3 BUSBAR PROTECTION FUNCTIONS
3.1 BUSBAR CIRCUITRY FAULT PROTECTION
Accuracy
Pick-up (IDMT) Setting +/-5%, or 20 mA, whichever is greater
Pick-up (DT) Setting +/-5%, or 20 mA, whichever is greater
Drop-off (IDMT and DT) > 0.95 x setting +/-5% or 20 mA, whichever is greater
Busbar trip with high speed contact
For 50 Hz: 8 ms (min), 12 ms (typical) at 3.5 × tripping
threshold
For 60 Hz: 6 ms (min), 10 ms (typical) at 4.5 × tripping
threshold
Busbar trip with standard contact
For 50 Hz: 13 ms (min), 17 ms (typical) at 3.5 × tripping
threshold
For 60 Hz: 11 ms (min) ,15 ms (typical) at 4.5 × tripping
threshold
3.2 BUSBAR CIRCUITRY FAULT PROTECTION
Accuracy
Pick-up (IDMT) Setting +/-5%, or 20 mA, whichever is greater
Pick-up (DT) Setting +/-5%, or 20 mA, whichever is greater
Drop-off (IDMT and DT) > 0.95 x setting +/-5% or 20 mA, whichever is greater
DT operation Setting +/-5% or 50 ms, whichever is greater
3.3 BUSBAR DEAD ZONE PROTECTION
Accuracy
Pick-up (IDMT) Setting +/-5%, or 20 mA, whichever is greater
Pick-up (DT) Setting +/-5%, or 20 mA, whichever is greater
Drop-off (IDMT and DT) > 0.95 x setting +/-5% or 20 mA, whichever is greater
Min. trip level 1.05 × Setting +/-5% or 20 mA, whichever is greater
DT operation Setting +/-5% or 50 ms, whichever is greater
3.4 THREE-PHASE OVERCURRENT PROTECTION
IDMT pick-up 1.05 × Setting +/-5%
DT pick-up Setting +/-5%
Drop-off (IDMT and DT) 0.95 x setting +/-5%
IDMT operate +/-5% or 40 ms, whichever is greater
DT operate +/-2% or 50 ms, whichever is greater
DT reset Setting +/-5%
Overshoot of overcurrent elements <30 ms
Chapter 16 - Technical Specifications MiCOM P747
390 P747-TM-EN-1
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