Areva MiCOM P125, Technical Manual

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P12y/EN RS/D32 Commissioning Test and Record Sheet
Page 38/48 MiCOM P125/P126 & P127
3.7 Non-directional overcurrent protection
3.7.1 Overcurrent sensitivity tests
Object:
The following tests verify that the relay overcurrent elements operate at the set thresholds.
Test with the following relay settings (all thresholds set as non-directional):
•
ON
•
1 In
•
Characteristic IDMT
•
Curve IEC_SI (Standard Inverse)
•
TMS 0.025
•
Reset time delay 0.04 s
Inject current of 0.95 In into the A phase input. Increase the current in 0.01In steps, pausing
for 2.5s between each step, until the relay operates. The current must then be reduced in the
same manner until the protection resets.
Repeat the above tests for all phases.
Repeat the above test for other overcurrent stages taking in account that the delay time for
nthe second and third threshold is DMT (t=0s). Make the test before on I>> after on I>>>.
3.7.1.1 Pass Criteria
For the relay to pass it shall operate as detailed below.
Delay trip IDMT (inverse time only for I>):
•
Pick-up should occur at 1.1Is ±2%.
•
Reset should occur at 1.04Is ±2%.
Delay Trip DT (definite time for I>, I>>, I>>>)
•
Pick-up should occur at : Is ±2%.
•
Reset should occur at 0.95 Is ±2%.
3.7.2 Overcurrent characteristic tests
Object:
The following tests verify that the relay overcurrent elements trip in the correct time.
Test with the following relay settings:
•
Is 1 In
•
Characteristic DT / IDMT
•
Curve IEC_SI (Standard Inverse)
•
TMS 1.0
•
Time Delay 1s
•
Directionality Non-directional
•
Reset time delay 0s
Enable stage 1 overcurrent and prepare the tests set so that A phase current can be
instantaneously applied at 2In and 10In respectively. Measure the operating times of the
relay start and trip contacts. Repeat the test with the element set to IDMT. Repeat the test
with the element disabled and verify that no start or trip elements operate.
Repeat the above testing for all phases and stages (with the exception of IDMT which is only
for the first stage).