Research Of Motion Performance And Mooring System Response Of TLP Floating Wind Turbine Under The Wind Current And Wave Combined Effect

Compared to onshore wind energy,offshore wind energy which has the advantages of long generation time and high wind resource quality,is a hot spot in wind energy development.But the energy of inshore wind resources is relatively small to the deep sea,and restricted by various factors such as route planning.Therefore,the technology of offshore floating wind turbine for deepwater has become the main research direction of offshore wind energy.However,the floating offshore wind turbine is affected by the complex loads from wind,wave,and current and these loads play an important role on the system.It is a difficult problem that how to calculate the coupling motion of the floating wind turbine system accurately.So,this paper studies the motion and mooring forces of the TLP floating wind turbine system under the complex environment load conditions,by using FAST and AQWA.The research is instructive for the optimization design of the wind turbine and the floating base of the TLP floating wind turbine system.The aerodynamic loads of wind turbine are calculated by FAST codes,based on the unsteady momentum theory of blade element.The wave loads are calculated by AQWA software,based on three-dimensional potential flow theory and the current loads are calculated by empirical model.Using Fortran to modify the FAST codes,so that it can call the hydrodynamic result calculated by AQWA to carry out the movement of floating wind turbine.Using the NREL5 WM wind turbine and the DeepC-Semi semi-submersible platform as an example,the calculation results are compared with the experimental data to verify the feasibility and accuracy of the calculation method.At last,the method is used to analyze the motion and mooring system of TLP FOWT under different working conditions.The study shows that the results of the new coupling method are in good agreement with the experimental data.For the TLP: Under operating conditions,the current loads have little effects on the motion of the system and the mooring system.Surge and heave are dominated by the low-frequency wind loads and wave loads have an important impact on pitch.Both wave and wind loads dominate the force of mooring system.Under extreme conditions,surge,heave and pitch are dominated by wave loads.Sum-frequency wave force plays a significant role in anchoring system.The research results provide some guidance for the structure optimization design of floating wind turbine.