基于拟合波形相关性的变压器励磁涌流识别新方法

A new method to identify excitation inrush current of transformer based on the correlation of waveform fitting

为了提高变压器差动保护识别励磁涌流与内部故障电流的能力,提出一种基于拟合波形相关性的变压器励磁涌流识别新方法。首先利用正弦拟合法拟合差动电流波形,然后通过相关性分析原理,计算出差动电流原采样信号及其拟合曲线的相关系数,以此来识别励磁涌流与内部故障电流。仿真结果表明:该方法具有原理清晰、识别迅速、区分度高、抗干扰能力强,且易于在微机中实现等优点。

In order to improve the ability of transformer differential protection to identify excitation inrush current and internal fault current, a new method based on the correlation of waveform fitting was proposed. First of all, the sine fitting method is used for fitting the differential current waveform, and then, the correlation analysis principle is used to calculate the original sampling signals and the correlation coefficient which is between differential current and its fit- ting curve. By using this correlation coefficient can identify excitation inrush current and internal fault current. The simulation results show that this method has clear principle, rapid identification, high distinguishability, strong anti- interference ability, and is easy to be implemented in the microcomputer.