NEED help building a transformer nitrogen bottle

old67cajun · Jan 19, 2020

need recommendation of nitrogen bottle and regulator to service skid transformers to re pressure nitrogen blanket. 34.5kv to550v three phase transformer, cooper material number 00022A65XXMA

junkhound · Jan 19, 2020

I know nothing about this, but do open some threads like this to see what I might learn.

Only suggestion would be to get recommendation from N2 supplier, such as Airco or whoever you would be buying the N2 from?

Hv&Lv · Jan 19, 2020

I get mine at Airgas. They have the regulators there also.less than $150 for bottle and regulator.

I buy the bottles because we keep them connected to our transformers with a regulator system that keeps the blanket at 2psi. We had a big bottle on one transformer for 25 years before it had to be replaced.

I couldn’t find that transformer with the number you provided.
I haven’t seen a padmount with an N blanket

old67cajun · Jan 20, 2020

could I get your email to share specifics?

roger · Jan 20, 2020

old67cajun said:
could I get your email to share specifics?

Click on the persons name you want to have a private conversation with and then click "start conversation", it is not a good idea to post private email addresses in public.

Roger

old67cajun · Jan 20, 2020

when i click on persons name all I get is a follow option nothing about conversation.

Dennis Alwon · Jan 20, 2020

old67cajun said:
when i click on persons name all I get is a follow option nothing about conversation.

You may need a few more posts before you get to send messages. I am not sure how many

Hv&Lv · Jan 20, 2020

I’m not sure exactly what’s going on with this thread but it seems my post was inappropriate for some reason but I don’t know why

mbrooke · Jan 20, 2020

Why do transformers need an N blanket? Do all 5MVA and over have one or a bottle? Round here all the ones in my POCO's substation appear to have one.

grich · Jan 20, 2020

mbrooke said:
Why do transformers need an N blanket? Do all 5MVA and over have one or a bottle? Round here all the ones in my POCO's substation appear to have one.

In my readings of railroading, I came across an article that described in detail the Milwaukee Road's electrified lines in the Pacific Northwest. In the 1930's, I think, a substation was destroyed when lightning caused arcing in a transformer that ignited gases from the cooling oil that had built up in the open spaces above the oil. After that, the open spaces in the transformers were pressurized with nitrogen.

mbrooke · Jan 20, 2020

grich said:
In my readings of railroading, I came across an article that described in detail the Milwaukee Road's electrified lines in the Pacific Northwest. In the 1930's, I think, a substation was destroyed when lightning caused arcing in a transformer that ignited gases from the cooling oil that had built up in the open spaces above the oil. After that, the open spaces in the transformers were pressurized with nitrogen.

Is this the same phenomenon called "gassing"

Tony S · Jan 21, 2020

Gassing is usually caused by arcing, one of the reasons buchholz units are fitted between the tank and conservator. I’ve had two transformers fail on gas both 11/3.3kV and on each the tap changer had failed.

mbrooke · Jan 21, 2020

That would make sense. Any idea if it can also take place from other reasons or just arcing? I know my POCO had a big issue with a few of its trafos gassing so much so they mentioned it in an annual report years back.

mivey · Jan 21, 2020

mbrooke said:
Why do transformers need an N blanket? Do all 5MVA and over have one or a bottle? Round here all the ones in my POCO's substation appear to have one.

Not all have a blanket. The blanket also helps keep out moisture with positive pressure. The tank breathes and when it cools it will draw in nitrogen rather than moist air. Tank seals will eventually leak.

Regular oil sample tests including DGA will help you see what is going on inside. Annual samples are highly recommended and more frequent for problem or high risk units.

mivey · Jan 21, 2020

mbrooke said:
That would make sense. Any idea if it can also take place from other reasons or just arcing? I know my POCO had a big issue with a few of its trafos gassing so much so they mentioned it in an annual report years back.

Overheating and chemical breakdown are key. Usually heat is the main culprit. If you have arcing in a normal transformer then you have reached a whole other level of problems.

mbrooke · Jan 21, 2020

mivey said:
Not all have a blanket. The blanket also helps keep out moisture with positive pressure. The tank breathes and when it cools it will draw in nitrogen rather than moist air. Tank seals will eventually leak.

Regular oil sample tests including DGA will help you see what is going on inside. Annual samples are highly recommended and more frequent for problem or high risk units.

Couldn't the air just go through a silica breather?

old67cajun · Jan 25, 2020

Simply need some quotes for pricing of a bottle and regulator ready to go. The project was suppose to start weeks ago, so time is crucial.

SceneryDriver · Jan 25, 2020

old67cajun said:
Simply need some quotes for pricing of a bottle and regulator ready to go. The project was suppose to start weeks ago, so time is crucial.

2-stage 0-15 PSI regulator from McMaster-carr:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

$555.19

McMaster-Carr isn't the cheapest option, but you can have it the next day if you want. Convenience is worth something.

Call your local Praxair branch for the cost of the nitrogen bottle, size your choice. Any welding supply store should be able to sell you a N2 cylinder. Note that you want to buy it, not rent it.

I'd probably add another ~$250 for gas lines, fittings, and other associated shmoo.

This is a SWAG, based on other pneumatics projects I've done (I've never plumbed a transformer for N2).

SceneryDriver

Hv&Lv · Jan 25, 2020

Nitrogen prices: https://www.unlv.edu/sites/default/files/32/6238-PRICING.pdf

Regulator: https://www.northerntool.com/shop/t...gfqGFajVNjgsBg4jG_Ce1U2OGtlIzR3xoCS3MQAvD_BwE

get a piece of hose while your there from the regulator to the transformer gauge.

I generally either remove the gauge and insert a hose barb or go in through the previously installed bleeder.

Qualitrol 070 Pressure Control Bleeder Series | Qualitrol Corp

Designed to balance pressure and vacuum conditions within a sealed vessel by releasing or admitting air and gas.

www.qualitrolcorp.com

you can get this in about an hour for less than $300 at a welding supply. They all have nitrogen, or at least did at every welding shop I’ve been to..

old67cajun · Jan 26, 2020

SceneryDriver said:
2-stage 0-15 PSI regulator from McMaster-carr:

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

$555.19

McMaster-Carr isn't the cheapest option, but you can have it the next day if you want. Convenience is worth something.

Call your local Praxair branch for the cost of the nitrogen bottle, size your choice. Any welding supply store should be able to sell you a N2 cylinder. Note that you want to buy it, not rent it.

I'd probably add another ~$250 for gas lines, fittings, and other associated shmoo.

This is a SWAG, based on other pneumatics projects I've done (I've never plumbed a transformer for N2).

SceneryDriver

What is swag?

NEED help building a transformer nitrogen bottle

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