Transformer dielectric coolant fluid 2

[ngs]

I would like to ask if anyone has used the product, Envirotemp FR3 Fluid manufactured by Cooper Power System to retro-fill an existing distribution transformer(7500 KVA)?

If so, would you recommend it?

Thanks, ahead of time.

ngs

 

[busbar]

No personal offense is meant, but it seems like a lot of time and effort could be saved asking Cooper directly.

 

[ngs]

Busbar,

I did contact the manufacturer and they claim to have the best transformer oil to be used as a retro-fill on existing transformers. Cooper also claims that there are current users of this FR3 which are several utility companies.

So, I emailed five of the utility companies, asking if they would recommend the FR3 and I only received one response so far, stating that they haven't retro-filled any existing transformers, but they did purchase transformers that use this FR3 from Cooper Power Systems.

My question, is a retro-fill using this product(FR3) on our transformers necessary? Our transformer is about 30 yrs old and I would like to ask for someone to point me in the right direction as far as what are some of the things that I need to consider if I go ahead with the retro-fill or replace the transformer?

 

[alehman]

Normally envirotemp or other less-flammable liquids are used where fire hazard of oil is a concern, if there are environmental concerns related to possible oil spillage, or as a replacement for PCB liquids. I don't know if envirotemp can be used in a PCB retrofill.

http://www.cooperpower.com/Library/TheLine/pdf/june02/03020.pdf

http://www.nttworldwide.com/tech2308.htm

 

[dpc]

Waukesha Transformer has a group that is doing a lot of transformer retrofit work involving this vegetable oil. You might check with them.

Also, my understanding is that Cooper markets two different grades of this oil.

 

[busbar]

ngs — If, for instance, the original fluid was mineral oil, a concern to me would be, “Will residual mineral oil affect the flammability rating of the new fluid?”

 

[jghrist]

If there is a possibility of PCB contamination of the old oil, it needs to be tested. Replacement of PCB contaminated oil needs to be done by a company specializing in this process.

 

[ngs]

Appreciate all of your inputs.

I learned am learning quite a bit.

Busbar, good question, I'll definitely look into it.

jghrist, In this case, our transformers are using mineral oil.

Thanks to all

 

[jnims]

The following is an excerpt from the latest draft of the IEEE Guide on Natural Ester Fluids:

Although in most cases different types of dielectric liquids are miscible (definite exception: silicone oil), such mixtures should be avoided in transformers and fluid processing equipment when possible due to possible negative impact on key environmental or fire safety characteristics. Obviously, some low percentage contamination can not be avoided when retrofilling, particularly transformers and other equipment with impregnated cellulose material. Successful retrofills with natural ester fluids replacing conventional mineral oil, HMWH, askarel have been reported. Consult the manufacturers of the fluids or the transformer for advice if mixing is permissible or has occurred.

This section of the Draft leads me to believe you would not be able to just drain the existing oil then add the new fluid.

As far as refilling versus replacing, you probably need to consider several issues. If the existing unit has been poorly maintained, refilling with a new dielectric fluid will not help remove all of sludge that has accumulated. If the unit has been heavily loaded during its life, the paper insulation may have lost most of its strength. You will need to look at the history of the transformer's dielectric and oil tests to get a feel for the remaining serviceable life. What is the cost of the retrofit versus a new unit? What kind of loss cost savings will you get from a new unit?

Unfortunately, this decision is rarely straight forward.

 

[jbartos]

Suggestion: Visit

http://www.cooperpower.com/Library/pdf/92046.pdf

for:
FM Approved Fluids
.
.
Environtemp(R) FR3(TM) (Natural Ester)

and Cooper Guidelines.
Remark: Since it is meeting FM standards, Insurance Companies will react to it handsomely in terms of lower insurance rates.

 

[WhiteLotus]

My company has used FR3 recently and the only concern was that it is more viscous than normal mineral oil. Normally we use NYNAS 10GBX or Caltran 30-60, but we used the FR3 because of its lower flash point which resulted in lower insurance rates.

 

[dsundin]

First, a disclaimer. I own a company that makes dielectric fluids, including vegetable oil fluids, and am a competitor of Cooper's (some of you probably know me).

The good thing about vegetable oils is their high firepoint and high rates of biodegradation. They are all good dielectrics, and they all have adequate cooling performance, especially since most manufacturers are used to working with fire resistant fluids now.

Vegetable oils can be used to retrofill transformers that were originally filled with standard transformer oil. The high firepoint of the vegetable oils helps ensure that the end result of the retrofill will have a firepoint above 300 C.

That being said, all vegetable oils have a glaring weakness: oxidation stability. Some oils will pass standard oxidation tests and some oils won't . Even the ones that do pass these standard mineral oil oxidation tests aren't as stable, to my knowledge, as standard D3487 transformer oil.

Just because the ASTM standard doesn't mention oxidation stability of these oils as a criterion doesn't mean that it's not important. The buyer should determine what criteria are important to him or her, and check with the supplier to make sure that the oil that he's considering meets these criteria.

I hope that I've been successful in keeping this post non-commercial, but it's something that I feel needs to be understood. I could say a lot more on this subject, but given that there are so few suppliers of vegetable oil dielectric fluids, it would be too commercially oriented.

 

[jbartos]

Suggestion to ngs (Electrical) Apr 27, 2004 marked ///\\I would like to ask if anyone has used the product, Envirotemp FR3 Fluid manufactured by Cooper Power System to retro-fill an existing distribution transformer(7500 KVA)?
///Ask the existing distribution transformer manufacturer for recommended retro-fill types of transformer oils and associated procedure. This would be the most valuable recommendation. Then, compare posted eng-tips from this Forum.\\\If so, would you recommend it?
///See my suggestion above.\\\

 

[stevenal]

Dsundin,

Seems a little strange that you are complaining about the fact that a biodegradable dielectric does in fact degrade. Isn't that what it's supposed to do? I know it's bad for it to degrade while in service, but the presence of O2 and moisture is a signal that it may no longer be so. I agree, mineral oil is more stable, both in the can and on the ground.

 

[dsundin]

Hi, Stevenal,

Oxidation and biodegradation are two completely different things. They have different mechanisms and pathways. The oxidation breakdown that I spoke of occurs during service, is a chemical reaction, and is a function of heat and the availability of oxygen. Oils break down to acids and sludge in your transformer. You don't want this type of breakdown.

Biodegradation, on the other hand, is what you want to happen when the oil is spilled on the ground. It means that the oil molecules can be used as a source of carbon by microbes in soil and water. The little bugs "eat" the oil molecules, a couple of carbon-chains at a time, until the molecule is no longer "oil". The molecular structure of some oils permit this to happen quickly, while some oils sit there for years. Silicone fluid, for example, is totally inert from a biodegradation standpoint.

The trick is to get stability against oxidation while maintaining the availability of the carbon atoms to be used as food by the little bugs.

In the rush to make a highly biodegradable transformer oil, some companies are forgetting that a transformer is designed to operate for *decades* before failure. And I haven't seen an old transformer yet that hasn't had some small cracks in gaskets or other openings. Oxygen will get into the transformer; it's shortsighted to make an oil that reacts negatively with it.

Thanks for your reply...

company websites:

http://www.dsifluids.com

(dielectric oils)

http://www.directsynthetic.com

(syntetic lubes)

 

[jbartos]

Comment on the previous posting: If there is a reference to some living organisms, e.g. bugs, would not it be more appropriate to call it "zoodegradation"? Biodegradation covers ecological degradation by biological processes. Please, notice that the silicon can be disintegrated by acids, for example, in time too.

 

[stevenal]

Dsundin,

I thought the bugs ate the carbon and emitted CO2. Is it really so different?

"The trick is to get stability against oxidation while maintaining the availability of the carbon atoms to be used as food by the little bugs."

Sounds like a pretty good trick to me. The oil needs to be stable while in the can, unstable in the bug, and know the difference. I think the real trick is to find a reasonable balance point.

And if you can't keep the O2 out of the transformer, how do you keep the bugs out?

 

[dsundin]

Hi, Stevenal,

You're right. It is a pretty good trick to get a highly biodegradable oil that will stand up to the heat and stress inside a transformer - for decades, even!

The bugs are really microorganisms that live in soil. Different types of soil and different environments have different bugs. Some microorganisms are better at degrading oil molecules than others are. They're not really airborne (to my knowledge - but I'm not a microbiologist) so microbiological breakdown inside of operating transformers isn't a big problem.


dws

company websites:

http://www.dsifluids.com

(dielectric oils)

http://www.directsynthetics.com

(synthetic lubes)