Negative Sequence - Unbalance - GE Multilin MIGII Instruction Manual

9.20 NEGATIVE SEQUENCE – UNBALANCE (46)
9.20NEGATIVE SEQUENCE – UNBALANCE (46)
This unit can be set for operating with a definite time, or according to the following equation:
The TAP46 setting fixes a value below which the relay will not trip.
There is also a fix non-tripping time between 230-250 ms.
DEFINITE TIME MODE:
Enable only Unit 46.
Set the Unit as follows:
FLA = In
TAP 46 = 0.1 x FLA
Curve type = TDEF
t = 1 s
Check the following:
• Apply 95% of TAP 46; the relay should not trip.
Apply 105% of TAP 46; acceptable tripping time range is between 1.00 and 1.06 sec. ±500ms
•
INVERSE TIME MODE:
Enable only Unit 46.
Set the Unit as follows:
FLA = In
TAP 46 = 0.8 x FLA
Curve type = CURVE
K = 1
Check the following:
Apply 1 x FLA; the relay should trip in 1.00 seconds (according to the above equation). ±500ms
•
• Apply 0.7 x FLA; wait for 2.5 sec. and check that the unit does not trip.
9
9-24
WARNING: Currents to be applied are negative sequence currents.
MIGII Digital Protection for Electrical Machines
9 RELAY COMMISSIONING
GEK-113188A