Transformer inrush current - 2
Transformer inrush current - 2
(OP)
Once more on the same topic..I could locate some literature for calculating the worst 1st cycle inrush, based on the Transformer parameters like flux density, dimensions etc.See attached.
Next, I tried my hand at calculating the reduction in inrush because of line reactance. The reduction was not as much as desired. 1540Amps reduced to 1340Amps approx for a 150kVA, 3Ph, Dy Transformer. The power supply cable was 4/0, 200m. Does anybody have any idea on the transient analysis program for carrying out a study?
It is my belief that accounting for source impedance & cable resistance will further lower the inrush value.
Next, I tried my hand at calculating the reduction in inrush because of line reactance. The reduction was not as much as desired. 1540Amps reduced to 1340Amps approx for a 150kVA, 3Ph, Dy Transformer. The power supply cable was 4/0, 200m. Does anybody have any idea on the transient analysis program for carrying out a study?
It is my belief that accounting for source impedance & cable resistance will further lower the inrush value.






RE: Transformer inrush current - 2
RE: Transformer inrush current - 2
Is someone disagreeing with you on this? The S&C white paper referenced in previous thread (I think) confirms this. The cable impedance effectively increases the source impedance.
RE: Transformer inrush current - 2
RE: Transformer inrush current - 2
Perhaps a transient program such as ATP can help - it may have already been modeled at some point, but you'll need a lot of specific data on the particular transformer of interest. And make quite a few assumptions.
http://www.emtp.org/
RE: Transformer inrush current - 2
For what you need a final value?
Take a worst case,as Dave recommended.
Best Regards.
Slava