Development of a Wind Turbine Blade Surface Coating to Reduce Damage due to Lightning

Lightning strikes and near-strikes on wind turbine blades cost wind farm operators millions of dollars every year, representing one of their largest O&M risks and expenses, as well as a primary cause of turbine downtime (resulting in lost power production). These negative effects increase the levelized cost of wind energy. With the incidence of lightning strikes increasing as turbines get larger, improved lightning mitigation strategies are necessary to better control lightning effects on future machines. An innovative metal oxide gelcoat additive will be developed to work in conjunction with the traditional wind turbine lightning protection systems that includes lightning receptors near the tips and a large down conductor connected to ground. The material will minimize static charge buildup on the interior and exterior of the blade, reducing the gradual damage currently caused by frequent near-strikes. The new coating will encourage lightning attachment at the intended disk receptors, reducing the likelihood of blade punctures due to direct strikes. In this project, an innovative semi-conductive surface coating will be developed and demonstrated for reducing the damaging effects of lightning strikes and near- strikes on wind turbine blades. In step one, the physical characteristics of the surface coating will be investigated in a controlled laboratory environment. In step two, the ability of the coating to negate static charge buildup on representative blade materials will be tested along with multiple application methods of the coating. In step three, large-scale, high voltage experimental lightning testing will be conducted to demonstrate the benefits of static charge reduction and manipulating lightning attachment processes on a realistic blade shape.