EMT Model Boundary Determination Using Floquet Theory-Based Participation Factors

To accelerate electromagnetic transient (EMT) simulations for power systems with inverter-based resources (IBRs), this paper proposes a new approach for determining the EMT model boundary using Floquet theory-based participation factors (PFs). The approach can significantly reduce the computational burden of EMT simulation to focus on a localized area whose components highly participate in the dynamics of interest such as sub-synchronous oscillations (SSOs), while the rest of the grid is represented using a simple Norton equivalent. Floquet theory enables the calculation of participation factors over a single cycle of the system in an EMT model, where the vector field exhibits periodic behavior around the synchronous frequency. A data-driven method is also proposed for estimating participation factors directly from the system's responses. The proposed EMT model boundary determination approach is first demonstrated on a two-area system and then validated on a 39-bus system with multiple IBRs.