利用电磁式电压互感器实现小电流接地系统行波故障定位和选相

摘要

提出利用电磁式电压互感器传变暂态行波信号,实现小电流接地系统各种故障类型快速识别和故障准确定位。建立了电磁式电压互感器行波传变特性分析模型,并以实际的电压互感器参数为例对其行波传变特性进行了研究,研究结果表明,电磁式电压互感器能够有效传变行波波头,满足行波故障测距要求。分析了三相电磁式电压互感器的行波传变特征及规律,分析发现,单相接地故障和各种短路故障暂态行波信号都以一定的规律有效传变到电磁式电压互感器二次侧,在此基础上,提出利用二次侧的暂态行波信号实现线路故障快速定位以及各种故障类型快速识别的原理与方法。现场试验结果证明了所述方法的正确性。%A new method using electromagnetic voltage transformers to transfer transient travelling waves is proposed to locating the line faults and identifies the faults type in neutral non-effective grounding system.Analysis model of electromagnetic voltage transformers for analyzing transform characteristics of traveling waves is built,and the transform characteristics is studied using parameters of practical voltage transformers.The results show that electromagnetic voltage transformers can transfer traveling waves surge effectively and meeting the needs of fault location.The transform characteristics and rules of travelling waves for three-phase electromagnetic voltage transformers are analyzed.The results show that there are certain rules for the transient traveling waves of single-phase earth fault and various short-circuit faults transferring to the secondary side of electromagnetic voltage transformers.On this basis,the principle and method that using the signals measured in the secondary side of electromagnetic voltage transformers to locate line faults point and judge the type of fault is proposed.Experimental tests verify the feasibility and correctness of the proposed method.