Experimental Emulation of Shutdown and Start-Up Procedures in Wave Basin Tests of a 15MW Floating Offshore Wind Turbine

Abstract Tests of floating offshore wind turbines (FOWT) conducted in wave basins usually focus on the behavior of the floater in waves and require proper emulation of the wind forces and effects of the turbine’s control system. Oftentimes, wind forces are applied to the model by means of an electromechanical device composed of several drone propellers, in an experimental approach known as Software-in-the-Loop (SiL). Such an approach allows not only the emulation of aerodynamics loads with constant or turbulent winds, but also to mimic transient stages of the system start-up and shutdown. The present work assesses a set of experimental results obtained for a 1:45 model scale of a semisubmersible floater supporting the IEA-15MW reference wind turbine, with emphasis on the dynamics during the turbine’s start-up and shutdown transient stages. A start-up control strategy was implemented in the SIL algorithm and tested in different environmental scenarios of waves and winds. Likewise, a shutdown control was also tested both with manual commands from a fictitious operator and automatically, in the latter case adopting a wind speed upper bound as the trigger for the shutdown procedure. No critical dynamic effects were observed during the transients, at least for the environmental conditions that were tested.