Proposal of a Novel Semi-Submersible Floating Wind Turbine Platform Composed of Inclined Columns and Multi-Segmented Mooring Lines

Typhoon Resistance Analysis of Offshore Wind Turbines: A Review

A typhoon is a tropical cyclone in the western Pacific Ocean and the China seas. Typhoons are some of the most destructive natural disasters on Earth. In China, typhoons have had major impacts on the stability and structural integrity of offshore wind turbines in the complex and harsh marine environment. In this research, first, the main causes of wind turbine damage were analyzed based on the characteristics of a typhoon and a wind turbine structure for typical typhoon-induced accidents. Second, the research progress of the anti-typhoon design of offshore wind turbines and the anti-typhoon strategy of wind farms operation and maintenance was summarized. Finally, the problems to be further solved in these research fields were presented to provide references for the development of offshore wind turbines, in particular, floating wind turbines in typhoon-prone areas.

Research on the Dynamic Performance of a Novel Floating Offshore Wind Turbine Considering the Fully-Coupled-Effect of the System

Floating offshore wind turbines (FOWTs) still face many challenges in improving platform stability. A fully submersible FOWT platform with inclined side columns is designed to tackle the current technical bottleneck of the FOWT platform, combining the structural characteristics of the semi-submersible and Spar platform. An integrated numerical model of FOWT is established considering the fully coupled effect, and the hydrodynamic performance of the novel FOWT, the semi-submersible FOWT, and the Spar FOWT are compared and analyzed under different wave incidence angles and wave frequencies, as well as the blade and tower dynamic response of the three FOWTs under the coupling effect of wind, wave, and current. The results show that the novel floating platform can significantly optimize the hydrodynamic performance and has a better recovery ability after being subjected to external loads. The novel floating platform can significantly reduce the heave peak and its corresponding wave frequency compared to the semi-submersible platform, reducing the possibility of heave resonance. FOWT operation should ensure positive wave inflow as far as possible to avoid excessive wave forces in the lateral direction. Both blade and tower dynamic response are affected by rotor rotation and tower vibration to varying degrees, while tower dynamic response is mainly affected by platform motion. This study suggests that the application of the novel FOWT concept is feasible and can be an alternative in offshore wind exploitation in deep water.

Assessment of Wind Turbine Aero-Hydro-Servo-Elastic Modelling on the Effects of Mooring Line Tension via Deep Learning

As offshore wind turbines are moving to deeper water depths, mooring systems are becoming more and more significant for floating offshore wind turbines (FOWTs). Mooring line failures could affect power generations of FOWTs and ultimately incur risk to nearby structures. Among different failure mechanics, an excessive mooring line tension is one of the most essential factors contributing to mooring failure. Even advanced sensing offers an effective way of failure detections, but it is still difficult to comprehend why failures happened. Unlike traditional parametric studies that are computational and time-intensive, this paper applies deep learning to investigate the major driven force on the mooring line tension. A number of environmental conditions are considered, ranging from cut in to cut out wind speeds. Before formatting input data into the deep learning model, a FOWT model of dynamics was simulated under pre-defined environmental conditions. Both taut and slack mooring configurations were considered in the current study. Results showed that the most loaded mooring line tension was mainly determined by the surge motion, regardless of mooring line configurations, while the blade and the tower elasticity were less significant in predicting mooring line tension.