Rotor Speed Recovery Strategy for Inertial Response Control of Wind Turbine Generators Considering Turbulent Wind

Inertial response control (IRC) makes variable-speed wind turbine generators (WTGs) provide short-term frequency support during contingencies by releasing the kinetic energy stored in wind turbine rotors. When frequency support is terminated, the rotor speed should be restored to optimum for maximum power point tracking (MPPT). Existing IRCs utilize rotor speed recovery (RSR) strategies with a consistent power reference function. However, under real turbulent wind with alternate gusts and lulls, the consistent power reference function may fail to restore rotor speed or cause unexpected secondary frequency drop (SFD). In this regard, this paper proposes a novel adaptive RSR strategy that not only restores rotor speed via the aerodynamic power enhanced by wind gusts, but also stabilizes the turbine at wind lulls by tracking a suboptimal power curve. Experiments on a wind power-integrated power system testbed validate the proposed RSR strategy can successfully restore rotor speed while attenuating SFD under turbulent wind.