Power system state and topology coestimation

Abstract

A joint power system state and topology estimator based on a combined Weighted Least Squares (WLS) and Weighted Least Absolute Value (WLAV) strategy is proposed. The resulting coestimation algorithm is devised to simultaneously provide estimates to the analog power system variables and validate the current topology of the electric network. This is accomplished by formulating state & topology coestimation as an optimization problem whose objective function involves both the analog measurement residuals and the operational conditions dictated by circuit-breaker statuses. The former are treated as arguments of a conventional WLS function, whereas the latter compose the LAV term. The paper presents a theoretical framework for state & topology coestimation and proposes a specialized primal/dual Interior Point approach to solve the corresponding optimization problem. Results obtained by applying the joint estimator to the IEEE 30-bus test system and to a real metropolitan system in Southern Brazil are reported in the paper, and indicate that this is a very promising approach to provide simultaneous solutions to both real-time modeling problems.