Lightning surge response of wind turbine grounding at low resistivity soil

Accidents caused by natural phenomena such as lightning are serious problems for the diffusions of wind power generations. To exploit high wind conditions, wind turbine generators are often constructed along the seashore where few tall structures exist; therefore, they are often struck by lightning. Most of the breakdowns and malfunctions of the electrical and control systems inside wind turbine due to lightning are caused by the voltage rise of the grounding system. At a disposal site like seashore where the resistivity of soil is very low, the voltage rise at grounding at the wave front typically becomes larger than that of the steady state because of the inductive behaviour of the grounding system. Voltage rise at grounding of wind turbine due to lightning at a disposal site are computed using electromagnetic analysis approach, and designing of proper grounding system at low resistivity soil is discussed. Finite Difference Time Domain (FDTD) method is used for electromagnetic analysis. Designing of grounding system of wind turbine at a disposal site is discussed.