Case studies · Failing connections
A broken jumper, 12 km out, fixed without an unplanned outage
The one customer it served noticed nothing. DFA reported each flare-up within about a minute, and meter pings led the crew to the pole.
- Where
- 25 kV circuit, United States
- DFA reported
- Series arcing, each flare-up within about a minute
- Circuit
- 25 kV, about 90 line-km
- Found
- A jumper broken at the surge arrester
- Outcome
- No unplanned outage
What DFA reported
A solid-copper jumper feeding a pole-top transformer broke where it attached to the surge arrester. Its stiffness kept it in contact, so it arced off and on, and the single customer it served reported nothing. DFA classified the flare-ups as series arcing and reported each one within about a minute.
What the crew found
Series arcing disrupts power-line-carrier meter traffic, so the utility pinged meters during a flare-up. Meters beyond the arcing answered off, which led the crew to the exact spot, about 12 electrical kilometers out on a circuit with about 90 line-km of conductor.
Why it matters
The utility replaced the jumper with only a short planned outage. DFA was its only notice.
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