Effect of distributed generation on relay protection of distributed system

On the basis of introducing the concept of distributed generation(DG) and the structure and protection configuration of traditional distribution system,this paper discusses detailedly the effects of DG on relay protection and automatic devices when DG is connected to different positions by using a distribution system containing DG as a model. It emphasizes the cooperation and operation behavior of three-sect current protection and inverse over-current protection when short fault occurs at different positions of various feeders,and also discusses effects of DG on automatic reclosing,which provides some theoretical basis for relay protection algorithm research of distribution system.