采用行波固有频率的混合线路故障测距新方法

New Method of Fault Location for Hybrid Lines by Using Traveling Wave Natural Frequencies

对于电缆-架空混合线路,由于波阻抗的不连续会形成混叠的固有频率频谱,因此,解决频谱混叠现象是提高固有频率测距法精度的首要问题。为此,提出一种基于聚类经验模型分解(EEMD)算法的行波固有频率的故障测距方案。首先利用EEMD算法得到一系列的固有模态函数(IMF)分量;然后选取聚集故障信息的IMF分量,引入多重信号分类(MUSIC)算法对其进行频谱估计得到固有频率主成分;最后利用故障行波的固有频率和故障距离的关系式即可实现故障测距计算。仿真对比显示了该方法可更好地解决混合线路故障测距时存在的频谱混叠问题,实现较高精度的故障定位。

For cables-overhead hybrid lines, due to the frequency spectrum aliasing produced by the discontinuous wave impedance, it is the first issue to solve the frequency aliasing phenomenon to improve the accuracy of fault loca- tion by natural frequency.A fault location method by using ensemble empirical mode decomposition （EEMD） is pro- posed. Firstly, series of intrinsic mode function （IMF） components are obtained by using EEMD. Then the IMF compo- nent containing fault information is selected and natural frequency spectrum of the first IMF component is estimated in order to get the principal components by introducing the multiple signal classification （MUSIC）. Finally, The fault location is calculated by using the equation between the natural frequency of the fault wave and the fault distance. The simulation analysis shows that the method can well solve the spectrum aliasing problem in fault location, and realize in high precision.