风电机组叶片雷击风险分布特征

Distribution Characteristics of Lightning Strike Risk Along Wind Turbine Blades

风机叶片极易遭受雷击损伤,严重威胁风电场安全稳定运行。该文基于自洽先导起始发展模型,提出雷击叶片表面任一位置计算方法,建立叶片下行雷击风险分布计算模型。定义地面雷击截收区域和临界叶尖保护失效雷电流,考虑雷电流幅值、叶片旋角和叶片长度,计算不同装机容量叶片雷击风险分布。结果表明,叶尖保护范围随雷电流幅值的降低而降低;临界叶尖保护失效雷电流随叶片旋角的增加而减小。靠近叶尖区域的雷击风险随叶片长度的增加而减小。该文将叶片划分为Z1、Z20和Z21区域,分析不同区域叶片雷击击穿过程,建议对不同区域进行差异化雷电防护。

Wind turbine blades are exposed to lightning strike damages,thus seriously threatening safe and stable operation of wind farms.Based on self-consistent leader inception and propagation model,in this paper,a calculation method for any position along wind turbine blade by lightning strike is proposed,and a model for the distribution characteristics of downward lightning strikes risks along wind turbine blade is established.The lightning collection area on the ground,and the critical lightning current for shielding failure of the blade tip are defined.Considering lightning current amplitude,blade orientation angle and blade length,the lightning strike risk distributions of wind turbines blades with different capacity are calculated.It is found that the shielding range of blade tip decreases with the reduction of the lightning current amplitude;the critical lightning current for shielding failure of the blade tip decreases with the increase of blade orientation angle;the lightning strike risk of blade tip decreases with the increase of blade length.The blade could be divided into three zones named Z1,Z20 and Z21 according to the blade structure and lightning strike risks.Lightning strike breakdown processes in different lightning strike risk zones are investigated.Therefore,a differentiated lightning protection method is recommended for different lightning strike risk zones of the blade.