Primary neutral Current and Transformer Inrush

[pwrtran]

Does the instantaneous current value of the 2nd harmonic from all 3 phases cancel each other on the neutral during a transformer inrush? The question was raised from setting up a neutral or ground element, do you need to avoid the inrush? Any differences between Wye primary and Delta primary?

Thanks!

 

[jghrist]

The instantaneous inrush current (all harmonics) will cancel on an ungrounded winding. There may be some neutral current in the CT secondary because of CT errors, but it will be small. This would not be the case for grounded wye primaries.

See thread238-206517

 

[pwrtran]

Thanks jghrist for the answer and the thread link. All even harmonics should cancel out.