Research on Magnetizing Inrush Current and Fault Identification of Transformer Based on Wavelet Analysis

Magnetizing inrush current caused by no-load closing of transformers frequently lead to malfunction of transformer differential protection, which will result in potential risks to power system. In some cases, electrical equipment may be damaged. Therefore, in this paper a method based on wavelet transform for identifying excitation inrush current and fault current is proposed. The wavelet transforms are performed on the current signal results. Through analyzing the results of wavelet transform, it is shown that this method can effectively identify between the excitation inrush current and the fault current, which helps to improve the effectiveness of transformer relay protection.