Ground (1 A), Neutral , Andd; Neutral Voltage - GE Multilin 489 Instruction Manual

CHAPTER 7: TESTING
7.2.3 Ground (1 A), Neutral, and Differential Current Accuracy
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
Courtesy of NationalSwitchgear.com
Applied Line- Expected Voltage

Neutral Voltage

Reading
200 V 2000 V
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.
In the
S2 SYSTEM SETUP
GROUND CT:
GROUND CT RATIO:
PHASE CT PRIMARY:
In the
S5 CURRENT ELEMENTS
PHASE DIFFERENTIAL TRIP:
DIFFERENTIAL TRIP MIN. PICKUP:
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
and verify accuracy of the measured values.
View the measured values in the
METERING
differential trip element is active.
Table 7–1: Neutral and Ground Current Test Results
Injected Expected
Current Current Ground Current
1 A Unit
0.1 A 100 A
0.2 A 200 A
0.5 A 500 A
1 A 1000 A
Table 7–2: Differential Current Test Results
Injected Expected Current Reading
Current
Differential
Phase A
0.1 A 200 A
0.2 A 400 A
0.5 A 1000 A
1 A 2000 A
Measured Voltage
A-N
CURRENT SENSING
"1A Secondary"
"1000:1"
"1000 A"
PHASE DIFFERENTIAL
"Unlatched"
"0.1 x CT"
only) the values shown in the table below into one phase only
A
A2 METERING DATA
menu or press the key to view the current values when
NEXT
Measured Measured Neutral Current
Phase A
Measured Differential Current
Differential Phase A
Phase B,C
100 A
200 A
500 A
1000 A
B-N C-N
menu, set:
menu, set:
CURRENT
Phase B Phase C
Phase B Phase C
7–5