Conceptual design, parameter optimization and performance investigation of a 10MW semi-submersible floating wind turbine in shallow water

Abstract

There is lacking of floating wind turbine supporting large wind turbine, i.e. 10 MW, aiming at shallow water applications. In this paper, a 10 MW semi-submersible floating wind turbine named OUCwind is proposed for shallow water, and a scale optimization procedure is proposed during the preliminary design stage. It offers an engineering-practical method to determine the main parameters of a new-proposed floater, and critical floater characteristics, such as floater stability, natural period, platform mass etc. are chosen as important design criteria. The hydrodynamic performance with different scale parameters are investigated and it is found that enlarging distance between columns is a cost-effective way to get better stability and hydrodynamic performance. The structural performance of the new-designed OUCwind floater are compared with other two well-known braceless 10 MW platforms, 10 MW-CSC, and OO-star. From the frequency-domain analysis results, the surge linear transfer function, mean drift force and quadratic transfer function near the surge natural frequency of OUCwind is relatively small compared with other two platforms. In the time domain, the new-designed OUCwind also performs better in surge motion and mooring line tension response compared with 10 MW-CSC and OO-star, especially under extreme condition. Nevertheless, for the heave and pitch motions, the wave-frequency response of the OUCwind platform is relatively large under extreme load conditions.