GE 889 Instruction Manual page 25

CHAPTER 1: INTRODUCTION
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889 GENERATOR PROTECTION SYSTEM – INSTRUCTION MANUAL
PHASE/NEUTRAL/GROUND TIME OVERCURRENT (51P/N/G)
Current:....................................................................Phasor or RMS
Pickup Level:..........................................................0.050 to 30.000 x CT in steps of 0.001 x CT
Dropout Level: ......................................................97 to 98% of Pickup
Level Accuracy:....................................................For 0.1 to 2.0 x CT: ±0.5% of reading or ±0.4% of rated,
Curve Shape:.........................................................IEEE Extremely/Very/Moderately Inverse;
Curve Multiplier:...................................................0.05 to 600.00 in steps of 0.01
Reset Time: ............................................................Instantaneous, Timed
Curve Timing Accuracy: ..................................Currents > 1.03 to 20 x pickup: ± 3% of operate time or ± ½
Voltage Restrained Function (51V):.............Modifies Pickup from 0.1 < V < 0.9 VT Nominal in a fixed
Add 1.5 cycles to the curve time to obtain the TOC operating time, i.e., from fault inception
until operation.
PHASE DIRECTIONAL OVERCURRENT (67P)
Relay Connection: ..............................................90º(Quadrature)
Quadrature Voltage: ..........................................ABC phase seq.: phase A (Vbc), phase B (Vca), phase C (Vab);
Polarizing Voltage Threshold:........................0.050 to 3.000 x VT in steps of 0.001 x VT
Current Sensitivity Threshold: .......................0.05 x CT
Characteristic Angle:.........................................0º to 359º in steps of 1°
Angle Accuracy: ..................................................± 2º
Operation Time (FlexLogic™ operands): ..Reverse to Forward transition: < 12 ms, typically;
NEUTRAL DIRECTIONAL OVERCURRENT (67N)
Directionality: .......................................................Co-existing forward and reverse
Polarizing: ...............................................................Voltage, Current, Dual
Polarizing Voltage:..............................................V_0 or VX
Polarizing Current: ..............................................Ig
Operating Current: .............................................I_0
Level Sensing: .......................................................3 x (|I_0| – K x |I_1|), Ig
Restraint, K: ...........................................................0.000 to 0.500 in steps of 0.001
Characteristic Angle:.........................................-90º to 90º in steps of 1°
Limit Angle: ............................................................40º to 90º in steps of 1°, independent for forward and
Angle Accuracy: ..................................................±2º
Pickup Level:..........................................................0.050 to 30.000 x CT in steps of 0.001 x CT
Dropout Level: ......................................................97 to 98% of Pickup
Operate Time (no direction transition):.....< 16 ms at 3 x Pickup at 60 Hz
whichever is greater;
For > 2.0 x CT: ±1.5% of reading
50:0.025A CT: For 0.5A to 4A: ±0.1A; For > 4A: ±0.2A
ANSI Extremely/Very/Normally/Moderately Inverse;
Definite Time, IEC A/B/C and Short Inverse;
IAC Extremely/Very/Inverse/Short Inverse;
2 4
FlexCurve A/B/C/D, I t, I t
cycle (whichever is greater) from pickup to operate
linear relationship
ACB phase seq.: phase A (Vcb), phase B (Vac), phase C (Vba)
Forward to Reverse transition: <8 ms, typically
reverse
< 20 ms at 3 x Pickup at 50 Hz
SPECIFICATIONS
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