Sizing aluminum conductors to a 15kV Power Transformer
Sizing aluminum conductors to a 15kV Power Transformer
(OP)
We've installed a specialty transformer that pulls 988 FLA at 15kV on the primary side per the nameplate. We are attaching the primary to some open bus that is rated 3000A and feeds other transformers as well. My question is about the size of these tap conductors. The transformer was somewhat oversized but will have a constant load of about 80% of it's rating. Do these tap conductors need to be upsized 125% of the FLA or can they be sized at the actual FLA?






RE: Sizing aluminum conductors to a 15kV Power Transformer
Thats a big tub if 15 kV is your primary voltage.
RE: Sizing aluminum conductors to a 15kV Power Transformer
Regards
Marmite
RE: Sizing aluminum conductors to a 15kV Power Transformer
I stumbled upon the Aluminum Electrical Conductor Handbook . It's waaay more than you'll ever need, but probably worth browsing through or having on your shelf as a nice reference guide. Wish I could get this in hardback for my collection:
http://www.aluminum.org/AM/Template.cfm?Section=20...
I was using Chapter 13 but that was for aluminum bus. It sounds like you were asking about aluminum conductor, you'll have to locate the appropriate chapter or chapters.
RE: Sizing aluminum conductors to a 15kV Power Transformer
RE: Sizing aluminum conductors to a 15kV Power Transformer
I definitely agree with Marmite. From a safety perspective, it is minimally more expensive to oversize the conductor.
I don't remember the NEC saying that conductors have to be oversized for the current, with the exception of applying correction factors. Article 310 says that conductors must be sized for the maximum current they will carry. I remember that breakers, unless they are rated as continuous current capable, must be rated at 125% of the maximum load current. Is this what you were thinking of?
RE: Sizing aluminum conductors to a 15kV Power Transformer