An Overview of Voltage Sag Detection Methods

Voltage sag characteristic is an important indicator of power quality. Considering the large number of voltage sag sensitive loads in power systems, it is essential to identify voltage sag accurately and quickly to ensure safe and stable operation. Based on the concept and characteristics of voltage sag phenomenon, this paper summarizes the principles of different voltage sag detection methods in the time domain and transform domain, and analyzes in detail the RMS method, the peak voltage method, the fundamental component method based on the time domain, the wavelet transform method based on the transform domain, the dq coordinate transform detection method based on the instantaneous reactive power theory, and other methods such as Kalman filter detection method based on detection delay, calculation amount of detection method, anti-interference ability, detection accuracy and other performance. The typical detection algorithms in the time domain and the transform domain are analyzed. Finally, the main detection methods listed in this paper are summarized.