Neutral Voltage; Phase Differential Trip Accuracy - GE Multilin 489 Instruction Manual

7.3.7 Neutral Voltage (3rd Harmonic) Accuracy
7.3.8

Phase Differential Trip Accuracy

Note
7–16
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GROUND CT:
Measured values should be ±0.25 A.
Inject the values shown in the table below either as primary values into a
GE Multilin 50:0.025 Core Balance CT or as secondary values that
simulate the core balance CT.
Verify accuracy of the measured values in the
CURRENT METERING
Injected Current
Primary 50:0.025 CT Secondary
0.25 A 0.125 mA
1 A 0.5 mA
5 A 2.5 mA
10 A 5 mA
The 489 specification for neutral voltage (3rd harmonic) accuracy is ±0.5% of full scale
(100 V). Perform the steps below to verify accuracy.
In the
S2 SYSTEM SETUP
NEUTRAL VOLTAGE TRANSFORMER:
NEUTRAL V.T. RATIO:
In the
S2 SYSTEM SETUP
GENERATOR NOMINAL FREQUENCY:
Measured values should be ±5.0 V.
Apply the voltage values shown in the table and verify accuracy of the
measured values.
View the measured values in the
METERING
Applied Neutral Voltage
at 180 Hz
10 V
30 V
50 V
These tests will require a dual channel current source. The unit must be capable of
injecting prefault currents and fault currents of a different value. Application of
excessive currents (greater than 3 × CT) for extended periods will cause damage to the
relay.
"50:0.025 CT"
menu.
Current Reading
Expected
0.25 A
1.00 A
5.00 A
10.00 A
VOLTAGE SENSING
"Yes"
"10.00:1"
GEN. PARAMETERS
"60 Hz"
A2 METERING DATA
menu.
Expected Neutral Voltage
100 V
300 V
500 V
489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 7: TESTING
A2 METERING DATA
Measured
menu, set
menu, set:
VOLTAGE
Measured Neutral
Voltage