Testing tertiary CT polarizing on Substation Power Transformer

[Walt M]

I am working on a project to replace a 75MVA 115/69KV auto transformer and have not recently run the polarizing test. The test I have run in the past uses a car battery connected to the isolated primary on the load side of the transformer breaker. The 3 phase conductors are shorted and tied to the battery negative. The battery positive is tied to ground. When the transformer breaker is closed, the connected electromechanical relay (JBCG) directional element will swing to open. At least that is as much of the test as I remember.
Has anyone done this recently and do I remember this correctly?

 

[Walt M]

Actually, I did not remember correctly. I was confusing the procedure of the current polarizing polarity test with the result of a potential polarizing test but I have it straight now, thanks.

 

[shockin]

Glad to help!