Feature Analysis Method of Voltage Sag based on Sag Slope

At present, most of the analysis of the amplitude and duration of the voltage sag is based on the probability distribution map of a large number of measured data, in order to solve this problem, a calculation method is proposed to transform the sag amplitude and duration into the sag slope and sag amplitude time, which can quantitatively express the tilt degree of the voltage sag waveform and the persistence at the lowest amplitude. After analyzing the simulation waveforms of short circuit fault and transformer excitation by slope calculation method, the values of sag slope and sag amplitude time obtained are more perfect than the original sag amplitude and duration description, which is beneficial to the follow-up study of voltage sag.