A Morphological Method for Discriminating of Inrush Current from power system fault in Power Transformers

This paper presents an accurate method for discrimination between transformer inrush current and power system fault. Analysis of the waveform of the current transient signal and calculated flux at the secondary windings is performed in order to determine whether the current is a fault or a magnetizing inrush current. Due to the symmetrical relation between the inrush current and related flux (at three phase), the proposed algorithm deals with a morphological technique in detection process. The proposed discriminator criterion is tested by various types of magnetization curves, different energization times and several various power system faults