Transient overvoltage phenomena on the control system of wind turbines due to lightning strike

This study proposes a simulation process for lightning protection. In addition, it analyzes and proposes lightning protection methods by simulating the effects of transient over-voltage on the control system that occur when lightning directly strikes a wind turbine. This study used Electro Magnetic Transient Program/Alternative Transient Program (EMTP/ATP) to build a lightning model and a tower-control line model according to actual wind turbine structures and local lightning characteristics in Taoyuan, Taiwan. Various lightning strikes and ground resistances were simulated with consideration to whether the tower and the control system were individual or interconnected ground systems to observe transient phenomena in the control line. The transient over-voltage of the insulating layer and conductor of the control line, and the coupling voltage between the control line and the tower were analyzed based on three simulation cases to propose lightning protection methods that are applicable to Taoyuan. Consequently, an applicable lightning protection method for wind turbines was developed according to requirements of the different installation sites, and the lightning information and a decision maker were used to estimate the degree of protection. Specific proposals can be made using the method proposed in this study, avoiding waste in lightning protection.