Transformer testing

[22574]

Can you suggest what is more advantage or helpful in Transformer testing, doing insulation resistance test or insulation power factor test.

Thank you.

 

[Elmir]

What kind of transformer does your question apply to, dry type or oil filled?

 

[22574]

For power transformer oil filled.

 

[oldfieldguy]

The power factor test is more comprehensive if I had to limit myself to just one, but why would we do that?

Power factor test set = $$$

Insulation resistance test set = $

Hiring a competent testing contractor to show up and do the tests usually means you get BOTH tests anyway. They are part of a pretty standard battery of tests on oil-filled transformers above a certain size.

old field guy

 

[marks1080]

I am familiar with insulation resistance testing (meggar test) when commissioning a transformer, but I've never heard of an insulation power factor test. Can someone please give me a brief explaination?

Thanks!

 

[marks1080]

megger****

 

[pwrtran]

It also called dissipation factor and test the real component of the leakage current through the insulation. Ideally, when insulation is in a good shape, the leakage current is purely capacitive. However, e.g. when water presents the leakage current will have resistive component.

 

[ScottyUK]

Google tan delta test - loads of hits.



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If we learn from our mistakes I'm getting a great education!

 

[Zogzog]

I agree with PF/DF and tan delta being good tests, megger wont tell you much on a transformer like this. There have also been some big strides in online Partial Discharge testing of oil filled transformers.

 

[pwrtran]

Another thing is
megger - DC
PF/DF/Tan_D tester - AC

 

[marks1080]

Thanks! I learned my one new thing today!

 

[Has0n]

What is the difference of a Vacuum Circuit Breaker and a Load Break Switch in terms of its usage?

 

[pwrtran]

Breaker - capable to interrupt a fault current
Load break switch , by its name - can interrupt the load current but not the fault current