Spare Cables - energize or de-energize?
Spare Cables - energize or de-energize?
(OP)
Here is the situation:
3 transformers each feeding a switchboard
Each switchboard has a breaker that connects to a cable to another switchboard as a cross tie for backup
Each cross tie cable has a breaker at each switchboard
All cross tie breakers are open.
My question that I have been struggling with is it better to leave the cross tie cable de-energized or energized?
My thoughts are that if it is energized and the cable faults, you would know about it before it is needed. The other thought is that it may be more detrimental to the cable to leave it energized with no load on it.
Thoughts/opinions/experiences?
Thank you all in advance.
3 transformers each feeding a switchboard
Each switchboard has a breaker that connects to a cable to another switchboard as a cross tie for backup
Each cross tie cable has a breaker at each switchboard
All cross tie breakers are open.
My question that I have been struggling with is it better to leave the cross tie cable de-energized or energized?
My thoughts are that if it is energized and the cable faults, you would know about it before it is needed. The other thought is that it may be more detrimental to the cable to leave it energized with no load on it.
Thoughts/opinions/experiences?
Thank you all in advance.






RE: Spare Cables - energize or de-energize?
You want to know you have a viable backup, so either you must reduce the risk of failure. That said figure what are the failure modes, and how do you reduce them?
With transmission lines, or power transformers we do that by using reduced voltage to energize them. For oil filled equipment we monitor the oil quality. What other factors can you control?
RE: Spare Cables - energize or de-energize?
RE: Spare Cables - energize or de-energize?
RE: Spare Cables - energize or de-energize?
Let's assume not underground, and not oil-surrounded. Could it then be isolable with breakers, but those breakers only shut for testing once a year? Or wold that"cycling" of the isolation breakers and insulation actually be worse than continuously keeping it hot?
RE: Spare Cables - energize or de-energize?
RE: Spare Cables - energize or de-energize?
The voltage isn't mentioned but the safety rules in some companies would require any medium or high voltage cable left dead for more than a day or so to be tested before it is made live.
Regards
Marmite
RE: Spare Cables - energize or de-energize?