基于电流行波高频能量比值的全并联AT牵引网单端故障定位方法

Single-end fault localization method for an all-parallel AT traction network based on high-frequency energy ratio of current traveling waves

针对现有全并联AT牵引网单端故障定位方法存在故障区段识别灵敏度低、行波第二波头易受故障点折反射影响的问题,提出了一种基于电流行波高频能量比值的全并联AT牵引网单端故障定位方法。首先,分析了自耦变压器绕组对地电容对高频分量的衰减特性,论证了相邻线路故障电流行波高频能量幅值的差异性,构建了能量比值差异度判据,利用差异度实现了故障区段定位。然后,分析了行波在全并联AT牵引网故障区段内的传播特性,揭示了反向量电流对端母线行波具有明显的故障突变奇异性。最后,提出了基于反向量电流行波的故障定位方法,通过准确标定行波初始波头、第二波头的到达时间,实现了故障的精确定位。仿真结果表明,所提方法在噪声环境下能准确辨识弱故障特征,提高了全并联AT牵引网故障定位的精确性。

The existing single-end fault location method of an all-parallel AT traction network has the problems of low sensitivity of fault section identification and the fact that second traveling wave head is easily affected by the fault point refraction and reflection.Thus a single-end fault location method based on the high-frequency energy ratio of the current traveling wave is proposed.First,the attenuation characteristics of the auto-transformer winding-to-ground capacitance on high-frequency components are analyzed.The difference in the high-frequency energy amplitude of fault current traveling waves in adjacent lines is demonstrated.An energy ratio difference criterion is established,and the fault section is localized using this difference criterion.Then,it analyzes the propagation characteristics of the traveling wave in the fault section of the all-parallel AT traction network,and reveals that the terminal bus traveling wave of the reverse direction current has the obvious singularity of the fault mutation.Finally,a fault location method based on the inverse direction current traveling wave is proposed.The precise location of the fault is determined by accurately calibrating the arrival time of the initial wave head and the second wave head of the traveling wave.Simulation results show that the proposed method can accurately recognize weak fault characteristics in a noisy environment,and improve the accuracy of fault location in an all-parallel AT traction network.