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PHASE A DIRECTIONAL TEST
•
Apply 4 times the pick up current at 0º on phase A. Positive is applied to terminal A1 and negative to
terminal A2.
•
Apply 60 V at 0º on phase C. Positive is applied to terminal A7 and negative to terminal A8.
•
Check that relay does not trip.
•
Gradually reduce the voltage to 4 V and check that relay still does not trip.
•
Reduce the voltage to 2.5 V and check that relay trips.
•
Apply 60 V at 180º on phase C.
•
Check that relay trips.
•
Apply 60 V at 320º on phase C.
•
Check that relay does not trip.
•
Apply 60 V at 130º on phase C.
•
Check that relay does not trip.
PHASE B DIRECTIONAL TEST
•
Apply 4 times the pick up current at 0º on phase B. Positive is applied to terminal B1 and negative to
terminal B2.
•
Apply 60 V with 0º on phase A. Positive is applied to terminal A5 and negative to terminal A6.
•
Check that relay does not trip.
•
Gradually reduce the voltage to 4 V and check that relay still does not trip.
•
Reduce the voltage to 2.5 V and check that relay trips.
•
Apply 60 V at 180º on phase A.
•
Check that relay trips.
•
Apply 60 V at 320º on phase A.
•
Check that relay does not trip.
•
Apply 60 V at 130º on phase A.
•
Check that relay does not trip.
PHASE C DIRECTIONAL TEST
•
Apply 4 times the pick up current at 0º on phase C. Positive is applied to terminal A3 and negative to
terminal A4.
•
Apply 60 V at 0º on phase B. Positive is applied to terminal B5 and negative to terminal B6.
•
Check that relay does not trip.
•
Gradually reduce the voltage to 4 V and check that relay still does not trip.
•
Reduce the voltage to 2.5 V and check that relay trips.
•
Apply 60 V at 180º on phase B.
•
Check that relay trips.
•
Apply 60 V at 320º on phase B.
•
Check that relay does not trip.
•
Apply 60 V at 130º on phase B.
•
Check that relay does not trip.
6.19. GROUND DIRECTIONAL UNIT (67NL)
Instantaneous trips (50NL, low level) are forced to test the directionality of the relay.
4 points are tested:
One located clearly inside the no-tripping zone
One located clearly within the tripping zone.
Another no-trip located at 5º from the upper limit of the no-tripping zone.
Another no-trip located at 5º from the lower limit of the no-tripping zone.
GEK-105593C
57
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