Transformer Room Design and MV switch gear etc

[emmjea001]

Hi, I am looking for a standard or guidance note covering the need for trenches or bund walls to mitigate against oil spilage and fire risk?

The local authority here only have approved designs for substations that are externally facing, in this case I have a client owned substation which is internal to the building, and I am worried about a tank rupture and subsequent spread of oil to other parts of the building and the associated fire risk?

The local authority do not seem concerned and have said it is not required, but I think it is. So looking for some guidance or typical details?

also wondering if (aside from good practice) there is any actual requirement for separation of rooms for LV switch/ TX / MV switch - or combination thereof

Thanks

 

[ScottyUK]

Probably depends on where you are located. Generally indoor transformers are either dry-types or filled with something non-flammable like Midel. Oil-filled gear inside buildings is not a great idea - do your fire codes have any comment?

 

[Marmite]

As Scotty says, it very much depends on the local codes. It's not unusual to have oil filled distribution transformers within a building, and the requirement for bunding will probably depend on the volume of oil. The transformer enclosure will need to have a fire rating in line with the local code.
MV switchgear, transformer and LV switchboard are often segregated in order to restrict access to staff who are trained and authorised to work on a particular item of plant. However, in a utility environment it's quite common to have all three in the same room, and there's no technical reason why they can't be. Again, check the local codes.

Regards
Marmite

 

[FreddyNurk]

Australia as an example have recently made changes to their standards and requirements, and now require bunding, fire rating of walls housing the transformer plus other considerations, thus ScottyUK's assertion is quite accurate.

The same issue goes for oil filled switchgear, after a relatively recent incident in Australia where oil filled switchgear suffered an internal failure during switching, a lot of places are either removing it, or putting procedures in place that the units can no longer be used for their original intended purpose (i.e. isolation of certain pieces of plant as an example).

However, if local codes don't require it, there's a lot of expense that can be involved to include it, and the client may not want to pay for it, unfortunately.

 

[emmjea001]

Thanks everyone for the input, some summary answers:

[ul]
[li]the local codes are very "loose" and do not require it, but they date back to the 1960's so to be expected - bottom line is both the local codes and the relevant departments really have very little to say on the matter - I've tried![/li]
[li]I would have gone for Dry type, but there is no manufacturer here, so lead time plus cost = no go (also as an aside I was concerned about dry type as the application is for use as backup, I think I will post separate query re this so as not to confuse issues)[/li]
[li]If you go the bund wall route - practically do you build it around the TX's after they on in position - as that would seem easiest as normally I seen these craned off onto the plaform then rolled into place on the slab?[/li]
[li]Bottom line is even if local codes do not require it, I want to specify best practice, then the client can at their risk opt to omit it if they choose.[/li]
[/ul]