GE Multilin 489 User Manual

7–16 489 GENERATOR MANAGEMENT RELAY – INSTRUCTION MANUAL
CHAPTER 7: TESTING
GROUND CT: “50:0.025 CT”
Measured values should be ±0.25 A.
Z 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.
Z Verify accuracy of the measured values in the
A2 METERING DATA Z
CURRENT METERING menu.
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.
Z In the
S2 SYSTEM SETUP ZV VOLTAGE SENSING menu, set
NEUTRAL VOLTAGE TRANSFORMER: “Yes”
NEUTRAL V.T. RATIO: “10.00:1”
Z In the S2 SYSTEM SETUP ZV GEN. PARAMETERS menu, set:
GENERATOR NOMINAL FREQUENCY: “60 Hz”
Measured values should be ±5.0 V.
Z Apply the voltage values shown in the table and verify accuracy of the
measured values.
Z View the measured values in the
A2 METERING DATA ZV VOLTAGE
METERING
menu.
7.3.8 Phase Differential Trip Accuracy
Note
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.
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
Courtesy of NationalSwitchgear.com

GE Multilin 489 Specifications

General

Brand	GE
Model	Multilin 489
Category	Relays
Language	English