Feeder protection challenges with high penetration of inverter based distributed generation

The increasing proportion of inverter based distributed generation (DG) in the power system may limit the short circuit power available at distribution substations and consequently cause significant troubles for the protection of distribution feeders where DG are connected. In this paper, the current practices of distribution network operators in dealing with higher penetration levels of DG are investigated and evaluated using a realistic 31-node distribution network model with limited short circuit supply. The paper discusses the challenges for the protection system related to the integration of increasingly significant amounts of DG and highlights the need for more sophisticated protection systems.