Using voltage measurements to improve the results of branch-current-based state estimators for distribution systems

Branch-current-based formulation provides an approach to the solution of the state estimator of distribution systems. However, voltage measurements were always neglected in the branch-current-based state estimator due to its special formulations. In distribution systems, a large proportions of measurements are voltage measurements, if voltage measurements cannot be integrated into branch-current-based state estimators, the value and accuracy of branch-current-based state estimators will be greatly degraded. Therefore, an algorithm of treating voltage measurements for the branch-current-based state estimator with a phase-decoupled formulation is proposed. The approach presented in the paper substantially improves the original method. A new algorithm with constant gain matrix and phase-decoupled formulation for the treatment of voltage measurements is developed. The innovative formulation can be used to improve the results of the branch-current-based state estimators. Tests show that the proposed method can handle voltage measurements effectively and the usage of load-forecasting data and some voltage measurements can further improve the accuracy of state estimator results.