Impacts of IBRs on Conventional Protection Functions and Emerging Alternatives

The increasing penetration of Inverter-Based Resources (IBRs) is profoundly transforming the classical electromagnetic behavior of modern power systems. Conventional protection schemes, historically designed around high fault currents, predictable sequence components, and the electromechanical characteristics of synchronous generators, are increasingly challenged in this new operating environment. The current-limiting behavior of IBRs, combined with their control-driven dynamic response, compromises fundamental assumptions underlying overcurrent, distance, directional, and sequence-based protection. As a result, traditional relays may experience underreach, overreach, false tripping, loss of directionality, or complete insensitivity to faults. These effects have been observed in recent…