GE Power Management
469 Motor Management Relay
7-3
7 TESTING
7.2 HARDWARE FUNCTIONAL TESTING
7
7.2.3 GROUND (1A/5A) AND DIFFERENTIAL ACCURACY TEST
The 469 specification for differential current and 1 A/5 A ground current input accuracy is
±
0.5% of 1
×
CT for
the 5 A input and 0.5% of 5
×
CT for the 1 A input. Perform the steps below to verify accuracy.
a) 5 A INPUT
1.
Alter the following setpoints:
S2 SYSTEM SETUP\CURRENT SENSING\GROUND CT:
5A Secondary
S2 SYSTEM SETUP\CURRENT SENSING\GROUND CT PRIMARY:
1000 A
S2 SYSTEM SETUP\CURRENT SENSING\PHASE DIFFERENTIAL CT:
5A Secondary
S2 SYSTEM SETUP\CURRENT SENSING\PHASE DIFFERENTIAL CT PRIMARY:
1000 A
2.
Measured values should be
±
5 A. Inject the values shown in the table below into one phase only and verify
accuracy of the measured values. View the measured values in:
A2 METERING DATA\CURRENT METERING
b) 1 A INPUT
1.
Alter the following setpoints:
S2 SYSTEM SETUP\CURRENT SENSING\GROUND CT:
1A Secondary
S2 SYSTEM SETUP\CURRENT SENSING\GROUND CT PRIMARY:
1000 A
S2 SYSTEM SETUP\CURRENT SENSING\PHASE DIFFERENTIAL CT:
1A Secondary
S2 SYSTEM SETUP\CURRENT SENSING\PHASE DIFFERENTIAL CT PRIMARY:
1000 A
2.
Measured values should be
±
25 A. Inject the values shown in the table below into one phase only and ver-
ify accuracy of the measured values. View the measured values in:
A2 METERING DATA\CURRENT METERING
Table 7–3: DIFFERENTIAL AND GROUND CURRENT TEST (5 A)
INJECTED
CURRENT
5 A UNIT
EXPECTED
CURRENT
READING
MEASURED
GROUND
CURRENT
MEASURED DIFFERENTIAL CURRENT
PHASE A
PHASE B
PHASE C
0.5 A
100 A
1.0 A
200 A
2.5 A
500 A
5.0 A
1000 A
Table 7–4: DIFFERENTIAL AND GROUND CURRENT TEST (1 A)
INJECTED
CURRENT
1 A UNIT
EXPECTED
CURRENT
READING
MEASURED
GROUND
CURRENT
MEASURED DIFFERENTIAL CURRENT
PHASE A
PHASE B
PHASE C
0.1 A
100 A
0.2 A
200 A
0.5 A
500 A
1.0 A
1000 A
