Damage detection in wind turbine blades using time-frequency analysis of vibration signals

The dynamic behavior of modern multi-Megawatt wind turbines has become an important design consideration. One of the major aspects related to the reliability of operation of the turbines concerns the safe and adequate performance of the blades. The aim of this paper is to develop a time-frequency based algorithm to detect damage in wind turbine blades from blade vibration signals. It is important that damage to blades is detected before they fail or cause the turbine to fail. A wind turbine model was developed for this paper. The parameters considered were the rotational speed of the blades and the stiffness of the blades and the nacelle. The model derived considers the structural dynamics of the turbine and includes the dynamic coupling between the blades and the tower. The algorithm developed uses a frequency tracking technique. Numerical simulations have been carried out to study the effectiveness of the algorithm.