Evolutionary approach to distribution network reconfiguration for energy saving

Network reconfiguration for loss reduction in distribution systems is a very important way to save energy. However, due to its nature, it is an inherently difficult optimization problem. In this paper, a new type of evolutionary search technique, evolutionary programming (EP), has been adapted and improved for this particular application. In order to improve the performance of EP, a fuzzy controlled EP (FCEP), based on heuristic information, is first proposed. The mutation fuzzy controller adaptively adjusts the mutation rate during the simulated evolutionary process. The status of each switch in a distribution system is naturally represented by a binary control parameter 0 or 1. The length of string is much shorter than that proposed by others. A chain-table and combined depth-first and breath-first search strategy is employed to further speed up the optimisation process. The equality and inequality constraints are imbedded into the fitness function by penalty factors which guarantee the optimal solutions searched by the FCEP are feasible. The implementation of the proposed FCEP for feeder reconfiguration is described in detail. Numerical results are presented to illustrate the feasibility of the proposed FCEP.