Study On Distribution Network Reconfiguration Based On Genetic Algorithm

This dissertation presents an improved method to study distribution network reconfiguration (DNRC) based on a partheno-genetic algorithm (PGA).Network reconfiguration is not only an important method in circulate and control of distribution system, but also an important part of distribution management system. In theory, network reconfiguration is a complex and many object combination optimization problem. From 1980' s, people had extensive study on network reconfiguration of distribution system, so many relatively mature methods and theory of network reconfiguration had formed and developed, such as OFP, BEA, ANN, ACO, SA, GA, Tabu and expert system,but all methods have many shortcoming. The ability of global searching and extensive application in other scopes of genetic algorithm had proved that it is attracting goal for us tO study how to apply genetic algorithm to network reconfiguration.On the base of analysis the specialty of distribute system, Structure Variable Dissipated Network (SVDN) is applied as simplified model of distribution network. The DNRC model, in which the objective is to minimize the system power loss, is set up. And the optimal result is gotten by analyzing the system power loss and switches operated times. This model is simple and easy to be implemented.The shortage of classical genetic algorithm in power system was pointed out. The predigestion of networks, the strategy of chromosome encoding and the PGA were proposed. It could be used to reduce the unsolvable code, to enhance the rate of the solvable code and to accelerate the calculating process by the kind of PGA. The paper presents an encoding method of neighboring switches neighboring in the chromosome and switches in the same loop in the same gene. The crossover operation is performed only on the corresponding genes. The mutation and inverse operation is limited within the gene. These strategies greatly reduce the infeasible solutions produced during gene algorithm operations in the application to distribution system reconfiguration. Furthermore, a distribution simplifying method is also proposed to reduce the length of chromosome and enhance the efficiency of the algorithm. The reciprocal value of active power losses is taken to be the fitness function, which will be simple and effective. In particular, the results of two standard test computations show that it could be used to reduce the unsolvable code, to enhance the rate of the solvable code and to accelerate the calculating process by the kind of PGA. At the end of the paper, the solution of true test computations are shown, in which network losing is minimized by distribution reconfiguration. The program is designed by using VC++6.0. The establishment of distribution system model and genetic algorithm is implemented by using Object-Oriented technology (OOT). It makes clear that the proposed algorithm has the effectiveness and practicability...