串联电容补偿线路接地故障的行波测距新方法

New Traveling Wave Grounding Fault Location of Series Capacitor Compensated Transmission Line

串补电容破坏了线路阻抗分布的均匀性,且过电压保护元件MOV(metal oxide varistor)为非线性元件,所以传统的故障测距算法不适用于串补线路。该文首先分析了串补线路上行波差动电流的不平衡输出,然后定义了适用于串补线路的行波差动电流。对于新定义的行波差动电流,串补线路内部故障时,地模和线模的行波差动电流不同,其相角差与故障点位置相关,据此提出了基于行波差动电流的接地故障测距原理。该原理不受过渡电阻、系统运行方式、MOV导通与否和串补装置运行状态的影响,PSCAD仿真结果表明,测距准确可靠。

Conventional methods of fault location are not suitable for power system with series compensated transmis-sion lines because of MOV with nonlinear V-A characteristic and the uniformity of impedance distribution is destroyed by series compensation capacitors. In this paper,the unbalance output of traveling wave differential current in series compensated lines was analyzed firstly;then a new traveling wave differential current adopt to series compensated lines was defined. When fault happen internally on series compensated lines,the traveling wave differential currents of zero mode and aerial mode are distinct. Actually,the phase contrast of the two differential currents depends on the fault location. On this basis,a principle of grounding fault location based on the traveling wave differential current is pro-posed. The method is immune to the transition resistance,the operating mode of system,the nonlinear characteristic of MOV,the operating state of series compensation. The scheme＇s accuracy is verified by PSACD simulation.