A new heuristic approach for optimal reconfiguration in distribution systems

This paper presents a novel approach for optimal reconfiguration of radial distribution systems. As an integral part of the distribution system configuration, a load flow algorithm based on graph theory is presented. The algorithm follows changes in system structure by traversing a directed graph of the system to find the depth-first search discovery order. For each switching-iteration, this discovery order generates down-stream-nodes vectors necessary for dynamic generation of two matrices: one is the branch node incidence matrix and the other the relationship between the bus current injection and branch currents. Thus avoiding creation of unconnected branches or forming closed loops. The developed load flow program is integrated with known heuristic techniques in a new heuristic search methodology for determining the minimum loss configuration of a radial distribution system. The technique consists of two parts: one is to determine the best switching combinations in all loops with minimum computational effort while the other is a power loss and voltage profile calculation of the best switching combination found in part one by load flows. Compared to other published articles, the efficient developed load flow reduces the switching combinations searched and gives the optimum solution in few number of load flow runs. To demonstrate the validity of the proposed algorithm, computer simulations are carried out on 33-bus system. The results show that the performance of the proposed method is better than that of the other methods. (C) 2010 Elsevier B.V. All rights reserved.