Distributed generation (DG) offershuge benefits to the power system network to cater tothe rapidly growing demand for electric power. The integration of DG units intoexisting power networks is beneficial to both utilities and consumers. However, the installation of DG units in distribution networks might impose some operational, technical,and economic impacts. Increased short-circuitlevel and changes in load flow direction are examples of the technical issues arising from the high penetration of DG. Such issues will affect the existing protection system, mainly overcurrent relays. Thus, to ensure reliable and selective operation of protection relays, the impacts of DG should be considered. Thispaper discusses the impacts of DG on the protection systems byidentifying various protection problems.The paperis complemented by a simulation case study on the impactsof DG on fault levels, protection coordination, and distance relays.The simulatedsystem was modeledusingDIgSILENT PowerFactory®software.