GE P741

P74
x/EN TD/Na7
Technical Data
(TD) 2
-8 MiCOM P74
1, P742, P743
TD
Performance Data
Busbar Protection
Busbar fault Accuracy
Pick-up: Setting ± 5% or 20 A up to 8 Pus, or
50 A from 8 Pus, Whichever Is Greater (WIG)
Drop-off: >0.95 x Setting or 20 A up to 8 Pus,
or 50 A from 8 Pus, WIG
Busbar trip:11 ms (min) & 13 ms (typical) at
1.4 x tripping threshold at 50Hz and at 1.7 x
tripping threshold at 60Hz
Circuitry fault Accuracy
Pick-up: Setting ± 5% or 20 A up to 8 Pus, or
50 A from 8 Pus, Whichever Is Greater (WIG)
Drop-off: >0.95 x Setting or 20 A up to 8 Pus,
or 50 A from 8 Pus, WIG
DT operation: ±5 % or 40 ms WIG
Dead Zone Protection
Accuracy
Pick-up: Setting ± 5% or 10 mA Whichever Is
Greater (WIG)
Drop-off: >0.95 x Setting or 10 mA WIG
Min. trip level: 1.05 x Setting ± 5% or 10 mA
WIG
DT operation: ±5 % or 20 ms WIG
Three phase overcurrent protection
Accuracy
Pick-up: Setting ±5 % or 10 mA Whichever Is
Greater (WIG)
Drop-off: 0.95 x Setting ±5 % or 10 mA WIG
Min. trip level of IDMT elements:
1.05 x Setting ±5 % or 10 mA WIG
IDMT shape: ±5 % or 40 ms WIG (under
reference conditions)*
IEEE reset: ±5 % or 40 ms WIG
DT operation: ±5 % or 50 ms WIG
DT reset: Setting ±5 % or 20 ms WIG
Characteristic
UK curves: IEC 60255-3 …1998
US curves: IEEE C37.112 …1996
Earth Fault Protection
Accuracy
Pick-up: Setting ± 5% or 10 mA Whichever Is
Greater (WIG)
Drop-off: >0.95 x Setting or 10 mA WIG
Min. trip level of IDMT elements: 1.05 x Setting
± 5% or 10 mA WIG
IDMT characteristic shape: ± 5 % or 40 ms
WIG (under reference conditions)*
IEEE reset: ±10 % or 40 ms WIG
DT operation: ±5 % or 50 ms WIG
DT reset: ± 5% or 50 ms WIG
Transient overreach and overshoot
Accuracy
Additional tolerance due to increasing X/R
ratios: ± 5% over the X/R ratio of 1 to 90
Overshoot of overcurrent elements: < 40 ms
Programmable scheme logic
Accuracy
Output conditioner timer:
Setting ±2 % or 50ms whichever is greater
Dwell conditioner timer:
Setting ±2 % or 50ms whichever is greater
Pulse conditioner timer:
Setting ±2 % or 50 ms whichever is greater
IRIG-B and Real Time Clock
Modulated IRIG-B:
Modulation ratio: 1/3 or 1/6
Input signal peak-peak amplitude:
200 mV to 20 V
Input impedance at 1000Hz: 6000 Ω
External clock synchronization:
Conforms to IRIG standard 200-98, format B
Un-modulated IRIG-B:
Input signal TTL level
Input impedance at dc 10kΩ
External clock synchronization per IRIG
standard 200-98, format B00X.
Performance Accuracy (for modulated and
un-modulated versions)
Real time clock accuracy: < ±2 seconds/day
Measurements
Accuracy
Phase current: ±1.0 % of Reading or ±1.0%
CT Ratio (RorCTR)
Phase local current: ±1.0 % of RorCTR
or ±(f-fn)/fn %
Phase remote current: ±1.0 % of RorCTR
or ±(f-fn)/fn %
Phase differential current: ±5.0 %
Bias current: ±5.0 %
Frequency: ±1 %
Disturbance records
Accuracy
Waveshape : Comparable with applied
quantities
Magnitude and relative phases: ±5 % of
applied quantities
Duration: ±2 %
Trigger position: ±2 %
(minimum trigger 100 ms)