Experimental Offshore Floating Wind Turbine Prototype and Numerical Analysis During Harsh and Production Events

Abstract

EOLINK have developed an innovative floating wind turbine in which the single tower is replaced by a set of legs providing a pyramidal architecture. A 1/10th scale prototype of EOLINK’s 12MW concept has been connected to the grid in April 2018 in France. Firstly, the paper describes the technical specifications of this device. Both the turbine and the floater have been designed using Froude scaling, in order to properly represent the EOLINK full scale 12MW concept. The device has been devised from scratch and deploys a Permanent Magnet Synchronous Generator (PMSG) and an individual electric blade pitch system. The patented mooring system comprises a single point mooring (SPM) system able to withstand very high tide ranges in shallow waters. Regarding monitoring, motions have been recorded using both an Inertial Measurement Unit (IMU) and high precision Global Positioning System (GPS) sensors. Mooring lines tensions have also been monitored. Wind is recorded using both an embedded anemometer on the floating turbine and onshore anemometers installed by IFREMER. This Institute has also measured wave height using a wave recorder. Secondly, experimental results during production and storm events are presented. The encountered environmental conditions highlight the capability of the EOLINK design to withstand harsh wind events, and its ability to produce 12MW using a small sized semi-submersible floater. Then, numerical analysis using FAST and Flexcom is compared with experimental results. Static analysis, decay-tests, Response Amplitude Operators (RAOs) and Power Spectral Densities (PSDs) results are detailed. Power production and the embedded control command capabilities are also presented.