Multi-Timescale Reduced-Order Modeling of Direct-Drive Wind Turbines for On-Demand Simulation Across Diverse Grid-Integration Scenarios

• • The AC current timescale reduced model achieves approximately 5–6× simulation speedup relative to the full-order model while reproducing fast current and voltage transients with steady-state consistency, directly enabling large-scale wind farm electromagnetic transient studies that would otherwise be computationally intractable. • • Six discrete timescale tiers—switching, AC current, mid-frequency, DC voltage, rotor speed, and operational—are explicitly mapped to dominant physical components and critical state variables, eliminating the ambiguity in model selection that previously forced engineers to choose between over-simplified controlled current source models and full-order representations. • • Trajectory sensitivity analysis identifies key components for retention within the target timescale, while slow variables are handled via steady-state consistency constraints; this structured reduction yields models that maintain fidelity in the dominant dynamic range without the empirical threshold tuning required by local switching approaches. • • The rotor speed timescale model accurately describes power transient evolution under conditions involving rotor inertia and slow-variable regulation, confirming that the framework extends beyond fast electromagnetic transients to electromechanical and operational timescales relevant for frequency response and stability assessment.