Wavelet-based signal processing method for detecting ice accretion on wind turbines

This paper presents the performances of a new method for detecting ice accumulation on wind turbines. The presented method is based on constructing a multiresolution analysis (MRA) to extract frequency components present in the electric currents flowing out of an electric generator driven by a wind turbine. The foundations of the proposed ice detection method are established based on the fact that ice accumulation leads to a slow increase in the wind turbine inertia, which triggers pulsations in the electromagnetic torque of the electric generator. Such torque pulsations create certain frequency components that can be extracted from the direct and quadrature components of the electric generator output currents. The Daubechies db6 basis functions are selected for constructing the desired MRA that will extract the frequency components from the electric generator output currents. The MRA-based ice detection method is implemented for simulation and experimental testing for two types of electric generators driven by wind turbines. Simulation and experimental performances demonstrate significant capabilities for fast, accurate, and consistent detection of ice accumulation on wind turbines. Furthermore, these performance results show that the responses of the proposed method are insensitive to turbine specifications, wind speed, and/or generator type.