Hi-pot testing - 33kV transformer - voltage and duration?

[khodges]

We have a 33kV transformer about to go for factory acceptance tests, and while this is a relatively small 300kVA unit, am unsure what voltage and duration should be used for the hi-pot test. What is recommended for such a unit? (Of note is that this unit is rated 170kV BIL).

What generally determines the appropriate test voltage and duration? (without simply refering to a standard ... I'm after a more detailed electrical engineering explanation)

 

[rbulsara]

Engineering wise it will only withstand the voltage for a time period it is desinged for. How do you expect to know what it is desinged for?

You must refer to the standards as the unit is built to some 'standard' and you can only test to meet that standard. Plus consult a professinal testing agency who has experience in this kind of testing. Also check out NETA ATA/MTS.