Study on the aeroelastic response of wind turbine blades with pitch system failure and strategies for typhoon resistance

The wind turbine with faulty pitch control system is unable to complete the pitch adjustment before the typhoon. The blades are exposed to extreme aerodynamic loads, which can result in blade failure. Currently, there are few proactive wind-resistant strategies for wind turbines with pitch system failures. In this paper, blade aeroelastic numerical simulations of the NREL 5 MW wind turbine in the typhoon environment are performed based on the CFD-FEM two-way fluid-structure coupling methods, and the blades are designed with composite layups, and the shutdown strategy for active typhoon resistance is proposed. It is found that by changing the yaw angle of the wind turbine can significantly and effectively reduce the wind load on the blades, reduce vibration of the blade tips, and improve the stress concentration on the wind turbine blades. Compared with the wind turbine without any active wind measures, the wind turbine active yaw can effectively reduce the load by more than 90%, and the blade tip displacement in all directions can be reduced by a maximum of 75%. Then the effects of blade stopping azimuth on blade aerodynamic load, blade deformation and dynamic response after wind turbine yawing 90° are discussed. Finally, it is summarized that the optimal stopping form of wind turbine with pitch system failure in typhoon environment is obtained, which can ensure the safety of wind turbine more effectively.