The lightning strike to the turbine blade will cause serious accidents and threaten safe operation of wind turbine. In this paper

a kind of novel lightning protection method is proposed and the surface discharge along blade due to lightning strike is directed to the receptor through the backside electrode. The lightning protection successful rate of the method is related to the surface discharge characteristics of the blade

therefore it is significant for improving effectiveness of the novel lightning protection method to study the influence of backside electrode on the surface discharge characteristics of wind turbine blade under lightning strike. Glass fiber/epoxy resin skin is adopted to simulate the actual structure of wind turbine blade

and the surface discharge morphology of the skin is observed by changing the size and position of backside electrode. The results show that the backside electrode will change the surface discharge morphology of the skin and increase the surface discharge length. The smaller the width and the longer the length of the backside electrode

the longer the length of the surface discharge. When the backside electrode is close to the lightning attachment point

and surface discharge can still be increased. While

when the backside electrode is far away from the lightning attachment point

the surface discharge is not increased any longer. The analysis indicates that the backside electrode influences the electric field distribution of the skin surface

enhances the process of secondary electron emission

thus leading to the increase of surface discharge length.