Review on Enhancing Microgrid Resilience- Robust Protection Strategy Employing Differential & Overcurrent Relays

The increasing penetration of Distributed Energy Resources has transformed traditional distribution networks into dynamic and complex microgrids, creating significant challenges for conventional protection schemes. Bidirectional power flow, low fault current contribution from inverter-based sources, and frequent transitions between grid-connected and islanded modes demand more intelligent and adaptive protection strategies. The reviewed literature clearly indicates that fixed-setting overcurrent relays are insufficient for ensuring reliable fault detection in such environments. Adaptive overcurrent relays improve coordination by adjusting settings according to system conditions,  while  differential  relays  provide  fast  and accurate detection of internal faults independent of fault current magnitude. Hybrid protection schemes integrating adaptive overcurrent and differential relays offer a comprehensive and robust solution. These approaches enhance selectivity, reduce fault clearing time, and improve overall system stability and reliability. Although challenges such as communication dependency and implementation complexity remain, the combined strategy represents a practical and scalable pathway toward resilient microgrid protection. Continued research and real-time validation will further strengthen the development of efficient, secure, and intelligent protection frameworks for future smart grids.

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