Extreme Response Prediction of a Multi-column Tension-leg-type Floating Wind Turbine Under Operating Conditions

摘要

The extreme response of a multi-column tension-leg platform (TLP) floating wind turbine (the WindStar TLP system) is analyzed here under operating conditions. Coupled dynamic response simulations are performed using FAST, a fully coupled aero-hydro-servo-elastic time-domain simulation tool. A land-based system (a U.S. National Renewable Energy Laboratory offshore 5 MW baseline wind turbine installed on land) is quantitatively compared with the WindStar TLP system. Extreme loads with different return periods are obtained by statistical load extrapolation. Peaks are extracted using peak-over-threshold analysis with time separation between peaks. The WindStar TLP system shows almost similar mean generator power output to the land-based system under operating conditions owing to its small dynamic motion responses to environmental loads. It shows greater characteristic load (blade I out-of-plane moment at the blade root and tower base fore-aft bending moment) under operating conditions than does the land-based system, with the characteristic load ratio reaching approximately 1.2. These results will help identify the extreme response differences between the two systems, and thus aid the development of relevant modifications to the initial WindStar TLP design.