Voltage dips due to electrical grid faults generate transients of the generator electromagnetic torque which result in significant high stresses and noticeable vibrations for the wind turbine mechanical system. These events may also have a detrimental effect on the fatigue life of important drivetrain components. An electro-mechanical model is built to simulate the grid disturbances that easily excite the asynchronous generator poorly damped stator flux oscillations, which cause high transients of the generator electromagnetic torque. This article focuses in estimating the resulting significant stresses transients that may have a detrimental effect on the fatigue life of drivetrain system due to voltage dips. A rainflow cycle counting method for the stress history during the voltage dip event, analyses mean and amplitudes of the counted cycles, their occurrence moment and time of duration.
13th International Conference on Applied Mechanics 2011, 2011
Voltage dip; Electro-mechanical model; Drivetrai; Induction generator; Rainflow count; Fatigue