Investigation On The Hydrodynamic Characteristics Of Semi-submersible Floating Platform For Offshore Wind Turbine

As an environmentally renewable resource, offshore wind energy has a promising future. The proposed and development of novel ?oating offshore wind turbine concept not only made the offshore wind energy be easily accessible, but also to large extent realized its exploitation. Semi-submersible platform for offshore wind turbine with small draught, good stability, convenient transportation and installation, low cost, is one of the preferred offshore ?oating wind turbine support structures.This article deals with the dynamic response characteristics of the Tri-?oater semisubmersible offshore wind turbine system in wind, wave and current environment by using SESAM software. Chapter I brie?y reviews and summarizes recent research progress of ?oating wind turbine foundations. Chapter II presents a numerical analysis method of the Tri-?oater wind turbine system’s dynamic response in wind, wave and current environment. Then, the following work was been carried out:In chapter III, the wave motion response of Tri-?oater system with no moorings and the dynamic response of Tri-?oater system with mooring lines, are veri?ed. The proposed numerical method is validated by comparing with the reference results.In chapter IV, the effects of mooring line parameters on the dynamic responses of the semi-submersible wind turbine system are analyzed. Then an optimization scheme is presented for the mooring line diameter, length, pre-tension and arrangement, which is lower cost.In chapter V, a sensitivity analysis of the Tri-?oater system parameters is carried out. Then, based on once-in-a-century metocean data in East and South China seas, a modi?cation scheme is presented for the draft and heave plate diameter of the original Tri-?oater system. Moreover, with the design standard for the ?oating wind turbine system, a mooring line design scheme is presented for such a modi?ed Tri-?oater wind turbine according to three different water depth conditions in East and South China seas. Finally, The dynamic responses of the modi?ed Tri-?oater are analyzed.Results show that, the scale parameter of heave plates has a great impact on the responses of ?oating wind turbine system. Reasonable choices of mooring line parameters will effectively control the dynamic response of system. The modi?ed Tri-?oater system improves the response performances signi?cantly in three different water depth conditions of East and South China seas. And the calculating results in time-domain coupled analysis further show, the modi?ed Tri-?oater wind turbine is able to meet operation demand under once-in-a-century extreme conditions.