Protective Relay Settings: relay_pickup
Protective relay settings and coordination parameters per IEEE C37 and IEEE 242. Covers IEEE C37.112-2018 inverse time-overcurrent curve constants (A, B, p, tr) for moderately/very/extremely inverse curves and SEL vendor extensions; IEC 60255-151 curve constants (k, alpha); CT accuracy classes C100/C200/C400/C800 per IEEE C57.13-2016 with burden limits; relay pickup guidance by ANSI device number (50, 51, 50N, 51N, 27, 59, 81U, 81O); coordination time intervals (CTI) per IEEE 242-2001; and CT saturation voltage thresholds.
| parameter type | record id | curve designation | curve name | curve standard | notes | time dial range max | time dial range min |
|---|---|---|---|---|---|---|---|
| relay_pickup | dev27_uv | 27 | Device 27 Undervoltage | ANSI IEEE | ANSI 27 = undervoltage; typical pickup 0.85 pu for motor protection (NEMA MG-1); 0.80 pu for generator loss-of-field; time delay 0.5-3.0s | 0.9 | 0.8 |
| relay_pickup | dev50N_ground | 50N | Device 50N Ground Instantaneous OC | ANSI IEEE | ANSI 50N = ground instantaneous OC; set 10-30% of CT secondary rating for sensitive ground detection | 0.3 | 0.1 |
| relay_pickup | dev50_phase | 50 | Device 50 Phase Instantaneous OC | ANSI IEEE | ANSI device 50 = instantaneous overcurrent; set above symmetrical fault current; must NOT pick up on maximum load; pickup = 125-200% max through-fault current | 2 | 1.25 |
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