Recently when we got the DGA result of transformer oil, the percentage of nitrogen and oxygen was very less It was below 5,000. But after two months when we took test again we found the value increased above 25000. What i understand these gases comes in to oil from atmosphere but i am not able to understand what may be the problem in our system that has increased these gases in such big quantity.

Did anybody face such experience ?

 

Paru, is this the oil you referred to in your Jan-09 thread?

Phil Corso

 

Hi phil
no this is another trafo. We had earlier high ppm for nitrogen and oxygen and then we did oil filtration. Both things came drastically down. But now after a month, there is increasing trend.

 

Paru, did you implement the precaution(s) inherent in my Jan remarks?

Phil

 

Phil
i remember you told about the temperature of oil when the sample was taken. But now in this case as i told ppm value were very less after filteration. After one or two months when the sample was taken ppm or N2 and O2 were very high.

I understand O2 and N2 comes from atmoshpheric air but how it is getting inside the oil ?

 

Paru,
most of the times the ingress of air occurs because of what is referred to as "breathing!"

Breathing is caused by the daily change of temperature allowing the ingress of air through via top to tank flanges, insulator flanges, or piping above the oil level, especially those associated with the conservator and "Buchholtz relay" piping?

Regards, Phil Corso ([email protected])

 

Ususally the changes in nitrogen and Oxygen contents occur due to the contaminated oil samples. These occur mostly during manual sampling were there are more chances of the apparent oil sampling.

Most reasons why these problems occur are that usually the oil samples would be Hot and when they are allowed to cool the oil contracts creating a vaccum. The vaccum created would pull air and the oil may get contaminated with the atmospheric air.

Thus a more conditioned sampling without exposure to the atmospheric gases could solve the problem of Nitrogen & Oxygen spikes.

 

I understand nitrogen and Oxygen become Because of Sampling touch atmosphere