Dynamic Response Analysis Of A Dual-module Semi-submersible Offshore Wind Turbine System Under Operation And Dismissing Conditions

To make the economy sustainable,green renewable energy has become the direction of energy development in all countries.As of 2019,wind power has accounted for 16%of the total global renewable energy generation.Although offshore wind power started late,it has developed promptly in the last few years around the world due to its stability and high power generation characteristics.Offshore wind power generation methods are divided into fixed and floating types.The fixed type has been industrialized and has low cost and is widely used.The floating type is vigorously developed in various countries,but the cost is high,and it is still in the development stage from basic research to verification experiment.Due to the influence of sea wind and waves,the installation of floating platforms is generally difficult.Not only that,the floating platform itself cannot be reused,which also leads to a waste of resources.If the floating platform can be reused and the wind turbine only needs to be replaced after the wind turbine fails,the overall cost will be highly reduced.Therefore,this article exploratively proposes a modular semi-submersible wind turbine integrated structure composed of semi-submersible modules and 5MW wind turbine modules.This integrated structure can better reduce the cost of offshore wind power and realize the reusable use of resources,thereby better alleviating my country’s land and energy pressures.The main research content and results of this article are as follows:(1)Propose a preliminary conceptual design plan for a new type of semi-submersible dual-module offshore wind turbine platform,and preliminarily draw up the displacement and design parameters.The system mainly includes a semi-submersible platform module and a fan module,and the two modules are fixed by a clamping device.The hydrodynamic and mechanical coupling effects between the two modules are considered,and a simplified numerical model is established.(2)A comparative analysis of the hydrodynamic response of the dual-module integrated structure and the conventional semi-submersible platform structure shows that the dual-module integrated structure can effectively reduce the pitch response of the semi-submersible module without significantly increasing the force of the anchor chain.(3)The removal process of the wind turbine of the new semi-submersible dual-module offshore wind turbine platform was simulated,and we analyzed different parameters’influence.The results show that when the dismantled ship is on the wave-facing side of the platform(position A)is the best relative position;when the Fender stiffness is 3×10~8N/m,the data is the best;the wave period will affect the relative displacement and collision between the two modules The best wave period is 6s～9s;the increase of wave height will adversely affect the demolition work.It is not recommended that the wave height of the demolition sea state exceeds 2.0m;comparing the simulation results of the three wind and wave combined sea states,it is not recommended to dismantle the system in sea conditions where the wind speed is above 8m/s.