One Word Ans

8/3/2019 One Word Ans

1/65

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 ,


2/65

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


3/65

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


4/65

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


5/65

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


6/65

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


7/65

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)


8/65

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


9/65

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


10/65

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


11/65

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


12/65

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


13/65

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


14/65

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


15/65

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


16/65

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


17/65

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


18/65

WT

= =

LMU

BT

PLCC


19/65

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


20/65

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


21/65

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


22/65

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 500kv HVDC 10

Shielding angle 800KV 20

Shielding angle for river crossing tower 10

Pollution level minimum creepage light 16mm / kV


23/65

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


24/65

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


25/65

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




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


26/65

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


27/65

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


28/65

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


29/65

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


30/65

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


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


31/65

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


32/65

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


33/65

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 (


34/65

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%


35/65

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


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


36/65

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


37/65

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


39/65

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.


40/65

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.


41/65

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


42/65

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


43/65

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)


44/65

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


45/65

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


46/65

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


57/65

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


61/65

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

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