Corona problem at 22kV

[Sahib]

Indoor 22kV minimum oil circuit breaker. Aluminium bus bars supported by polymer insulators. The cubicle space heater faulty for some time. Bluish sparking observed at the base of some of the insulators. No discharge from the exposed bus bars. Will changing those insulators solve the issue? Thanks.

 

[rlundsrud]

Have you tested the dielectric strength of the oil? It must be greater than 22 kv, otherwise replacement of the oil is necessary.

 

[rlundsrud]

I would also note that you should do something soon as a corona is often the precursor to a flashover. The corona will degrade the insulator due to the ultraviolet radiation that it produces. As the insulator degrades the likelihood of a flashover occurring will increase. It goes without saying that this is an undesirable result.

Some interesting info on this can be found here.
www.dbc.wroc.pl/Content/3458