Load pseudomeasurements in distribution system state estimation

Distribution system state estimation (DSSE) is an essential tool in active distribution grids in order to enhance the awareness of the power system operators regarding the state of the distribution system. One of the peculiarities of the DSSE is the lack of adequate real-time measurements. Thus, in this paper a three-phase DSSE algorithm enhanced with an advanced approach for modeling pseudomeasurements is proposed. The major innovation of the proposed methodology is the development of a DSSE algorithm based on limited real-time measurements. The proposed DSSE algorithm takes into account the unbalanced nature of the distribution systems and the presence of virtual measurements. The pseudomeasurements are obtained from historical data, through a Gaussian Mixture Model (GMM) methodology, improved by the Calinski & Harabasz (CH) criterion and the Expectation Maximization (EM) algorithm. The performance of the proposed methodology is illustrated on the IEEE 13 node test feeder and compared with the case where the pseudomeasurements are modeled through a normal distribution.