【摘要】 电压暂降起止时刻是重要的暂降特征量,在分析改进S变换基础上提出一种改进S变换基频幅值向量和基频差分平方向量相结合的暂降检测方法。首先通过改进S变换基频幅值向量判断信号是否发生暂降,再利用改进S变换基频差分平方向量检测暂降信号起止时刻,最后依据基频幅值向量和暂降起止时刻的检测误差曲线来确定改进S变换高斯窗宽调节因子,达到更优时频分辨率。所提方法能更准确地检测发生在不同持续时间、不同波形点和不同幅值深度的暂降所对应的起止时刻。仿真和实测结果验证了方法的有效性。更多还原

【Abstract】 Voltage sag starting-ending moment is an important characteristic. On the basis of analyzing improved S transform,the fundamental frequency vector and its difference squared vector of improved S transform are constructed to detect voltage sag starting-ending moment. Initialy,the fundamental frequency vector is used to decide whether sag happens or not,then its difference squared vector is employed to detect the starting-ending moment of sag. According to fundamental frequency vector and sag starting-ending moment detection error curve the Gaussian window width of improved S transform can adaptively obtain better time-frequency resolution. The proposed method can detect sag starting-ending moment of different durations,waveform points and amplitudes with highee precision. Simulated and practical signals validate the effectiveness of the proposed method.更多还原