Protection strategies for ADNs: A comprehensive review

Microgrids possess inherent benefits, but their power management, control, and protection systems present technical challenges. The integration of distributed energy resources (DERs), including renewable energy sources (RERs), energy storage systems (ESSs), and electric vehicles (EVs), has a substantial impact on microgrid protection. Key issues such as fault detection and location, coordination with microgrids and islanding, and the high penetration of EVs complicate the design of protection systems. Moreover, changes in fault levels, power flow direction, relay coordination, and concerns about the adequacy of circuit breakers (CB) ratings and fault ride-through (FRT) capability are crucial factors influencing protection strategies in Active Distribution Networks (ADNs). Well-implemented protection solutions are essential for microgrids, promoting reliability, safety, and overall system performance. This paper reviews existing protection strategies for each challenge, acknowledging the limitations of current methods and identifying potential areas for further research. Furthermore, a comparison of protection strategies is made based on cost, complexity, and reliability, highlighting the strengths and weaknesses of various approaches. Finally, conclusions, final remarks, and future research trends are presented.