cable termination failure
cable termination failure
(OP)
We had a failure of 34.5 KV cable termination in 34.5 KV/13.8 KV Transformer during switching of 25.4 MW motor (through Softstarter). The concerned motor & Transformer are in different parts of plant.Is there any contact between switching & termination failure.






RE: cable termination failure
1 - switching can produce transient voltages exceeding normal voltages which might push a weakly insulated termination over the edge.
2 - High-resistance contacts will be most challenged during starting. We had a motor which tripped on current unbalance within seconds of DOL start, and we found an open circuit at the T-lead lug crimp Presumably it was a bad connection that degraded due to 6*FLA starting current which means 36*normal I^2*R in a high-resistance connection. Should not be as much a factor for soft start.
3 - prior to starting, terminations are at room temperature and there may be condensation/moisture present. Once the motor is running, the heat from conducting current in the cable tends to drive moisture away. Of course the terminations at that voltage are sealed and it shouldn't make a difference, but in real world it may not be the case.
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(2B)+(2B)' ?
RE: cable termination failure
RE: cable termination failure
RE: cable termination failure
seems like a transient voltage or sheer luck would be the more probable causes