基于频谱序列峭度分析的小电流接地故障区段定位研究

针对基于暂态重心频率的配电网故障区段定位方法在故障点下游存在重心频率选取困难的不足,提出对故障监测点零序电流分量的傅里叶频谱分析序列进一步采用峭度分析。对于故障点上游区段,零序电流暂态重心频率分量幅值远高于次谐振频率分量幅值,其频谱分析图近似单一冲击形状,从而峭度计算值较大。对于故障点下游区段,零序电流分散分布在各个谐振频率分量上,其频谱分析图成多冲击形状,从而峭度计算值较小。因此,利用相邻两监测点峭度计算值的最大差值即能判定故障区段。大量ATP/EMTP仿真证明所提方法在故障点下游暂态重心频率不明显时仍能有效判出故障区段,可以作为暂态重心频率判据的补充。

Study on the small-current grounding fault location based on the kurtosis analysis of spectrum sequence

In order to avoidthedifficulty of selecting gravity frequency on the downstream of fault point when transient center frequency method is used for fault location in distribution network, this paper puts forward that the Fourier spectrum sequence of zero sequence current component should be analyzed further using kurtosis analysis. For the upstream section of fault point, the amplitude of zero sequence current transient gravity center frequency is much higher than the other resonance frequency components, and the spectrum diagram is approximate to a single shock shape, thus the calculated kurtosis value is larger. For the downstream section of the fault point, the zero sequence current dispersion is distributed in each resonant frequency components, and its spectrum analysis graph is similar to multi-shock shape, thus the calculated kurtosis value is small. Therefore, the maximum difference of the kurtosis value of adjacent monitoring points is used to determine the fault section. A large number of ATP/EMTP simulations show that the proposed method can effectively find fault segments when the gravity frequency in the downstream of the fault point is not obvious, which can be used as a supplement to the transient center of gravity frequency criterion. This work is supported by Science and Technology Project of Headquarter of State Grid Corporation of China (No. 52020116000F).