基于最优组合赋权改进S变换的电压暂降检测方法

电压暂降是电能质量问题的一种,为了能更准确快速地对电压暂降进行检测分析,文章提出了一种基于改进S变换的电压暂降信号检测方法,利用基频幅值差分平方向量检测电压暂降信号的起止时刻,通过定义起止时刻误差、暂降深度误差、局部标准差、峰度和能量五个指标得到其与改进S变换高斯窗调节因子的关系曲线,应用最优组合赋权法对该五项指标进行赋权,从而得到S变换的最优参数。仿真结果表明,通过文中提出的方法易于得到基频幅值差分平方向量曲线以及突变点曲线,从而更准确地定位暂降发生的起止时刻;相位跳变曲线能够更好地反映电压暂降的相位跳变情况;基频幅值曲线能够更准确地检测出电压暂降的暂降深度;时间幅值平方和均值曲线能更精确地反映电压暂降发生的起止位置。

Modified S-transform method of voltage sag detection based on optimal combination weights

Voltage sag is one of the problems of power quality. In order to detect and analyze voltage sag more accurately and quickly, this paper proposes a detection method of voltage sag signal based on improved S-transform, which uses the difference square vector of fundamental frequency amplitude to detect the start and end time of voltage sag signal, and defines the start and end time error, sag depth error, local standard deviation, kurtosis and energy The relation curve between the five indexes and the adjusting factor of the improved S-transform Gaussian window is obtained, and the five indexes are weighted by the optimal combination weighting method, so as to obtain the optimal parameters of the S-transform. Finally, the simulation results show that the method proposed in this paper is easy to get the difference square vector curve of the fundamental frequency amplitude and the curve of the mutation point, so as to more accurately locate the start and end time of the sag; the phase jump curve can better reflect the phase jump of the voltage sag; the fundamental frequency amplitude curve can more accurately detect the sag depth of the voltage sag; the time amplitude is flat The square and mean curve can more accurately reflect the starting and ending position of voltage sag.