Risk of Lightning Strike to Wind Turbines for Maintenance Personnel Inside the Hub

Wind Turbines offer preferred impact spots to lightning, bearing high risks for humans being on or in the facility during a thunderstorm. Depending on the position of a person during the lightning strike to the facility, the risk varies. In case maintenance work is done inside the hub, people and electronics are protected against direct strikes because of the Faraday cage structure of the hub. Major phenomena that may be hazardous to humans inside the hub are induced voltages due to magnetic fields, step and touch voltages and shock waves. Control boxes that normally form a closed metallic shielding against lightning current and induced fields are usually open during maintenance, leaving the electronics unprotected. To specify the magnetic fields inside the hub, a method-of-moments simulation is used, validated by respective near field measurements. The measurements were performed using a 1.3 kA surge current that has been injected into the hub. As during real lightning strikes, currents up to 200 kA may occur, the numeric model has to be extrapolated taking nonlinear material effects of the hub’s cast iron into account.     «

Wind Turbines offer preferred impact spots to lightning, bearing high risks for humans being on or in the facility during a thunderstorm. Depending on the position of a person during the lightning strike to the facility, the risk varies. In case maintenance work is done inside the hub, people and electronics are protected against direct strikes because of the Faraday cage structure of the hub. Major phenomena that may be hazardous to humans inside the hub are induced voltages due to magn...     »