GE 750 - Overvoltage 1 (2)

GE Power Management 750/760 Feeder Management Relay 17-
37
17 COMMISSIONING 17.7 PROTECTION SCHEMES
17
17.7.25 OVERVOLTAGE 1 (2)
a) FOR WYE VTs
Test Connections per Figure 17–1: RELAY TEST WIRING – WYE CONNECTION on page 17–4.
Pickup with One Phase For Operation:
1. Inject
V
an
= V
bn
= V
cn
= 0 into the bus voltage input of the relay. The PICKUP indicator should be off.
2. Slowly raise
V
an
until the PICKUP indicator comes on. This is the pickup voltage.
3. Lower
V
an
until the PICKUP indicator goes out. This is the reset voltage, which should be the pickup value
minus 2% of VT.
4. Repeat steps 1 through 3 except adjust
V
bn
and V
cn
in turn.
Pickup with Two Phases For Operation:
1. Inject
V
an
= V
bn
= nominal voltage and V
cn
= a voltage above the pickup into the bus voltage input of the
relay. The PICKUP indicator should be off.
2. Slowly raise
V
an
until the PICKUP indicator goes on. This is the pickup voltage of V
an
.
3. Reduce
V
an
until the PICKUP indicator goes off. This is the reset voltage of V
an
which should be the pickup
value minus 2% of VT.
4. Raise
V
an
until the PICKUP indicator comes on.
5. Repeat steps 1 through 4, substituting
V
cn
for V
an
, V
an
for V
bn
and V
bn
for V
cn
.
6. Repeat steps 1 through 4, substituting
V
bn
for V
an
, V
cn
for V
bn
and V
an
for V
cn
.
Pickup with Three Phases For Operation:
1. Inject
V
an
= V
bn
= V
cn
= a voltage above the pickup voltage into the bus voltage input of the relay. The
PICKUP indicator should be on.
2. Slowly lower
V
an
until the PICKUP indicator goes out. This is the reset voltage, which should be the pickup
value minus 2% of VT.
3. Raise
V
an
until the PICKUP indicator comes on. This is the pickup voltage of V
an
.
4. Slowly lower
V
bn
until the PICKUP indicator goes out. This is the reset voltage, which should be the pickup
value minus 2% of VT.
5. Raise
V
bn
until the PICKUP indicator comes on. This is the pickup voltage of V
bn
.
6. Slowly lower
V
cn
until the PICKUP indicator goes out. This is the reset voltage, which should be the pickup
value minus 2% of VT.
7. Raise
V
cn
until the PICKUP indicator comes on. This is the pickup voltage of V
cn
.
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
= 0 into the bus voltage input of the relay. The PICKUP indicator should be off.
2. Slowly raise
V
ab
until the PICKUP indicator comes on. This is the pickup voltage.
3. Lower
V
ab
until the PICKUP indicator goes out. This is the reset voltage, which should be the pickup value
minus 2% of VT.
4. Repeat steps 1 through 3 except adjust
V
bc
.