Application Of Order Analysis Based On Instantaneous Frequency Estimation In Wind Turbine Gearbox Fault Diagnosis

Wind turbine gearbox is an important part of the wind turbine. The failure of a wind turbine gearbox will cause the abnormal operation or prolonged downtime of the entire wind turbine, so how to make a timely and effective diagnosis of the wind turbine gearbox failure is a problem needed to be solved in the wind power industry. In the wind turbine gearbox fault diagnosis technology, the most mature way is to detect and analyse the vibration and noise signal from the gearbox. In particular, the vibration signal contains a large number of fault message. Due to the special operating environment and operating conditions, the wind turbine gearbox is always under variable load with a constantly fluctuating speed and the vibration signal is non-linear and non-stationary. Some traditional vibration signal processing methods, such as time domain analysis, frequency domain analysis can’t be used to process non-stationary signal. The frequency domain analysis method will produce serious "frequency smear" if used to process non-stationary signal. Therefore, we need to find an effective way to deal with the wind turbine gearbox vibration signals and an accurate method to extract fault feature.In this paper, the author proposed to research the application of order analysis based on instantaneous frequency estimation in wind turbine gearbox fault diagnosis after reviewing and comparing the domestic and international wind turbine gearbox vibration signal processing methods. The vibration mechanism of a wind turbine gearbox was analysed and the typical fault types and vibration signal characteristics were summarized. A theoretical model of a wind turbine gearbox test rig was established and a real test rig was built by team work in the laboratory. A detailed vibration signal test program was designed and a data acquisition and analysis system was developed. On the theoretical and experimental basis prepared above, the author proposed to combine the instantaneous frequency estimation based on local mean decomposition and order analysis to do the wind turbine gearbox vibration signal processing and fault diagnosis, and the analysis result of simulation and experimental data shows that the method can effectively process the vibration signal of wind gearbox and accurately deal with the fault identification and diagnosis in some degree.