一种基于图像的配电网单相接地故障选线方法

An Image-based Single-phase Grounding Fault Line Selection Method in Distribution Network

摘要:

中针对中性点经消弧线圈接地引起故障电流微弱，故障特征不明显，导致谐振接地系统发生单相接地故障时选线速度慢、选线困难等问题，提出了一种基于图像的配电网单相接地故障选线方法。该方法获取各馈线故障零序电流，通过连续小波变换(CWT)得到CWT系数矩阵，将系数矩阵生成RGB图像；然后，通过感知哈希算法计算正常馈线与故障馈线生成RGB图像之间的汉明距离，以汉明距离判断各RGB图像之间的差异，进而确定故障馈线；最后，对比了基于皮尔逊相关系数选线方法和基于EMD分解零序电流高频分量选线方法，结果表明所提方法应用于谐振接地系统中选线速度快，且不受故障电阻、故障位置、故障初始相角等因素的影响。

Abstract:

Aiming at the problems that the fault current is weak caused by the neutral point grounded through arc suppression coil, and the fault characteristics are not obvious, which leads to slow and difficult line selection when a single-phase ground fault occurs in resonant earthed system, an image-based single-phase grounding fault line selection method in distribution network is proposed. This method obtains the zero-sequence current of each feeder fault, through continuous wavelet transform (CWT), the zero-sequence current obtains the CWT coefficient matrix, and then the coefficient matrix is generated into RGB images. Finally, the Hamming distance between RGB images generated by the normal feeder and the faulty feeder is calculated by perceptual hash algorithm, which is used to judge the difference between RGB images, and then the faulty feeder is determined. The line selection methods based on Pearson correlation coefficient and based on EMD decomposition of high frequency components of zero-sequence current are compared. The results show that the proposed method has fast line selection speed and is not affected by factors such as fault resistance, fault location and initial phase angle of the fault when applied to the resonant earthed system.