Voltage Sag Impact on Wind Turbine Tower Vibration

In order to study the voltage sag impact on mechanical vibration of wind turbine structure a detailed model that considers all three electrical, mechanical and aerodynamic aspects of the wind turbine must be considered. A drawback of many works in the area of wind turbine simulation is that either a very simple mechanical model is used with a detailed electrical model or vice versa. Hence the effects of interactions between electrical and mechanical components are not accurately taken into account. In this paper, three simulation programs - TurbSim, FAST, and Simulink - are used to model the wind, mechanical and electrical parts of a wind turbine, and its controllers in detail. Simulation results obtained from the model are used to observe the interaction of all three factors affecting the operation of a wind turbine system. Especially, the voltage sag impact on tower vibration is investigated, considering different power system characteristics (i.e. short circuit level (SCL) and X/R ratio), and wind turbine operating conditions.