Network Reconfiguration Research Based On Reducing Feeder Losses

Distribution network reconfiguration is an important aspect of distribution automation system. The study of distribution reconfiguration is quite actively over the past ten years. It has tremendous economic and society benefit to improving power system's safety and economy by distribution reconfiguration and developing distribution network potential.This thesis focus on the problems,including the topology analysis,power flow calculation and distribution reconfiguration algorithms.Topology analysis is an indispensable part of network reconfiguration. The sound model of the network and the efficiency of the topology analysis are determined to the performance of reconfiguration algorithm. The structure of the network topology includes the description of the network and the state variable. According to the feature of the distribution network,a mathematical model has been built up for distribution,which combine with the structure of the network and the topology analysis.The thesis introduces several power flow calculation methods which are applied in distribution network and It makes a deep analysis of the features and the serviceable range of the power flow methods.Based on the especial structure of the distribution network,the back/forward power flow method have predominate advantages.It can easily be programmed,be more stable and take up little computer resource. The results indicate that the algorithm has a fine convergency.The time spent in the power flow calculation make a large proportion in network reconfiguration.Based on the features of the distribution network reconfiguration,just the part of the network power flow be affected.So a simplified power flow method is adopted,and the efficiency of the network reconfiguration has been improved greatly.The traditional branch-exchange algorithm performance not very well in deciding the exchanged branch.So a method based on improved branch-exchange algorithm is proposed.In this thesis,the mothod is proposed that calculate the power flow just for one time in reconfiguration and it evidencely improve the reconfiguration efficiency. The coordinate axis is found on P-Q plane.And this thesis also propose that nominal branch exchange is the center of circle,and then have a comparison of distance from the center of circle to the waiting list of the exchange branch. It can quickly and exactly decide the waited exchange branch.The performance test results of IEEE33-bus system and IEEE69-bus system mdicate that the improved branch-exchange method has high efficiency.