Report: TR-441 · Feeder West breaker
Device: Microprocessor relay (anonymized)
Format: Trip report decode. Not a coordination textbook.
Relay summary block
Event: TR-441
Breaker: 52-W
Target: 51P / 50P
Pickup: 51P phase B
Fault I: ~6.2 × In (phase B)
Duration to trip: 312 ms
Pre-fault V: normal
Targets asserted: 51P
Targets not asserted: 67, 27, 59
If nobody reads the target list, every trip becomes ‘something on the line.’
Decode (plain language)
| Field | Meaning here | | --- | --- | | 51P B pickup | Timed overcurrent saw phase B first | | 50P not latching alone | Not a pure instantaneous story | | 312 ms | Coordination window — check downstream fuse/breaker curves | | No 27/59 | Not an undervoltage / overvoltage primary tale |
Ops hallway version: “blink again.”
Relay version: overcurrent on B with a clock.
Wrong next steps heard same day
- Close breaker immediately (no inspection of B-phase cable / load).
- Raise pickup “so it stops nuisance tripping.”
- Blame utility without comparing TR-441 timestamp to PQ-monitor events.
Required packet before reclose authority
- TR-441 PDF + COMTRADE / event file archived.
- Walkdown notes on Feeder West B-phase (heat, smell, torque marks).
- Curve check: does 312 ms match the intended coordination?
- Cross-ref plant PQ events in the same minute (caption sheet if sag present).
- Reclose checklist signed — not a radio “go.”
A trip report is a witness. Raising the setting is erasing testimony.
Adjacent fences
PQ captions own sag evidence. Black-start scripts own grid-loss drills. Invoice autopsies own tariff lines. UPS cascades own island failure trees. TR-441 owns one protection event as readable truth. Do not coordinate by folklore.
Close
The breaker told the truth once. The plant’s job is to keep the file—and not argue with the pickup bit.