Impacts of Distributed Generation on Power System Protection

Distributed generation (DG) offers huge benefits to the power system network to cater to the rapidly growing demand for electric power. The integration of DG units into existing 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-circuit level 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. This paper discusses the impacts of DG on the protection systems by identifying various protection problems. The paper is complemented by a simulation case study on the impacts of DG on fault levels, protection coordination, and distance relays. The simulated system was modeled using DIgSILENT PowerFactory® software.