Case studies · Lessons
44 warnings, then a line burned down
In a blind study DFA grouped 44 of a feeder's 178 faults as one tree contact. Nobody acted, and 23 months later the conductor broke.
- Where
- Blind study, United States
- DFA reported
- The same fault, 44 times
- Faults on the feeder
- 178 in 23 months
- Cause
- Wind pushing vegetation into the conductors
- Outcome
- Conductor broke; wire down, sustained interruption
What DFA reported
Within days of installation, DFA began flagging a repeating phase-to-phase fault, grouping 44 of the feeder's 178 faults as the same fault at the same place. Researchers tied the faults to wind from one direction at sufficient speed, matched that to a section of line, and recommended a patrol for vegetation pushing the conductors together.
What the crew found
The utility ran the project as a blind study, so nobody acted beyond business as usual. Its communicating reclosers had logged all 178 faults, but nothing in those records showed which ones were related.
Why it matters
The fault kept recurring for 23 months until the damage broke a conductor: a live wire on the ground and a sustained interruption. Acting on the report would almost certainly have prevented dozens of momentary interruptions and the downed conductor.
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