Efficient Branch-Current-Based Distribution System State Estimation Including Synchronized Measurements

Deregulation and privatization actions are creating new problems of control, management and reliability, because of new players and new technologies spreading in distribution systems. Such new scenarios require more comprehensive and accurate knowledge of the system to make control actions efficient and reliable. In particular, attention must be paid to phase angles estimation to avoid critical situations. In this context, the use of phasor measurement units (PMUs) looks promising. This paper presents an efficient branch-current-based distribution systems state estimation. The estimator allows synchronized phasor measurements provided by PMUs to be included. In addition, the branch current state model is extended so that the knowledge of the voltage profile is significantly improved. The estimator is expressed both in polar and rectangular coordinates and a comparison between the obtainable accuracy and computational efficiency is presented. Furthermore, the possibility to treat radial and weakly meshed topology, also in presence of dispersed generation, is analyzed. The results obtained on different distribution networks are presented and discussed.