基于电流行波能量和小波变换的输电线路故障选相研究

Study on Faulty Phase Selection Based on Energy of Current Traveling Wave and Wavelet Transform

根据输电线路的故障行波进行故障相的识别,考虑故障时的电压初始相角对行波特性的影响,提出了针对不同电压相角区间的故障识别原理,即对线路故障进行分区讨论。利用小波变换的时频特性提取故障后各相α模电流的行波能量,根据不同故障类型中各相电流行波能量的相对关系确定相应的选相方法和判据。运用PSCAD/EMTDC得到的仿真结果表明,划分不同相角区间的思想和利用电流行波能量的相对关系进行故障选相的方法具有选相迅速、准确的特点,不受故障类型、故障时刻、接地电阻和故障位置等因素的影响,适应性良好。

As transient component, travelling wave has been widely used in power system fault diagnosis, especially in fault location. When fault traveling wave is used to implement the recognition of faulty phase, considering the influence of initial voltage phase angle on characteristics of traveling wave during fault process, the authors propose a fault recognition principle for different voltage phase angle intervals, i.e., transmission line faults are dealt with by partitioning. Using the time-frequency characteristic of wavelet transform, the post-fault α modal energy of current traveling wave in each phase is picked up and corresponding phase selection methods as well as the criteria are determined according to the relative relation among energy of current travelling wave in each phase of different types of faults. Results of simulation based on PSCAD/EMTDC show that adopting the thinking of dividing different phase angle intervals and using the relative relation of current travelling wave energy, the proposed fualty phase selection method can rapidly and precisely select faulty phase and not affected by fault type, fault time, fault position and transition resistance, so the proposed method is feasible and adaptive.