Electromagnetic Analysis of Interconnected Groundings at Wind Farm

Abstract

Interconnection of the grounding system of wind turbines reduces steady-state grounding resistance, however, the transient behavior during a lightning strike to an interconnected wind turbine grounding system remains to be discussed. This paper investigates the influence of interconnection on the lightning surge response of wind turbine grounding system. Two different numerical methods, Numerical Electromagnetics Code (NEC-4) based on Method of Moments (MoM), and Virtual Surge Test Lab (VSTL) based on Finite Difference Time Domain (FDTD) method, are used for lightning surge analysis of wind turbine grounding systems. Comparison of results using NEC-4 and VSTL are made to clarify the usefulness of these methods for transient analysis of a large grounding system. The influence of soil parameters, front time of injected current, and the type of a conductor employed for interconnection, on the response of interconnected wind turbine grounding is discussed.