暂态零序电流波形差异的单相接地故障选线

Faulty line selection ofsingle phase grounding based on transient zero sequence current waveform difference

配电网结构日趋复杂,系统发生单相接地故障的概率较高。文中在选定频段(SFB)内配电网零序电流分布特征研究的基础上,提出了基于暂态零序电流波形差异的配电网单相接地故障选线新方法。该方法利用小波包变换引入基于SFB的馈线零序电流特征分量的概念,定义符号化处理后的各馈线零序电流特征分量的互差绝对值之和为馈线零序电流波形差异系数,并根据故障馈线零序电流波形差异系数最大的特点进行选线,凸显了故障馈线与健全馈线之间的差异。PSCAD仿真表明文中方法选线准确率和可靠性高,不受故障电阻、故障距离、中性点接地方式、电弧和噪声的影响。

The structure of distribution network is becoming more and more complex.In this paper, based on the research on the distribution characteristics of the zero sequence current in the selected frequency band (SFB), a new method of single phase grounding faultyline selection based on the difference of the transient zero sequence current waveform is proposed. The method introduces the zero sequence currentcharacteristic component of feeder based on SFB by utilizing wavelet packet transform. By defining the absolute sums of the mutual deviations of the zerosequence currentcharacteristic components filtered out by sign function as the waveform difference coefficient of the zero-sequence current of each feeder, the faulty feeder is selected according to the maximum waveform difference coefficient of the zero sequence current of faulty feeder,which highlights the difference between faulty feeder and healthy feeder. A lot of PSCAD simulations show that the proposed method has high accuracy and reliability, and is not affected by fault resistance, fault distance, neutral grounding mode, arc and noise.