Minimum-loss network reconfiguration: A minimum spanning tree problem

Topological reconfiguration of power distribution systems can result in operational savings by reducing the power losses in the network. In this paper, an efficient heuristic is proposed to find an initial solution for the minimum-loss reconfiguration problem with small optimality gap. Providing an initial solution for a mixed-integer programming (MIP) problem, known as “warm-start”, allows for a significant speed up in the solution process. The network reconfiguration for loss reduction is mapped here into a problem of finding a minimum spanning tree (MST) in a graph, for which there are a number of efficient algorithms developed in the literature. The proposed method leads to very fast solutions (less than 1.4 s for systems up to 10 476 nodes). For the test systems considered, the solution provided by the proposed method lies within a relative optimality gap of about 2.2% with respect to the optimal solution. The existing MST algorithms guarantee the scalability of the proposed routine for large-scale distribution systems. Sensitivity factors are also employed to refine the solution to a smaller optimality gap.