Oil leak from transformer secondary bushing


Thread Starter

EC&I Engineer

On site we have a 2 MVA oil filled transformer 6.3kV/0.42kV. There is a small leak form the bushing base connection to the transformer tank. We want to replace the gasket of the bushing. Is there any procedure for this kind of activity? I guess that the bushing needs to be lifted somehow, take out the old gasket and replace it with the new one. But also the tank oil will be exposed to atmosphere also we might need oil recirculation and o2 measurement and of course during the work execution to make a small kiosk around the area with the use of dehumidifier. Any proposal will be appreciated.
EC&I Engineer... I can't provide you with a proposal. However, I would like to tell you of a related experience:

In my youth, I was responsible for group of electricians whose task was to return a repaired core & coil into its tank. On the last task, installation of the insulators, an electrician advised me that he dropped a bolt into the tank.

A plan was immediately devised. Simple enough... use a broom handle with a magnet taped to it to "fish" for the bolt. Of course "Murphy" of Murphy Law fame was hoovering around. The broom handle wasn't long enough.

Easy fix... send someone into the tank, and while poised (precipitously) on the core-structure, he could find the bolt!

Unfortunately, "Murphy" had a buddy. None of the men in the group could fit through the tank cover, except one. You guessed it. I was selected.

Regards, Phil Corso