High-fidelity modeling framework of grid-forming inverter-based resources to improve dynamic stability of future Japanese power system

Renewable energy sources (RES) like wind and solar, along with storage systems commonly termed as inverter-based resources (IBRs), are important in achieving energy transition. Although IBRs offer environmental benefits like CO2 reduction, IBRs introduce challenges particularly in regions with high-RES penetration. Issues like reduced system inertia, limited short-circuit current contributions, and system congestion are emerging. Currently, Japan plans to install HVDC lines by 2030 to transfer power from Hokkaido to mainland regions, leading to a projected System Non-synchronous Penetration (SNSP) of 62%. However, this integration may exacerbate grid stability issues. To address these challenges, this paper proposes a high-fidelity modeling framework that includes grid-following (GFL) control for existing IBRs and grid-forming (GFM) control for future systems. This proposed approach includes flexible synchronization, virtual inertia support, oscillation damping, and fast current control, allowing adaptation to large disturbances. As a numerical case study, this paper introduces a study on 113-bus synthetic grid model of Hokkaido area, constructed from publicly available data, in MATLAB/Simulink capable of executing time domain and frequency domain analysis within RMS simulation framework. The simulation predicts a possible instability under increased SNSP with GFL-controlled IBRs. Strategic integration of GFM IBRs significantly improves stability, offering a solution for resilient grid operation in future with high-RES penetration.