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Oil Spill in a Transformer

02/07/2017 9:11 AM

Hi all, we have a transformer (1MVA) on one of our sites. It is spilling oil from its overflow outlet;however, the temperature and pressure gauge shows nothing. Control circuitry has been double checked. Found nothing faulty in that either. Shouldn't the pressure gauge show something? Why is it spilling oil if there is no issue with the temperature and pressure? Please share your thoughts on the matter.

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#1

Re: Oil spill in a Transformer

02/07/2017 9:28 AM

How about level? Is there too much oil? What does the manufacturer's information recommend? What does the dipstick say?

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#12
In reply to #1

Re: Oil spill in a Transformer

02/08/2017 3:23 PM

You are referring to the dipstick that refilled the oil level last time while it was arctic vortex outside?

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#2

Re: Oil spill in a Transformer

02/07/2017 9:42 AM

Does the transformer have a conservator? If it does the warm oil level should be 50% on the gauge glass. Over filling will force oil through the breather. If a desiccant air filter is fitted it will need replacing.

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#3

Re: Oil spill in a Transformer

02/07/2017 11:26 AM

If it has a open air breather on it and you get regular wide temperature swings while the transformer itself isn't running warm it's entirely possible that its been collecting and condensing moisture out of the air for some time drop by drop and you now have a fair amount of condensation water in the bottom.

If it has an accessible drain plug I would be tempted to open it a crack and see if you get clean oil or water out. If it's got any amount of water a good talk with the manufacturer about what to do with it will be in order.

They may say to just drain and refill it with fresh oil or they may require it to be taken out of service and gone through.

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#4

Re: Oil spill in a Transformer

02/07/2017 11:48 AM

If by "...shows nothing..." you mean that the pressure gauge reads 0psi and the temperature gauge reads the ambient temperature, then the oil level is probably below the sensing points for those gauges and your transformer windings are in danger of becoming uncovered. If you mean they are showing nothing unusual then you have to justify why the oil is overflowing.

In either case, the transformer should be removed from service immediately to determine what is actually happening. Do not attempt anything until the unit is de-energized, isolated, and properly grounded/earthed.

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#5
In reply to #4

Re: Oil spill in a Transformer

02/07/2017 1:30 PM

But Darwin awards do raise our average intelligence.

Just kidding. Be safe and perform a proper shut down before working on this transformer.

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#10
In reply to #4

Re: Oil spill in a Transformer

02/08/2017 1:03 PM

GA. And the OP should hire a qualified electrical testing company to inspect and test the transformer to determine the cause of the problem and its condition. I would recommend that they search the excellent resources of the InterNational Electrical Testing Association (NETA) for a member firm near their location:

NETA Member Search

NETA members are independent of manufacturers and other interests, and are certified as to their qualifications, experience, and training.

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#6

Re: Oil Spill in a Transformer

02/07/2017 1:57 PM

overflow outlet

New one on me; if it has one of these then the pressure shouldn't build up, making the pressure gauge rather redundant. Where's the transformer breather and filter assembly; does the transformer have one of those?

Are you sure it isn't an oil refill point or similar?

Are you sure the transformer just doesn't have a missing plug that the oil is spilling out of as the oil temperature cycles?

Has the transformer been overfilled or mounted on an angle?

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#7

Re: Oil Spill in a Transformer

02/08/2017 6:59 AM

.

Is this similar to that which you are discussing/explaining? 1MVA Tfx with conservator tank

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#8

Re: Oil Spill in a Transformer

02/08/2017 8:39 AM

Maybe the temperature and pressure gauge are faulty. Put your hand on it.

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#9

Re: Oil Spill in a Transformer

02/08/2017 9:07 AM

Best hope that it was made in the USA after 1979, or you have a much bigger problem to deal with. EPA doesn't like old transformer oil.

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#11

Re: Oil Spill in a Transformer

02/08/2017 3:22 PM

Have you looked with IR thermometer, or with IR camera? Was it overcharged, and now things have warmed up? Spoiler alert, Sum Dum Az was working on this?

Have you listened with stethoscope for boiling sounds, as in energy dissipation internally due to arcing, shorting? Signs of fire, yet? I just want to see the video when this blows sky high.

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#13

Re: Oil Spill in a Transformer

02/08/2017 11:13 PM

Can we have a photo of your transformer overflow outlet. I dont see any transformer oil overflow outlet for my conservator tank Transformer.

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#14
In reply to #13

Re: Oil Spill in a Transformer

02/09/2017 11:11 AM

Conservator type transformer won't have an overflow - it is a sealed system, to prevent contact of the oil with the atmosphere but still allow expansion and contraction with temperature. Same for a sealed, gas-blanketed type. If what I suspect is the case with the OP, he has a free-breathing type of transformer (very uncommon in modern units, but sometimes used on smaller, older transformers). They had a vent, with a screen and sometimes dessicant or other means to try to somewhat isolate from atmospheric contamination.

The other possibility is that what the OP is calling the "overflow" is really the pressure relief device, and its bellows has burst. That is a wholly different problem, and one that needs to be remedied.

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#15
In reply to #14

Re: Oil Spill in a Transformer

02/09/2017 12:10 PM

Agreed, so let's include a leaky SPR (Sudden Pressure Relay) gasket. But this is a relatively small unit so I wonder if it has any of these devices that are usually found on much larger power transformers. The pressure gauge is puzzling, especially since we don't know if it reads gauge (starting at zero) or differential (zero center, bidirectional).

If it is differential then it has to be a totally sealed (no breather) tank; if absolute then it would be used to indicate the pressure of a nitrogen blanket above the top oil, again in a sealed tank; or it could be used as indicator that the breather/desiccant is blocked.

I suspect that this is the inlet piping for a PRV (Pressure Reducing Valve) that used to be attached to a nitrogen tank, and over the years it was lost or removed because nobody knew why it was there. They probably filled the transformer cold and topped it off until oil appeared at the "overfill". Of course as the transformer warms up as it is loaded (or overloaded), the oil expands and flows out through this unintentional vent or non-desiccant filled breather.

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#16
In reply to #15

Re: Oil Spill in a Transformer

02/09/2017 3:39 PM

And since we can't read the OP's mind or see his transformer, we may never know...

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#17
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Re: Oil Spill in a Transformer

02/10/2017 8:07 AM

He jumped for answers before considering and looking at the problem properly.

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#18
In reply to #17

Re: Oil Spill in a Transformer

02/10/2017 9:26 AM

Yeah, that is why he posted. He can't handle the truth...like so so many others.

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#19
In reply to #18

Re: Oil Spill in a Transformer

02/10/2017 11:40 AM

Frig, I handled the truth just today, dropped and broke it and a shard cut me, it hurt.

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#20
In reply to #18

Re: Oil Spill in a Transformer

02/10/2017 11:53 AM

That is why I posted the picture of the Tfx. If he had responded he would have had an answer as the system is sealed on that picture. If it is an old 19plonk unit with no conservator tank there is clearly a plug missing, hence no pressure on the guage.

They always post and offer no feedback and no proper info and quickly folks make assumptions and get of the rails and pretty soon up each other noses. And the competition to be the winner...oh boy!

Gets to too serious and becomes daft. An injection off humour is better than eating the hole in a doughnut. A Scottish philosopher stated that, a man from Glasgow, by the name of Dew Spititoot.

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#21
In reply to #20

Re: Oil Spill in a Transformer

02/10/2017 12:08 PM

Yeah Dew Spititoot was a real goer and a getter.

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#22
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Re: Oil Spill in a Transformer

02/10/2017 12:14 PM

So were Ali Bendoon and Phil MacCavity, real goers and getters. Phil was Irish, I know by the spelling of his surname.

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#23
In reply to #14

Re: Oil Spill in a Transformer

02/10/2017 6:33 PM

In this case, OP should know whether it is a hermetically sealed transformer or it is a Conservator Tank transformer and I do agree with you that it may be the Over Pressure Relief valve that had burst and OP may be thinking it is an overflow outlet.

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#24

Re: Oil Spill in a Transformer

02/11/2017 2:14 PM

Yet another poster who comes to CR4, asks half a question, and then sits back mum and lets the forum tie itself in knots trying to answer.

I call this trolling.

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#25
In reply to #24

Re: Oil Spill in a Transformer

02/11/2017 6:18 PM

Yeah.. at least the person that post a question should reply to show his/her sincerely asking help from this forum.

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#26
In reply to #24

Re: Oil Spill in a Transformer

02/13/2017 11:06 AM

At least gnomes are not trolls. Good on ya, mate.

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