中压配电网中的部分瞬时故障在发展为永久故障之前可能会多次发生，而准确辨识这类重复发生的瞬时故障有助于实现故障预警、减少永久性故障的发生并且提高供电可靠性。通过建立瞬时故障的暂态等值电路并对其故障电流进行分析，表明重复性瞬时故障在发展为永久性故障的过程中，故障电流具有强相似性。文中提出了一种基于零序电流波形相似度的重复性瞬时故障辨识方法。采用改进动态时间规划（dynamic time warping，DTW）算法计算零序电流的近似波形和暂态波形序列间的距离。而后通过DTW距离获得波形相似度，实现重复性瞬时故障的辨识。通过大量PSCAD/EMTDC仿真数据以及现场实测数据，验证了所提辨识算法在多种影响因素下的准确性和有效性。
英文摘要:
Temporary faults in a medium-voltage distribution network may recur many times before they evolve into permanent faults. To accurately identify recurrent temporary faults can help to realize fault anticipation, reduce the occurrence of a permanent fault and enhance the power supply reliability. An equivalent circuit of a temporary fault is established and the temporary fault current waveform is analyzed. The results demonstrate that the zero-sequence current waveforms between recurrent faults are similar before they evolve into a permanent fault. A recurrent temporary fault identification method based on the zero-sequence current waveform similarity is proposed in this paper. An improved dynamic time warping (DTW) distance algorithm is used to calculate the general and transient waveform sequence distance of zero-sequence current. Then, a waveform similarity is obtained by DTW distance to identify recurrent temporary faults. Amount of simulated data in PSCAD/EMTDC and field-measured data validate the accuracy and effectiveness of the proposed identification algorithm under varying influencing factors.