Application of Improved Sage-Husa Kalman Filter in Voltage Sag Detection

Voltage sag is one of severe problems in power quality.The Sage-Husa Kalman filter applied in the detection of voltage sag possesses such advantages as high response speed,low calculation burden and simple structure,however the filter divergence occurs easily when the system order is high.To avoid the filter divergence and speed up real-time response of Sage-Husa Kalman filter,the estimator of noise covariance matrices in Sage-Husa Kalman filter is improved,and based on the improved filter a fast detection method of voltage sage is given.The effectiveness of the proposed detection method is verified by simulation and experiments.