State Estimation of a Distribution System Using WLS and EKF Techniques

State estimation of a discernible active distribution network is researched. A system is discernible if the state of the network can be completely ascertained. An active distribution network is one that includes Distributed Generation (DG) units. A modified IEEE34-node test feeder including two DG units is analyzed. The forward-backward sweep technique provides the state estimation measurement data. The state estimation is done using the Weighted Least Squares (WLS), as the traditional method, and Extended Kalman Filter (EKF), as an alternate method. The aim of the two estimators is to determine the most likely state with the available measurements. It is concluded that the EKF technique shows higher performance with fewer iterations. Another advantage of the EKF is that it has foreknowledge about the state and finds the most probable state in much less time than the WLS technique.