State Estimation of Unbalanced Electric Distribution Systems using Positive Sequence Equivalents and Homotopy Methods

A fundamentally different approach for formulating the state estimation problem associated with electric power distribution systems is proposed in this paper. This formulation is developed in the positive sequence frame of reference, which remarkably reduces the complexity of developing a distribution system state estimator. In order to estimate the operation state of unbalanced multiphase distribution networks by using the proposed positive sequence-based state estimator, the distribution network is also modeled through positive-sequence equivalent models. Furthermore, a homotopy-based solution method is incorporated in the developed program to enhance the performance of the proposed approach towards the convergence. The validity and the effectiveness of the proposed method are numerically demonstrated in the 13-bus test distribution system.