A comprehensive review of distribution generation integrated DC microgrid protection: issues, strategies, and future direction

The evolution of small-scaled distributed generators and emerging power electronic devices opens up a new arena of power generation, distribution, and consumption. Operationally, the DC microgrid has attracted significant attention as it offers considerable safety benefits, cost-effectiveness, energy efficiency, and reliability as compared to traditional AC microgrid systems. Looking at the protection aspects, the DC microgrid has some serious issues both for low-voltage and mid-voltage DC system. It needs to be focused on bidirectional power flow, non-zero crossing point, detection and mitigation of grounding faults, high value of fault current, etc., for an adequate solution. In recent times, these issues are considered by various researchers to arrive at a robust and reliable approach toward protecting the DC microgrid. But certain important areas are still out of sight for researchers. In a blend of conventional and modern approaches, there are many hindrances in developing a flexible universal protective scheme. This work focuses on the protection aspects parallel with the challenges and tried to unearth the loopholes which open up a wider area of research to develop a more robust protective architecture. An extensive review has been done systematically and chronologically keeping in mind the DC microgrid architecture, standards, protection hurdles, traditional as well as latest protective measures, and suggested some reliable improvements. In addition, the futuristic possibility to invent a novel comprehensive approach based on the best technology and techniques is presented in a more secure, reliable, and efficient protection system to combat the power system faults, keeping in view the different modes of operation and configuration of the microgrid.