In view of the shortcomings of insufficient real time and detection accuracy in traditional voltage sag detection methods

a kind of voltage sag detection method combining improved dq transform and adaptive sequential morphological filtering is proposed in this paper.In order to enhance the anti-noise performance and shorten response time of the proposed method

an adaptive sequential morphological transformation is added to the original mathematical morphological filtering algorithm and a new detection process is designed.The key parameter combinations in the proposed method are optimized and determined by screening statistical methods.The voltage sag model with harmonics plus noise is designed.The method proposed in the paper is tested by the single-phase voltage sag signal with compound disturbance and compared with the methods proposed in the other similar literature.It is proved by the test that the new method can detect the occurrence of voltage sag in time and have good anti-interference ability

and it can provide valuable help for the design of governance equipment of voltage sags for sensitive loads.