FastLE: a new load extrapolation method for site-specific wind turbines using the load distribution meta-model

Abstract. To ensure the safety of wind turbines at specific sites, IEC 61400-1 mandates the extrapolation of loads as a key requirement. Given the variability in wind parameters across different turbine sites, particularly in complex terrains, this task demands significant computational resources for simulations. However, the method recommended in the standard falls short of providing comprehensive assessments and rapid iterations necessary for all turbine locations in wind farm optimization designs. This paper presents a rapid load extrapolation method, named FastLE, which is based on a load distribution meta-model and tailored for specific sites. Based on 20 test cases, the blade root out-of-plane bending moment for a 50-year return period was calculated using both the International Electrotechnical Commission method and the FastLE method introduced in this paper. Through comparative analysis, the mean absolute percentage error is only 3.165 %, and the computation time for a single calculation has been reduced from 20 h to less than 1 s. The results show that the FastLE method can complete load extrapolation calculations for wind turbines in seconds with high accuracy. This makes it suitable for ensuring structural integrity during iterations of wind farm layout optimization or turbine type optimization, thereby reducing the safety risks associated with wind turbines.