a small currents at one end shield earthed appear and may punch in weak end to flashover breakdown

[AhmedIbrahimHassan]

I installed HV cable 132KV from auto transformer to 132KV switchyard side, a little bit away from the transformer approximate and different distance ( 300m to 1 KM), therefore I have much more 5 times puncture in cable join in different places sometimes in 132KV side connection and often at another side on 132KV bushing Auto transformer side?
we checked a lot of type of concerning and worrying possibility points and cases but really still I won't able to discover my problem to fixing once this explosion, some times we faced to explosion in bushing cable connection side and made disaster situation for example once the end of the faulty cable has burned to more than two hours.

so may we can get some help to discover this problem and/or happened in different places and found its problem and fixed by some solution??


my best regards

 

[krisys]

Your query is not clear.

However, if the cable is single core, the shield earthing really needs some special attention (engineering and calculations). In fact the recommendation should come from the cable vendor. Then follow the vendor recommendation properly. There should not be any problem.

But all other requirements such as insulation coordination etc. are in line with the requirement.

 

[prc]

Just a question. Where are the Lightning arresters? Only at switchyard and nothing at transformer end? Then you are for trouble.

 

[pwrtran]

Transformer is inductive and the your cable in capacitive, I was wondering if it reached a "sweet" point of resonance!
Another thing is the poor workmanship on the cable terminations, it happens quite often!