Protective Relay Settings: motor protection setting
ps dev49 alarm to ps dev51N lrg
Protective relay settings, coordination parameters, and motor/bus protection data per IEEE C37, IEEE 242, IEC 60255, and IEEE 3004 series. Covers: IEEE C37.112 inverse time-overcurrent curve constants (A, B, p, tr) and IEC 60255-151 constants (k, alpha); CT accuracy classes C100/C200/C400/C800 per IEEE C57.13; relay pickup guidance by ANSI device number; CTI per IEEE 242; motor nameplate voltages, surge withstand levels, vibration limits, and relay alarm/trip thresholds per IEEE 3004.8-2016; ANSI device function numbers for motor and bus protection (Tables B.1/B.2/B.3); online partial discharge assessment thresholds; and dual-tie bus differential CT scheme fault response results per IEEE 3004.11-2019.
| parameter type | record id | description | device number | iec 61850 logical node | nema designation | standard | trip threshold |
|---|---|---|---|---|---|---|---|
| motor protection setting | ps dev49 trip sf10 | Thermal overload (49) trip — service factor 1.0 | 49 | PTTR | OL | IEEE Std 3004.8-2016 | 115% FLA (service factor 1.0) |
| motor protection setting | ps dev49 trip sf115 | Thermal overload (49) trip — service factor 1.15 | 49 | PTTR | OL | IEEE Std 3004.8-2016 | 125% FLA (service factor 1.15) |
| motor protection setting | ps dev50G hrg | Ground fault (50G) zero-sequence CT — high-resistance grounded system | 50G | IEEE Std 3004.8-2016 | Set just above system charging current (high resistance grounded) | ||
| motor protection setting | ps dev50G lrg | Ground fault (50G) zero-sequence CT — low-resistance grounded system | 50G | IEEE Std 3004.8-2016 | 5% to 10% of ground fault current (low resistance grounded) | ||
| motor protection setting | ps dev50 trip | Short-circuit (50) instantaneous overcurrent trip | 50 | PIOC | IEEE Std 3004.8-2016 | 1.6 to 2 times locked rotor current (set above motor inrush) | |
| motor protection setting | ps dev51N lrg | Ground fault (51N) residual — low-resistance grounded system | 51N | PTOC | IEEE Std 3004.8-2016 | 5% to 10% of ground fault current (low resistance grounded) |
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