Ground (1A), Neutral And Differential Current Accuracy; Neutral Voltage (Fundamental) Accuracy - GE 489 Instruction Manual

7.2 HARDWARE FUNCTIONAL TESTING
The specification for neutral, differential and 1 A ground current input accuracy is ±0.5% of 2 × CT. Perform the steps below
to verify accuracy.
1. Alter the following setpoints:
S2 SYSTEM SETUP\CURRENT SENSING\GROUND CT:
S2 SYSTEM SETUP\CURRENT SENSING\GROUND CT RATIO:
S2 SYSTEM SETUP\CURRENT SENSING\PHASE CT PRIMARY:
S5 CURRENT ELEMENTS\PHASE DIFFERENTIAL\PHASE DIFFERENTIAL TRIP:
S5 CURRENT ELEMENTS\PHASE DIFFERENTIAL\DIFFERENTIAL TRIP MIN. PICKUP:
2. Note: the last two setpoints are needed to view the neutral and the differential current. The trip element will operate
when differential current exceeds 100 A.
Measured values should be ±10 A. Inject ( I
3.
accuracy of the measured values. View the measured values in:
A2 METERING DATA\CURRENT METERING
or press the
NEXT
Table 7–1: NEUTRAL AND GROUND CURRENT TEST
INJECTED
CURRENT
1 A UNIT
0.1 A
0.2 A
0.5 A
1 A
Table 7–2: DIFFERENTIAL CURRENT TEST
INJECTED
CURRENT
0.1 A
0.2 A
0.5 A
1 A
7
The specification for neutral voltage (fundamental) accuracy is ±0.5% of full scale (100 V). Perform the steps below to verify
accuracy.
1. Alter the following setpoints:
S2 SYSTEM SETUP\VOLTAGE SENSING\NEUTRAL VOLTAGE TRANSFORMER:
S2 SYSTEM SETUP\VOLTAGE SENSING\NEUTRAL V.T. RATIO:
S2 SYSTEM SETUP\GEN. PARAMETERS\GENERATOR NOMINAL FREQUENCY:
Measured values should be ±5.0 V. Apply the voltage values shown in the table and verify accuracy of the measured
2.
values. View the measured values in:
A2 METERING DATA\VOLTAGE METERING
APPLIED NEUTRAL
VOLTAGE AT 60 HZ
10 V
30 V
50 V
7-4

7.2.3 GROUND (1A), NEUTRAL AND DIFFERENTIAL CURRENT ACCURACY

only) the values shown in the table below into one phase only and verify
A
key to view the current values when differential trip element is active.
EXPECTED MEASURED
CURRENT GROUND
READING CURRENT
100 A
200 A
500 A
1000 A
EXPECTED CURRENT READING
DIFF. PHASE A DIFF PHASE B,C
200 A 100 A
400 A 200 A
1000 A 500 A
2000 A 1000 A
EXPECTED NEUTRAL
VOLTAGE
100 V
300 V
500 V
489 Generator Management Relay
1A Secondary
1000:1
1000 A
unlatched
0.1xCT
MEASURED NEUTRAL CURRENT
PHASE A
MEASURED DIFFERENTIAL CURRENT
PHASE A

7.2.4 NEUTRAL VOLTAGE (FUNDAMENTAL) ACCURACY

Yes
10.00:1
60 Hz
MEASURED NEUTRAL
VOLTAGE
7 TESTING
PHASE B PHASE C
PHASE B PHASE C
GE Power Management