Subsynchronous oscillations (SSOs) represent an emerging challenge for grid operators integrating increasing quantities of inverter-based resources (IBRs) such as solar, wind, and battery systems. While electromagnetic transient (EMT) simulations can capture these phenomena with high fidelity, they become computationally prohibitive for analyzing large-scale interconnected systems.
A new generalized dynamic phasor (DP) framework addresses this limitation by providing a scalable alternative that preserves the ability to analyze SSO behavior. The approach models grid-following and grid-forming IBRs using their respective dynamic phasor representations, while synchronous generators are represented with detailed multi-mass turbine models. This enables engineers to perform linearized analysis through eigen decomposition—a technique essential for identifying which oscillation modes pose stability risks and designing effective damping solutions.
The framework was validated against industry benchmark models and tested on a modified 68-bus system containing multiple IBRs and artificial intelligence data center loads. Results demonstrated the method's ability to characterize IBR-induced oscillation modes and compare mitigation strategies. Two solutions were evaluated: a decentralized damping controller optimized via particle swarm optimization, and switching problematic grid-following IBRs to grid-forming control configurations.
Notably, the research also examined how large computational loads—increasingly common as data centers expand—interact with grid frequency response characteristics and turbine dynamics. This is particularly relevant as AI computing facilities become major electricity consumers in some regions.
The dynamic phasor approach maintains sufficient accuracy while reducing simulation time substantially compared to full EMT studies, making it practical for planning studies and real-time analysis. By bridging the gap between computational efficiency and physical fidelity, this framework equips transmission planners and IBR operators with better tools for maintaining stability as the grid's composition fundamentally shifts toward converter-based generation.
