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9.14
GROUND IOC HIGH SETTING UNIT (50NH)
• Enable only 50NH function.
• Set its time delay and pickup to the minimum possible.
• With 0.9 times the pickup current the relay should not trip.
• With 1.1 times the pickup current the relay should trip in between 10 to 50 ms.
• With 4 times the pickup current the relay should trip in between 10 to 40 ms.
9.15
GROUND IOC LOW SETTING UNIT (50NL)
• Enable only 50NL function.
• Set its time delay and pickup to the minimum possible.
• With 0.9 times the pickup current the relay should not trip.
• With 1.1 times the pickup current the relay should trip in between 10 to 50 ms.
• With 4 times the pickup current the relay should trip in between 10 to 40 ms.
9.16
PHASE TOC UNIT (51P)
The 3 curves IEC or ANSI (Inverse, Very Inverse, Extremely Inverse) and the Definite Time are tested with three
points for each curve (one "no-trip point" and two "trip points"). This gives us a total of 12 points for each protection
unit. The tests are carried out for different phases. Each point is tested with a different pick up and dial in order to test
the whole range of the relay.
Enable 51P function only, and set its current pickup value to the minimum possible.
• Set the relay as follows:
51P Settings Group
Curve
Time Dial
• Apply 0.9 times the pickup current into phase A and the relay should not trip.
• Apply 1.5 times the pickup current and the relay should trip between 15.3 and 19.7 sec.
• Apply 5 times the pickup current and the relay should trip between 4.1 and 4.5 sec.
9-6
RELAY COMMISSIONING
INVERSE
1
MIF Digital Feeder Protection
9.16.1.
IEC INVERSE CURVE
GEK-106273L
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