Research On Reconfiguration Of Distribution Network With Distributed Generation Based On Refined Adaptive Genetic Algorithm

With increasing global energy crisis and human’s growing demand for clean energy, distributed generation (DG) with its advantages of clean, environmental protection, high efficiency has gradually become a research hotpot of power department. However, a large number of DG access to distribution network not only changed the topological structure of "designed in closed loop and operated in open loop", but also puts forward the new requirement to the reconstruction of rules:regardless of its objective function or constraints. Therefore, the study of the distribution network reconfiguration of DG is of great significance.Above all, this paper discusses the status of distribution network reconfiguration, introduces types of DG and mathematical model, and further analyzes the impact of DG interconnection on power distribution system.Secondly, the flow calculation models are constructed respectively according to the different features of PV nodes, PI nodes and PQ (V) nodes. In view that Back/forward Sweep Method cannot cope with weakly meshed distribution network and PV nodes, this paper presents a new power flow calculation based on superposition theorem when coping with weak ring network, the ring is divided into pure radial network and loop network, using the forward and backward substitution for pure radial network and the loop current method for solving pure ring network, then superposition on the results; during handling DG units in PV node, the calculation method of reactive power compensation based on the sensitivity impedance matrix is applied. Improved Layered Forward-backward Sweep Method is put forward, implementation of parallel computing in the same level of the pure radial network and loop network, increases the calculation speed. The example of IEEE33-bus has proved the efficiency of the algorithm for the treatment of various types of distributed power supply.Finally, in view of different types of DG accessing to distribution network will have a significant impact on the distribution network reconfiguration, the paper presents an improved adaptive genetic algorithm to solve the optimization problem of distribution network reconfiguration with DGS.In this paper, loop-based binary encoding is adopted, power point and the T-junction be in the closing state, so as to shorten the encoding length and improve the proportion of feasible solution. Aiming at the generation of infeasible solutions in distribution network reconfiguration and its harm, the judgment method based on adjacency matrix is proposed in this paper, so as to improve the searching efficiency. Because of the previous adaptive genetic algorithm for Pc and Pm adjustment applying only to the later evolution, the paper puts forward an improved adaptive genetic algorithm. The algorithm of Pc and Pm is adjusted to change according to genetic algebra, this not only ensure the global convergence of the algorithm, but also effectively reduces the number of iterations, improves the speed of convergence.In this paper, Matlab R2009b is used to program, taking the minimum network loss as objective function, and the feasibility of the algorithm is verified through the calculation of IEEE33node, PG&E69node system simulation of the United States of America.