GE 750 - Measurement of Input Voltage

GE Power Management 750/760 Feeder Management Relay 17-
13
17 COMMISSIONING 17.6 METERING
17
17.6.2 MEASUREMENT OF INPUT VOLTAGE
Test Connections per Figure 17–1: RELAY TEST WIRING – WYE CONNECTION or Figure 17–2: RELAY
TEST WIRING – DELTA CONNECTION on page 17–4.
a) BUS VOLTAGE
Expected Accuracy:
Phase-neutral voltages ± 0.68 V for 50 to 130 V
± 2.18 V for other voltages within specified limits
Phase-phase voltages ± 0.68 V for 50 to 130 V (
V
ab
and V
cb
)
± 1.36 V for 50 to 130 V (calculated
V
ac
)
± 2.18 V for all other voltages within the specified limits (
V
ab
and V
cb
)
± 4.36 V for all other voltages within the specified limits (calculated
V
ac
)
Actual Values Displays:
Under subheading
A2 METERING \ VOLTAGE \
AB: BC: CA
: (Magnitude)
AVERAGE LINE VOLTAGE
(Magnitude)
AN: BN: CN:
(Magnitude)
(not available when connected Delta)
AVERAGE PHASE VOLTAGE:
(Magnitude) (not available when connected Delta)
LINE A-B VOLTAGE
(Phasor)
LINE B-C VOLTAGE
(Phasor)
LINE C-A VOLTAGE
(Phasor)
PHASE A-N VOLTAGE
(Phasor) (not available when connected Delta)
PHASE B-N VOLTAGE
(Phasor) (not available when connected Delta)
PHASE C-N VOLTAGE
(Phasor) (not available when connected Delta)
POS SEQ VOLTAGE
(Phasor)
NEG SEQ VOLTAGE
(Phasor)
ZERO SEQ VOLTAGE
(Phasor)
NEUTRAL (3VO) VOLTAGE
(Phasor)
Procedure:
1. Inject 1-phase voltage of various values into the relay bus voltage input one phase at a time, and observe
the magnitude. Note that for Wye VTs the positive sequence, negative sequence and zero sequence mag-
nitudes are 1/3 of the phase voltage magnitude for this test. For Delta VTs the zero sequence voltage will
be displayed as 0. The positive sequence and negative sequence magnitudes will be
√
3 of the line voltage
magnitude.
2. Inject 3-phase voltage of various values and angles into the relay bus voltage input and note the measured
voltage phasors & symmetrical components. For Delta VTs the zero sequence voltage will be shown as 0.