The present study aims to address the knowledge gaps in dynamic power cable designs suitable for large floating wind turbines and to develop three baseline power cable designs. The study includes a detailed database of structural and mechanical properties for three reference cable models rated at 33 kV, 66 kV, and 132 kV to be readily used in global dynamic response simulations. Structural properties are obtained from finite element method (FEM) models of respective cable cross-sections built in UFLEX v2.8.9—a non-linear stress analysis program. Extensive mesh sensitivity studies are performed to ensure the accuracy of the predicted structural properties. The cable’s structural design is investigated using global response simulations of an OC3 5MW reference wind turbine coupled with the dynamic power cable in a lazy wave configuration. The feasibility of the present reference cable in floating offshore wind applications is assessed through a simplified analysis of cable fatigue life and structural integrity analysis of the cable in extreme environmental conditions. The analysis results suggest that the dynamic power cable does not significantly affect the response characteristics of the floating wind turbine in the analyzed lazy wave configuration. Furthermore, a simplified fatigue analysis demonstrates that the proposed cable design can sustain representative environmental loading scenarios and shows favorable dynamic performance in a lazy wave configuration.

An integrated offshore wind and wave energy system is an attractive concept in areas with abundant wind and wave energy resources. The sharing of supporting platform and facilities, e.g., mooring systems, offers significant cost savings. This will effectively lower the levelized cost of energy (LCOE). In the present study, a conceptual design consisting of a braceless semi-submersible floating horizontal axis wind turbine (FHAWT), three flap-type wave energy converters (WECs), as well as a torus (donut-shaped) point absorber-type WEC is proposed. The flap-type WECs harvest wave energy through the flap motion caused by oscillating wave surge, while the torus WEC absorbs wave energy generated from its heaving motion. The absorbed mechanical power of the power take-off (PTO) systems is calculated based on linear damping forces and the motions of the WECs relative to the supporting platform. Hydrodynamic interaction between the WECs and the supporting platform is considered by including the coupling terms in the added mass and potential damping coefficient matrices. A fully coupled aero-servo-hydro-elastic numerical model of the concept is constructed. The feasibility study of the concept is carried out using time-domain simulations. Only operational environmental conditions are simulated based on simultaneous wind and wave hindcast data of a selected offshore site. The effects of the WECs on the wind turbine, platform motions, and WEC power take-off are examined. Based on the power performance of WECs, recommendations are also provided for optimum power absorption.