融冰风机叶片的接闪特性试验

Experimental Study on Lightning Attachment Characteristics of the Ice-melting Wind Turbine Blades

风力发电机常遭受雷击、覆冰等灾害,严重影响风机正常运行。在叶片上加装电热融冰装置可有效去除叶片覆冰,但对叶片雷击概率以及原有防雷配置(接闪器加引下线)可靠性的影响尚不清晰。为研究融冰装置对叶片接闪特性的影响机理,设计了1:30缩比可旋转的3 MW融冰风机叶片开展长间隙雷击放电试验。试验结果表明雷电先导在叶片迎风面发展时,融冰叶片相比普通叶片更易发生接闪器失效、雷击融冰装置及叶身交界处的现象,最严重情况下接闪器保护效率仅为55%。搭建了融冰叶片电场分布模型,发现融冰装置改变了叶片表面原有电场分布,融冰装置与叶身交界处的电场畸变,更易产生电晕。同时叶片旋转使周围的正电荷以弧形分布,加速了融冰装置上方稳定先导的形成,使其更易遭受雷击,应当加强融冰装置处的雷击防护。所得结果为加强叶片雷击防护与融冰防护的深度结合提供了参考。

Wind turbines often suffer from disasters such as lightning strikes and ice coating,significantly impacting the normal operation of the turbines.The installation of electrothermal ice-melting devices on the blades can effectively re-move ice from the blades,but the impact on the lightning strike probability on the blades and the reliability of the original lightning protection configuration(receptors and down conductors)is not yet clear.To investigate the mechanism of the effect of ice-melting devices on the lightning attachment characteristics of the blades,a 1:30 reduced-scale rotatable 3 MW ice-melting wind turbine blade was designed for long-gap lightning discharge experiments.The experimental results indicate that when the lightning leader develops on the windward side of the blade,the ice-melting blade is more prone to have the phenomena of lightning receptor failure,and lightning strike at the junction of the ice-melting device and the blade body.In the most severe case,the protection efficiency of the lightning receptor is only 55%.A model of the electric field distribution on the ice-melting blade was established,revealing that the ice-melting device alters the original electric field distribution on the blade surface,causing distortion of the electric field at the junction of the ice-melting device and the blade body,making it more prone to corona discharge.Simultaneously,the rotation of the blade causes the surround-ing positive charges to distribute in an arc shape,accelerating the formation of stable leader above the ice-melting device,making it more susceptible to lightning strikes.Therefore,enhanced lightning protection measures are recommended for the ice-melting device location.The obtained results provide reference for the in-depth integration of lightning protection and ice-melting protection for turbine blades.