Good Morning all,
I am seeking guidance on whether high-voltage switchgear and the associated transformer can be located within the same enclosure. My initial thought is that this practice should be discouraged due to fire separation concerns. I would appreciate your insights on this matter, and if anyone could direct me to a relevant clause or standard that addresses this issue, I would be very grateful.
Many thanks in advance.
Matt Murphy.
Dry transformers may be open winding or resin encapsulated, and open transformers are often seen in warmer parts of the world, not so much here.
In the UK normally at least the HV primary windings are encapsulated and often the secondary too, so the winding is a solid kebab like cylinder of insulating material with terminals.
In the pics below the green one is a WEG one in Brasil, the red one is a similar offering from Bowers in Derby , both I think are designed to IEC 60076-11:
Again in Europe normally these would be inside some sort of enclosure, imagine something rather like a ventilated sheet metal shed and certainly no exposed terminals in an areas where personnel had access, and certainly not where they have to go to operate switchgear.
Some of the rest of the world is more liberal, but with good reason we are not (!)
More fully encapsulated are attractive if the air cleanliness or humidity is not well controlled but the power rating for a given size and weight is lower. Also any permanent building will need access for the thing to be positioned, so allow for either tele-handler forks or some sort of hoist.
Any controls or indicators go on the outside of the enclosure, although panels can be removed (as here to allow visual inspection, when non energised !)
As regards cooling, the transformer makers publish installation advice and also how to be regs compliant in different jurisdictions, and it would be worth asking for that as much of that as possible it is not already available - the ventilation illustration is from one such makers manual.
If it is a UK DNO, they will also have their preferred pre-approved models and house rules about installation, and may well refuse to connect something they do not recognise, or at least expect a delay while evidence is collected so again, check with them for documentation.
M
