Harmonic analysis of transient currents during sympathetic interaction

The phenomenon of sympathetic interaction between transformers, which is very likely to occur when a transformer is energised onto a system to which there are other transformers already connected, changes significantly the duration and the magnitude of the transient magnetising currents in the transformers involved. This phenomenon is discussed in the paper, with the harmonic content of the transient currents and its associated overvoltages being analysed. It is shown that the importance of taking into consideration the saturation characteristics of the transformers already in operation when studying transformer transient inrush.