The document is a checklist to commission various AC Side equipment - Transformers (Power, Auxillary & Inverter) , HT Panels, Relays, Circuit Breakers, LA, CT, PT, C&R Panel.

1. S.NO. EQUIPMENT DETAILS TEST DETAILS
INSULATION RESISTANCE TEST
PI TEST
VOLTAGE RATIO & TAP CONTINUITY TEST
MAGNETIC BALANCE TEST
VECTOR GROUP TEST
WINDING RESISTANCE (HV SIDE) AT ALL TAPS
WINDING RESISTANCE (LV SIDE) AT ALL TAPS
MAGNETIZATION CURRENT TEST
BDV OF TRANSFORMER OIL (And Oil Filterization)
TAN ᵹ & CAPACITANCE CHECKS
OLTC operational test
Checking of: 1)Valves position (on / off), 2)Gasket joints to avoid oil leakage, 3)Earthing
CONFIRMITY TEST (1) Visual external damage to any part of the transformer (2) Buchholz alaram + trip
contacts (3) WTI & OTI alaram + trip contacts (4) MOG contacts (5) Phase Sequence Check (6) colour of
silica gel/Oil level/leakage, if any (7) Abnormality, if any.
INSULATION RESISTANCE TEST
PI TEST
VOLTAGE RATIO & TAP CONTINUITY TEST
MAGNETIC BALANCE TEST
VECTOR GROUP TEST
WINDING RESISTANCE (HV SIDE) AT ALL TAPS
WINDING RESISTANCE (LV SIDE) AT ALL TAPS
MAGNETIZATION CURRENT TEST
BDV TEST OF TRANSFORMER OIL (And Oil Filerataion)
Checking of: 1)Valves position (on / off), 2)Gasket joints to avoid oil leakage, 3)Earthing
CONFIRMITY TEST (1) Visual external damage to any part of the transformer (2) Bucholz alaram + trip
contacts (3) WTI & OTI alaram + trip contacts (4) MOG contacts (5) Phase Sequence Check (6) colour of
silica gel/Oil level/leakage, if any (7) Abnormality, if any.
INSULATION RESISTANCE TEST
PI TEST
VOLTAGE RATIO & TAP CONTINUITY TEST
MAGNETIC BALANCE TEST
VECTOR GROUP TEST
WINDING RESISTANCE (HV SIDE) AT ALL TAPS
WINDING RESISTANCE (LV SIDE) AT ALL TAPS
MAGNETIZATION CURRENT TEST
BDV TEST OF TRANSFORMER OIL
LIST OF PRE-COMMISSIONING TESTS OF AC EQUIPMENTS
POWER TRANSFORMER1
INVERTER TRANSFORMER2
3 Auxiliary transformer

2. CONFIRMITY TEST (1) Visual external damage to any part of the transformer (2) Phase Sequence Check
(3) colour of silica gel/Oil level/leakage, if any (4) Abnormality, if any.
PHYSICAL CHECKING OF VARIOUS ELECTRICAL & MECHANICAL PARTS
CONTINUITY & CONTROL CIRCUIT CHECK
11kV VCB
IR Test (1) Close Condition (RY, YB,BR, RE, YE, BE) (2) Open Condition (RR', YY', BB')
Contact Resistance Test
Timing Test (1) Open time (2) Close time
Coil resistance test (1) Closing coil (2) Tripping coil-1 (3) Tripping coil-2 (4) Motor winding
Control Circuit & Operational checks (1) Manual charging of spring (2) Mechanical closing & tripping (3)
Charging of spring through motor (4) Tripping through relays/releases (5) Breaker close command
blocking when relay / releases is in operated condition (6) Abnormality, if any
Maintenance & general check-ups (1) Inspection for physical damage (2) cleaning & tightness of
breaker bolts (3) Alignment of breaker (4) Earthing connection (5) Gas pressure low operation (6)
Abnormality, if any
CT
IR TEST (P - E, S- E, P - S, S -S)
Winding Resistance Test
Magnetization characteristic check
Ratio, Polarity & Circuit check
General checks 1) Inspection for physical damage 2) Continuity check for ammeter and/or relay circuits
PT
IR TEST (P - E, S- E, P - S, S -S)
Winding Resistance Test
Ratio, Polarity & Circuit check
General checks 1) Inspection for physical damage 2) Continuity check for Voltmeter and/or relay
circuits
LBS
IR TEST on each pole
Measurement of contact resistance for all three phases
Manual checking of operation (close or open) by Handle
Checking of Interlocks (mechanical and electrical)
HVDC Test
Bus Bars:- 1) IR TEST 2) Contact Resistance Test
CHECK UP OF ALL ALARAMS AND ANNUNCIATION
SPACE HEATER OPERATION CHECK
INTERFACE CHECK BETWEEN PANELS
TESTS OF PROTECTIVE RELAYS ON SETTINGS CONFIGURED
11 KV HT PANELS, RMU
PANELS, C&R PANEL, RTCC
PANEL
4

3. NUMERICAL Relay
1) Seconday Injection Test (according to service setting of relay)
a) Time Current characteristics tests for O/C unit
b) Instantaneous O/C unit protection
c) Time Current characteristics tests for E/F unit
d) Instantaneous E/F unit protection
2) General Checks:- Inspection for physical damage, wiring check, Resetting of LEDs with cover
TRIPPING Relay (86, Numerical Relay)
1) Insulation resistance test (between all terminals and body, between various ciruits)
2) Coil Resistance Test
3) Coil Pick up & drop off test
4) General Check:- Inspection for physical damage, wiring check of relay, cleaning & pressure of relay
contacts, Flag operation and resetting of flags with cover
DIFFERENTIAL (Numerical) Relay (87 T)
1) Differential Pick-up check
2) Stability Check
3) Secondary Injection Test
a) Time Current characteristics tests for O/C unit
b) Instantaneous O/C unit protection
c) Time Current characteristics tests for E/F unit
d) Instantaneous E/F unit protection
4) Over Fluxing
5) Under Voltage unit test
6) Over Voltage unit test
7) Restricted E/F Protection (HT Side)
8) Restricted E/F Protection (LV Side)
9) General Check up:- Inspection for physical damage, wiring check of relay, LED indication & Push
button operation, Service setting re-stored
Auxiliary Relay (Electromechanical Relay)
1) Insulation resistance test (between all terminals and body, between various ciruits)
2) Coil Resistance Test
3) Coil Pick up & drop off test
4) General Check:- Inspection for physical damage, wiring check of relay, cleaning & pressure of relay
contacts, Flag operation and resetting of flags with cover
MULTIFUNCTION RELAYS
4

4. IR Test (1) Close Condition (RY, YB,BR, RE, YE, BE) (2) Open Condition (RR', YY'. BB')
Contact Resistance Test
Timing Test (1) Open time (2) Close time
Coil resistance test (1) Closing coil (2) Tripping coil-1 (3) Tripping coil-2 (4) Motor winding
Control Circuit & Operational checks (1) Manual charging of spring (2) Mechanical closing & tripping (3)
Charging of spring through motor (4) Tripping through relays/releases (5) Breaker close command
blocking when relay / releases is in operated condition (6) Abnormality, if any
Maintenance & general check-ups (1) Inspection for physical damage (2) cleaning & tightness of
breaker bolts (3) Alignment of breaker (4) Earthing connection (5) Gas pressure low operation (6)
Abnormality, if any 7) test for leakage of air / gas
Insulation Resistance (R-E, Y-E, B-E)
Contact Resistance Test
Checking of mechanical interlok between Isolator & Earth switch (if the model is Isolator with Earth
switch)
Opretional Checks (1) Mechanical Check (2) Electrical Check (the operating mechanism of the 3 poles
shall be well synchronized)
Insulation Resistance (P-E)
Counter Test
Maintenance & General check-ups (1) Inspection for physical damage (2) Cleaning & tightness of bolts
(3) Earthing connection (4) Abnormality, if any
IR TEST (P - E, S- E, P - S, S -S)
Winding Resistance Test
Magnetization characteristic check
Ratio, Polarity & Circuit check
General checks 1) Inspection for physical damage 2) Continuity check for ammeter and/or relay circuits
IR TEST (P - E, S- E, P - S, S -S)
Winding Resistance Test
Ratio, Polarity & Circuit check
General checks 1) Inspection for physical damage 2) Continuity check for Voltmeter and/or relay
circuits
IR TEST (P - E, S- E, P - S, S -S)
Winding Resistance Test
Ratio, Polarity & Circuit check
7 LA
Horizontal Mounted Double
Break Isolator & Earth switch
6
CT8
PT9
5 SF6 CIRCUIT BREAKER
CVT10

5. Capacitance measure of capacitor section
General checks 1) Inspection for physical damage 2) Continuity check for Voltmeter and/or relay
11 INSULATORS HIGH VOLTAGE TEST
PHYSICAL CHECKING OF LAYING & TERMINATION
CONTINUITY TEST
INSULATION RESISTANCE TEST
PI VALUE
HIGH VOLTAGE TEST (DC/AC)
PHYSICAL CHECKING OF LAYING & TERMINATION
CONTINUITY TEST
INSULATION RESISTANCE TEST
EARTH RESISTANCE TEST
PHYSICAL CHECKING OF CONNECTIONS
CONTINUITY OF GROUNDING CONNECTIONS & JOINTS
CHECKING OF COMPLETE EARTHING NETWORK
Checking of interpanel wiring, protection relays, terminal block contacts, earthing
Ensuring the interlock between Isolators & SF6 circuit breaker
IR test between Control, CT, PT circuits & earth
16
Battery, Battery charger &
DCDB
Checking of connections, physical damage, voltage at output terminals
17 UPS & Battery Checking of connections, physical damage, voltage at output terminals
18 PLCC,Wavetrap Checking of connections, earthing
C&R Panel15
14 EARTHING
LT CABLES13
12 HT CABLES
CVT10