一种识别输电线路单相接地故障下第二个反向行波的方法

A Method to Identify the Second Reverse Travelling Wave Induced by Single-phase-to-ground Fault in Transmission Line

识别第2个反向行波来自于故障点反射波还是对端母线反射波是单端行波测距和行波测距式距离保护的关键。基于输电线路单相接地故障的交叉透射现象,提出一种不受线路两侧母线结构影响的识别第2个反向行波的新方法。首先利用初始行波与第2个反向行波进行初步测距,判定故障区域;然后根据故障区域确定第2个反向行波的特征波对;最后根据第2个反向行波与其特征波对的极性关系判断第2个反向行波的来源,若第2个反向行波与特征波对的极性相同,则为来自故障点的反射波;若极性相反,则为来自对端母线的反射波。大量EMTP仿真验证了所提方法的可行性和有效性。

Identification of the second travelling wave reflected from the fault point or the remote-end bus is the core of travelling wave based single-end fault location and distance protection with fault location. A method was proposed to identify the second reverse travelling wave based on the cross transmission phenomenon of modal travelling waves in the single-phase-to-ground fault of transmission line, which is independent of the configuration of buses at both ends. The method firstly utilizes the initial travelling wave and the second reverse travelling wave to locate the fault initially and determine the fault area. Then, the relevant characteristic travelling wave of the second reverse travelling wave was recognized according to the fault area. Finally, the polarity relation of second reverse travelling wave and its relevant characteristic travelling wave was used to identify the source of second reverse travelling wave. If the polarity of the second reverse travelling wave and the polarity of the relevant characteristic travelling wave is the same, the second reverse travelling wave is reflected from the fault point; otherwise, from the bus at the remote end. A large number of EMTP simulation cases were carried out, verifying the correctness and validity of the method.