Abstract: “Distributed Generation (DG) is used to improve the system reliability. However, DG Contribution in fault current may cause the loss of the existing protection coordination. This problem can drastically deteriorate the system reliability and it is more serious and complicated when there are several DG Sources in the System. Hence, the above conflict in reliability aspect unavoidably needs a detailed investigation before the installation or enhancement of DG is done. In this Research work it is proposed to model of composite DG fault current to find the threshold that existing protection coordination is lost. Cases of protection misco-ordination are to be described, together with their consequences. And attempt will be made to prevent reliability degradation from recloser fuse misco-ordination due to Distributed Generation.”

Keywords: Distributed generator, distribution network, protection equipment coordination, DG capacity