Study On Mooring System Of Floating Offshore Wind Turbine Platform

With the development of wind energy utilization and the technologies’ mature, windpower as a sustainable clean energy is becoming an integral part of China’s energydevelopment strategy. The development and utilization of offshore wind power has greatsignificance to solve the densely populated coastal areas.In recent years the use of offshore wind power generally concentrates in the coastal sea.With the development of offshore resources, due to geographic and environmental constraintsof offshore waters, the use of wind power is bound to go deep-sea development. Because piletype of wind turbine foundation most applicated in shallow water can not meet thedevelopment requirements of deep-sea, offshore floating wind turbine fixed foundation fixeddevelopment will become floating foundation. Due to the complexity of the interactionsbetween offshore wind turbines floating foundation and mooring system, in the study of themooring system, there are still many urgent problems needed to solve. In this paper, wedesign a kind of foundation for5MW wind turbine, the main research contents are as follows:Based on the summarized the design process of the floating structure, a kind offoundation for5MW wind turbine is designed. By comparing the hydrodynamic performanceand economy, an optimal design is chosen. And then the mooring system of this foundation isanalyzed.The hydrodynamic performance of the platform is calculated and compared by twomethods: three-dimensional flow theory and Morrison formula. The response curve and thenatural period are substantially the same. But the amplitude of the response calculated by theMorrison formula is significantly less than that calculated by the three-dimension flow theorydue to the inclusion of the viscous force.The hydrodynamic performance of different center of gravity height and different waterdepth are calculated and compared. The discipline of this change impact on the hydrodynamicperformance is achieved.Base on the calculation of the environment load of the platform, the preliminary designand the time domain simulation in3hours are conducted. The complete state and damagedstate results meet the safety requirements according to the relevant specifications of the offshore platform.The displacement and tensile of the mooring system are calculated and compared due tothe following factors: different pre-tension, different fairlead position, different arrangementof the fairleads and different length of the wire rope. The discipline of the impact of thesefactors is then studied, which could be the basis for the design and optimization of theselection of the mooring system for the offshore wind turbine floating foundation.