in Electrolysis Where by reaction areCompelled
Charging DC potential is applied the positive electrode attracts the . .
. negative sulphate Iron
Station Batteries are LED ACID CELL
+Ve plate Led peroxide
--Ve plate Spongy Led
Separators Micro process P V C / SinteredElectrolyte Sulphuric Acid H2SO4
35%Acid 65% D. M. Water
Specific Gravity (Normal) 1200
Fully charged condition 1210
IN 220 V Battery
Capacity 300 AH
Boost voltage 283.0v 2.65 v each
Fully charged 2.16 v each
Float voltage 235.5v 2.16v each
Discharge cell 1.8 v each
Curative discharge ones in year
Discharge current 30A X 10 hours
Boost +ve terminal 88
th
cell
IN 48 V Battery
Capacity 300 AH
Float voltage 51.8 v 2.16 v each
Boost voltage 63.5 v 2.65 v each
Boost +ve terminal 20th cell
% Of Battery Capacity
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Discharge current X Hour X 100
Ampere Hour (300 AH)
E.g. 29 A X 9 Hours X 100 = 87 % = 300 AH
Half Yearly - Earth Fault Relay checkYearly - All Battery check
Charger Transformer winding 50 M.ohm
Curative Discharge Maintanance Three years once
To discharge at 1.8v
CELLS
1. Series current I : n E amps
R + nr
2. Parallel current I : E amps
R + r / n3. Series & Parallel I : n E amps
R+ nr / m
LINES
Cost of variation Tower 30 35 %
Cost of variation conductor 35 40 %
Cost of variation Installation, Earthing 25 30 %
Cost of variation Insulator 4 5 %
Cost of variation Hardware 2 3 %
Moose conductor 61---54 / 3.53 + 7 / 3.53
Moose sectional area 31.77mmMoose mass per 1Mts length 2.004kg
DC resistance 0.05552 ohms / km
Moose minimum tensile strength 161.2Kn
All aluminum alloy conductor (AAAC) 61 / 3.53mm
ACSR Aluminum Conductor Steel Reinforced 75
. 54 Al-3.53mm / 7 Steel-3.53mm
AAAC Diameter of conductor 31.95mm
AAAC approx. Wt 1.666kg per mts
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Earth wire 7 / 3.66mm steel Dia 10.98mm
Copper bond suspension 1, tension - 2
IEC Industrial electro technical commission
IN 400 KV
No of insulator in V string 2 x 23 (120kn) HVDC 38 No of insulator in Pilot string 23
Double Single suspension 1 x 23 (120kn)(3.85mts-length)
Suspension 2 x 24
Single tension 1 x 24
Double tension 2 x 23 (160 kn)(4.11mts-length)
ACSR Moos conductor impudence 0.345 ohms / km
DC resistance 2.5 ohms / km
Double tension insulator 2*23 no 160kn
Long rod insulator are made of electro porcelain
Railway crossing, river crossing 24 insulators
IN 220 KV
Single suspension 13 or 14 / 70kn
Pilot 13 or 14 / 70kn
Double suspension 2 x 14 / 70kn
Single tension 14 or 15 /120kn
Double tension 2 x 15 / 120kn
Insulator creepage distance 292mm
Distance between subs conductor (spacer) 450mm (45cm)
Maximum load on the conductor is 70 % of UTS
ACSR PANTHER 110 / 132kv 30stans / 3mm+ 7 / 3mm
ACSR ZEEBRA 220 / 220kv 54 /3.18mm+ 7 / 3.18mm
ACSR MOOSE 400kv-54 / 3.53mm + 7 / 3.53mm
ACSR BUSIMIS 800 KV-AC, 500 KV-HVDC
EARTH wire 7 / 3.66mm
INSULATOR Disc 255 mm dia 120 KN mechanical strength
Typical corona extinction level in 400kv is 320kv
Shielding angle 132kv / 30
Shielding angle 220kv / 30
Shielding angle 400kv / 20
Shielding angle 500kv HVDC 10
Shielding angle 800KV 20
Shielding angle for river crossing tower 10
Pollution level minimum creepage light 16mm / kV
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Pollution level minimum creepage medium 20mm / kV
Pollution level minimum creepage heavy 25mm / kV
Pollution level minimum creepage very heavy 31mm /kV
AC line insulator standard disc
DC line insulator antifog disc type
Tower earthing
Pipe earthing G S pipe 25mm dia and 3060 mm length
Pipe earthing (in soft soil) G S pipe 25mm dia and 2.50mts length
Counter pies earthing 15-meter earth wire buried 1meter depth
for radial direction
Earth value (max) 8 to 10 ohms
Railway crossing, river crossing double earthing
Self supporting tower D type towerTransposition tower C type tower
Height of tower single circuit 30mts
Height of tower double circuit 45mts
Max sag allowed 12.47mts
Railway clearance 19.3mts, 18mts(220kv)
Telecom clearance 4.5mts
Mid span joint 30 meter away from the tower
TOWER
A - Self supporting towers
B Conventional guyed towers
C Chaintle guyed towers
Type of Tower
S/C D/C
A DA Type Tower 0 to 2 degree
B DB Type Tower 2 to 15 degreeC DC Type Tower 15 to 30 degree (Transposition Tower)
D DD Type Tower 30 to 60 degree
Transposition tower
Single circuit C type
Double circuit DC type
Tension tower
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0 degree - Sectional tower
2 to 15 degree
15 to 30 degree
30 to 60 degree - Dead end tower
Dead end , River end - Anchor Tower - DD type45 Single Pilot
Above 45 Double Pilot
Foundation
Foundation Depth 3.01 meter
1. Normal dry
2. Wet
3. Partially submerged
4. Fully submerged
5. Dry fissured rock6. Wet fissured rock
7. Hard rock foundation
8. Block cotton soil
Required Squire Area
A type 36 Sq m
B type 56 Sq m
C type 84 Sq m
D type 126 Sq m
Special Tower Is used at location such as those involving long spans for River crossing
,Valley crossing, Creek crossing , Power line crossing falling on the line route.
No of insulators
400kv Dia 255mm
Single suspension 1 x 23nos 120 KN (255 x 145 mm)
Pilot 1 x 23 nos 120 kn
V string 2 x 23 nos 90 KN
Double suspension 2 x 24 nos 160 KN (280 x 145 mm)
Disc
220 kv 120kn - 255 X 145 mm
400 kv - 120kn 255 x 145 mm (1 x 23)
160kn 280 x 145 mm (2 x 24)
800 kv - 210kn 280 x 170 mm (2 x 40) , (2 x 35)
UPSEB - 300kn - 320 x 195 mm (2 x 29) , (2 x 31)both for suspension & tension
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220kv Dia 255mm
Single suspension, Pilot 13 or 14 / 70 KN
Double suspension 2 x 14 / 70kn
Single tension 14 or 15 / 120kn
Double tension 2 x 15 / 160kn
Shielding Angle
110kv-30 ,220kv-30 ,400kv-20 ,800kv-20 ,+ - 500kv 10
Span Normal
800kv 400mts, 450mts
400kv 400mts
220kv 335, 350, 375mts
Spacer 45 centimeters
Clearance
In EHV lines the clearance above ground shall not be less than 5.2 m + 0.3 m for every
33 KV
Single circuit Ph to ph 11mts
Double circuit ph to ph 8mts
Mid span clearance ph to earth wire 9mts
Clearance for 400kv with any other line 6.1mtsTele communication clearance 6.1mts
Earth wire to conductor 9.0 mts
Railway clearance minimum (400kv) 19.3mts
Railway clearance minimum (220kv) 15.4mts
Railway clearance minimum (132kv) 14.6mts
Railway clearance minimum (66kv) 14.1mts
Road Crossing (High Way) 12.7mts
Railway crossing must be at an angle of 65*to 90*
National High way, State High way 12.70mts
500kv HVDC earth clearance 12.5mtsCircuit-To-Circuit 16mts
800kv 15.0 mts
800kv conductor to conductor 15.0 mts
Live part to nearest part Minimum ground clearance P & T clearance
400kv 3.1mts 8.84 mts 4.88 mts
220kv 2.8mts 7.01mts 3.05 mts
110kv 1.4mts 6.10mts (132kv) 2.74mts
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63kv 1.0mts 5.49mts
33kv 0.8mts 3.70mts
Line to Line
400kv 6.2mts
220kv 4.58mts132kv 3.05mts
vertical clearance for 400kv / 220kv 5.2 mts
Right of way ROW Ph to earth
800kv 85mts 12.0mts
500kv HVD 51mts 12.5mts
400kv 52mts 8.842mts
400kv single circuit 48mts
220kv 35mts 7.015mts132k 27mts 6.1mts
110k 22mts
66k 18mts 5.5mts
wind span :- In between two center point of the span either sides of the tower
A B C
c d
Wind span of the tower B = a / 2 + b / 2 a b
Weight span of the tower B = c + d
Transposition tower :-
Changing position of the phase conductor at every 1/3 of the line length
To equalize Impedance per phase Normally C type DC type tower with 0 degree
Wind zone 1=33, 2=39, 3 =44(normal), 4 =47, 5 =50, 6 =55
Wind zone standardization = 35, 45, 50 mt / sec
Composite insulators (very light):-Fiber glass rod as core+ silicone ashed material
Vibration damper (4R) is damping 4 resonant frequencies
Basic wind speed is 44 m / sec
Life of tower normal 50 years, HVDC tower 150 years, River crossing 500 years
Types of survey
Walk our survey, preliminary survey, Detail survey, Check survey
Topographical map is 1: 50,000
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Line survey 1 cm = 5km
Height of the single circuit Tower is 30 mts
Height of the double circuit Tower is 45mts
Shielding angle of the tower is 20
Maximum height of the tower is 135 meter (N.Sagar-Gooty)
Standard tower extension 3, 6, 9, 12, 18, 25 mtsTower extension will be fixing at bottom
Lug extension 1.5mts, 2.5mts, 3.5mts
In normal soil-soil investigation is doing up to 7 mts depth
In river crossing soil investigation is doing up to 40 mts depth
Tack welding below wrist level in S/ circuit
Tack welding below Bottom crass arm level in D/ circuit
Maintain sub conductor spacing 6 per 400 mtsRepair sleeve more then two stands broken in outer layer
Copper bond length 500 mm in length
Spacer rod ( retaining rod ) 4 rods for each side
Vibration Damper 1) stock bridge Vibration Damper, 2) spacer damper
In ERS polymer insulator are used
Absorption index megger value of15sec to 60sec
Hot line stick is Fibre Epoxy
Insulator materials Alumina, feldspar, SilicaMaximum height of tree bellow line 5.5mts
Depth of foundation 3.1mts
Chimney 1: 1.5 :3
Maximum sag allowed 12.87 mts
Power line crossing clearance 6.10mts
500 kv HVDC earth clearance is 12.5mts
First HVDC project at AP to MP
HVDC 500MW conversion 300 MVAR will consume at both ends
H V D C Power Loss = 4 % onlyD.C Line :Regulate have much of power sent to use
TSC-Thyrestor Switching Capacitor, TCR-Thyrestor Controlled Reactor
Synchronizing is 90% of system voltage in both sides
Current carrying ofBersimis conductor is 950A
Thalcher to Kolar line length 1400 km
Break even distance in HVDC is 650 700km (Repeated station)
HVDC 500MW conversion 300 MVARwill consume at both ends
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Dead time of HVDC is 200 msec
Right of way (ROW) ofHVDC is 46mts
500 kv HVDC Earth clearance 12.5mts
Chandrapur HVDC 500 MW Back to Back
HVDC Transmission AdvantagesRequired only two conductors
Less transmission voltage drop , Better voltage regulation
Less Corona loss
Less Interference with communication lines and no insatiability of power transmission
In HVDC Frequency meter not required
Regulate have much of power sent use
HVDC use as Assynchronizing
G R Ground Return
M R Metallic Return
Basic wind speed is 44km / sec
In ERS polymer insulators or used
ERS erection, power grid adopt GINPOLF method
ERS supplied by LINPSEY manufacturing company Canada
F type towers where angle is >60 in 800kv
Maximum height of ERS tower is 78 mts
If the joined of fiber OPGW at 600c
OPGW Inter portion consist of Aluminum tube which houses the optical fiber and
outer . . portion is Ordinary G I wire and act as Earth wire
With out shutdown PID , OPGW , Put non Auto mode
Hot line maintenance is hot stick method and bare hand method
Hot stick method - Line man work with an insulated stick on the live conductorBare hand method Line man who does the maintenance job is at the same potential of
the . conductor And is totally insulated from the ground by using insulated
ladder
Bare hand method
Clearance for 400kv 7 feet ,
Clearance for 220kv 5 feet ,
Tools Glass based Epoxy Resin
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Hot line maintenance Change of insulators,
Hot line maintenance shunting is doing after 3rd insulator
Hot man should not wear any ring, chain, watch, which make cause circulating current
Hot line stick EPOXY GLASS 100kv / ft / 5minutes
Hot line Insulation Resistance 100kv / ft / 5 minutesHot line leakage current 14 micro amp / ft
Hot line suit Faraday Cage FIBRE 25%,NOMEX 75% (Metaly cotton cloths)
Hot line Ladder EPOXY GLASS RESIN
Hot stick tester :- Leakage current not less than 30 micro ampere
Hot line work should taken Auto recloser shell be in OFF for the line at both end
First Hotline bare hand method First Hotline bare hand technique in power Grid and in
. . . India was Carried out on Salem Bangalure 400kv in
1990
Dress - Mentally Cotton Cloths
P P Rope-Poly Propylene Rope
Midspan joint should be 30mts away from tower
Polymer insulators are using in ERS
ERS supplied by LINPSEY manufacturing company in Canada
ERS errection, power grid adopt GINPOLE method
LILO:- For existing Line divert to connect another substation
Thrunelveli: -Multicircuit substationKanpur :-Unique Sub station
Kayankulam :-Unique power substation
GAS Insulated substation
Thermal power :- Coal ,Fuel , Gas
Wind power :-Air
Hydro power :-Water
Nuclear power :-Uranium
Solar Power :-Sun Light
Ramagundam , Singarolli :-500 MWLightning :- 2 x 10*8 volts and : 4 x 10*4 current , 10 5 second
Trichy Neyveli II 164.17km
Trichy Ney-TS-I Ex 172.26km
Trichy Madurai I 130.37km
Trichy Madurai II 130.37km
Selam Neyveli I 174.9km
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Selam Neyveli II 178.7km
Selam Bangalore 181.357km
Selam Hosur 127.7km
Selam Udumelpet I 150.5KM
Selam Udumelpet II 147.6KM
M R T
FSK Frequency Shift Key
VDU Visual Display Unit
VTS Voltage Transformer Supervision
PSB Power Swing BlockSOTF Sw bus bar protection scheme itch On Fault
REF Restricted Earth Fault
P40 YTG 33 phase selector
PUR Permissive Under Reach
POR Permissive Over reach
J1 , J2, K D C Supply
E C V T Volt
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H A C Supply
A C T Terminals
L Event Logger , Annunciation
B Bus bar
C protection circuit
D meteringU potential free contact
Meter Calibration
Error Limit - 0.25 + or -
Line loss - 2%
Meter Error - 1%
Considerable Allowed Error - 3%
Monitor Equipment
DR , EL , Recording Instruments , Fault Locator
Ranza Fault Locator Ranza is a Numerical Relay (Digital)
Sorel Disturbance Recorder -
Analog channel 8 ,Digital channel 12 -16
Analog channel C T-1R,2Y,3B,4N CVT 5R,6Y,7B,8N
Horizontal line 100ms apart printed
Voltage 2 cm - 480v peak to peak
Current 2 cm - 10,000 Amp peak to peak
20 db Transmission lossBPL exchange 24 subscriber , 16 Trunk
The capital investment of the protective relaying may be order of 3 5 % of the total
Cost of substation equipment.
Modern static relay capable of sensing fault with in 20ms
The dead time of 400kv system is 0.3sec
The recline time depends on operation of breaker which is 2.5 sec
Station protection Bus Bar, Stub, TEEDType of relay 1)Disc type 2) Magnetic type 3)Digital type -Electromagnetic Digital
Electromagnetic static
Current operated relay-Normal current flow 180 (over line)
Burden of the ct metering core is 40va accuracy 0.5
LBB operating current is 200mA after 200m sec
Fault current 130kv is 31kA
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Coupling device does impedance matching of line and HF filter
Wave trap Available 0.5 Mh , 1.0 Mh , 2 Mh (0.5 Mh)
Power swing blocking time for 40m.sec
Current setting of stub protection is 2500
MVAR generated by 400kv line is 0.55MVAR / km
The transformer differential relay production operate in harmonics exceeds 20%
Over fluxing relay (k=V/F) < 2.35 alarm. >2.35 trip 1.25 setting time 50 sec
Impedances of shunt reactor is opprox 3200 ohms
Shunt reactor backup protection relay set for 70% impedance, time delay 1.5sec
P 40 stability angle varies from 30 to 90, depends up on the line length
SF 6 due point should be less than - 15 degree C
Power equation V1 V2 x sin Q Sin Q is the load angle depends up on X
X
Bushing C T used for R E F relay
CT super vision relay dial setting 1.4 volts
Operating time of Bus bar protection is 1 cycle
Accuracy of Fault locater is 3%
P S B Power Swing Block relay
Carrier aided signal through NSD 40
RAZFEE relay tripping time 3ms
Auto re close 80% to 90% of the fault in power system or transient in nature
Auto re close are employed to successfully restore the system stability
Dead time 1 phase auto re close 0.6 sec
3 phase auto re close 0.5 sec
Reclaim time = 25 sec
Delayed time = 51 secRasfee relay tripping time - 3 ms
SOTF relay is in service only for 200 m sec at the time of charging
Loss in coupling capacitor should be with in 0.5db
LMU is for maximum power transfer from carrier equipment to line
Zero sequence Impedance of the line = Z Q = 1.064 ohms / km
Positive sequence impedance of the line = Z1= 0.0275+0.331 ohms / km
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Breaker failure protection 20%of the full load current expected by the CB is
not cleared by set time relay operate
50 Hz 1 Harmonic
100 Hz II Harmonic150 Hz III Harmonic
Fault locator
% of fault location = Fault impedance X 100
Line impedance
Zone I 80% of the line length and instaneous Trip (
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Analog data transmission is every 10 sec
Digital data by exemption every 4 sec
RTU is synchronized with GPS (Global positioning system) time and every 15 minutes
it . will check and correct
RTU Terminal units :-Analog (parameters)&Digital (equipment) Datas from RTU is
transmitted to the Nearest sub LDC through PLCC
Class I data (digital data) status indication of CB, Isolator
Class II data (analog data) V, I, P, Q, F
Normally scads scan class II data. If any events occur in class I data will over come
and transmit every 4 sec
System operation means system monitoring and managementDuring auto reclose NGR reduces secondary arcing current
SIL (surge impedance load) it is the theoretical loading limit of TL at reactive VAR
absorbed by the line Equals the capacitive VAR supplied by the line
100 MW generators can generate 60 MVAR and it can absorb 50 MVAR
For REFbushing C T is using
In steady static stability safe load angle is 30To down load SEM data 486 computers is sufficient (Dos based)
Burden of SEM is 0.5 VA / phase
Current setting of stub protection is 2500A
0ver fluxing is creating- voltage increasing = voltage k>1.11
Frequency decreasing frequency
Over fluxing relay working at HV , LV, Frequency
Auto re close is set at 600ms to 1sec
Reactor Backup timing 1 sec from 0.5 sec
Restraint bias 50% and 30%
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Instantaneous Tripping relay time is less then 100ms
Differential (87R) DTH-31 setting bias 15
Circulating current 400kv main CT+ 400 Tie CT+ 400kv Neutral CT+ 230kv CT
. . 87 (all are 1000/1A)
REF Is circulated relay
VTS Voltage Transformer Supervision
Synchronizing - 90% of system voltage &Frequency in both side
Carrier Aided signal though NSD 40 PLCC
STUB Line protection - 51 ST Over Current Protection
STUB LINE PROTECTION- 51 ST (current relay)Normal dial setting current in 1 amp.
Timer set 0.3sec.
Stub line protection used during the bus shutdown.
Fuse Failure Relay 97
RANZA (Fault Locator)- % of the faulty line length will be displayed
Fault Locator (Madurai feeder) Type- XTF Ph fault-57P, Earth fault 57N
Transformer
Differential DTH 31
Circulating current CAG 34
Differential over current CDD 41 voltage /frequency =k>1.11
Over load CAG 39
Over fluxing GTTM 22Differential (Bus bar) SBNH 163
Shunt reactor
Differential CAG 34
Restricted Earth fault CAG 14
Back up YTG 33
Reactor Backup Protection 87 RC ,RB
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Transformer & Reactor Test
Transformer , Reactor , Bushing , & Breaker also tested UST mode
Transformer , Reactor Winding , ABB - CVT , also tested GST mode
Measurement of winding resistance All three phase Jumper removedMagnetic Balance test
Magnetizing current test
Measurement of polarity and phase relationship
Floating Neutral voltage measurement
Short circuit test
Bucholze relay test
IR value Insulation test
Tan delta & Capacitance measurement
Dissipation Factor COS Q / SIN Q = Tan delta
Capacitance and Dissipation Factor Tan delta test.UST modeTan delta Dissipation Factor 0.007
The rate of change of Dissipation Factor (Tan delta ) 0.001 / year
The rate of change of Capacitance value max + or 1%
WTI and OTI calibration
Auto Reclose 186A,152X,186B 186L / O RYB
Auto Reclose
Reclaim time 25 sec
Dead time 1 secDead timer 0.5 sec
Timer for Delayed Auto reclose 2.5sec
L B B protection 50 zx , 50 zy (2 / 50z Timer)50 Z
L B B protection
Timer 2/50z time (plug) setting 0.2 sec
Circuit Breaker - Trip Circuit supervision (TC-1) 195RYB
Circuit Breaker - Trip Circuit supervision (TC-2) 295RYB
Phase Selector 21 RYB
VT Fuse Failure Relay 97
STUB Line Blind Zone protection 51-ST
STUB Line Blind Zone protection 0.3 sec
Carrier Lock Out 85 LO
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Reactor Differential protection 87R
Reactor Differential protection Setting Bias 30%
Reactor Restricted Earth Fault protection 64R
Reactor Back up protection 21R (YTG 33)98R (Timer)Reactor Back up protection - 60% of the Reactor Impedance
- Zone 3 = 1.25 sec
Differential Over Current Protection (67 AX,BX,CX,NX)
Differential Over Current Setting 0.2 Amps
Over Fluxing Protection 99
Circulating Current Differential Protection (87)
Circulating Current Differential Protection
Current setting 0.1 Amps
Over Load Protection
Current Setting 1Amps
Dial Setting - 10 Amps
Disturbance recorder
Having 8 Analog channels 4 in current & 4 in voltage
Having 16 Digital channels-logic-Protection
Digital signal cannot transmit for a long distance therefore repeaters are provided
Digital signal is faster then Analog signalMinimum 20-25 second time will take to reach a data from RTU station to RLDC
Router is using to communicate to the other station
TCP / IP-Transmission control protocol ,Internal protocol
PROTECTIVE RELAYING
Protective relaying is one of the several features of system design with minimizing
damage
to the equipments. And interruptions to services when electrical features occur
It is sensitively, selectively speed and reliability .
Protective relaying is design as minimizing damage to equipment interruptions when
electrical features occurs .
1.Over current relay - increase 10 %. Current and time relay 10 sec
2.Over voltage relay - 110 % for 5 sec (Trichy 4 sec) , 140 % Instantaneous first line of the defense
2.back up relaying =>functions only when primary relay fail
Primary relaying may fail because of failure in any of the following
1. Current or voltage supply to the relays
2. DC tripping voltage supply3. Protective relaying
3. Tripping circuit
4. Circuit beaker
Protective layers operate
1. Magnetitude voltage, current or both
2. Frequency
3. Phase angle
4. Duration5. Rate of change of
6. Direction of order of change
7. Harmonies or wave shape
Zone of protection the section that is protected by a set of relays is called the zone
of protection
Inputs current, voltage, frequency, power input supply carrier input PLCC
System voltages are usually transformed from 400kv to 110 volt by CVTFeeder protections
1. Lightning strokes
2. Phase / earth fault
3. Over voltage
Representative value of a lightning stroke
Voltage =2*10^8 volts
Current =4*10^4 amps
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Duration 10^-5 sec
LAS are provided on the both side of transformer.
The mainly used scheme 400kv systems are
1. Distance scheme2. Phase comparison scheme
Distance relay scheme
The relay system is made to operate only when the distance of fault point from
the
Relaying point is with in the relay setting.
The relay compares the ratio of voltage and current in the protected feeder.
Distance protection (impedance protection)\basically of three types of distance relay
1.Impedence relay, 2. Reactance relay, 3. Admittance mho relay
Micro mho typ distance relays have been employed generally on medium
And long lines. The relays capable of looking in one direction only towards the fault
On the protected feeder section.
Micro mho Protection (Main I) distance protection (impedance protection)
Fault locator circuit Micro mho protection
Line V T Supply ^
To operation depends upon voltage to current ratio.
It is compares the fault current seen by the relay and the voltage at the relaying pointto drive the distance of the fault . It is designed to operate only for fault
Occurring between the fault location and selected reach point .
Micro mho (21)-Main-1 protection 186 RYB 186 T (3 Phase)
Main I micro mho
Main II phase comparison P40 + ZTCM
Micro mho relay tripping time - 8ms
ZONE OF PROTECTION
zone 1 80% of protected length . time delay instantaneous
zone 2 100%protected line length + 50% of the shortest time delay 500m.zone 3 200% of protected line =>1500ms
zone 4 20% of protected line =>1500ms
V.T. SUPERVISION.
The voltage transformer Supervision uses drive the NPS components of the line Voltage
and line current.
An unbalanced fault in the voltage transformer circuit causes NPS voltage above setting
without detectable NPS current and cause VTS to operate.
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SYNCHRONIZING SCHEME
The differences in phase voltage and frequency are with in selected limit before closing
- Up two section of a power system.
Distance relay by remote end this means slow and un selective tripping and wide
spread block out
PERMISSIVE UNDER REACH SCHEME
For protection of 21 the relay is permissive command to other end
On receiving permissive trip command + operation of zone 2 will lead to immediate
tripping called aided trip
PERMISSIVE OVER REACH
In fault on zone 2 at the remote end zone comparator operation along with carrier
receive signal give instant tripping with aided trip indication.
Code 1 direct trip signal Hand trip, over voltage, Shunt reactor, LBB.Code - 2 Permissive Inter trip signal zone 2 relay operation causes Breaker tripping
CARRIER lock Out relay for tripping of an receipt of inter trip signal and at the same
time
It Lock out carrier
SWITCH ON TO FAULT
For SOTF action at least one of zone comparator operation is needed additionally
SOTF:- Need 3 phases Trip
SOTF system detection is activated by using on External breaker closing signal.Time 220 m / s Instantaneous
This features is available only when all three pole dead signal is present for a period of
200ms or 110ms
under this condition when any of the low set current detector pickup with out voltage
detector operation .
Three phase tripping with SOTF indication will be initiated.
(P- 40) Phase comparison relays schemes (principle relay)
Main II ProtectionCurrent Operated Relay (current in put relay)
Minimum Operating time 10 ms
Average Operating time 20 ms
Main CT (2000A) + Tie CT (2000A) 78 21 ABC (phase selector relay)This method provides high speed and selective unit type protection.
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Comparison of phase angle between two sides communicated to any time phase angle
30
If phase3 angle to change to high so trip command will come
The phase comparison relay schemes are generally recommended below 300 KM long
line Because the effective of line charging current and alteration of carrier signals.
This relay schemes the phase radiation ship between current entering and leaving
the protected feeds sections employing the power line carrier communication
1. Comparison of phase angles between two sides communicated to any time phase
angle 30
2 .If phase angle to change to high so trip command will be come.
When the difference between the phase angle of currents at both end crosses a preset
value the line trips
To take maintenance inform CPCC for test and also inform other end
Put both end to out of service
C T wire short and check current ZERO
Protection operated test apply current 5,6 7,8 9,10
I 1 - Positive phase sequence Low set , High set
I 2 -Negative phase sequence Low set , High set
Put dummy Load 75 ohms
P 40 (78) Main-2 protection 86 RYB 86 T (3 Phase)
Over voltage protection 59RYB(2 / 59 Timer) 86 OV T
V / I = Z (Z Distance )
DIFFERENTIAL PROTECTION RELAY
Transformer Differential relay is Unit protection
Primary 1000 / 1 for 400kv
Secondary 800 / 1 for 220kv
The Differential protection provides complete protection for winding and terminal faults
The system operate on circulating current principle in CT at each side balance each
other
An internal fault creates an un balance and operation of relays
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DTH 31 used for Two winding transformer used as 0.33 VA phase at rated current 1A
DTH 32 used for 3 phase 3 winding transformer used as 0.39 VA per phase at rated
currant 1A
The relay operates when differential current exceeds 15% relay rated current (fixed )
The bias setting is (adjusting) 30%High set current 10 times of the normal current (normal 1A)
Second harmonic content of the differential current exceeds 20%
Interposing C Ts are used for ratio correction when ever necessary should be adopted
on the -Inter posting CT by connecting them in star / delta.
Type of differential relay is used in our substation DTH 31
Harmonic Restraint of Differential relay is turned for 2 nd Harmonic
In Transformer Differential relay 400kv main CT and Tie CT 5 th core as used
For Through fault Differential relay has to restrain
Transformer Differential relay in our substation is Group A protection
Differential relay is one that operates when the Vector difference of two or more similarElectrical quantities exceeds a pre determine values
PHASE SELECTOR RELAY ( 21 )
Phase Selector Relay is also provided with P-40 for identification faulty phase and also
for
Auto re close
OVER VOLTAGE ( 86 ov ) , (86 ovx)
86 OV Main & Tie Breaker TC-1& TC-2 also LBB of Main & Tie Breaker
86 OVX Remote end trip CH-1,CH-2 ,Auto re close Lock Out of Main & Tie
Breaker
Time delay 110% for 5 sec Vn 69.85 = 440v (Trichy-4 sec)
Instantaneous 140 % < 100 ms instantaneous Vn 88.90v = 560v
POWER SWING BLOCK
Power swing black will be detected out side of operating zone.
More than 40 m/s Power swing block. Less than 40 m / s as fault.
Time to enter operating zone from outer zone.
BUS BAR PROTECTION
Incoming current and out going current are balanced maintain in Bus Bar Protection
If any Bus fault the current will be high that time
That time Bus Bar Protection operated zone A & zone B
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VS = IF (RCT+ 2RL ^2) 86.6V setting = 100v
RCT Resistance across CT , RL Load Resistance of conductor
All Bus Bar protection are Differential protection,
Fast acting Differential relay,
Bus Bar protection scheme for 400 kv system is high impedance Circulating Current
relay scheme .
Bus bar protection relay scheme is the vector sum of the currents Entering
and leaving the bus zone is compared.
This relay discriminate internal and external faults.
Current flowing through Secondaries will be balanced
Current will become unbalanced and will cause voltage rise at relay point Then Bus Bar
protection operated
Fault level in Bus Bar is higher then lines or Transformer
High set current which distinguishes between CT open condition or Bus fault condition
2000/1 setting 75v
Bus bar protection is stable and free from thro faults.
High Impedance un biased differential protection is used for the protection of bus bar.
Bus bar main lone and Bus bar check Zone is connected to separate current transformer
(C.T)-
- Cores on all connected breakers accept the bus bar breaker.
CT wire supervision VT X 31 CTR 2000 /1 setting 10v
Plug setting 75 volts
BUS WIRE SUPERVISION
Bus wire supervision is provided for alarm and tripping in case of CT wire open
Setting 14 v and delay 3 seconds
Zone A - All CTs connected Bus I
Zone B - All CTs connected Bus IIZone C - All CTs connected Bus I or Bus II
Bus wire supervision 14 and delay of 3 seconds
LOCAL BREAKER BACK UB PROTECTION (L B B)
Line Main CT core 4 (1000 / 1A) 50z
Line Tie CT core 4 (1000 / 1A) 2/50z Fault Locator
Reactor Bushing CT core 2 (1000 / 1A)
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This relay is provided for protection ,in case of Breaker failed 0 Trip during a fault
condition the operation of LBB will initiate tripping of other feeder. And Bus feeding
to the faulty Breaker
There by isolating the faulty Breaker
Current (plug) setting 20% of 1Amps
Relay with stand twice the rated current continuously
100 times rated current for 1 sec
Accuracy + or 10% of the current setting for any fault condition
For Feeder
Phase 1.2 amps
Neutral 0.4 amps
Time delay 200 ms
For Transformer
Phase 0.2 amps
Neutral 0.2 amps
Time delay 200 ms
REACTOR PROTECTION
DIFFERENTIAL RPOTECTION
Differential protection is working at circulating current principle .
The Differential protection relay provide complete protection for winding and terminal
fault
RESTRICTED EARTH FAULT 64 R Group - B
Restricted Earth fault protection is complete winding for Earth fault
The Differential protection will not provide protection for fault near the Neutral side
Of the winding. If the Earthing in done through Impedance
LINE REACTOR BACK UP 21R Group A
It may pick up due to non-availability of 110-v supply of CVT and it can be
checked
operation of this protection
IEEE NOTATIONS FOR VARIOUS RELAYS
IEEE DEVICE NUMBER TYPES OF RELAY
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21 R - Reactor Distance Back Up Relay
21- Phase selector relay
24 - Volts / Hertz relay
25 - Check Synchronize Relay 25 SK
27 - Under Voltage relay
30 - Annunciator relayDTH-31 - Directional protection relay
32 - Directional power relay
37 - Under current relay
40 - Field failure relay
P-40 - Phase comparison relay
46N - Negative sequence over current relay
49 machine or transformer thermal relay
50 - Instantaneous over current relay
50Z - LBB Local Breaker Back up relay
51 ST - Stub line protection relay (current test)51 - AC time over current relay
52A - Circuit Breaker auxiliary switch (normally open)
52B - Circuit Breaker auxiliary switch (normally close)
55 - Power factor relay
59 - Over voltage relay
60 Voltage or current balance relay
64 - Restricted earth fault protective relay
67 - Directional over current relay
67N - Ground directional over current relay68 - Blocking relay
74 - Alarm relay
76 - DC over current relay
79 - Auto re close relay
81 - Frequency relay
85 - Lock out relay
86 over voltage relay
87 - Differential relay
87 - Circulating current relay
94 - Tripping relay95 Supervision Relay
95x Zone Bus Wire Shorting Realy
97 - VT fuses fail relay
99 - Over fluxing relay
TRANSFORMER PRODUCTION
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Transformer : Transforming electrical voltage one stage to another stage for self
induction
or mutual induction with do not power change
Efficiency : 98%
DIFFERENTIAL PROTECTION RELAY
Transformer Differential relay is Unit protection
Connected between Main Bushing CT and 220kv CT
When differential current exceeds 0.35 amps
The Differential protection provides complete protection for winding and terminal faults
The system operate on circulating current principle in CT at each side balance each
other
An internal fault creates an un balance and operation of relays
DTH 31 used for Two winding transformer used as 0.33 VA phase at rated current 1A
DTH 32 used for 3 phase 3 winding transformer used as 0.39 VA per phase at rated . .
. . currant 1A
The relay operates when differential current exceeds 15% relay rated current (fixed )
The bias setting is (adjusting) 30%
High set current 10 times of the normal current (normal 1A)
Second harmonic content of the differential current exceeds 20%
Interposing CTs used for ratio correction when ever necessary should be adopted on the
-Inter posting CT by connecting them in star / delta.
Type of differential relay is used in our substation DTH 31
Harmonic Restraint of Differential relay is turned for 2 nd Harmonic
In Transformer Differential relay 400kv main CT and Tie CT 5 th core as usedFor Through fault Differential relay has to restrain
Transformer Differential relay in our substation is Group A protection
Differential relay is one that operates when the Vector difference of two or more similar
Electrical quantities exceeds a pre determine values
TRANSFORMER 400KV BUSHING CT
Core 1 500 / 1A - O / C , O / L ,& E / F
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Core 2 1000 / 1A - Spare
Core 3 505 / 1.5 - WDG . Temp
TRANSFORMER 220KV BUSHING CT
Core 1 Spare
Core 2 Differential Over Current , Over Load Protection
CIRCULATING CURRENT- CAG 34
Circulating current relay is a unit production working on the circulating current
principle
Normal condition current flowing through the relay is 0.
For any fault zero current will flow through the relay causing instantaneous tripping
This relay will operate for phase to phase and phase to earth.
Normal setting 0.1amps.
OVER FLUX RELAY GTT21
0ver fluxing is creating- voltage increasing = voltage k>1.11
Frequency decreasing frequency
Power frequency and voltage causes both an increase in stress on insulation.
And working Magnetic flux proportionate increase.
System voltage and frequency maintain under 360 to 420, 49 to 51.5.
Transformer is applied to the over flux relay which operates if the E / F ratio crosses the
setting.
When Voltage increase 10% rated value at 50 Hz
Setting 2.5v / Hz Alarm 2.25 v / Hx Alarm 3.5 sec
RESTRICTED EARTH FAULT PROTECTION
Connected between main CT and Neutral CT
DIRECTIONAL OVER CURRENT
OIL TEMPERATURE
WINDING TEMPERATURE
O L T C , & P R D
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DISTURBANCE RECORDER
Disturbance Recorder is a vital component of EHV feeder protection system.
Disturbance Recorder is monitor various system parameters like Voltage, line .
Current, System frequency, Various Relay contacts, states the records the parameters in. case of fault
Soral has 8 Analog Channels, 16 logic Channels.
Normal recording 1 sec post fault, and 0.3 sec free fault
It Connected to a Time synchronizing system of getting accurate timing of fault and
relay operation
EVENT LOGGER (PERM200)
Event Logger helps an analyzing a Disturbance by providing the events like
Relay operation, Tripping, Healthiness of relay, Auxiliary system etc.
And also record of various switching operations carried out.
Event Logger - plant status and Alarm status in every 4.00 hours
SUBSTATION PROTECTION
Bus Bar Protection , L B B , Differential Protection, Circulating Current
Lightning Arrester , Lightning Mask
Stub Line protection 51 ST (External resistance 3.3 k ohm)
Voltage Increasing - Frequency Decreasing Over flux is Creating
Fuse failure relay 97
P L C C
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PLCC- Frequency allotted by international authorities from 30kHz to 500kHz
PLCC
Used for communication purpose ,and also used tele metering , tele signaling , tele
control ,
Tele printer , tele protection Data transferring signals etc.- In modern power system communication between Load Dispatching Centers to
Generating station
- And substation
PLCC -Ph to Ph coupling used in PLCC (0 4 kHz)
-Channel 1-Speech channels
-Channel 2-Protection channel 1 instant telephone speech, protection coupler
NSD-60,NSD-61
- Channel 3-Protection channel2 used for CPCC, and all substations for instant
communication
AF Multi fluxer used for transmitting Voice, Fax, telemetering, Teleprotection signals
Speech Channels not used for Telemetering
Speech Channels bandwidth can be increased to 300 to 3400 Hz
PLCC level adjustment for speech O3EE 12 & 13
Level adjust with Level Oscillator and Level Generator Receive level O3EH-
10&11 measured and Adjust pot O3EH6
Protection as will as telemetering both can not be used in same channels
Protection coupler / modem
Level adjustment NSD 60-R 126 available on mother board of NSD 60
Level adjustment NSD 61- pot 11 of G3EP
Telemetering :- For transmission of real time Data from different substation, Generating
station to LDC,through- Modem Such as NSK 3 & NSK 4 Parameters such as
MW,MVAR,V,F Transmitted to LDC by using Transducer
LMU
Line Matching Unit Used for matching for line impedance and impedance of
the PLCC equipment 320 ohms per phase
ETI 21 Single channel
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ETI 22 Double channel
PLCC Make ABB-ETI 21,BPL-9505,WS-WSP 100 & PUNCOM
PLCC E P O B E filter-TF&RF, O-Audio frequency level, B Power
supply unit
1st-speech & Data (ETI-21) 2nd speech & protection 3rd
speech & protection Data available only speech panel
AGC Automatic Gain Control
PLCC Power Line Carrier Communication (Band width 4 KHz)
PTCC Power tele communication
GDT Gas Discharge Tube
DTMF Dual Tone Multi Frequency
FSK Frequency Shift Key
RF Radio Frequency 0 to 4 KHz
R T U Remote Terminal Unit
AGC Automatic Gain Control (AGC volt 5 +1v
Adopted PLCC carrier frequency range 30 to 500 KHz
Protection channels in PLCC NSD 4,NSD 41, NSD 60,NSD 61(Trichy), of ABB
Carrier Aided signal though NSD 40 PLCC
NSD 40 Code 1 Direct trip
NSD 60 (4codes) Code 1 Direct tripCode 2 & 3 Permissive trip in conjunction with M1, M2
Code 4 Check loop test code
NSD 61 Code 1 & 2 Permissive trip in conjunction with M1, M2
Code - 3 Direct trip (3codes)
Modem (Tele metering) NSK3, NSK4, NSK5
Modem (Tele protection
Signal protection) NSD-40, NSD-41,NSD-60, NSD-61
By employing Modem NSD-60, NSD-61
Telephone EPAX 200.3 MDX50 of BPL
Balancing Transformer One circuit dead or earth fault, in other circuit signal
should . affected
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Protection coupler 4 codes, code1-Direct, code2-Permisive, code3spare,
code4 - Supervision
Rx frequency more than TX frequency
Tx Rx difference 4 Khz
Prot ch 1 to Prot ch 2 Rx diff 12Khz
Prot ch 1 to Prot ch 2 Tx diff 8 khz
Audio frequency 0-4 Khz
Speech frequency 300 to 2.2 Khz
IF frequency 16 Khz
ETI-21 power output 20W ( 3 tier P7EA, P7EB, P7EG )
ETI 21S power output 40w ( 4 tier P7EA, P7EB, P7EG,P7ES )
D B- Level Tx +15db, Rx -20db max
VDU Visual Display Unit
COUPLING 1,ph to ground, 2. Ph to ph, 3.line to line
Speech 300 Hz to 2000 Hz
Tele protection ,tele metering 2000 Hz 3400 Hz
Protection 2830 Hz, in fault 2580 HzPilot 3631 Hz
Data 2520 Approximate
Carrier Aided signal through NSD.40
POP Point of Presales
DTMF Dual Tone Multi Frequency
BPEL BPEL Exchange generally for inter phasing with PLCC
E3EB RF pre amplifier
P5EA Power amplifier-20 W
N5EA Power amplifier- 40 W
P3EO Will be connect to PLCC outdoor equipment
AUTO TRANSFORMER (400 / 230 / 33 kv ) TELK / Kerala
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Transportation filled N2 Gas to a pressure slightly greater then 0.15kg/cm2
WINDING connection symbol YnaOd 11
Victor Diagram (HV , LV ) Star , IV Delta
Territory winding 33 kv
Capacity 315 KVATransformer Bushing insulation level - 1050kv peak
Volt / Current 400V / 455A , 230V / 791A
PRD : - Make M/S Sokrut Udyog Pune (or) QUALITROL make
Operating Pressure 0.5 to 0.7 kg/cm2
Operating Time Instantaneous at any temperature
Operating valve resetting - Automatic
SPR - Sudden Pressure Relay
COOLING FAN - Make G E C 36
- 3 Phase , 740w, 1.5A , Rpm 570OIL PUMP
- Axial flow 5 HP / 3400 lit / minute
Volume of Oil - 68800 / lit
Oil circulation - 3400 x 4 lit/m
ON LOAD TAPE CHANGER
Make - BHEL
- 415V , 1.1KW , 2.75A , 1500rpm
control voltage - 110vswitching operation 33
No of steps - 17 taps of 1.25%
Steps for Tolerance - + or 10%
OLTC oil minimum BDV 50KV , Moisture content 20ppm
Due point - 40 c
Positive pressure - 0.04 to 0.07 bar
Mercury Filled Vacuum pressure Gage PIRANI type or MELEOD type
Supply of dry N2 gas is ( -40c)
BUCHHOLZ RELAY Gas operated relay
Transformer such as arcing, , partial discharge or local over heating Normally
Resulting generation of gas .this gas is collected in the relay housing and actuate an
alarm contact.
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DRYING OUT PROSES
When the equipment is opened (T/F or S/R) and the winding insulation is
exposed
To atmosphere with draining of oil . it is a must that it should be taken in drying out
1. Conservator should be isolate from the transformer2. rubber hose should not use in the process
3. Do all the procedures and drying out start
4. Raise the oil temperature above 60c
5. study increase of IR value of the winding
6. To check BDV of the oil is the value of more than 60kv
7. Check moisture content of the oil is less than 10ppm
8. Insert N2 (-40) to the positive pressure of 0.1cc and it is stopped and kept 12
hours
9. Then the nitrogen pressure is released and let due point is measured .
10.The due point is about 20 or below then the dryness of transformer isachived
11.Oil BDV is 60kv
12. moisture content < 10 ppm
13. Due point Nitrogen out let -20
Testing for Bushing Current Transformer (or) Turret
Polarity checkApply DC voltage (1.5 v DC) to primary ,the secondary side MA . . .
. . Meter deflectedRatio Test : - Apply AC current from variyac S1 & S2 , to measured primary volts
Insulation Resistance Test To remove Neutral Bushing connection
Check from the neutral to other three phase
Transformer Bushing Voltage Current Insulation Level
HV bushing 420 kv 800 A 1425 kvp
IV bushing 245 kv 1250A 1050 kvp
LV bushing 52 kv 2000A 250 kvp , 105 kvp / f
Neutral bushing 36 kv 630A 170 kvpRated Line Earth voltage 21 kv
Insulation level 1050 kvp
Main insulation oil impregnated paper
Short time current rating 3125 kA / sec
Minimum Greepage 6125mm
Transformer Air Cell Never exceeded 0.07kg/cm2 at 1.00psi
Transformer fan start 67c and pump start at 76c
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Transformer Bushing C T (400 KV )
Core 1 500/1A over current, Over load, Earth fault
Core 2 1000/1A Spare
Core 3 505/1.5 Winding Temperature
Transformer Bushing C T (230 KV )
Core 1 1000/1A Spare
Core 2 1000/1A Differential over current , Over load protection
Transformer Neutral Bushing C T
Core 1 Circulating current
Core 2 Over load protection
Transformer Protection
1 Differential Protection 87T 400kv side 500/1A , 220kv side 1000/1A (Group
B)
It is connected between 400kv CT and 220kv CT
Current setting :0.35A restrained ,and 8A for un restrained
2 R E F -64T 1000/1A , Voltage setting : 40v (Group A)
It is connect ed between 400kv Bushing CT and 220kv Bushing CT and
Neutral CT .
Circulating current 400kv main CT+ 400 Tie CT+ 400kv Neutral CT + 230kv
CT 87 . (all are 1000/1A)
3 Differential over current 67RYB-500/1A-PMS-1.5 ,TMS-0.15sec
4 Differential Earth fault 67N-500/1A,TMS-0.4sec
5 Over load 500/1A,time-10 sec -110% Alarm (Group A)
6 Over flux(Group A)
7 Buchholz(Group A)
8 Pressure Relief Device Operating pressure-8 PSI (Group A)
9 Sudden pressure
10 Oil temperature (Group A)11 OLTC Buchholz (Group B)
12 Winding temperature (Group B)
13 Fire protection (Group B)
14 MOG-Magnetic Oil Gauge
Basic Insulation Level ( BIL ) 220KV 400KV
L A 198kv 336kv
Transformer 900kv 1300kv
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Other Equipments 1050kv 1425kv
Supporting insulator - - 1425kv
SHUNT REACTOR Will control the dynamic over voltage
To compensate shunt capacitance of T / L either switched or un. . . switched
Control over voltage under abnormal conditions of system
Take care of switching transients
SHUNT REACTOR Rated power 50 MVAR (Mega Volt Reactive VAR)
Gapped core construction, gapped core between air gaps are
. . Epoxy resin to prevent movement between individual
lamination
Core segments are radial laminated configuration, to prevent
. fringing flux Five limbed core construction has been adopted
ES Sending Voltage Z ER
ER Receiving Voltage ER > ES
Impedance V^2 ES
Z (impedance)
Reactor winding Resistance - 6.6 ohms for each winding
P X I R60 sec = 1.88
R600sec
Capacitance of Leading MVR or Lagging MVR Neutralized ,and control over voltage,
Neutral current and fault current by inductive coil
Active power V1 cos 0
Reactive power V1 sin 0
Apparent power = Active power/ Reactive power
Basic Insulation Level SI-1050kvp ,LI-1300 kvpNeutral Bushing 550kvp
Vibration level 200microns peak to peak (Half yearly maintenance)
Measure with Transducers or optical detector -10% of the 2nd
Harmonic
Noise level 81db
OIL BDV-60-145kv,15ppm
Tan delta 0.00158
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Capacitance 446.80 pf
IR Value 1000 m.ohms
Oil 36,000 lit for BHEL ,38,000 lit for CGL
Shunt ReactorCore I PS Differential protection 87R 200 / 1A
Core II PS Restricted Earth Fault protection 64R - 200 / 1A
Core III PS Back up protection 21R - 200 / 1A
Core IV 1.0 metering - 200 / 1A
Turret CT cores
Core I PS Differential protection - 200 / 1A
Core II PS Main 1 protection ,LBB - 1000 / 1A
Core III PS Main 2 protection ,DR , FL - 1000 / 1A
Core VI PS winding Temperature
Reactor Protection
400 kv Bushing CT having 4 core
core 1 = 200/ 1A class PS - Differential Protection circuit
core 2 = 200/ 1A class PS - Restricted Earth Fault Protection
core 3 = 200/ 1A class PS - Back Up Protection circuit
core 4 = 200/ 1A class 1.0 - Metering circuit
Turret CT having 4 core
core 1 = 200/1A class PS - Differential Protection circuit
core 2 = 2000/1000/500/1A class PS Adopted 2000/1A Main-II-Protection
core 3 = 2000/1000/500/1A class PS Adopted 1000/1A Main-II-Protection,
LBB . . . core 4 = 69/1 class 5 Winding Temperature Indicator(WTI)
only B phase
NGR 3 MVAR
NGR IR Value test with 5kv megger
P X I = R15 sec / R60 sec = Giga ohmsUnder fault condition current flow from Neutral to Ground is limited by NGR .
To limit the Earth fault current. It is connected Neutral point of Shunt Reactor.
Disconnect Jumper and Earth connection take winding resistance with 5kv megger
IR Measurement winding to earth, take 15 seconds and 60 seconds value is ratio called
Absorption co efficient should be more then 1.3
IR value primary to Earth 900 m ohms
Tan Delta 8.00310
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Capacitance 310 pf
Key Diagram for Reactor 400kv Feeder
Reactor Bushing CT (400kv ) Reactor Turret CT NGR Bushing CTNeutral
CT
NGR Bushing
Core 1 = 200/ 1A class PS - spareCore 2 = 200/ 1A class PS - Restricted Earth Fault Protection
1 High Impedance Differential Protection (87R) 200/1A, Setting Voltage 15v
This relay offers high impedance to external faults and less impedance to internal
faults
It is connected between 400kv bushing CT and Neutral CT87R(Differential)
2. Restricted Earth Fault (64R) 200/1A (CAG) Group B
It is connected between SR-400kv bushing CT and Neutral CT for Bus
Reactor . 64R (REF)It is connected between SR-400kv bushing CT and NGR- CT for Line
Reactor
3. Reactor Differential Protection (87RR) DTH-31 1000/1A (Group-A)
C T Ratio 200/1 Class PS Burden 10VA
It is connected between 400kv bushing CT and Reactor CT
Current setting : 0.25A restrained ,and 8A for un restrained
4. Over load
5. Reactor Backup impedance Protection (21R) YTG 33- 500/1A
It is connected between Reactor CT and line CVT or Bus I / Bus II CVT,
Time delay for Bus reactor ;1 sec
Time delay for Line reactor ;1.2 sec
6 Over flux plug setting -1.25, time setting 50 sec
7 Buchholz
8 Pressure Relief Device 0.6kg cm^2
9 Sudden pressure
10 Oil temperature
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11 OLTC Buchholz
12 Winding temperature (Reactor CT core 4 200/1)
13 Fire protection
14 MOG-Magnetic Oil Gauge
CAPASITIVE VOLTAGE TRANSFORMER ( C V T )
Steping down the Voltage for measuring voltage, Protection, and Control, and also
PLCC
400 kv CVT400 / V 3 , 22KV 110 v / V 3
Consist of 1) Capacitor part, 2) EMU Electro Magnetic Unit
Core 1 (3PS) Main 1 protection, Fault Locator circuit, Even Logger
Core 2 (3PS) Main 2 protections, Disturbance Recorder, Reactor Back Up
. protection, O/ V protection
Core 3 (0.5) Metering Circuit ,Synchronizing Circuit ,Auto Reclose scheme
Burden 200 , 200 , 200 VA
Class 3p 3p 0.5
Breaking current 600 KA
Tan delta - 0.007KA
Dissipation Factor (Capacitance) 4400PF
Secondary Capacitance 88000pf
Insulation class A
220kv C V TCore 1 (3PS) Over current, Metering, Synchronizing ckt
Core 2 (0.5) Earth fault protection
Measure Capacitance in GST,UST mode
UST - Top and Bottom of HF point
GST Top and Earth
Primary Winding test - 5kv or 10kv megger
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Secondary Winding test - 500v megger
Insulation value
Primary Winding - 400Mego ohms 5kv megger
Secondary Winding - 100Mego ohms 500v megger
In case of line CVT fail - The Distance relay may be pick up
CURRENT TRANSFORMER
Stepping Down the current for measurements, protection and control .
Load current which can be 1000ds of amperes are reduced by the C TS to just a few
amperes under normal condition
CT Make W/S accuracy 0.5 %
Tank oil capacity 840 lit
N2 Gas 0.2 to 0.5 bar
Annual maintenance
IR value
Secondary to secondary
Secondary to Earth
Primary to secondary 5kv megger
Secondary to Earth 500v
Secondary Winding
Core to core resistance check
Polarity Check Apply 1.5v at Primary in secondary some deflection will come
Current Injection test use Primary Injection Kit 2000 / 1A
Un used secondary core should be short
Tan Delta measurement Top and Common point (Only UST mode)
Primary Injection (current) testNitrogen pressure (test 0.3 positive pressure)
I R value Carried out on dry & Sunny day
Primary to D3 ,Secondary ,Earth (5kv megger)- > 1000 Mega ohms
Secondary to Secondary ,Earth (500kv megger ) - >100 Mega ohms
Short the secondary terminals (core) which are not used
Core 1 2000 / 1000 / 1A ACTR 2000 / 1A Bus Bar protection check zone
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Core 2 2000 / 1000 / 1A ACTR 2000 / 1A Bus Bar protection main zone
Core 3 2000 / 1000 / 500 / 1A ACTR 1000 / 1A (class 0.5) Metering
Core 4 2000 / 1000 / 500 / 1 A ACTR 1000 / 1A Main 1 prot Micro mho, LBB,
Fault . Locator, Cir. current
Core 5 2000 / 1000 / 500 / 1 A ACTR 2000 / 1A Main 2 prot (P-40) Disturbance
Recorder
Metering
Main CT+ Tie CT
Line VT supply ( 63.5/ph )
Export mainexport check iport main import chek ICT primary
bushing CTICT secondary
bushing CT VARH export VARH import main
Transformer Protection
Differential Protection 87T 400kv side 500/1A , 220kv side 1000/1A(Group B)
It is connected between 400kv CT and 220kv CT
Current setting :0.35A restrained ,and 8A for un restrained
Circulating current 400kv main CT+ 400 Tie CT+ 400kv Neutral CT + 230kv CT
. . 87 (all are 1000/1A)
R E F -64T 1000/1A , Voltage setting : 40v(Group A)
It is connect ed between 400kv Bushing CT and 220kv Bushing CT and
Neutral CT .
Differential over current 67RYB-500/1A-PMS-1.5 ,TMS-0.15sec
Differential Earth fault 67N-500/1A,TMS-0.4sec
Over load 500/1A,time-10 sec(Group A)
Over flux(Group A)
Meter
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Buchholz(Group A)
Pressure Relief Device Operating pressure-8 PSI(Group A)
Sudden pressure
Oil temperature(Group A)OLTC Buchholz(Group B)
Winding temperature(Group B)
Fire protection(Group B)
MOG-Magnetic Oil Gauge
Reactor Protection
High Impedance Differential Protection (87R) 200/1A, Setting Voltage 15v
This relay offers high impedance to external faults and less impedance to internal
faults
It is connected between 400kv bushing CT and Neutral CTRestricted Earth Fault Protection (64R) 200/1A(Group B)
It is connected between 400kv bushing CT and Neutral CT for Bus Reactor
It is connected between 400kv bushing CT and NGR- CT for Line Reactor
Reactor Differential Protection (87RR) 1000/1A
It is connected between 400kv bushing CT and Reactor CT
Current setting : 0.25A restrained ,and 8A for un restrained
Over load
Reactor Backup impedance Protection (21R) YTG-33 - 500/1A (Group-A)
It is connected between Reactor CT and line CVT or Bus I / Bus IICVT, 60% of Reactor impedance
Reactor Backup Protection Timer 98R (VTT)
Time delay for Bus reactor ;1 sec
Time delay for Line reactor ;1.2 sec
Bushing CT
Line end 200/1A Differential
R E F
Back up
Metering
Neutral end ratio 200/1A DifferentialR E F
W T I /
Power Swing Block Timer 40ms
Over flux
Buchholz trip (Group B)
Pressure Relief Device(Group B)
Sudden pressure
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Oil temperature(Group B)
OLTC Buchholz
Winding temperature(Group B)
Fire protectionMOG-Magnetic Oil Gauge
NGR(Group B)
LINE PROTECTION
Main 1 protection-Micromho 21
Main 1 protection trip relay-186R,186Y,186B (VAJ)
Main 2 protection Phase Comparison (P-40) Prot-78
Main 2 protection trip relay- 86R, 86Y, 86B (VAJ)
P-40 operating time minimum 10ms, max 20msPhase Selector- 21R,21Y,21B YTG-33 Reactor Back up
YTG-31 Main 2
Over Voltage protection 59 R Y B
140% -Instantaneous,
-110% for 4 sec
Over Voltage protection 86OV- Main & Tie - 59R,59Y,59B (VTU)
86-OVX remote end trip via CH-1,CH2
Circuit Breaker Trip coil 1- CKT Supervision 195A,195B,195C
Circuit Breaker Trip coil 2- CKT Supervision 295A,295B,295C
Auto reclose 186A,152X,186B (VARM)
Auto reclose Lock out 186x,186y,186z (VAJ)
V T fuse fail -97
LBB Protection main 50Z (CTIG) dial setting 1.4 / 0.2 amps
LBB Protection Tie 50ZT (CTIG)
LBB Timer 2/50Z
ZONE 0 1.064 ohms
ZONE I 80% of protected line impedanceTime delay Instantaneous (< 100ms )
ZONE II 120% of protected line impedance (or)
100% of protected line impedance + 60% of the A/ T (or)
50% of the shortest line impedance
Time de