Study On The Fault Location Algorithm Of Distribution System With Distributed Generators

With the increasing demand for the electricity,the energy crisis becomes more and more serious.The new clean energy represented by wind power generation and photovoltaic power generation has been connected to the power distribution network system in the form of distributed generators(DGs).Distributed power supply has the advantages of environmental protection and renewable,but the access of large-scale and multi-type distributed power supplies also induces a series of new problems in the traditional distribution network,such as the misoperation rate of traditional relay protection systems is increasing,and the traditional fault localization technology is also no longer applicable.After the distribution network with distributed power supply breaks down,to ensure the reliability and safety of power supply system,it is very important to locate the fault point quickly and effectively.As the fault location algorithm for traditional distribution network systems is not suitable for distribution networks with DG access,based on the characteristics of the distribution network with DC,a large number of traditional fault location algorithms have been improved for fault location in distribution network with DGs and the effect has been well verified.However,the improved algorithm still has a series of problems,for example,they have lower convergence speed and are easily falling into local optimum.Therefore,studying the improved fault location algorithm and further improving the effectiveness of fault location of the algorithm are significant for improving the power supply stability of the distribution network with DGs.In this thesis,the fault location in distribution network system with distributed generation is studied.The following three aspects of work are mainly studied:Firstly,Based on the simulation of the voltage and current changes in the distribution network system respectively,which induce by the access to distributed power sources,we analysis the impact of distributed power on the distribution network system,in the aspects of the overall performance and fault location;Secondly,Based on the comprehensive summary of the existing fault location algorithm,via the programming and case analysis of the particle swarm algorithm,which is more widely used,the general positioning process and principle of the fault location algorithm in the DG distribution network are studied;Finally,We improved the existing firefly fault location algorithm by appropriately reducing the probability of multiple faults in the algorithm.Case studies were carried out in the situation of single point fault,double point fault and information distortion.Compared with the original binary firefly algorithm and particle swarm optimization algorithm.the results show that the improved firefly algorithm has a series advantages,such as fewer times into local optimal solution,fewer fault tolerances,and higher precision.