Wavelet Energy Transmissibility Function and its Application to Wind Turbine Bearing Condition Monitoring

Condition or health monitoring techniques and methods have been widely used for engineering systems fault detection and diagnosis. However, there is a major challenge with monitoring the systems operating under time varying loadings especially when the system loads are unknown or hard to measure. To address this problem, a new concept, wavelet energy transmissibility function (WETF), is proposed in this paper. The main advantage of this new method is that it can remove the impact of varying loadings but it does not require any loading information. Further the proposed method is robust to noise and is sensitive to system property changes. The effectiveness of the proposed method has been well demonstrated by a numerical example, the theoretical study and the analysis of the field vibration data from bearings of operating wind turbines.