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SUMMARYThis paper presents an effective approach based on simple examination and retrieval procedure (SERP) that can be used in evolutionary algorithms, such as genetic algorithm (GA) and binary particle swarm optimization (BPSO), for solving distribution feeder reconfiguration problems. The proposed approach is able to improve the search efficiency by identifying and modifying the illegal chromosomes that represent switching operation plans. The concept of simple examination is done by checking the numbers of normally opened switches on a branchless line segment in distribution systems. By applying the proposed approach, the number of illegal chromosomes during the regeneration process in evolutionary algorithms can be reduced. The idea of retrieval procedure is done by trying to use the information from historical local optimal solutions to repair the illegal chromosomes as many as possible. A 33-Bus distribution system and a practical distribution system of Taiwan Power Company (TPC) are used in this paper to verify and validate the effectiveness of the proposed procedure. The simulations consider the distribution system with and without distributed generation (DG) for power losses problems. Simulation results show that integration of the proposed procedure to GA and PSO provides more efficient and stable solutions for feeder reconfiguration problems.

In distribution automation, restoration process is done by switching actions of sectionalizing switches and tie switches on the system. The determination of the state of these switches is mainly logical reasoning with less mathematical process. Thus, knowledge-based systems are ideal tools to accomplish the task. In this research, CLIPS is used to develop the proposed system by taking advantages of its object-wiented feature. By applying object-oriented technique, the actual status of a distribution system component can be reflected properly by updating the attributes of all the objects.By referring to the empirical rules of previous work, the distribution system restoration procedure can be divided into three stages: Group restoration, Zone restoration and Load transfer. The unique feature o f the proposed expert system is that the variation of load currents is considered. By doing so, the restoration strategies can be more accurate. practical and effective. A simulation on a small distribution system is performed, the results are compared with the same system which has constant load currents.