Mating Control of a Wind Turbine Tower-Nacelle-Rotor Assembly for a Catamaran Installation Vessel

摘要

The assembly and installation costs of an offshore wind farm can approach20% of the capital expenditures; therefore, time eficient installationmethods are needed for installing offshore wind turbines. This studyinvestigates the feasibility of a novel wind turbine installation conceptusing a catamaran. The catamaran is designed to carry wind turbine assemblieson board and to perform installation using lifting grippers. Theinstallation of a rotor-tower-assembly onto a spar foundation is consideredwith a focus on the mating process of a tower-nacelle-rotor assembly.The spar foundation has been pre-installed at a representative site inthe North Sea, and the catamaran has thrusters regulated by a dynamicpositioning system. Numerical modelling of various components of theconcept are introduced. Time-domain simulations of the system are performedin irregular waves, and the relative motion and velocity betweenthe tower bottom and the spar top are analysed during the mating process.It was found that the active heave compensator can effectively reduce therelative heave velocity and the risks of structural damage during the matingprocess.