输电线行波测距中雷击与短路故障的识别

掌握超高压、高压输电线路上雷电冲击发生的位置和频次等信息,对输电线路的防雷保护及系统运行水平的提高具有重要的理论和现实意义,故而利用现有可检测与定位线路雷击的行波测距装置,提出了一种基于小波包能量谱和暂态行波特征分析的雷击与短路故障识别方法。通过对500kV输电线路的非故障性雷击、故障性雷击以及普通短路故障的仿真研究,提取出电流行波信号的特征和信号各频段的能量分布规律,结合这些特征和规律提出了对3种暂态过程进行识别和分类的具体算法。EMTDC仿真验证了该算法的正确性。

Identification of Lightning Strike and Fault in the Traveling Wave Location of Transmission Line

Lightning strikes on EHV transmission lines are quite common and may lead to insulation breakdown or some other damage to the power system.The information of the location and times of lightning strikes on transmission lines is very useful for the researchers on lightning strike protection.The existing traveling wave location device can be used to detect the lightning strikes on transmission line,however,common faults happened on those lines can also be detected by that device which is not able to identify those two kinds of transient signals.This paper presents an algorithm to identify lightning strike and the general faults based on wavelet packet energy-spectrum and the transient traveling wave characteristic.Through analyzing the current signals generated by lightning strikes that do not cause any fault,and the state of fault including general faults and lightning strikes that will cause short-circuit on the 500kV transmission line,the signal characteristics and its energy distributions rules of all frequency bands are found,then a idiographic method for identification of the three transient processes is proposed.The Electromagnetic Transient Program(EMTDC) is used to simulate the time-domain signal.Db4 wavelet packet transform is used to analysis the transient signal.The simulation results indicate that the proposed method is effective with reasonable accuracy and its accuracy is not effected by fault angle,transient resistance condition and fault location.This could make it possible for the traveling wave location device to accurately collect the lightning strike information.This paper presents an algorithm to identify lightning strike and the general faults based on wavelet packet energy-spectrum and the transient traveling wave characteristic.Through analyzing the current signals generated by lightning strikes that do not cause any fault,and the state of fault including general faults and lightning strikes that will cause short-circuit on the 500kV transmission line,the signal characteristics and its energy distributions rules of all frequency bands are found,then an idiographic method for identification of the three transient processes is proposed.The Electromagnetic Transient Program(EMTDC) is used to simulate the time-domain signal.Db4 wavelet packet transform is used to analyze the transient signal.The simulation results indicate that the proposed method is effective with reasonable accuracy and its accuracy is not effected by fault angle,transient resistance condition and fault location.This could make it possible for the traveling wave location device to accurately collect the lightning strike information.