Consideration of different operation modes of UPFC in power system state estimation

Power system state estimation is one of the functions performed in modern control centers. When FACTS devices are in a power system they should be taken into account in state estimation. In the paper, existence of UPFC, i.e. the most universal FACTS device, in a power system is considered. UPFC can operate in different modes. It can operate with full utilization of its possibilities or as SSSC or STATCOM. The aim of the paper is to present results of investigations of features of power system state estimation performed with use of the knowledge about actual operating modes of UPFC. The investigations have been made for the WLS power system state estimation. After the proposed approach to state estimation is outlined the results of the computational investigations are presented. During investigations, such features of the state estimation as conditioning of estimation process, accuracy of results, number of iterations in calculations are analyzed. At the end, conclusion from the carried out investigations are drawn.