Research On Fault Diagnosis Of Wind Turbine Bearing Based On Vibration Signal

Wind power of our country has developed rapidly in recent years,however,the high cost of operation and maintenance has been one of the important factors that affect the economic performance of wind farm.As an important part of wind turbine,bearing is the main source of wind turbine failures due to long term operating under complex load and special working environment.Therefore,research on fault diagnosis of wind turbine bearing is of great significance for ensuring the safety and stable operation of wind turbine and reducing the cost of operation and maintenance of wind farm.In this paper,two fault diagnosis algorithms are proposed for wind turbine bearing based on the vibration monitoring data.(1)The first fault diagnosis algorithm is based on variational mode decomposition(VMD)and Teager energy operator(TEO).First,vibration signal is decomposed into several intrinsic mode function(IMF)components by means of VMD,which is a recently proposed signal decomposition method.Then,the most sensitive IMF component is selected according to kurtosis criterion.And TEO is applied to the most sensitive IMF in order to highlight impact signal.Finally,spectrum is obtained by applying Fourier transform to Teager energy of the selected IMF,thus extracting the fault characteristic frequency(FCF)to diagnose bearing fault.(2)The second fault diagnosis algorithm is based on order analysis.The algorithm considers the influence of variable speed of wind turbine on fault diagnosis,which is the deepening and expending of the former.Firstly,the order analysis technology is applied to resample vibration signal of wind turbine under variable speed operating conditions,thus the non-stationary vibration signal in time domain is converted into stationary signal in angle domain.Then the VMD-TEO method is utilized to analyze the stationary signal in angle domain to calculate the order spectrum,from which the fault characteristic order(FCO)can be extracted to diagnose fault of wind turbine bearing.Under the MATLAB environment this paper completes the implementation of the above algorithms.Then the algorithms are applied to analyze simulation and experimental signal,and analysis results validate the effectiveness of the VMD-TEO method and order analysis for fault diagnosis.Comparison studies show the advantages of fault diagnosis methods proposed in this paper over empirical mode decomposition(EMD)and conventional spectrum analysis.