Dry Nitrogen for Transformer Preservation

Can you tell us more about your 150 Million Volt Amp Transformer?

My 32KVA and 15KVA transformers are kept under CLEAR clean oil.The vent on the side will sometimes be on a vacuum.This is a small brass relief or safety valve,with a ring on the end(vent valve is above oil level)in dry air area.

I have seen the smaller of my transformers "wick" a small amount of oil,to the outside of the case.Alarming at first blush,until I remembered I had moved an electrode gasket.A slight tightening fixed it.

I am sorry I cannot directly answerer your question other than to say that there seems to be a fairly large amount of daily equalization of pressure in my large case (50KVA) transformer.This happens even without a load of any sort being present.Looking forward to hearing some speculation on this matter,as I also,find it highly interesting,and look forward to any guess/possibility of an answer.

Regards

Joe in Texas

It seems to me that if the transformer manufacturer was confident they could build a zero leakage transformer, they wouldn't have put the bottle on it in the first place. I suspect the transformer passed a minimum leakage specification when it was built, but that specification allowed for greater than zero leakage. Very small leaks can not be detected with a soap bubble test and if the transformer has a number of these small leaks, the gas usage will add up.

How long you intend storing the transformer.Normally air or nitrogen is filled for transport and air bottles are kept to make up any leakage.After receipt at site OIl should be filled up.

Dear guest,

Please see the Link provided, specifically section 6.2 and 6.3 of the manual. You should be aware that the relief valve will allow gasses to escape at around 7psi. If you have the pressurized tank un-regulated, or regulated above the tank relief value, you will be re-filling your tank quite often.

These are links to suppliers of automatic pressuring systems that give some additional clues as to the pressure values to be expected.

Even without energizing a transformer, it is a tank full of oil, and any tank full of oil out in the sun or in high ambient temperatures can create some very high internal tank pressures, and that will force some of the oil out around the seals. Transformers are not expected to hold a seal against high pressure.

Regards, CJM