Doble Testing

[JasonSummers]

Could somebody please point me towards the details of a "Doble Test". The test in question is regarding a large power transformer. (Power generation facility main transformer) My research shows that it entails a little more than PF IR and Megg test.
Thank you for your assistance, Jason

 

[DanDel]

Doble testing is a very sophisticated and non-destructive method of testing various types of electrical equipment, as long as it is performed by a qualified, experienced person. Check out their website:

http://www.doble.com/

or search this forum for more info.

 

[buzzp]

I believe they put on free training at various locations within the US throughout the year. I just went to one locally and believe it was free [can't remember since I did not foot the bill ]

 

[chiefwvfc]

A doble test is a power factor test, and there are several suppliers of PF test equipment, such as: Doble, Megger, and On-line Monitoring Inc.

 

[ScottyUK]

Jason,

If this is a large and expensive transformer, it may be worth doing an Frequency Response Analysis (FRA) test, as developed by the CEGB in the UK, to get a 'fingerprint' of the transformer against which future tests may be compared.

We used FRA after a generator transformer fed in to a severe close-in fault, and we were concerned that winding movement might have occurred. The FRA test would (probably) pick this up more easily than a Doble type test, and possibly avoid the need to drain thousands of litres of oil.

The FRA test doesn't replace the Doble test, but it is a useful complement to it. Like the Doble test, it is a job best left for the specialists who are experienced in interpreting the results.

 

[jbartos]

Suggestion: Visit

http://www.usbr.gov/power/data/fist/fist3_30/3_30_4_7.htm

etc. for more info

 

[JasonSummers]

I would like to thank everyone who took the time to read this post and provide me with information on Dobble testing.
The more info...the better!!
Thanks, Jason