Numerical and experimental investigation of a floating overhead power transmission system

A promising concept of floating offshore overhead power transmission system (FOPTS), in which the power transmission tower is installed on a TLP-type floating foundation, is investigated experimentally and numerically to study its feasibility. A numerical method is proposed in which the potential flow theory is used to evaluate the floating foundation hydrodynamics. The lumped-parameter method with a wake oscillator model is applied to the aerodynamic modelling of the overhead in order to determine the wind-induced motion and the corresponding internal force of the conductors. Multi-body simulations are performed in Simscape® by coupling the floating foundation hydrodynamics and the conductor aerodynamics. Wind-tunnel experiments on a simplified FOPTS model are carried out to study the coupled motion of the TLP tower and the overhead conductor. The proposed numerical method is validated by comparison of the conductor tension and motion to the experiment. Numerical simulations have been performed under realistic offshore environments based on the meteorological data of the Sea of Japan. Wind-wave misalignment effects on the structure of the FOPTS are investigated, and the safety of the conductors, the mooring lines, and the sea navigation are discussed.