Investigating the effect of distributed generators on traditional protection in radial distribution systems

The recent changes in power network structure, development in green energy technologies and increased attention on environmental concerns have led to increase the installation of renewable energy based distributed generations (DG) in distribution networks. The increasing penetration of distributed generation in the distribution power system creates new technical and economical challenges; protection is one important topic of these challenges. High penetration of DG will have unfavorable impact on the traditional protection methods; the impact depends on the number, location and size of injected DG. To ensure safe and selective protection devices coordination, the impact of DG should be taken into account when planning DG interconnection. This paper focuses on investigating the impact of DG on the system protection coordination in radial distribution network; also restrictions of DG capacity is presented in this work in order to keep traditional protection scheme for distribution network unchanged; detailed simulations using MATLAB and PowerWorld simulator are conducted.