GE 489 - Manual (Page 225)

GE Multilin 489 Generator Management Relay 7-13
7 TESTING 7.3 ADDITIONAL FUNCTIONAL TESTS
7
7.3.6 GE MULTILIN HGF GROUND ACCURACY
The specification for GE Multilin HGF 50:0.025 ground current input accuracy is ±0.5% of 2 × CT rated primary (25 A). Per-
form the steps below to verify accuracy.
1. Alter the following setpoint:
S2 SYSTEM SETUP Ö CURRENT SENSING ÖØ GROUND CT: "50:0.025 CT"
2. Measured values should be ±0.25 A. Inject the values shown in the table below either as primary values into a GE Mul-
tilin 50:0.025 Core Balance CT or as secondary values that simulate the core balance CT. Verify accuracy of the mea-
sured values in:
A2 METERING DATA Ö CURRENT METERING
7.3.7 NEUTRAL VOLTAGE (3RD HARMONIC) ACCURACY
The 489 specification for neutral voltage (3rd harmonic) accuracy is ±0.5% of full scale (100 V). Perform the steps below to
verify accuracy.
1. Alter the following setpoints:
S2 SYSTEM SETUP ÖØ VOLTAGE SENSING ÖØ NEUTRAL VOLTAGE TRANSFORMER: "Yes"
S2 SYSTEM SETUP ÖØ VOLTAGE SENSING ÖØ NEUTRAL V.T. RATIO: "10.00:1"
S2 SYSTEM SETUP ÖØ GEN. PARAMETERS ÖØ GENERATOR NOMINAL FREQUENCY: "60 Hz"
2. 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:
A2 METERING DATA ÖØ VOLTAGE METERING
INJECTED CURRENT CURRENT READING
PRIMARY 50:0.025 CT SECONDARY EXPECTED MEASURED
0.25 A 0.125 mA 0.25 A
1 A 0.5 mA 1.00 A
5 A 2.5 mA 5.00 A
10 A 5 mA 10.00 A
APPLIED NEUTRAL
VOLTAGE AT 180 HZ
EXPECTED NEUTRAL
VOLTAGE
MEASURED NEUTRAL
VOLTAGE
10 V 100 V
30 V 300 V
50 V 500 V