Study on overvoltage of signal line in wind turbine by lightning strike

When lightning directly strikes a wind turbine, the transient overvoltage of the signal lines in the wind turbine would influence the operation of wind turbine. To analyze the lightning transient characteristics of the signal lines accurately, this paper established a simplified model of wind turbine using the nonlinear model of the grounding resistance in PSCAD/EMTDC, which takes into account the soil ionization characteristics, and a simulation is made. The results show that the overvoltage of the signal lines would be very high; the insulation layer in the bottom is the most vulnerable to breakdown. For this reason, this paper puts forward protective measures by installing surge protective devices (SPD) in the end of the signal lines, which can effectively reduce the overvoltage of the wind turbine and the signal lines. The overvoltage of the insulation layer would be far less than its withstanding voltage.