Case studies · Recurrent faults
Six faults in nine hours, no outage, no calls, and a branch removed
A hanging branch tripped a recloser six times without an outage. DFA grouped the faults into one report, and a targeted patrol found it.
- Utility
- Pedernales Electric Cooperative
- DFA reported
- Recurrent fault, phase C to ground, about 300 A
- Circuit
- 12.5 kV, 153 miles of primary, 1,008 meters
- Found
- A branch hanging on a remote single-phase tap
- Outcome
- Removed with no outage and minimal conductor damage
What DFA reported
During a storm, a detached branch hanging on a remote single-phase tap caused six faults over nine hours. A hydraulic recloser cleared each one with a trip and a reclose. Nobody lost power and nobody called, so ordinarily the co-op would have done nothing. DFA grouped the six faults into one recurrent-fault report: phase C to ground, about 300 A, behind a single-phase recloser.
What the crew found
At 300 A the circuit model alone listed many possible locations. The co-op used DFA's details to rule out some of the circuit's reclosers, confirmed the operating one with meter blink counts, and sent a targeted patrol that found and removed the branch.
Why it matters
The co-op calls it an averted fire hazard, found with minimal crew time. It also corrected the phasing on its map.
“In one case, we were able to pinpoint the location of a branch on an overhead line that could have become an ignition source for wildfire in a rural subdivision.”Robert Peterson, director of control center and emergency preparedness, Pedernales Electric Cooperative (2018)
Keep reading
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