Water inside transformer
Water inside transformer
(OP)
The transformer damaged and We found a lot of water in side transformer after we did detank in factory.
We tried to investigate the reason why water ingress to transformer.
Many time we found the water accomulated the bushing box as this cable box didn't follow IP54 and I suspected that water can penetrate from bushing gasket on top during heavy rain for long time in case we never filled up the oil to it.
But vendor didn't agree with our suspection as they mention about
Transformer alway has positive oil pressure ,due to it has the conservator on top sothat transformer will not allow water ingress into transformer.
So my question is above mention is correct or not ?
When is transformer negative pressure or pressure down ?
What is the possible reason water coming inside the transformer ?
Please help !!!!
We tried to investigate the reason why water ingress to transformer.
Many time we found the water accomulated the bushing box as this cable box didn't follow IP54 and I suspected that water can penetrate from bushing gasket on top during heavy rain for long time in case we never filled up the oil to it.
But vendor didn't agree with our suspection as they mention about
Transformer alway has positive oil pressure ,due to it has the conservator on top sothat transformer will not allow water ingress into transformer.
So my question is above mention is correct or not ?
When is transformer negative pressure or pressure down ?
What is the possible reason water coming inside the transformer ?
Please help !!!!






RE: Water inside transformer
If the transformer does not have a pressurization scheme such as a dry nitrogen supply and possibly a diaphram in the conservator, at least the top of the conservator may be subject to negative pressure during periods when droppng ambient temperatures and/or dropping loads reduce the transformer temperature.
Bill
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"Why not the best?"
Jimmy Carter
RE: Water inside transformer
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As Waross mentioned, the water in the transformer tank could very likely be a result of a breakdown of materials on the inside of the tank.
We used the Hydran unit on a job we just finished, and it has many alarms for moisture and gas quality. It's a useful addition for such an expensive piece of equipment. (No, I don't work for GE.)
RE: Water inside transformer
RE: Water inside transformer
Water can enter a transformer through a number of routes. As mentioned, through the bushing gaskets, but also you may have put the water in during the filling process with contaminated oil, entry into the conservator if it isn't sealed and you haven't got good moisture control on the breather, etc.
A transformer manufacturer will generally say that their design isn't to blame, but did they actually offer any useful explanation as the problem?
What sort of damage was it? did the tank rupture? What size transformer was it? Could it have got water in it during travel to the factory?
Probably more questions than answers, but there probably needs to be a little more info to make an informed decision on.
Ausphil
RE: Water inside transformer
Muthu
www.edison.co.in
RE: Water inside transformer
Some time back I found free water at tank bottom in a new transformer just before commissioning. IR between core and tank was showing zero. This water was from oil in the drums. When you check oil from a drum, you should use a sampler thief as water will be at bottom .If you take sample from top everything will be ok ,but free water will be remaining at bottom.
You have to investigate and findout the reason.There are many possibilities.It need not be fre water.High humid air can also create such situations.
RE: Water inside transformer
There is also one more potential area. Many transformers have a pressure relief valve on their conservators. This is usually very low pressure (maybe 2 psi to move) and often bidirectional. That may have failed and allowed water ingression.
------------------------------------------------------------------------
If it is broken, fix it. If it isn't broken, I'll soon fix that.
RE: Water inside transformer
Other than that... With the unit having a COPS tank. The only way to get a negitive pressure inside the main tank is to have the breather pipe blocked off by either isolation valves being closed or shipping plugs in the Deisicant breather were left in after hot oil fill... or the valve or valves to the Conservator were closed while the unit was still warm.
As was mentioned earlier. There's a low negitive pressure, approx -1.5 to -2.5 psi, depending on the volume, in the upper section of the conservator if there is a bladder installed.