Renewable distributed generation: The hidden challenges – A review from the protection perspective

Abstract

This review paper is focused on the impact of distributed generation (DG) on distribution system protection. The integration of DG is transforming the traditional radial distribution system into a multi-source system that requires protection that is capable of maintaining proper coordination under bi-directional and variable power flow conditions. The multiple types of DGs with different short circuit characteristics mean that the protection must also be effective under conditions of unpredictable fault currents. New grid code requirements demand that DGs remain connected under fault conditions to provide grid support and improve system reliability and security of supply. A discussion is given of the traditional protection techniques for the distribution system and the shortcomings of such techniques when DGs are integrated into the system. The paper also presents a wide survey and review of recent techniques proposed by various researchers to mitigate the effects of DG integration on the performance of distribution system protection. Centralised and distributed techniques have been proposed that include deployment of intelligent smart devices and communication systems to enhance and provide novel ideas for solving the protection problem. The implementation challenges of these techniques are discussed and proposals for the future given.