基于改进S变换的复合电压暂降源识别特征分析

电压暂降是较常见、影响较大的电能质量问题,识别电压暂降扰动源对改善和治理电压暂降具有重要意义。分析了由线路短路故障、感应电动机启动、变压器投入等单一电压暂降扰动源和复合电压暂降扰动源引起的电压暂降现象,提出采用改进S变换分析复合电压暂降扰动源识别特征。根据基频幅值曲线和2~5倍基频幅值和曲线,从统计量、熵和能量等方面构建电压暂降识别特征指标,将这些特征指标作为支持向量机的输入实现对不同类型电压暂降扰动源的分类识别。仿真结果表明,采用改进S变换构建电压暂降识别特征指标比标准S变换在电压暂降扰动源分类识别上效果更好。

Method to identify composite voltage sag disturbance sources based on generalized S-transform

Among various types of power quality problems, voltage sag is more common and influential. The identification of voltage sag disturbance sources has great significance to improve the power quality. Different voltage sags, caused by single voltage sag disturbance sources such as short-circuit fault, starting induction motor, transformer energization and composite voltage sag disturbance sources, are analyzed. This paper proposes to analyze identification features of composite voltage sag disturbance sources based on generalized S-transform. According to the fundamental-frequency amplitude curve and sum of amplitude curve of 2nd to 5th harmonic, the feature indices of voltage sag are constructed in terms of statistics, wave morphology, entropy and energy. Then support vector machine (SVM) is employed to perform the identification of different types of voltage sag disturbance sources. The simulation results show that using feature indices of voltage sag based on generalized S-transform is better than those based on standard S-transform in identification of voltage sag disturbance sources.