Mooring System Design for the 10MW Triple Spar Floating Wind Turbine at a 180 m Sea Depth Location

Abstract

This works presents a methodology for the design of a mooring system for the Triple Spar floating wind turbine that supports the INNWIND 10MW wind turbine. The mooring system keeps the platform at the desired location and avoids the drift caused by wind, currents and nonlinear hydrodynamics. A semi-taut mooring system configuration, combining steel chain and polyester is chosen to reduce the cost. The basic configuration is defined using static equations and provides a smooth relationship between the restoring force and the displacement, to prevent snap loads. A dynamic analysis for the environmental conditions of the Gulf of Maine is performed to verify the performance of the design. The tensions on the lines are well below the maximum breaking limit for the different materials. Nevertheless, the chain weight can not be decreased as it provides the required mooring system stiffness. It has been verified that the polyester segment does not contact the seabed that could potentially damage it. The dynamic analysis also shows that the anchors do not experience vertical forces and the lines do not impact the platform heave plates. A complete load analysis must be performed to fully validate the proposed design.