Transient grounding characteristics of a wind turbine foundation with grounding wires and plates

Lightning damages to facilities inside or in the vicinity of wind turbines become remarkably common. Most of the breakdowns and malfunctions of the electrical and control systems inside or in the vicinity of wind turbines are caused by ground potential rise due to lightning current flowing into the foundation with grounding electrodes and wires consisting of the wind turbine grounding system. To clarify the transient characteristics of the wind turbine grounding systems and to understand the mechanism of the breakdowns and malfunctions, we have carried out field tests. In this paper, the measurements and analyses of the transient grounding characteristics carried out at a wind turbine site are described.