Additional Functional Testing; Overload Curve Test - GE 489 Instruction Manual

7 TESTING

7.3 ADDITIONAL FUNCTIONAL TESTING

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\GEN. PARAMETERS\GENERATOR RATED:
S2 SYSTEM SETUP\GEN. PARAMETERS\GENERATOR VOLTAGE PHASE-PHASE:
(Note: This is equivalent to setting FLA = 1000 A – For testing purposes ONLY!)
S2 SYSTEM SETUP\CURRENT SENSING\PHASE CT PRIMARY:
S9 THERMAL MODEL\MODEL SETUP\SELECT CURVE STYLE:
S9 THERMAL MODEL\MODEL SETUP\OVERLOAD PICKUP LEVEL:
S9 THERMAL MODEL\MODEL SETUP\UNBALANCE BIAS K FACTOR:
S9 THERMAL MODEL\MODEL SETUP\HOT/COLD SAFE STALL RATIO:
S9 THERMAL MODEL\MODEL SETUP\ENABLE RTD BIASING:
S9 THERMAL MODEL\MODEL SETUP\STANDARD OVERLOAD CURVE NUMBER:
S9 THERMAL MODEL\MODEL SETUP\ENABLE THERMAL MODEL:
S9 THERMAL MODEL\THERMAL ELEMENTS\THERMAL MODEL TRIP:
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\CURRENT METERING
3. Thermal capacity used and estimated time to trip may be viewed in:
A1 STATUS\GENERATOR STATUS
AVERAGE PHASE PICKUP LEVEL
CURRENT DISPLAYED
1.05 × FLA
1050 A
1.20 × FLA
1200 A
1.75 × FLA
1750 A
3.00 × FLA
3000 A
6.00 × FLA
6000 A
10.00 × FLA
10000 A
Generator Rated MVA
FLA
= ---------------------------------------------------------------------------------------------------------- -
×
3 Generator Phase-to-Phase Voltage
NOTE
GE Power Management
1.04
1000
Standard
1.10xFLA
0
1.00
No
Yes
Latched or Unlatched
EXPECTED TIME TO
TRIP
never
795.44 sec.
169.66 sec.
43.73 sec.
9.99 sec.
5.55 sec.
489 Generator Management Relay
7.3 ADDITIONAL FUNCTIONAL TESTING

7.3.1 OVERLOAD CURVE TEST

600
4
TOLERANCE RANGE MEASURED TIME TO
TRIP (SEC.)
n/a
779.53 to 811.35 sec.
166.27 to 173.05 sec.
42.86 to 44.60 sec.
9.79 to 10.19 sec.
5.44 to 5.66 sec.
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