GE 889 - Page 23

CHAPTER 1: INTRODUCTION SPECIFICATIONS
889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL 1–13
OVERALL PERCENT DIFFERENTIAL PROTECTION
Differential/Restraint Characteristic:.........Dual Slope, Dual Breakpoint
Minimum Pickup level:......................................0.05 to 1.00 x CT in steps of 0.01
Slope 1 range:.......................................................1 to 100% in steps of 1%
Slope 2 range:.......................................................1 to 100% in steps of 1%
Breakpoint 1:.........................................................0.50 to 2.00 x CT in steps of 0.01
Breakpoint 2:.........................................................2.00 to 30.00 x CT in steps of 0.01
2
nd
harmonic inhibit level: ..............................0.1 to 40.0% in steps of 0.1%
2
nd
harmonic inhibit mode:............................Per-phase, Average, 2-out-of-3, 1-out-of-3
5
th
harmonic inhibit level:...............................1.0 to 40.0% in steps of 0.1%
Dropout level:........................................................97 to 98% of Pickup
Operate time:........................................................< 16/22 ms at >3 x Pickup @60Hz (harmonic inhibits
disabled/enabled)
< 18/26 ms at >3 x Pickup @50Hz (harmonic inhibits
disabled/enabled)
Level accuracy:....................................................± 0.5% of reading current, or ±1% of rated
GENERATOR UNBALANCE (46)
Stages:......................................................................2 (I
2
t trip with linear reset and definite-time alarm)
Trip/Alarm Pickup Level: ..................................0.00 to 100.00% FLA in steps of 0.01
Constant K:.............................................................0.00 to 100.00 in steps of 0.01
Maximum Time:...................................................0 to 1000 s in steps of 1 s
Reset Time: ............................................................0.00 to 1000.00 s in steps of 0.01 s
Alarm Delay:..........................................................0.00 to 600.00 s in steps of 0.01 s
Pickup Accuracy:.................................................± 0.025 A or ±3% of reading, whichever is greater
Operate Time:.......................................................< 20 ms at 1.10 x pickup at 60 Hz
Timing Accuracy:................................................± 3% of operate time or ± 20 ms (whichever is greater)
Generator Unbalance Element: ....................Trip and Alarm
INADVERTENT ENERGIZATION
Operate time:........................................................<12 ms at >3 x O/C Pickup@60Hz
<15 ms at >3 x O/C Pickup@50Hz
LOSS OF EXCITATION (40)
Operating Condition:.........................................Positive-sequence impedance
Characteristic: ......................................................2 independent negative mho circles (LOE circle 1, 2)
Circle 1(2) Diameter: ..........................................0.1 to 300.0  (in secondary) in steps of 0.1
Circle 1(2) Offset: .................................................0.1 to 300.0  (in secondary) in steps of 0.1
Reach (Impedance) Accuracy:......................± 5%
Under Voltage (UV) Supervision Level: ......0.00 to 1.50 x VT in steps of 0.01 x VT
UV Pickup Accuracy: .........................................as per phase voltage inputs
Pickup Delay: ........................................................0.00 to 600.00 s in steps of 0.01 s
Timer Accuracy: ..................................................± 3% of delay setting or ± ½ cycle (whichever is greater)
Operate Time:.......................................................< 3 cycles