大气条件下雷击风机叶片初始流注区电场强度与临界长度研究

Research of Electric Field of Lightning Initial Streamer from Wind Turbine Blade and Critical Length Based on Atmospheric Conditions

通过利用有限元仿真软件COMSOL建模,计算下行先导发展过程中叶片尖端附近背景电势。基于临界长度判据,研究不同大气条件下雷击风机叶片初始流注区电场强度与临界长度,并分析临界背景电势。揭示初始流注区电场强度与临界长度影响叶片上行先导起始的机理,据此提出雷击风机叶片上行先导起始评价体系。此后深入分析大气条件对初始流注区电场强度与临界长度的影响。研究表明,当雷电情况不变时,不同大气条件下初始流注区电场强度与临界长度发生变化,导致临界背景电势改变,进而影响叶片上行先导的起始;大气条件变化使得初始流注区电离程度改变,从而影响初始流注区电场强度与临界长度,其中空气压强与温度影响较为明显,湿度影响则较小。相关结论为风机防雷基础理论研究提供有益参考。

With finite element simulation software COMSOL,this paper calculated background potential of wind turbine blade.Based on critical length criterion,electric field of lightning initial streamer from blade and critical length were studied under different atmospheric conditions,and the critical background potential was analyzed.The mechanism of initial streamer electric field and critical length affecting the upward leader inception from blade was revealed,thereby accordingly the assessment system of lightning upward leader inception from wind turbine blade was proposed.Moreover,the impact of atmospheric conditions on initial streamer electric field and critical length was explored.It is shown that when lightning conditions are constant,the initial streamer electric field and critical length change under different atmospheric conditions,leading to the change of critical background potential,which in turn affects the upward leader inception from blade.The change of atmospheric conditions makes the ionization degree of initial streamer zone different,which affects the initial streamer electric field and critical length.The influence of air pressure and temperature is more obvious,while the effect of humidity is smaller.The conclusions provide a useful reference for the theoretical research on wind turbine lightning protection.