The Comparison of WLS and WLAV Based State Estimator in Practical Power System

Abstract

State estimation (SE) has been the core of energy management system for power grid. This paper describes the WLS estimator and the WLAV estimator. The convergence, Good Measurement Rate (GMR) and computational efficiency of the two estimators are compared in a practical power system in China. The results show that the Weighted Least Absolute Value (WLAV) estimator requires more iterations and takes up more CPU time due to a large number of inequality constraints. It is worth noting that the robustness of the WLAV estimator makes it has better estimation accuracy and higher GMR in the unknown-oriented SE. Although the Weighted Least Squares (WLS) estimator itself cannot resist the influence of bad data, the application of bad data identification can effectively improve its GMR and accuracy of SE. Compared with the impact of inequality constraints on the computational efficiency of the WLAV estimator, the WLS estimator with bad data identification can guarantee the computational efficiency and ensure the GMR of SE.