Voltage sag detection method based on dq transform and complex wavelet transform

In order to compensate the voltage sag quickly and effectively with the dynamic voltage restorer, it is necessary to detect the voltage sag quickly and effectively. Based on the common problem of voltage sag in power system, various detection methods of dynamic voltage restorer (DVR) are analyzed and studied in this paper, and the detection methods of dq transform and complex wavelet transform are proposed. This method can detect the amplitude and phase changes of the voltage dip, and realize the accurate detection of the phase and duration of the voltage dip. The dq transform can detect the amplitude and phase changes of the voltage sag, and the complex wavelet transform can accurately detect the phase and duration of the voltage sag. The effectiveness of the proposed method is verified by simulation with MATLAB software. The results show that this method can detect the voltage sag amplitude, phase and duration of voltage sag, which provides a basis for the future research of voltage sag detection and related treatment.