On the Induced Currents to Wind Turbines by the Earth's Atmospheric Electric Potential: Experiments With Drones

Abstract

We live in an electrified atmosphere where a potential difference of about 250 kV is established between the ground and the ionosphere. The resulting potential gradient induces electric charges on the objects immersed in the atmosphere, which are more significant in tall objects. Several works have identified interferences to sensors in wind turbine rotor blades being attributed to electrostatic charging of blades. This paper presents a novel experiment using vertical wires lifted by a drone to study the currents resulting under fair-weather atmospheric conditions. Two current components are identified, one resulting in point/corona discharge and the other related to the movement. Based on the experimental results, a model for predicting induced currents on wind turbines is proposed, and estimates for thunderstorm conditions are made. The results presented in this paper are important for designing the electromagnetic compatibility measures to ensure the reliability of multi-megawatt wind turbines with blades equipped with active control systems and higher use of sensors.