GE Feeder Management Relay 750 User Manual

8-18 750/760 Feeder Management Relay GE Multilin
8.4 PROTECTION SCHEMES 8 COMMISSIONING TESTS
8
2. Inject current below the pickup level into Phase A and slowly increase until the Pickup LED is on. Note the pickup value
is the pickup current of the Curve in use.
3. Slowly reduce the current into Phase A until the Pickup LED goes off and note the dropout level, which should be 2%
of CT less than pickup when pickup ≤ CT or 97 to 98% of pickup when pickup > CT.
4. Reduce the current to zero.
5. Repeat Steps 2 to 4 for current injected into Phases B and C.
6. Set all input voltages to 0 and slowly increase Phase A current until the Pickup LED comes on. Check that this current
is 9 to 11% of the measured full voltage pickup current.
7. Increase input voltage V
ab
until the Pickup LED goes out. This should be at 9 to 11% of the nominal phase-phase volt-
age. This test establishes the lower knee of the operating characteristic.
8. With the Pickup LED still off, increase voltage V
ab
to 60% of the nominal phase-phase voltage.
9. Increase the Phase A current until the Pickup LED comes on. This should be at 59 to 61% of the full voltage measured
pickup current.
10. With the Pickup LED still off, increase voltage V
ab
to 130% of nominal.
11. Increase Phase A current to 90% of normal pickup and hold this value. Slowly decrease V
ab
until the Pickup LED just
comes on. This should be at 89 to 91% of nominal V
ab
. This establishes the upper knee of the characteristic, and
shows the pickup is not altered above 90% voltage.
12. Reduce current and voltages to 0.
13. Repeat Steps 6 through 12 for current injected in Phase B and controlling voltage V
cb
.
14. Repeat Steps 6 through 12 for current injected in Phase C and controlling voltage V
ca
.
To check trip timing with voltage restraint, set the input voltage to a given level, establishing a new pickup current, and then
following the procedure outlined earlier under Timing.
b) PHASE TOC 2
The procedure to test this element is identical to that for Phase TOC 1, except for the blocking from logic inputs, in which
case the following procedure should be used:
1. Inject current to cause a Pickup.
2. Assert a logic input to provide a "Block Phase Time 2". The Pickup LED should immediately go out.
3. Repeat Steps 1 and 2 for logic inputs "Block Phase O/C", "Block All O/C" and “Block 1 Trip Relay” as required.
c) PHASE IOC 1
The procedure to test this element is identical for Phase TOC 1, except for the procedures below. Pickup, indication and
operation are subject to the "phases required for operation" test, but not subject to the "linear reset timing" and "voltage
restrained Phase TOC" tests.
The following procedure checks pickup with two phases for operation:
1. Inject current into Phase B at 150% of pickup.
2. Inject current at a level below the pickup level into Phase A.
3. Slowly increase the Phase A current until the Pickup LED comes on and note the pickup value.
4. Slowly reduce the Phase A current until the Pickup LED goes out. Note the dropout level, which should be 2% of CT
less than pickup when pickup ≤ CT or 97 to 98% of pickup when pickup > CT.
5. Repeat Steps 1 through 4 for phase pair B and C and phase pair C and A.
The following procedure checks pickup with three phases for operation:
1. Inject current into Phases B and C at 150% of pickup.
2. Inject current at a level below the pickup level into Phase A.
3. Slowly increase the Phase A current until the Pickup LED comes on and note the pickup value.
Courtesy of NationalSwitchgear.com

GE Feeder Management Relay 750 Specifications

General

Brand	GE
Model	Feeder Management Relay 750
Category	Protection Device
Language	English