VMD-SWT联合算法在故障行波检测中的应用

Application of VMD-SWT Joint Algorithm in Fault Traveling Wave Detection

针对现有输电线路行波检测方法易出现频谱混叠及对噪声敏感的问题,提出了变分模态分解VMD(variational mode decomposition)和同步挤压小波变换SWT(synchrosqueezing wavelet transform)相结合的故障行波检测方法。首先对故障行波信号进行连续小波变换,得到小波量图确定分量个数;然后利用VMD自适应分解成多个模态分量,再通过SWT对所选模态中心频率附近的小波系数挤压重组,锐化时频曲线,得到故障发生时刻并计算故障位置。与希尔伯特黄变换相比,该方法的信号分离能力好,噪声鲁棒性强。算例和仿真表明,该方法可以准确标定故障行波波头,受故障距离和过渡电阻的影响较小。

Aimed at the problems of spectral aliasing and noise sensitivity in the traveling wave detection method for transmission lines,a novel method for fault traveling wave detection is proposed based on the combination of variational mode decomposition(VMD)and synchrosqueezing wavelet transform(SWT). First,continuous wavelet transform is performed on the fault traveling wave signal to obtain the number of components in the wavelet quantity map. Then,VMD is used to adaptively decompose the fault traveling wave into a plurality of modal components. Afterwards,the wavelet coefficients near the center frequency of the selected modal are recombined and squeezed by SWT,and the time-frequency curve is sharpened to obtain the fault occurrence time and fault location. Compared with Hilbert-Huang transform(HHT),this method has better separation ability and stronger noise robustness. The results of an example and a simulation experiment show that the proposed method can accurately calibrate the fault traveling wave head,which is less affected by the fault distance or transition resistance.