Analyzing the Effect of Lightning Channel Impedance on the Induced Overvoltages in Wind Turbines

Lightning is a natural phenomenon that can cause serious damages in power systems including wind farms. Wind Turbines (WTs) are tall structures and are often installed in areas with high lightning activity levels which makes them exposed to direct strike. One of the parameters affecting the lightning performance is the impedance of lightning channel. In this paper the effects of this impedance on the induced overvoltage in wind turbines is investigated. The case study is carried out on a WT with 2 MVA of rated power where direct lightning strike with maximum current magnitude of 50kA is struck to the WT. The results of different scenarios are compared, and it is shown that as the value of lightning channel impedance gets higher, the overvoltage caused by the corresponding lightning strike, with the same current magnitude, increases too. This shows the importance of the lightning channel impedance's effect on high-voltage studies of WTs, as it can help in selecting proper lightning protection devices.