The Research On Relay Protection Of Distribution Network With DG

Due to the gradual consumption of fossil fuels and increasingly seriousenvironmental issues, renewable energy have received increasing attention. As aresult,distributed generation technologies are developed rapidly.However, theapplication of distributed generation technology has brought considerablechallenge to the operation and control of power system.In order to improve thesecurity of power systems with DG, the traditional distribution network protectionmust make adjustments and improvements to meet the requirements of the DGaccess.Therefore, This paper presents a thorough study of the influence on relayprotection of distribution network after DG accessing, And the solutions arepresented respectively.Distributed generation technologies including its concept,background，classification， operation mode and advantages are introduced in this paper. Thenthe paper analyzed the impacts of relay protection of distribution network afterDG accessing.Focus is made on the impacts of distributed generation on theOver-current protection and autoreclosure. According to the characteristic of thedistribution network,a improved pilot protection scheme which is conbinedoriginal over-current protection is applied in distribution network with DG,thisscheme makes the protection of distribution network more rapidly and flexiblely.PSCAD/EMTDC simulation results verify effectiveness and correctness of theproposed method.The papar also proposes a idea that make the distribution network ofconventional open loop running mode change to the closed loop mode, At the sametime puts forward a corresponding relay protection scheme.Closed loop operationmode of distribution network have more advantage than the network operation inopen loop mode when DG access in distribution network. The correspondingprotection scheme which proposed in this paper can also makes the operation of distribution network stablely and reliablely.