GE 750 - Page 441

GE Power Management 750/760 Feeder Management Relay 17-
35
17 COMMISSIONING 17.7 PROTECTION SCHEMES
17
8. Lower V
an
until the PICKUP indicator goes out. This is the programmed Minimum Operating Voltage of V
an
minus 2% of VT.
9. Slowly raise
V
an
until the PICKUP indicator comes on. This is the Minimum Operating Voltage level.
10. Reduce
V
bn
until the PICKUP indicator goes out. This is the programmed Minimum Operating Voltage of
V
bn
minus 2% of VT.
11. Slowly raise
V
bn
until the PICKUP indicator comes on. This is the Minimum Operating Voltage level.
12. Reduce
V
cn
until the PICKUP indicator goes out. This is the programmed Minimum Operating Voltage of
V
cn
minus 2% of VT.
13. Slowly raise
V
cn
until the PICKUP indicator comes on. This is the Minimum Operating Voltage level.
b) FOR DELTA VTs
Test Connections per Figure 17–2: RELAY TEST WIRING – DELTA CONNECTION on page 17–4.
Pickup with One Phase For Operation:
1. Inject
V
ab
= V
cb
= nominal voltage into the bus voltage input of the relay. The PICKUP indicator should be
off.
2. Slowly lower
V
ab
until the PICKUP indicator comes on. This is the pickup voltage.
3. Continue to lower
V
ab
until the PICKUP indicator goes out. This is the Minimum Operating Voltage minus
2% of VT.
4. Raise
V
ab
until the PICKUP indicator comes on, and continue to increase until the indicator goes out. This
is the reset voltage, which should be the pickup value plus 2% of VT.
5. Repeat steps 1 through 4 except adjust
V
bc
.
Pickup with Two or Three Phases For Operation:
1. Inject
V
ab
= nominal voltage and V
cb
= a voltage between the Minimum Operating Voltage and the pickup
voltage into the bus voltage input of the relay. The PICKUP indicator should be on.
2. Slowly raise
V
cb
until the PICKUP indicator goes out. This is the reset voltage, which should be the pickup
value plus 2% of VT.
3. Reduce
V
cb
until the PICKUP indicator comes on. This is the pickup voltage of V
cb
.
4. Continue to lower
V
cb
until the PICKUP indicator goes out. This is the programmed Minimum Operating
Voltage of
V
cb
minus 2% of VT.
5. Slowly raise
V
cb
until the PICKUP indicator comes on. This is the Minimum Operating Voltage level.
6. Reduce
V
ab
until the PICKUP indicator goes out. This is the programmed Minimum Operating Voltage of
V
ab
minus 2% of VT.
7. Slowly raise
V
ab
until the PICKUP indicator first comes on and then goes out. This is the reset voltage,
which should be the pickup value plus 2% of VT.
8. Lower
V
ab
until the PICKUP indicator comes on. This is the pickup voltage of V
ab
.