基于自适应多尺度形态学和CEEMD的谐振接地故障选线研究

Research of resonant grounding fault line selection based on adaptive multi-scale morphology and CEEMD

为解决小电流谐振接地系统的故障选线不准确的问题,提出了一种基于自适应多尺度形态滤波和互补集合经验模态分解(CEEMD)相结合的选线方法。利用自适应形态学滤波方法可以有效地抑制电力系统故障过程伴随的宽带白噪声和孤立脉冲噪声。去噪后通过比较故障线路与非故障线路经CEEMD分解和希尔伯特黄变换(HHT)的特征分量一阶差分极性与相位进行选线。与经验模态分解(EMD)和集成经验模态分解(EEMD)相比,CEEMD能够更好地减小模态混叠的影响,同时减小分解误差。在MATLAB仿真软件中,对不同故障位置、过渡电阻、故障初始角进行分析,对上述方法进行了验证。大量仿真表明,该方法不受初始故障角、故障位置及过渡电阻的影响。

In order to solve the problem of inaccurate fault line selection in small current resonant grounding system,a method for line selection based on adaptive multi scale morphological filtering and complementary ensemble empirical mode decomposition(CEEMD)is proposed in this paper.The adaptive morphological filtering method can effectively suppress the wideband white noise and isolate impulse noise associated with the power system fault process.After de noising,the line selection is conducted by comparing the first order differential polarity and phase of the characteristic components which exist in the faulty line and the non faulty line through the CEEMD decomposition and Hilbert Huang transform(HHT)transform.Compared with empirical mode decomposition(EMD)and ensemble empirical mode decomposition(EEMD),CEEMD can reduce the influence of modal aliasing and the decomposition error better.In the MATLAB simulation software,different fault locations,transition resistances and fault initial angles are analyzed,and the above methods are verified.A lot of simulation results show that the method can′t be influenced by initial fault angle,fault location and transition resistance.