风力发电机雷击次数的改进计算模型与方法

Improved calculation method of annual lightning flash number for wind turbine

随着风能在中国能源比例中的持续增长,对风力发电机可靠性的要求变得越来越高。因此,风力发电机的防雷保护已成为重要课题。准确的风电发电机雷击次数是确定合理防雷措施的前提,针对现有IEC风机年雷击次数计算公式存在的问题,利用蒙特卡洛方法计算不同引雷半径公式下的风机下行雷击次数;同时借鉴Rizk提出的高层建筑物上行雷击次数计算模型,应用于风机上行雷击次数计算。仿真分析结果表明:风机下行雷击次数和上行雷击次数均随风机高度增加而增大,下行雷击占总雷击事件比例随风机高度增加而下降;IEC公式计算得到的风机年雷击次数偏大,改进后的年雷击次数计算方法较为符合实际观测情况,可为风场防雷分析提供可靠依据。

With the increasement of wind power generation,reliability of wind turbine becomes more and more important. Lightning protection of wind turbine has become a hotspot recently. Accurate annual lightning flash number determination is on the premise of proper lightning protection measurements. The formula for the number of lightning flashes according to IEC was introduced and its problems were also analyzed. Combined with the rotation of wind turbine blades,the annual number of lightning flashes under different equivalent attractive radius formulas was calculated by the means of Monte Carlo simulation.Model proposed by Rizk for assessment of lightning stroke incidence in high building was applied to calculate the number of upward flashes for wind turbines. The simulation results show that the annual number of downward flashes and upward flashes both increase with the height of the tower,while the percentage of the downward flashes decreases. The calculation method proposed in this paper is in good agreementwith actual situation compared with the IEC formula,which could provide reliable evidence for lightning protection in wind farms.