GE 750 User Manual

GE Power Management 750/760 Feeder Management Relay 17-
47
17 COMMISSIONING 17.8 MONITORING
17
17.8.10 OVERFREQUENCY
Test Connections per Figure 17–1: RELAY TEST WIRING – WYE CONNECTION or Figure 17–2: RELAY
TEST WIRING – DELTA CONNECTION on page 17–4.
1. Inject voltage at a frequency below the pickup level into phase A.
2. Slowly increase the frequency until the element generates an output.
3. Slowly reduce the frequency until the element resets.
Indications and Operations caused by the various Functions are as outlined under Phase Time O/C,
with the following exception.
There is no Trip function for this element.
Timing:
1. Connect the Stop Trigger.
2. Preset the voltage source frequency to a minimum of 110% of pickup. Turn voltage off and reset the timer.
3. Inject the preset voltage into phase A and note the measured delay time. Reset the timer.
4. Repeat step 3 four more times and obtain an average of the time intervals.
5. Disconnect the “Stop Trigger.”
17.8.11 POWER FACTOR 1(2)
Test Connections per Figure 17–1: RELAY TEST WIRING – WYE CONNECTION or Figure 17–2: RELAY
TEST WIRING – DELTA CONNECTION on page 17–4.
Minimum Operating Voltage/Current Supervision:
1. Inject fixed values of voltage and current at about nominal values, at unity power factor. Slowly increase
the angle of lagging current, waiting for a time longer than the delay setting before each adjustment, until
the element generates an output.
Indications and Operations caused by the various Functions are as outlined under Phase Time O/C,
with the following exception.
There is no Trip function for this element.
2. Slowly reduce voltage
V
a
magnitude until the power factor feature resets. Note the dropout voltage, which
should be at about 30% of the selected nominal voltage. Return
V
a
to nominal.
3. Repeat step 2 for
V
b
.
4. Repeat step 2 for
V
c
.
5. Slowly reduce
I
a
and I
b
magnitude to 0. The power factor feature should remain operated.
6. Slowly reduce
I
c
magnitude to 0. The power factor feature should reset.
7. Return
I
a
to nominal. The power factor feature should operate again. Return I
b
and I
c
to nominal.
8. Decrease the angle of lagging (balanced) current until the feature drops-out and resets the output relays.
Timing:
1. Connect the Stop Trigger.
2. Preset the 3-phase voltage and current inputs to a power factor more lagging than the pickup level. Turn
voltages and currents off, and reset the timer.

GE 750 Specifications

General

Brand	GE
Model	750
Category	Relays
Language	English