Research On Distribution Network Protection Technology Considering Distributed Generation

Distributed power generation technology not only has less pollution to the environment,but also can effectively reduce the network loss of the system and reduce the economic cost of users.Looking at the development trend of the power grid,it can be seen that the distributed power(Distribute Generation,DG)penetration in the large power grid is getting higher and higher,and it has a unique advantage to integrate the distributed power with the large power grid.However,this also brings a series of problems.As far as relay protection is concerned,the operating characteristics of the distribution network will be changed,and the traditional protection cannot operate normally.This paper focuses on the relay protection strategies of DG distribution networks and the protection technologies involved.First,this paper systematically summarizes the current research status of relay protection technology for distribution networks with and without DG at home and abroad,introduces several different representative distributed power generation technologies,studies its mathematical models,and focuses on the analysis of photovoltaic power generation and Power generation principle and output characteristics of wind power.Secondly,after the impact of DG access on the protection of the distribution network,the effects of different DG access capacity and access locations on the protection of the distribution network are studied,and the short-circuit current and reclosing after DG access are also analyzed.And the impact of island operations.Then,after studying the application status of artificial intelligence algorithm in fault location of distribution network,the idea of ??fault location using limit learning machine algorithm is integrated into the protection scheme of distribution network,and the traditional limit learning machine is used in fault diagnosis.The shortcomings ofslow convergence and low accuracy are combined with improved particle swarm optimization with strong global search ability.A limit learning machine fault location algorithm based on improved particle swarm optimization for power distribution network is proposed and compared through simulation.The algorithm has high reliability,good fault tolerance and faster convergence speed.Finally,based on the research of fault location algorithms,the concept of planning islands is introduced,and the distribution network is divided into different regions with the DG grid connection point as the critical point.For different fault types in different regions of the system,an improved limit learning machine algorithm is proposed.The distributed pilot grid protection scheme for distributed power distribution networks with distributed power supplies realizes fast and reliable protection of the entire distribution network area.