基于小波理论的输电线路故障信号检测的研究

输电线路发生故障后,其行波信号是一个突变的、具有奇异性的信号。小波分析具有很多有用的性质,利用小波多分辨率的特性可将突变信号进行多尺度分解,然后通过分解后的信号来确定突变信号的突变位置。Lipschitz指数被用来定量描述函数的奇异性。当小波变换尺度越来越精细时,小波变换模的极大值信号的突变点位置越精确。其衰减速度取决于信号的突变点的Lipschitz指数。小波变换不仅可以确定突变位点发生的时间,而且可以进一步判断突变点的性质。主要通过检测小波变换模极大值来找到信号的奇异点,从而确定信号发生突变的位置。

Research on Fault signal in Power Transmission Line Based on Wavelet Theory

After a transmission line fault occurs,its traveling wave is a mutational and singular signal.Wavelet analysis has lots of useful properties.The mutational signal can be resolved in multiple-dimensioned by proerties of wavelet multiple resolution ratio,and then define the mutational position of the mutational signal by resolved signal.Lipschitz index is used to quantitatively describe singularity of the function.When the transform scale of the wavelet becomes finer and finer,the mutational position of the maximal value of the wavelet transform pattern is more precise,whose decay rate depends on lipschitz index of the muational point.The wavelet transform can define not only the occurrence time of the mutational point,but also further determine characteristic of the mutational point.The singular point of the signal has been found by dectecting the maximal value of the wavelet transform pattern,thus defining the position of the signal occurrence mutation.