基于小波分析的超高压输电线路故障定位的研究

Research on fault location for EHV transmission line based on wavelet transform

将小波变换对信号奇异性的检测功能和滤波特性应用到超高压输电线路的测距和选相中,将行波模分量和初始电流的工频段分量结合起来构造新的选相判据;利用线模、零模小波变换的模极大值与突变点的对应关系,确定故障初始行波到达线路两端的时刻来计算故障点的距离。大量EMTP的仿真结果表明:该方法具有选相准确、完全能消除接地电阻影响、定位精度高的特点,且基本不受故障类型、故障电压相角大小、故障位置的影响。

This paper introduces the wavelet transformation applied in EHV transmission line fault locating by detecting singularity and filtering,and a new method to select phase constructed by combining with module component of traveling-wave and power current.Employing the corresponding relationship between the module maximum of wavelet transformation and the singularity point ,it can be determined the time that initial traveling-wave arrives at the two ends of the line,further the fault point distance can be computed with the time.A great number of EMTP simulation experiments to be conducted shows :such method can select accurately fault phase,completely eliminate the affection of ground resistance and locating accuracy is also high.This method is basically unaffected by different fault type,phase of fault voltage and fault allocation.