Transformer current

[mull982]

Hello

I was wondering if anyone could show me the calculation for figuring out the max current on the line side of a transformer we have here at our plant. The transformer is a 25MVA, 230KV to 4.16KV Delta-Wye transformer. From what I read, the load side can produce up to 3500Amps, but I was wondering what amp load the transfer will draw on the line side.

Thanks for the help

Mull982

 

[coulter]

Couple of basic formulas:

P = sqr(3)EI
And that is truth for both sides of the xmf (for 3 phase).
P(pri) = P(sec)

For the primary side,
I = P/E/(sqr(3)) = 25x10^6/230x10^3/1.732

For the secondary side,
I = P/E/(sqr(3)) = 25x10^6/4.16x10^3/1.732

Turns ratio of the xfm = voltage ratio = 1/current ratio:
E(pri)/E(sec) = I(sec)/I(pri)

carl

(hit the post button too soon)

 

[kingpb]

Hello

I was wondering if anyone could show me the calculation for figuring out the max current on the line side of a transformer we have here at our plant. The transformer is a 25MVA, 230KV to 4.16KV Delta-Wye transformer. From what I read, the load side can produce up to 3500Amps, but I was wondering what amp load the transfer will draw on the line side.

Thanks for the help

Mull982

Give or take 63A @ nominal 230kV.

Please be advised, that equipment of this type requires specially trained people to work on, or around it. Not to say that you were planning too, but do not attempt to work on or make changes to this system without proper supervision, and oversight.