A Suppressing Method of Transformers Inrush Current under Non-Sinusoidal Excitation

The inrush current of transformers often result in a malfunction of the differential relay and also causes a stress impact to the transformer. These have an adverse effect on the security and stability of the power system. Harmonic effects in power systems have been significantly increasing in the last decade. Transformer is an important example that causes sensitive effect to distorted waveforms. In this paper, SIN^m(omegat) waveforms represent distorted waveforms because studies on SIN^m(omegat) waveforms appear to be simpler for more predictable results. An active suppression method is proposed in this paper. The suppression method covers sinusoidal and non-sinusoidal excitation. Using the suppression method, the inrush current can be eliminated or effectively suppressed