Microgrid Protection Against Internal Faults: Challenges in Islanded and Interconnected Operation

Microgrids have gained significant interest over the last 20 years and are perceived as key components of future power systems. Microgrids are defined as distribution networks with distributed energy resources (DERs) (e.g., distributed generators, storage devices, and controllable loads) operating in a controlled and coordinated way. Moreover, microgrids should have clear electrical boundaries and the ability to operate connected to the main power network or islanded. The coordinated control of microgrid resources increases energy efficiency, minimizes the overall energy consumption, and reduces the environmental impacts of energy production. At the same time, the ability of microgrids to seamlessly transition to islanded operation when upstream network faults occur increases the reliability and resilience of the customer supply. Furthermore, microgrids have been adopted as prominent and viable solutions for rural electrification in developing countries, isolated areas, or areas with weak power transmission infrastructures.