Electrostatic model to understand the influence of salt deposit in gfrp material during lightning discharges

Abstract

A methodical experimentation and mathematical modeling is carried out to study the influence of salt deposit on wind turbine blade material (Glass Fiber Reinforced Plastics/GFRP) during lightning discharges. Electrical discharge measurements combined with optical emission spectroscopy technique and electrostatics is utilized to understand the dynamics of surface discharge and the level of damage on GFRP material. COMSOL simulation studies shows that the electric field intensity on the surface of the polluted GFRP gets enhanced when compared to that of virgin GFRP, irrespective of the applied voltage profile and polarity. Flashover voltage, discharge current and optical emission spectroscopy measurements indicates that the deterioration of GFRP material is severe when there is an adhesion of salt deposit. It is also observed that the damage induced on GFRP material is severe for winter lightning (switching impulse voltage of 250/2500 μs) compared to that of summer lightning (lightning impulse voltage of 1.2/50 μs) due to a longer front and tail period of the pulse.