Transformer oil (insulation oil) 1

[HassLiebe]

How often you are testing the insulation oil in the transformer? And what are the best parameters for the testing?

I know about moisture, tan/delta, DGA, breakdown. Are the any others? What are the prior for transformer?

 

[thermionic1]

Most users will sample annually. If a problem is detected, the sampling interval is generally decreased, depending on the results of the sample and the unit importance. In IEEE world IEEE C57.104-2019 is used for aid in interpretation & test selection. There is a similar document in the IEC world. Most oil labs will offer both "packages" and ala carte ways of selecting which tests to run and analyze. There are two different sample types. #1 DGA - finding fault gasses. #2-Quality - physical properties of the oil and it's suitability for continued use. Note DGA is taken in a syringe and Quality in a bottle. Best to do both samples at the same time as the lab costs are roughly $250 for both. Most analysis is based on trending, so keeping an annual schedule helps.

If you are responsible for managing a facility, I recommend you check with your insurance company, as they will likely have something to say about what tests and when.