Power Supply from PT

Dear Sir,

Primary Side of PT/CVT never shall be tapped. PT/CVT secondray voltage will be used used to differnt circuits. For metering, for protection. It shall from the respective core with relevant accuracy.

Regards,

N.Suresh

The question is about tapping power supply from the secondary of a PT for purposes other than metering and protection. Eg. 110V, AC supply is required in a 3.3kV switchboard for auxiliaries and whether it is advisable to tap power supply from the 3.3kV/110V PT (of adequate VA rating/burden) for the auxiliaries.

Regards,

Take a look at the KVA rating! That alone should (hopefully) give you a slight indication why not.

If that's not enough; what do you think will happen to your protection and metering if you load a PT? Think about that for a few seconds.