Modeling Lightning Current Distribution in Tower Base of Wind Turbine

Wind power generation has expanded rapidly worldwide over the past 15 years. Europe's wind farms generated 458 TWh of electricity in 2020 and total wind energy capacity exceeded 220 GW [1] (88% onshore and 12% offshore). This covered about 16% of the electricity demand in Europe (EU27+UK) and 27% in Germany. Therefore, a reliable and safe operation of wind turbines (WT) is becoming evermore crucial. Especially high requirements are set for their lightning protection system, since due to their height and open unshielded locations WTs are assessed as very exposed structures to lightning. Most of the breakdowns and malfunctions of the electrical and control system of WT are caused by a ground potential rise (GPR) due to lightning. To investigate this issue in more details, the field measurements were carried out at the specific WT in Japan and a corresponding numerical model was designed for analyzing of lightning current distribution within the WT and arose dangerous overvoltage for electrical equipment without and with overvoltage protection measures at the tower bottom based on installation of surge arresters (SA) due to different lightning components.