识别变压器励磁涌流和内部短路电流的小波能量谱图解法

Discrimination of transformer inrush current and inner short circuit current with wavelet energy spectrum diagrammatic method

基于小波多分辨率分析理论,提出了一种以能量变化率的比值作为判据,区分变压器励磁涌流和内部短路电流的新方法—小波能量谱图解法。它从信号的小波能量谱图中提取特征量,作为模式识别的依据来鉴别励磁涌流和内部短路电流。仿真计算表明该方法简单有效,具有一定的应用前景。

How to identify transformer inrush current is a main problem to transformer relay. Based on the wavelet and multi-resolution theory, a new method is proposed to construct the protection judgment to discriminate the inrush current and internal fault by the ratio of high frequency segments in different scales of energy spectrogram.This method extracts the feature values from the energy spectrogram of the signal transformed by wavelet,and with these values,it can identify inrush current from internal short circuit current. Simulation results show that this new method is brief, effective, and applicable in practice.