MAGNETIZING INRUSH CURRENT DETECTION METHOD MAGNETIZING INRUSH CURRENT RESTRAINT METHOD AND DEVICE

摘要

The present invention proposes a magnetizing inrush current detection method and device for a transformer. The method comprises: obtaining (S210) a difference current i(n) for each AC phase of the transformer; calculating (S230), for each AC phase at least two factors (Ax(n) Bx(n)) for waveform symmetry recognition on the basis of the difference currents obtained within one period; for each type of factor obtaining (S240) the maximum value of the three factors corresponding to the three AC phases to serve as a maximum phase factor of that factor; based on the maximum phase factor obtained using a waveform symmetry recognition algorithm (S250) to calculate a corresponding waveform symmetry parameter k; and if the waveform symmetry parameter k meets a requirement for waveform asymmetry (S260) then determining that a magnetizing inrush current has occurred.