Effect of Shut-Down Procedures on Dynamic Responses of a Spar-Type Floating Wind Turbine

The design standards (IEC, DNV and GL) define a minimum set of combinations of external conditions and design situations as load cases. Like other design load conditions, the design situations relating to fault and shut-down events shall be addressed. Emergency shut down occurs in the presence of severe faults to prevent turbine damage. For pitch-regulated turbines, blade pitching to feather provides an effective means of aerodynamic braking. The blades are pitched to feather at the maximum pitch rate. This action exerts huge loading on the turbine and may challenge the structural safety. In this paper a 5-MW spar-type wind turbine is used as a case study. By using the HAWC2 code, the turbine pitch actuator fault and shut-down scenarios are simulated through external Dynamic Link Libraries. The shut-down scenarios are: normal shut down wit