Posibility of using an oil type transformer inside a containerized substation with a control room 2

[Rwelagedara]

Dear All,
Is it permissible to use an oil type transformer inside a containerized substation with a control room inside where a operator will be there all 24 hours a day.The substation will be as per the attached image with a LV compartment, HV panel , a transformer and a control room.All compartments will be separated by partitions.

- Is it compulsory to use a dry type transformer considering the presence of an operator inside?Is there any international standard stating this requirement?

- can we use an oil type transformer for this, along with any safety precautions incorporated(such as any specific separation walls to control room)?

 

[FreddyNurk]

I don't know that its explicitly compulsory, particularly as I'm unaware of your location specific standards and regulations, but there are a number of considerations that may make you lean away from putting the operator in such an area.

Oil containment in case of a leak would take up more space, the local standards here specify that adjoining walls less than certain distances require fire rated (and sometimes capable of withstanding a transformer explosion) walls. That would mean (at least here) that your operator room would require similar sort of walls. Whether you have enough room in what looks like a standard ISO shipping unit is another question.

Also, from an ergonomics and access point of view, if the space is intended to be inhabited then minimum access, egress and lighting requirements would need to be met, such as size of door, backup lighting and so on.

Conversely, I understand that dry type transformers can be more prone to transport based damage than oil types, and if your reason for using a container is to make it transportable, then that may be an issue.

Best practice is not to have an operator anywhere near that equipment at all, but whether that is achievable with your requirements is not up to us.

EDMS Australia

 

[itsmoked]

I don't know about regs on this but I think it's a BAD idea no matter how you cut it. If you get some nasty arc-flash with a big fire you're not going to want people a few feet away.

I'd re-think the plan and use two containers that can be placed with a few feet of separation. If you're talking a 40 footer get two 20s instead. If a 30 then a 20 and a 10.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[unclebob]

One thing is sure, that transformer won't be filled with oil, since it's inside. Most likely, these insulating fluids can be used: FR3 Envirotemp, R-Temp, Silicone and 40 years ago PCB's, due to their low flammability characteristics. Insulating gas can be use also.

 

[itsmoked]

uncle; Last time I was at Helm's power plant I saw enormous, probably 200MVA, oil filled transformers indoors. A hand full of them. Each in their own room that gave them about 10ft of clearance all all around each. They all had a truck load of CO[sub]2[/sub] bottles associated with each of them.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[prc]

Unclebob- ester filled units are also prone to tank rupture spilling out hot fluids and fire. These are fire resistant only and not fire proof. Mineral oil filled large GTs are provided in underground hydro power stations, but normally these are accommodated in caverns carved out from rocks.I believe dry type units are ideal for the proposed use as in case of stadiums, data centers etc. But dry type also can catch fire,but may not burn furiously as in case of fluid filled units.

 

[scottf]

What are the ratings of the transformer? Is going with a dry-type cast-coil design not an option?

 

[cuky2000]

For reference, see below a link from the National Fire Protection Association (NFPA) regarding oil filled transformer safe distance and firewall requirement in the US.
Beware that dry-type transformer is also combustible.
There is relatively new transformer protection used in the offshore platform but this may be an overkill for this type of protection.

https://www.nfpa.org/assets/files/AboutTheCodes/853/853_F2019_ECG_AAA_FDmeetingagenda_04_18.pdf

 

[dpmac]

One option may be the use of "QuadCon" containers.
Four separate smaller containers are coupled together to become one standard 20 foot container.
When on site the "Control" container could be separated and placed farther away.
When project is over, its re-coupled and the system shipped elsewhere using standard means.

We use these containers for our smaller AC 400KVA Test Sets, VFD controls and high power thumpers.

http://www.seabox.com/products/list/quadcon-dry-freight-containers

 

[FreddyNurk]

Others who have put transformers in transportable containers such as these have made efforts to ensure that at no point in time an operator is nearby to the equipment. Such means can include separate wireless connections and communications equipment for an operator to stand nearby but not inside the enclosure.

As others here have also indicated, use of a dry type is not as benign as first thought either, at least in terms of potential fire and personnel risk.

EDMS Australia