Investigation of lightning strike effects on wind turbine critical components

Abstract

Wind energy is a renewable, pure form of energy that does not contribute on the environment pollution and in CO 2 , emissions and is inexhaustible. Wind turbines are usually located at high altitude areas as well as in flat terrains, where there is usually increased number of lightning strikes that could cause operational problems in a power plant. Lightning can be considered as current source and its main parameters are the peak current, lightning current steepness, charge transferred and specific energy which are linked with thermal, mechanical and electromagnetic effects on the affected structure or even live beings. In the current paper is simulated a large-scale wind turbine and is investigated the impact of a lightning strike on its critical components focusing on the blades, the nacelle, the tower and the base. The simulation is executed on a software platform that can extend conventional models of physics into models that solve simultaneously coupled physics phenomena. With the use of COMSOL software it is simulated a lightning strike which hits the surface of a wind turbine and is investigated its effect on many other critical points to understand the risk to which these are exposed and to prove the necessity of the design of a reliable lightning protection. It is presented the wind turbine model and the definition of physical and mathematical models in the simulated lightning simulation program environment. The assessment is based on specific and realistic scenarios and the simulation results are presented. The extracts are demonstrated either in 2D or 3D on the geometry of the wind turbine and at predetermined times. These will drive the proposal of a reliable lightning protection system for the wind turbine focusing on the most vulnerable points which are blade tips and the back of the nacelle. The simulation results show the importance of material continuity and limited changes in the conductors’ direction in order the reliable protection of the wind turbine to be ensured.