Time Domain Analysis Of Motion Response And Mooring Tension Of Semi-submersible Offshore Wind Turbine Platform

Wind energy is a renewable energy that is undergoing rapid development.Traditional wind power comes from onshore wind farms.However,the large population on the land and the lack of cheap land.However,the vast sea area has stronger and more stable wind energy that can be used by wind farms.Therefore,it is necessary to build offshore wind farms.Now,the foundation of offshore floating wind turbine platforms mainly includes four types: semisubmersible,tension leg,barge-type,and Spar.Among them,the semi-submersible wind turbine platform has good stability,is suitable for different water depth ranges and is convenient for construction and transportation,which has always attracted attention.Based on the AQWA software,this paper uses the parameters of the NREL 5 MW offshore wind turbine to independently design the foundation of the semi-submersible wind turbine platform,studies the motion response of a semi-submersible offshore wind turbine platform under maximum operating conditions and extreme load conditions and the time-domain changes of mooring tension under the combined action of wind-wave-current.Study the influence of wave and current at different angles,wave deformation in current on the motion of semi-submersible wind turbine platform and mooring tension,when the wind and waves are in the same direction.In addition,this paper also studies the effect of different mooring arrangements on the motion response and mooring tension of offshore floating wind turbine platforms influences.The results show that when the wave height increases under the action of the current,the heave of the offshore floating wind turbine platform also increases.Compared with waves and currents in the same direction,when the waves and currents are opposite,the surge PSD and heave PSD are both increase,but the frequency of the peak PSD is different.When the wave and the current intersect obliquely,the propagation direction of the wave will be changed,but the influence on the motion response of the structure is not obvious.The current has a great influence on the tension distribution of each mooring line.Waves have the least influence on the tension distribution of each mooring line.The angle between the mooring lines has little effect on the motion response of the platform.When the number of mooring lines is larger,the motion response is smaller,and the mooring tension is smaller.The larger the mooring radius,the greater the platform’s motion response and the smaller the tension of the mooring line.These results provide a reference plan for the optimal design of the mooring arrangement of offshore structures.