Load mitigation method for wind turbines during emergency shutdowns

Wind turbines experience countless shutdowns during their lifetimes. A shutdown is a transient process characterised by pitch-to-feather manoeuvre of three blades. Such pitch often collective, open-loop, and can substantially slow the rotor speed within several seconds. However, undesirable structural responses may arise because imbalanced aerodynamic loads acting on rotor. To address this issue, paper proposes method that actively adjusts individual rate each blade an emergency shutdown. This founded minimal intervention principle uses blade-root bending moment measurements as only inputs. The control objective to minimise differences in flapwise among blades Using high-fidelity aeroelastic model, we demonstrate controller performance under representative steady wind conditions with vertical shear. Compared baseline strategy, proposed effectively reduces maximum nontorque at main shaft tower bottom moment; reductions vary between 10% 40% investigated conditions. present work be further extended reduce fatigue damages or handle complex loading scenarios offshore shutdowns. • used inputs controller. An emphasis laid large shear imbalance. Aeroelastic simulations turbine various methods are performed. extreme moments shaft.