MV Cable û Defective Termination

[VTer]

Attached is a photo of a defective termination on the HV air terminal chamber on 25kV/480V transformer.

It looks like the silicone tape somehow ripped and is exposing the lug and what seems like the cable insulation. I am the new to this facility and I am not sure about the cable type, size or the termination type. Not sure how long this has been sitting like this either. All the information I have for now is the photo taken through ATC door window - attached.

I would like to leave this transformer in service until the shutdown and then correct the termination issue. This transformer feeds critical equipment that would cause a large economic loss if it was shut down. We have a planned PM shutdown in a month.

There is enough clearance and the environment is pretty well controlled. There are no obvious signs of corona and we will keep monitoring this cable on daily basis.
If there are any cable/termination experts out there please advise if in your opinion we should immediately disconnect this transformer and MV cable from service or would it be ok to stay energized for a month?


"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[7anoter4]

In my opinion, this is result of a short-circuit dynamic effect on the cable lug. The cable lug was not tightly screwed- the cable core was very rigid and the distance between termination end and the lug was not enough to shape well the cable up.

 

[arfarsi1389]

hi
in my opinion this comes frome loos connection and hi temp relation by it.just try tight connection and that's it.

 

[VTer]

We do not know what caused this to rip. The silicon tape was only ripped somehow - the termination was good. It has since been re-taped and seems to be good now.

"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla

 

[collies99]

It is not detrimental, can probably operate like this for a fairly long time being indoors or inside a switchgear. If this was an outdoor terminations, then water ingress could be an issue.

Dielecttic stress is alresfy conttolled at the lower end of the skirt assembly, the rest is just creepage control from the exposed parts. I think uou can wait until the next maintenance cycle to effect repair.

Take an IR reading/photo and compare to the othet phases, and if no hot connection relative to the other phases, you are good to go.

 

[VTer]

Hi Collies,

Thank you. That is exactly what we did and found no issues. It was just the top sealant silicon tape that ripped. It was replaced and is performing fine. I was just curious if anyone has seen the tape rip like that. It almost seemed like a knife ripped right through it. I have no idea what could have caused something like that to happen. It could have been small physical cut when the termination was first sealed that eventually caused this to happen over time?


"Throughout space there is energy. Is this energy static or kinetic! If static our hopes are in vain; if kinetic — and this we know it is, for certain — then it is a mere question of time when men will succeed in attaching their machinery to the very wheelwork of nature". – Nikola Tesla