基于暂态相关性分析的小电流接地故障选线方法

小电流接地系统发生单相接地故障时，接地点产生的暂态故障电流包含了整个系统中全部的暂态故障电流特征量。非故障线路的三相暂态电流主要表现为对地电容电流，考虑到系统中存在的电感影响，健全线路中的两相电流差非常小，且波形与自身的暂态零序电流明显不相关，而故障线路的两相电流差与其暂态零序电流表现出明显的相关性。利用这一特征，首先对母线电压进行小波变换，通过三相近似系数比例AR检测配电网是否发生了单相接地故障，并找出故障相；然后，运用相关性分析比较各条线路的两相电流差与零序电流的相关性，能够正确地选出故障线路，文章通过MATLAB/SIMULINK建模，验证了该方法的正确性。

Fault Line Selection Algorithm Based on Correlation Analysis of Transient Information of Fault Signal in Neutral Un-effectual Grounded System

In case of single-phase grounding fault in small current neutral grounding system, the transient ground fault current contains the information of the whole system’s fault characteristics. The main component of transient phase current of health line is capacitive current to ground. Considering the effect of inductance in the system, the differential current of health feeder is very small and the phase current waveform and zero sequence transient current are significantly irrelevant. Meanwhile the waveform of the fault line and differential current show a significant correlation. Taking the advantage of the feature of small current system in case of signal-phase fault, the fault phase can be detected by the approximation ratio of three phase bus voltage. Then the fault line can be diagnosed by using the correlation analysis and comparison of each line’s transient differential current and zero sequence current correlation. The simulation in MATLAB/SIMULINK is carried out to verify the feasibility of the proposed method.