WLS state estimation in polar and rectangular coordinate systems for power system with UPFC: Significance of types of measurements

The paper presents a comparative investigations of the state estimation of a power system with UPFC in the polar and rectangular coordinate systems, paying special attention to types of utilized measurements. The estimation with the use of the weighted-least-squares method is considered. During investigations, impact of a coordinate system, in which the state vector is considered, stress of a power system, a data redundancy, and types of utilized measurements on such parameters of a state estimation as: the number of iterations, the condition number of the gain matrix, parameters characterizing accuracy of calculation results is analyzed.