Case studies · Failing connections
A glowing substation switch, found within two hours
No calls, no SCADA alarm, normal meters. DFA reported series arcing, and a lineman found the failing switch before two days of storms.
- Utility
- Mid-South Synergy
- DFA reported
- Series arcing, late on a Saturday
- Where
- Rural, unmanned 25 kV substation
- Found
- Within two hours
- Outcome
- Replaced that evening with no outage
What DFA reported
Late on a Saturday, DFA reported series arcing on a circuit fed from a rural, unmanned 25 kV substation. The co-op had no member complaints and nothing on SCADA, and pinged meters looked normal. DFA also estimated that the failing device carried most of the circuit's load, which put it at or near the substation.
What the crew found
The crew patrolled near the substation. On arrival the lineman heard sizzling and saw light at a blade switch on the substation structure. The co-op found the switch within two hours of the report, moved all three of the substation's circuits to alternate sources, and replaced the switch that evening.
Why it matters
Thunderstorms crossed the area on each of the next two days. The switch sat on the bus side of the breakers, so a failure could have dropped every circuit on the substation and started a fire. Instead the co-op made the repair in daylight, without storm pressure and without an outage.
“It makes me wonder what we did before DFA.”Robert Taylor, engineering specialist, Mid-South Synergy (Texas A&M Engineering Experiment Station, 2018)
Keep reading
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DFA tracked a failing clamp for a month on a 268-mile oilfield circuit. The co-op's first series-arcing search found it as it burned through.
A broken jumper, 12 km out, fixed without an unplanned outage
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