Equivalent equation of earth resistance for ring electrode of wind turbine
Earth resistance is a one of the most important issues for wind turbine lightning protection. Although various equations have been proposed to simulate earth resistance, it is still difficult to accurately estimate an actual wind turbine earth impedance because of its complex shape combined with a concrete foundation, auxiliary vertical and ring electrodes. This report clarified how the shape and size of the foundation and the auxiliary electrodes affects to the earth resistance using FDTD (Finite Difference Time Domain) calculation. An equivalent equation to practically simulate wind turbine earthing can be proposed with some correction parameters and improved conventional equations.