Research Of Three-Phase Power Flow And Service Restoration For The Distribution Network With The Distributed Generation

Now,the whole world is facing serious challenges from energy and the environment,and developing and utilizing new energy technologies is imminent.So distributed generation gets more and more attention of experts and scholars in the industry of power because of its advantages.Distributed generation brings tremendous impact on the aspects of the grid structure,power lossand voltage distribution.Therefore,if there is a power outage in the distribution network with distributed generation,the method of service restoration is also different with that in the traditional distribution network.To do careful research of the fault recovery in the distribution network with distributed generation,we must firstly do the research of power flow calculation.Therefore,in this thesis,three-phase power flow and service restoration problem of distribution network with distributed generation has been researched in-depth:1.The calculation methods of power flow and three-phase power flow were analysised and compared.And the main function of distribution network fault diagnosis system-power flow calculation and service restoration subsystem' was simply introduced,as well as some of the operating interface.2.The principle of three-phase Newton power flow was analyzed in detail.According to the convergence theorem of Newton-like power flow algorithm that is been put forword,we improved it and expanded its convergence domain.So we has put forword the new convergence theorem of Newton-like power flow algorithm based on affine invariants and given the detailed proof.At the same time we have got a necessary condition for the convergence of Newton's method which is easily used for judge the suitability of the selected initial value.The correctness and validity of the convergence theorem of Newton-like power flow algorithm was proved by the simulation of IEEE node system.At last,according to the advantage of a strong global convergence of differential evolution algorithm and lettting the Newton method as the core,we have put forword Newton power flow calculation method based on differential evolution and affine invariants.We also call it DE-NR algorithm.This DE-NR algorithm can provide reasonable initial value to Newton method,so Newton method will get a inevitable convergence result when it is used to calculate three-phase power flow.3.The improved binary gravitational search algorithm was proposed to apply in the service restoration of the distributed network with distributed generation according to the actual situation of fault.In the recovery process,we firstly introduced the method and procedure of the island division,and then,we improved the inadequacy of GSA algorithm.In the first place,we made the gravitational constant be a linear descending number in the process of improving the GSA.Secondly,fitness variance ?2 was proposed to judge the prematurity.In order to overcome prematurity,improved binary gravitational search algorithm which is Newton combined the complex method that has a strong local search ability was put forword.Finally,IBGSA has been confirmed more efficient and practical than the binary particle swarm optimization through examples.The final chapter of this thesis,main concluding remarks are summarized and presented at the end of this thesis as well as some interesting problems which deserve further study.