Analysis of wind turbine structural loads under grid fault

New grid codes require wind turbines to ride-through grid faults. This poses great challenges for the design of both electrical system and mechanical structure of wind turbines. The purpose of this research is to illustrate the impact of a grid fault on the mechanical loads of a wind turbine. To study the structural loads of wind turbine under grid fault, a complete model including both mechanical and electrical parts must be constructed. A drawback of wind turbine simulation is that either a simple mechanical components is used with a detailed electrical model, or a simple electrical components with a detailed mechanical model is used, which could not provide a throughout insight on the structural loads caused by sudden disturbances on the grid. In this research, a proper combination of different simulation packages, namely FAST (Fatigue, Aerodynamics, Structures and Turbulence) and Matlab, is used to model the electrical and mechanical aspects of a wind turbine respectively. The effect of a grid fault on the wind turbine flexible structure is assessed for a typical fixed speed wind turbine, equipped with an induction generator. A set of simulations reflecting the structural dynamic response of a wind turbine to a grid fault are presented and analyzed.