利用线路分形维数的配电网故障选线方法

Fault Line Selection Method for Distributed Network Using Fractal Dimensions of Lines

故障选线是配电网络长期存在的问题。配网线路短、分支多以及分布式电源的大量接入,造成故障识别率进一步降低。根据故障情况下,健全线路波形之间较强的相似性,故障波形与健全线路波形之间存在较大差异的特点,从波形相似度出发,取故障后1/4工频周期作为分析时窗,采用分形理论对配电网小电流接地系统多点的暂态零序电流进行分析,利用故障线路和健全线路分形维数之间的差异,比较线路不同测量位置暂态零序电流分形维数,提出新的故障辨识方法。仿真和实验验证了判据的准确性和有效性。

Fault line selection is a long-standing problem in distributed network.Due to the characteristics of distribution network(e.g.,short lines and multiple branches),as well as the access of a large number of distributed generations,the rate of fault recognition is further reduced.However,in the case of fault,healthy lines share more similarities while there exist big differences between the fault and heathy lines.On this basis,the first quarter of post-fault powerfrequency cycle is taken as an analytical time-window,and the fractal theory is used to analyze the transient zero-sequence current at multiple locations in the small current ground system of distributed network.According to the difference in fractal dimension between fault and healthy lines,the fractal dimensions of transient zero-sequence current at different locations of lines are compared,thus a novel fault recognition method is proposed.Simulation and experimental results showed that the proposed recognition criterion was accurate and effective.