基于同步时频特征分析的配电网接地故障定位方法

Grounding Fault Location Method of Distribution Network Based onSynchronous Time-frequency Characteristic Analysis

针对谐振接地网络发生高阻、小故障角度单相接地故障时故障特征不显著等问题,利用同步相量测量技术,提出了基于广义S变换时频分析的接地故障区段识别方法。利用广义S变换提取某一高频段内的频域特征量,计算故障后1/4工频周期各测量点在该时频窗内的零序电流时频特征量,计算不同测量点零序信号之间时频特征分布相似度,构建综合时频特征分布相关系数矩阵,结合模糊C均值聚类,实现接地故障区段的识别。结果表明,所提方法能准确定位出故障区段,不受故障距离、故障初相角等因素影响。

Aiming at the problems that high resistance occurs when the grounding network resonates and the characteristics of single-phase grounding faults with small fault angles were not significant,a grounding fault segment identification method based on generalized S-transform time-frequency analysis was proposed by using synchrophasor measurement technology.The generalized S-transform was used to extract the frequency domain characteristic quantities in a certain high-frequency band,calculate the time-frequency characteristic quantities of zero-sequence current at each measuring point in the 1/4 power frequency cycle after the fault in the time-frequency window,calculate the time-frequency characteristic distribution similarity between the zero-sequence signals at different measuring points,construct the comprehensive time-frequency characteristic distribution correlation coefficient matrix,and combine the fuzzy C-means clustering to realize the identification of the grounding fault section.The results show that the proposed method can locate the fault section accurately without the influence of fault distance,fault initial phase angle and other factors.