GE Multilin 489 Instruction Manual page 268

Test
Minimum Pickup
Single Infeed Fault
7–18
Courtesy of NationalSwitchgear.com
Slope 2 Check
Set fault current, I
At this value the relay should operate according to the following formula.
I
=
XOP2
Set fault current, I
Switch on the test set.
The relay should operate.
Switch off the current.
Set fault current, I
Switch on the test set.
The relay should restrain.
Switch off the current.
Directional Check
Set pre-fault current, I
At this value the conditions for CT saturation detection are set and the
relay will enable the directional check.
Set fault current, I
Switch on the test set.
The relay should restrain.
Switch off the current.
Repeat steps from Minimum Pickup Check onward for phases B
and C.
Test Results
Phase A
Calculated Measured
Test Phase A
CT
equal to 2.5 × CT.
Y
2 Slope 2 setting
–
--------------------------------------------- -
× 2.5 CT ×
2 Slope 2 setting
+
equal to 0.95 × I
x XOP2
equal to 1.05 × I
x XOP2
and I equal to 3.5 × CT.
x Y
equal to 0.95 × I
x XOP2
Phase B
Calculated Measured
Phase B
5 × CT 5 × CT
CT
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 7: TESTING
(EQ 7.7)
.
.
.
Phase C
Calculated Measured
Phase C
5 × CT
CT