小波包在配电网单相接地故障选线中的应用

应用在卓越尖空间皆具有良好聚焦特性的小波包，以适当频率带宽，对故障后暂态电气量进行分解。对于中性点接地方式不同的配电网，按照能量的观点，选择不同的频带来实现故障选线。基于选出的故障选线时频窗，提出了一种新的选线判据：以波形识别作主判据，以模值比较作副判据，经逻辑排序，最终给出邦联选线序列。理论及大量的ＥＭＴＰ仿真表明：该选线方法可以准确、可靠地实现单相故障接地选线，适合于接地方式不同的各种配电网，

WAVELETS PACKET BASED DETECTION OF PHASE-TO-GROUND FAULT IN DISTRIBUTION AUTOMATION SYSTEM

Wavelet packets with the advantage of time frequency zoom is used in this paper to decompose the post fault transient electrical quantities by the proper frequency span. In view of energy, the different frequency band is chosen corresponding to the distribution system with the different neutral grounding mode. Based on the chosen time frequency window, a novel method is proposed in this paper, which synthetically uses the waveform recognition as the main criteria and the maximal module as the secondary criteria to perform the detection of the fault line. Theoretical analysis and lots of simulation using EMTP show that the proposed method can reliably and exactly choose the faulty line in single phase to ground fault and it is suited for various distribution systems with different neutral grounding modes. Moreover, this method can be easily used in site without adjusting protective settings.