风波联合作用下5MW海上风力机的疲劳载荷特性分析

Fatigue load characteristic analysis of 5 MW offshore wind turbine under combined wind and wave loads

海上风力机在风和波浪的联合作用下运行,受到风、波浪等产生的随机交变载荷作用,在设计寿命期间要受到超过108的载荷循环,风力机疲劳荷载特性是风力机设计的重要问题。文章以NREL 5 MW单桩式海上风力机为研究对象,采用IEC标准中Kaimal谱模拟风况、莫里森公式模拟海浪,建立海上风力机的动态模型,应用FAST软件研究风力发电机组在IEC疲劳工况下,正常发电、发电出现脱网故障、启动、正常停机的荷载特性,得到叶片、塔筒上的载荷分布等,研究风力机叶片、塔筒载荷变化规律,为风力机结构疲劳寿命损耗估算、优化设计提供可靠依据。

Offshore wind turbines operate under combined action of wind and wave. Due to the characteristic of random load caused by wind and wave, the wind turbine bears more than 108cycle loads so its fatigue is very important in wind turbine design. In this paper, Kaimal spectral and Morison formula in IEC standard are used to simulate wind and wave conditions. A dynamic model of the NREL 5 MW offshore wind turbine with monopole foundation is established in FAST. The fatigue load characteristics of wind turbine generator system are studied in the modes of IEC design load cases such as power production,power production plus occurrence of fault,start up,normal shut down. The load and its distributing of the tower and blades are analyzed. The results provide a reliable basis for the optimal design and estimation of fatigue life of wind turbine.