Strength Assessment Procedure using Grid Strength Impedance Metric with PSCAD

With the growing integration of inverter-based renewable energy sources, modern power systems face increasing challenges in maintaining grid strength across a wide frequency spectrum. Traditional indices, such as the short circuit ratio (SCR), primarily assess grid strength at the fundamental frequency, which is inadequate for evaluating the impact of dynamic, power electronics-based devices such as inverters on grid stability. This limitation poses significant risks to the performance and reliability of consumer electronics, which depend on a stable and robust grid connection for seamless operation across various frequencies. This paper proposes a comprehensive procedure to assess grid robustness using the grid strength impedance metric (GSIM), which analyzes system stability across all frequency ranges, particularly in the context of consumer electronics integration. Through detailed PSCAD-based simulations of the Jeju Island power grid, we extract frequency-dependent impedances and evaluate grid strength both with and without the connection of Grid-Following (GFL) inverters. The results demonstrate that while grid strength is high at the fundamental frequency, potential instability arises at higher frequencies, especially when inverter output is at its peak. These findings underscore the importance of robust, frequency-wide analysis to ensure the reliable operation of consumer electronics in modern power systems.