Fully distributed optimal power flow for unbalanced distribution networks based on ADMM

Abstract

The optimal power flow (OPF) problem is important for the economical operation of distribution networks. With the increasing penetration of distributed generation (DG) in the distribution networks, conventional method of centralized optimization have some vital drawbacks which distributed OPF methods are able to overcome. Furthermore, distribution networks are inherently unbalanced and most of the existing distributed algorithms are designed for balanced networks. This paper proposed a fully distributed method based on alternating method of multipliers (ADMM) to solve the OPF problem on unbalanced distribution networks. Besides the ordinary constraints of voltage and power, the maximal branch current constraints is considered in the OPF problem which is convexified by means of semidefinite programming (SDP) convex relaxation. The optimal solution can be obtained by parallel computing with communication among adjacent buses. Numerical tests demonstrate the exactness and convergence of the proposed algorithm.