GE 750 - Measurement of Real Power & Watthours

GE Power Management 750/760 Feeder Management Relay 17-
15
17 COMMISSIONING 17.6 METERING
17
17.6.3 MEASUREMENT OF REAL POWER & WATTHOURS
Test Connections per Figure 17–1: RELAY TEST WIRING – WYE CONNECTION or Figure 17–2: RELAY
TEST WIRING – DELTA CONNECTION on page 17–4.
Expected Accuracy:
Real Power: ± 1% of full scale currents 5% to 199% of nominal voltages 50 to 130 V
Watthours: ± 2% of full scale currents 5% to 199% of nominal voltages 50 to 130 V
Actual Values Displays:
Under subheading
A2 METERING \ POWER \
3
Φ
REAL POWER
Φ
A REAL POWER
(not available when connected Delta)
Φ
B REAL POWER
(not available when connected Delta)
Φ
C REAL POWER
(not available when connected Delta)
Under subheading
A2 METERING \ ENERGY
POSITIVE WATTHOURS
NEGATIVE WATTHOURS
Procedure:
1. To reduce the time required for watthour measurements, set the input VT and CT ratios to high values.
Inject 3-phase voltage and current of various values and angles into the relay. Note that real power is mea-
sured and displayed.
2. Maintain voltage and current at various settings for a time sufficient to achieve a minimum of 20 MWh for
each test interval. Check that watthours is measured and displayed. Note that watthours for load in the
positive direction and in the negative direction are stored in separate registers. The test procedure should
be performed for loads in each direction.
17.6.4 MEASUREMENT OF REACTIVE POWER & VARHOURS
Test Connections per Figure 17–1: RELAY TEST WIRING – WYE CONNECTION or Figure 17–2: RELAY
TEST WIRING – DELTA CONNECTION on page 17–4.
Expected Accuracy:
Reactive Power: ± 1% of full scale currents 5% to 199% of nominal voltages 50 to 130 V
Varhours: ± 2% of full scale currents 5% to 199% of nominal voltages 50 to 130 V
Actual Values Displays:
Under subheading
A2 METERING \ POWER \
3
Φ
REACTIVE POWER
Φ
A REACTIVE POWER
(not available when connected Delta)
Φ
B REACTIVE POWER
(not available when connected Delta)
Φ
C REACTIVE POWER
(not available when connected Delta)
Under subheading
A2 METERING \ ENERGY \
POSITIVE VARHOURS
NEGATIVE VARHOURS
Procedure:
Follow the procedure outlined in the previous section above.