Accumulation characteristics of precipitation static on rotating wind turbine blades and its influence on the lightning attachment characteristics

Abstract

The linear velocity at the tip of large wind turbine blades can reach 100 m/s, generating static electricity through friction with airborne particles. However, the accumulation characteristics of precipitation static on the blade surface and its impact on the lightning attachment characteristics are rarely reported. The authors constructed a platform for measuring charges on rotating wind turbine blades and employed the electrostatic probe method to obtain the accumulation characteristics of surface charges under different environmental conditions. The experimental results show that positive charges accumulate on the blade surfaces, peaking at 0.69 μC/m² under experimental conditions. The charge density is positively correlated with airborne particle concentration and blade rotation speed, while it is negatively correlated with relative air humidity. Additionally, the authors developed a model of the electric field distribution on wind turbine blades considering the effects of precipitation static. Simulation results indicate that the electrostatic field induced by precipitation static weakens the field strength in the vicinity of receptors, reaching a minimum of only 38% of the original strength, thereby increasing the probability of lightning protection failure. The findings provide an effective supplement to the lightning attachment mechanism of rotating wind turbine blades.