Insights and Challenges on the Protection of Grid-Forming Converter Interconnection Lines

This article demonstrates the challenges in protecting inverter-based resource (IBR) interconnection lines, assuming grid-forming IBR models are connected to conventional and inverter-dominated grids. In this context, the performance of traditional directional, phase-selection, and distance protection functions was evaluated. The PSCAD software was employed to model and simulate a typical system to interconnect IBRs to the transmission grid, producing a massive set of fault simulations on the IBR interconnection line. Finally, tests were conducted on a commercial relay employing a representative set of fault scenarios to validate the conclusions. The results highlight the particularities and challenges presented by grid-forming IBRs to conventional line protection functions and emphasize the importance of standardizations in grid codes worldwide to ensure the reliable operation of electrical power systems in the energy transition scope. Moreover, the studies support investigations to identify protection solutions for these systems.