Determining the Relationship between Required Frequency Response Reserves and Short Circuit Capacity of Renewable Energy Sources Location via KEPCO Power System

초록

As power systems shift toward inverter-based resources (IBRs), maintaining stability depends on both total available inertia and system strength. This paper addresses frequency security by determining the required frequency response reserves (FRR) as an explicit function of the short-circuit capacity (SCC) at the renewable interconnection bus. For a fixed contingency, lower SCC at the connection point increases the required FRR and raises the secure operating level of inertia (SOLI); conversely, higher SCC reduces both for the same event. We show that, for a fixed contingency and nadir standard, lower local SCC at the renewable interconnection bus systematically increases both the required FRR and the SOLI. This SCC–FRR formulation enables system operators to set region-specific FRR targets and to assess the impact of renewable siting in weak versus strong areas without changing the underlying frequency-security standard. We substantiate this with a regional analysis on KEPCO’s system, using data-driven operating snapshots and dynamic frequency simulations for three areas with different SCC and renewable siting patterns. The results reveal local system strength differences across areas and demonstrate that relocating renewable connections alters FRR needs and shifts SOLI in proportion to local SCC. Jeonnam needs approximately 14–23% higher SOLI and 28–45% more FRR than other areas under the same nadir criterion. © 2013 IEEE.

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