基于FTU和“S”信号注入法的配电网接地故障定位技术的研究

Research on technology of grounding fault location combining FTU and 'S' signal injecting method in distributiom grid

配电网由于分支多、接地电阻大,单相接地故障定位问题长期以来没有得到很好解决。提出了FTU与'S'信号注入法相结合的配电网单相接地故障定位技术,利用线路FTU检测线路零序电压和零序电流判断接地故障的区段,再向线路中注入'S'信号,沿线路利用电磁感应原理检测该信号,从而确定接地故障点的准确位置。为了保证'S'注入信号不受线路对地电容的分流影响,深入研究了FTU配置的临界区段长度计算方法。该定位方法可实现带电准确快速定位,现场试验充分验证了该技术的正确性与可行性。

Due to the large amount of branches and high grounding resistance of distribution grid,the single-phase-to-earth fault location has not been solved effectively.The single-phase-to-earth fault location technology is proposed by combining FTU and ＂S＂ signal injection method.Firstly,the zero-sequence voltage and zero-sequence current are measured by using line FTU so that the fault area is located.T hen the ＂S＂ signal is injected,a nd the signal can be measured by electromagnetic induction theory so as to find the exact location of grounding fault.To avoid the influence of distributed capacitance to ＂S＂ injection signal,the calculation method of length of FTU isolation area is intensively studied.Moreover,the on-line location is possible by using this method.The correctness and feasibility of this technology have been fully proved by site experiments.