On the analysis of lightning response of interconnected wind turbine grounding systems

This paper deals with the use of the transmission line approach to analyse the transient behaviour of isolated and interconnected grounding systems of wind turbines under lightning discharge. The effects of the soil resistivity as well as the grounding systems interconnection type (cascade and closed) have been studied. As main results, the interconnection leads to a decrease of the impedance and consequently on the transient potential of the grounding systems. This decline is accentuated for high soil resistivities where the discharge current requires a larger system to fast dissipate current into the ground. Also, it is shown that the closed grounding systems are more suitable than the cascade ones.