GE 489 - Manual (Page 221)

GE Multilin 489 Generator Management Relay 7-9
7 TESTING 7.3 ADDITIONAL FUNCTIONAL TESTS
7
7.3ADDITIONAL FUNCTIONAL TESTS 7.3.1 OVERLOAD CURVE ACCURACY
The specification for overload curve timing accuracy is ±100 ms or ±2% of time to trip. Pickup accuracy is as per the current
inputs ( ±0.5% of 2 × CT when the injected current is less than 2 × CT and ±1% of 20 × CT when the injected current is equal
to or greater than 2 × CT). Perform the steps below to verify accuracy.
1. Alter the following setpoints:
S2 SYSTEM SETUP ÖØ GEN. PARAMETERS ÖØ GENERATOR RATED MVA: "1.04"
S2 SYSTEM SETUP ÖØ GEN. PARAMETERS ÖØ GENERATOR VOLTAGE PHASE-PHASE: "600"
(Note: This is equivalent to setting FLA = 1000 A – For testing purposes ONLY!)
S2 SYSTEM SETUP Ö CURRENT SENSING Ö PHASE CT PRIMARY: "1000"
S9 THERMAL MODEL Ö MODEL SETUP ÖØ SELECT CURVE STYLE: "Standard"
S9 THERMAL MODEL Ö MODEL SETUP ÖØ OVERLOAD PICKUP LEVEL: "1.10 x FLA"
S9 THERMAL MODEL Ö MODEL SETUP ÖØ UNBALANCE BIAS K FACTOR: "0"
S9 THERMAL MODEL Ö MODEL SETUP ÖØ HOT/COLD SAFE STALL RATIO: "1.00"
S9 THERMAL MODEL Ö MODEL SETUP ÖØ ENABLE RTD BIASING: "No"
S9 THERMAL MODEL Ö MODEL SETUP ÖØ STANDARD OVERLOAD CURVE NUMBER: "4"
S9 THERMAL MODEL Ö MODEL SETUP ÖØ ENABLE THERMAL MODEL: "Yes"
S9 THERMAL MODEL Ö THERMAL ELEMENTS ÖØ THERMAL MODEL TRIP: "Latched" or "Unlatched"
2. Any trip must be reset prior to each test. Short the emergency restart terminals momentarily immediately prior to each
overload curve test to ensure that the thermal capacity used is zero. Failure to do so will result in shorter trip times.
Inject the current of the proper amplitude to obtain the values as shown and verify the trip times. Motor load may be
viewed in:
A2 METERING DATA Ö CURRENT METERING
3. Thermal capacity used and estimated time to trip may be viewed in:
A1 STATUS ÖØ GENERATOR STATUS
(EQ 7.4)
AVERAGE PHASE
CURRENT DISPLAYED
PICKUP LEVEL EXPECTED TIME TO
TRIP
TOLERANCE RANGE MEASURED TIME TO
TRIP (SEC.)
1050 A 1.05 × FLA never n/a
1200 A 1.20 × FLA 795.44 sec. 779.53 to 811.35 sec.
1750 A 1.75 × FLA 169.66 sec. 166.27 to 173.05 sec.
3000 A 3.00 × FLA 43.73 sec. 42.86 to 44.60 sec.
6000 A 6.00 × FLA 9.99 sec. 9.79 to 10.19 sec.
10000 A 10.00 × FLA 5.55 sec. 5.44 to 5.66 sec.
NOTE
FLA
Generator Rated MVA
3 Generator Phase-to-Phase Voltage Ч
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