中文摘要：

对电压暂降三大特征量即持续时间、相位跳变和幅值的准确检测是实现电压暂降有效补偿的前提。文中提出复小波变换和有效值算法相结合的电压暂降检测方法。详细研究了复小波变换奇异性检测原理及其在电压暂降起止时间检测中的应用,采用具有四阶消失距的复Gaussian小波（Cgau4）能准确检测电压暂降发生、恢复时刻和相位跳变,利用有效值算法实现电压暂降幅值的检测。通过在Matlab中对有无畸变情况下的的电压暂降问题建模仿真,验证了该算法的有效性,实验结果表明该方法能精确检测电压暂降三大特征量。

英文摘要：

The accurate detection of duration time, amplitude and phase jump of voltage sag is the primary problem for voltage sag compensation. A voltage sag detection method based on complex wavelet transform and RMS algorithm is proposed in this paper. The principle of wavelet singularity detection and its application in the starting and ending times for voltage sag detection are studied in detail. The begin-end time, phase jump and amplitude of voltage sag is detected by using the fourth derivative of a complex Gaussian wavelet （Cgau4） and RMS algorithm. The performance