Expected wind turbine load estimation based on the wind field joint pdf constructed using the mixture Gaussian-EM algorithm

The stable boundary layer (SBL) is a stably stratified atmospheric layer that usually forms in the night over land when the earth cools as a result of a net loss of radiation[7]. The wind field characteristics in SBL distinctly differ from those in unstable boundary layer that forms in the daytime. Figures 1(a) and 1(b) show how the longitudinal wind speed and the wind direction change with the time. The variations in wind field characteristics accordingly affect the wind turbine responses such as extreme load, power output, and fatigue damage. Understandings in the wind field characteristics variation and the corresponding impacts on a wind turbine, therefore, very important not only for designing but also for managing a wind turbine effectively.