EHV
Circuit breaker
1. IR test on each pole by Megger (Between
poles and lower poles to ground).
2. IR
tests on control circuits.
3. Functional check of breaker operation on minimum and maximum
specified control voltages
4. Checking
of interlocks with isolators & earthing switches.
5. Checking of remote operation and tripping from protection relays and from
other devices as per approved scheme.
6. Measurement
of contact resistance
7. Testing
for leakage of compressor and hydraulic oil system.
8. Checking
tightness of termination connectors.
9. Checking tightness of earthing connections.
10. Checking of
insulators for cracks etc.
11. Checking
the settings of pressure switches.
12 Check level of pressure of air, oil and gas
as per the manufacturer's manual.
13. Check
direction of compressor motor and oil pump.
14. Check
operation of breaker at minimum specified pressure.
15. Check for
air leakage in air reservoir.
16. Check for closing and opening time and
simultaneous closing of all poles through oscillograph.
17. Tripping of
circuit breaker at reduced or over voltage i.e. at 85 - 105% .
18.
Checking of hydraulic system and oil leakage in oil
pump.
Lightning
Arrestor
1. Continuity check (for metal oxide type only)
2. Check for
connection to ground.
3. Check
insulators for cracks.
4. Check reading
of leakage current.
5. HT and IR
test of each element.
Current
Transformer
1. IR
test on each winding, winding to earth and between windings.
2. Checking of winding ratios by primary
injection set.
3. Polarity
check on each winding.
4. Continuity
check for all windings.
5. Check for
connections to correct taps.
6. Measurement of knee point voltage and
secondary winding resitance for
the CTs used for differential protection.
7. Checking
of oil level.
8. Checking
of continuity and IR values for cables from CT to Marsh Box.
9. Checking
tightness of earthing connections.
10. Checking of
insulator for cracks.
11. Check
output after loading of the main circuit.
Potential/
Capacitive Voltage Transformer
1. IR
test of primary winding by HV megger between windings and earth
2. IR test of secondary winding by LV megger
between windings and winding to earth
3. Checking
of voltage ratio
4. Verification
of terminal markings and polarity
5. Checking
of oil level
6. Checking
of continuity and IR values for cables from PT to Marsh Box
7. Checking
tightness of earthing connections
8. Checking
of insulator for cracks
9. Check output on charging
of the system with connected meters/relays
No comments:
Post a Comment