nitrogen filling for transformers

i think nitrogen have colling characteristic

Nitrogen is inert gas and hence helps blanketing the transformer oil from Oxygen.

Oxygen can be very detrimental for transformer oil.

Nitrogen, is the cheapest inert gas and hence is popular.

Cheers.

Power transformers are filled with DRY nitrogen to prevent cellulose-based insulating materials (such as kraft paper) from absorbing water or from condensation occurring during temperature changes and to reduce transformer shipping weight. If the unprotected insulating materials were allowed to absorb moisture from the air, their insulating capabilities and insulation resistance could be significantly degraded even if the transformer is filled with brand new transformer oil, potentially leading to early reliability failures.

Bert

Dear Mr.Bert

Your Statement about "Why nitrogen is filled while transporting transformers? Why only nitrogen is used? why not any other chemical or gas?" Is very precise and good.

I am in Power Transformers Mfg Field for last 20 Years. This Doubt I was also having But It was not correctly cleared to mind. Your Statement is made me further clear.

I would Like to clariffy one more thing. In Same case they use Nitrogen During Drying Cycle also. What is the reason and what are the advantages.

Thanku

Seshapani

seshapani@yahoo.com

India

Dear friend,

Nitrogen is such a gas, which can be generated easily and can be stored. cheap in cost. which is having charecter of blocking the oxygen ,which shield (inhert
gas)the area, where oxygen enters. In case of transformer, which is highy sensitive to oxygen entry, which absorbes moisture from air and looses its insulation capacity and gains weight . for protecting this effect, normally nitrogen is fill during trasit of trnsformer.

keshavamurthy

Dear Sir,

Nitrogen is basically filled in the transformer during Transport. Oil is normally not filled in Bigger Transformers/Reactors during transit or oil is filled upto core level of the transformer. Nitrogen makes the transformer not to abosrb external moisture during transit. This notrogen is taken out by Vaccuming the transformer prior to oil fill. A Gauge is normally provided in the Tranformer Oil Outlet Valve to indicate the Nitrogen/Vaccum Pressure.

Afterwards Oil is filled in.

The main Purpose of Nitrogen is to protect the transformer against Moisture.

Best Regards,

N.Suresh

Nitrogen used during transport is commercial quality dry nitrogen.Nitrogen is or was preferred because of its inert nature and easy availabilty. Once upon a time carbon dioxide was also used.Today generally dry air is used to seal off transformer during transport from safety angle and from easiness of working at site.

Please also help me to know the quantity of Nitrogen that should be filled in a transfomer during transportation and storage. Regards, Mwape

Mr. Mwape,

Our Transoformers are set to 6 PSI. this gives the nitrogen enough pressure to still act against the oxygen and the moisture.

CH&PP

There is one 40MVA oil cooled transformer (yet to commission), filled with 95% oil and we are trying to fill 5% Nitrogen in that transformer so that there should not be any foreign component inside. But even though there is no leakage, nitrogen is not withstanding inside transformer, within a day or two pressure guage is showing 0. vaccum is creating inside automatically.

Why is it soooo? Pls reply.

Just because you dont see oil leaks on the transformer doesnt mean the transformer is not leaking. Since you said it is filled only 95% the top part that is not filled is absorbing some air thru some other opening which you might not be seeing with your naked eyes. Thus reason why the gauge is showing 0 after a day or two. Try to Put the gas and use soap water to detect any leaks on the top section of the transformer since it is yet to be commissioned. Hopefully you will see the point(s) which are releasing the gas.

Generally, <...nitrogen...> is inert. It also comes from a source where very little water is present. In order for corrosion to occur, water and oxygen need to be present; by using <...nitrogen...>, one, or both, of these materials are excluded and corrosion becomes less likely.

It will not support combustion, which may be important.