Simultaneous estimation of state variables and network topology for power system real-time modeling

• A method to simultaneously estimate state variables and network topology is proposed.
• The strategy combines WLS & WLAV criteria into a bi-objective optimization framework.
• An interior point approach is employed to solve the inner loop optimization problem.
• State & topology coestimation is performed by a proposed outer loop algorithm.
• Method is validated through several case studies performed on distinct test systems.

A combined Weighted Least Squares (WLS) and Weighted Least Absolute Value (WLAV) strategy is proposed to devise a joint state and network topology (S&T) estimator for power system real-time modeling. This is accomplished by formulating S&T coestimation as a multi-objective optimization problem combining both analog measurement residuals and operational conditions dictated by circuit-breaker statuses. The former are treated as arguments of a conventional WLS function, whereas the latter exploits the selective properties of the LAV criterion. The paper presents the theoretical framework for S&T coestimation, and proposes a specialized primal/dual interior point method to solve the corresponding optimization problem. Results obtained by applying the joint estimator to the IEEE 24-bus test system and to a real metropolitan system in Southern Brazil are reported in the paper. They indicate that S&T coestimation is a very promising approach to provide simultaneous solutions to both real-time modeling problems.