Doble Power Factor Test set

[Arevaengineer]

What are the applications of this instrument besides transformers( power and instrument.Is it of any help on Medium voltage ( 1kV-52kV)equipment.In what way?
Thanks to everyone in advance for thier inputs.

 

[jbartos]

Comment: The Doble test can be applied to transformer, circuit breaker, etc. bushings, for example.

 

[electricpete]

The Doble test can be applied to rotating equipment.
Also limited tests on oil-filled capacitors.

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[DanDel]

The applications of the Doble PF test systems are usually exclusively MV or higher. Procedures are listed for power & distribution transformers, instrument transformers, bushings, C/Bs, regulators, arrestors, capacitors, rotating machinery, liquid insulation, and cables.
Practically anything with insulation can be tested. Basically, the PF testing sets up the insulation under test as a dielectric between two conductors, just like a capacitor. Losses through the insulation are measured in watts, which is compared to total (VA) power impressed on the equipment during the test, to calculate the PF. Typically, for good insulation, the ratio between watts loss and total VA (a major component of which is the reactive power used create the electric field in the dielectric) will result in a very low PF value.

 

[jbartos]

Suggestion: Visit

http://www.usbr.gov/power/data/fist/fist3_18/vol3-18.pdf

for Doble Testing on capacitors

 

[Arevaengineer]

Dandel,jbartos

Thanks for your inputs. To measure the insulation of a circuit breaker for example,we can use AC power frequency hipot test.Does it imply that for new equipment we can use AC Power frequency test in case of Circuit breaker and PF for old equipment.Is PF test the best measure of insulation.
Is it required in the industry(utility or oil and gas)or specified anywhere in IEC to carry out this test specially on MV circuitbreaker and associated bushings.

 

[electricpete]

I would say if you have oil-filled bushings or oil circuit breaker it is very common test for circuit breakers.

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[DanDel]

The main advantage of the PF test over the DC Hipot test is that PF tests are always non-destructive, since the voltages used are not above the ratings of the equipment tested.

 

[jbartos]

Comment: The DC Hipot test is simpler. If the DC voltage level is reasonable, it does not necessarily have to be destructive.