中文摘要：

针对现有的电压暂降检测方法进行了分析研究,提出了基于改进αβ变换和数学形态学的电压暂降检测方法。首先利用单相电压移相一个大小可调的角度来构造新的αβ两相电压;然后经过dq变换将电压的基波分量转换成直流分量;最后通过数学形态学滤波器对非直流量进行滤波,得到相应的暂降幅值和相位跳变。改进的方法不仅抑制了电压暂降起止时刻可能出现的＂异动＂现象,而且利用形态学滤波器代替传统低通滤波器,有效地提高了检测速度和精度。仿真结果证明了改进方法的有效性。

英文摘要：

For existing methods of the voltage sag detection are analyzed, proposes the method based on improved αβ transform and mathematical morphology. Firstly, the single-phase voltage is shifted with an adjustable angle to construct a new two-phase αβ vectors; then, the fundamental components are converted to DC components by dq conversion; finally, the AC components are removed by the morphological filter and the voltage amplitude and phase angle jump are obtained. Improved method not only inhibits the ＂transaction＂ phenomenon possibly emerged in voltage sag starting and ending time, but also effectively improves the detection speed and accuracy by the use of morphological filter instead of the traditional low-pass filter. Simulation results show the effectiveness of the improved method.