Magnetizing inrush current effects on large transformer arrangements

In this paper the effect of the magnetizing inrush currents, occurring during the energization of transformers, is examined. A case study is presented for an industrial arrangement consisting of five large transformers and three generators. The transformers are modeled using the Hybrid/XFMR model implemented in the well known transients program ATP-EMTP. This model can give an accurate representation of the core of the transformers. Various scenarios are simulated in order to investigate the occurrence of magnetizing inrush currents and the parameters affecting the peak value and the shape of the waveforms. Finally, various methods to reduce inrush currents are presented and evaluated.