GE 750 - Page 468

17-
62
750/760 Feeder Management Relay GE Power Management
17.9 CONTROL SCHEMES 17 COMMISSIONING
17
5. Slowly raise V
an
until the 2 CLOSE relay operates. This is the operating level of setpoint
UNDERVOLT
RESTORE MIN VOLTS
for V
an
.
6. Inject
V
an
= V
bn
= V
cn
= nominal voltage into the bus voltage input of the relay.
7. Reduce the injected voltages to cause an undervoltage trip, then set
V
an
and V
cn
to nominal.
8. Slowly raise
V
bn
until the 2 CLOSE relay operates. This is the operating level of setpoint
UNDERVOLT
RESTORE MIN VOLTS
for V
bn
.
9. Inject
V
an
= V
bn
= V
cn
= nominal voltage into the bus voltage input of the relay.
10. Reduce the injected voltages to cause an undervoltage trip, then set
V
an
and V
bn
to nominal.
11. Slowly raise
V
cn
until the 2 CLOSE relay operates. This is the operating level of setpoint
UNDERVOLT
RESTORE MIN VOLTS
for V
cn
.
b) FOR DELTA VTs
Test Connections per Figure 17–2: RELAY TEST WIRING – DELTA CONNECTION on page 17–4.
Procedure To Check Minimum Voltage with One Phase For Operation
1. Assert or De-assert a logic input to simulate an open breaker.
2. Set Undervolt Restore Delay to 0.
3. Inject
V
ab
= V
cb
= nominal voltage into the bus voltage input of the relay.
4. Reduce the injected voltages to cause an undervoltage trip, then set
V
cb
to 0
5. Slowly raise
V
ab
until the 2 CLOSE relay operates. This is the operating level of setpoint
UNDERVOLT
RESTORE MIN VOLTS
for V
ab
.
6. Repeat steps 3 through 5 except adjust
V
cb
.
Pickup with Two or Three Phases For Operation:
1. Assert or De-assert a logic input to simulate an open breaker.
2. Set Undervolt Restore Delay to 0.
3. Inject
V
ab
= V
cb
= nominal voltage into the bus voltage input of the relay.
4. Reduce the injected voltages to cause an undervoltage trip, then set
V
cb
to nominal
5. Slowly raise
V
ab
until the 2 CLOSE relay operates. This is the operating level of setpoint
UNDERVOLT
RESTORE MIN VOLTS
for V
ab
.
6. Inject
V
ab
= V
cb
= nominal voltage into the bus voltage input of the relay.
7. Reduce the injected voltages to cause an undervoltage trip, then set
V
ab
to nominal
8. Slowly raise
V
cb
until the 2 CLOSE relay operates. This is the operating level of setpoint
UNDERVOLT
RESTORE MIN VOLTS
for V
cb
.