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•
Apply 1.5 times the pick up current and the relay should trip in 16 sec. Acceptable time range between
13.91 and 18.82 sec.
•
Apply 5 times the pick up current and the relay should trip in 2.03 sec. Acceptable time range between
1.88 and 2.13 sec.
EXTREMELY INVERSE CURVE
• Set the relay as follows:
51NT Settings Group
Curve
Time Dial
•
Apply 0.9 times the pick up current into phase C and the relay should not trip.
•
Apply 1.5 times the pick up current and the relay should trip in 3.87 sec. Acceptable time range between
3.24 and 4.65 sec.
•
Apply 5 times the pick up current and the relay should trip in 0.20 sec. Acceptable time range between
0.16 and 0.24 sec.
DEFINITE TIME
• Set the relay as follows:
51PT Settings Group
Curve
Time Dial
•
Apply 0.9 times the pick up current into phase A and the relay should not trip.
•
Apply 1.1 times the pick up current and the relay should trip in 1 sec. Acceptable time range between
0.97 and 1.03 sec.
•
Apply 4 times the pick up current and the relay should trip in 1 sec. Acceptable time range between 0.97
and 1.03 sec.
6.18. PHASE DIRECTIONAL UNIT (67PL)
Instantaneous trips (50PL, low level) are forced to test the directionality of the relay.
4 points are tested:
•
One located clearly inside the no-tripping zone
•
One situated 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.
Enable only 50PL function and its related trip, and set its pick up and time delay to the minimum possible
•
Set the relay as follows:
Directionality Settings Group
51 PT Directional
51NT Directional
50PH Directional
50PL Directional
50NH Directional
50NL Directional
Phase Angle
Ground Angle
V Loss Logic
GEK-105593C
EXTREMELY INVERSE
0.05
DEFINITE TIME
1.0
NO
NO
NO
YES
NO
NO
45
-45
Permission
56
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