Adaptive short-time frequency support for doubly-fed wind turbines with enhanced frequency nadir and accelerated speed recovery

High wind penetration reduces system inertia and challenges frequency stability. This paper proposes an adaptive short-time frequency support strategy for doubly fed induction generators (DFIGs) that raises the frequency nadir during the support stage and accelerates rotor-speed recovery while mitigating the secondary frequency drop (SFD). Firstly, a rate of change of frequency based disturbance factor is introduced to adaptive scale the power-increment trajectory to the disturbance severity, and an exponential recovery trajectory is employed to smooth power withdrawal and prevent SFD. Secondly, under explicit wind turbine safety constraints, the strategy aims to maximize frequency nadir improvement while minimizing recovery time. The strategy is validated on an RT-LAB real-time platform across multiple load disturbances, wind penetrations, and wind speeds. Results show that, relative to existing methods, the proposed strategy increases the frequency nadir by up to 0.3Hz and shortens rotor speed recovery time by up to 18.8s, while preserving wind turbine operational safety offering practical insights for applications in high-renewable power systems.