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Fault Diagnosis Approach for Incipient Bearing Fault in Wind Turbine under Variable Conditions

For the extreme operating environment and variable working conditions of wind turbine and difficulty in finding fault feature accurately and promptly, a new incipient bearing fault method based on selecting optimal IMF (Intrinsic Mode Function) and Hilbert spectrum was proposed. Firstly, non-stationary time-domain signals are converted to stationary or quasi-stationary angle-domain signals; secondly, the EMD (Empirical Mode decomposition) method is used to decompose modal for angular waveform signal and obtain the IMF, and optimal IMF components are selected by cross-correlation criteria and kurtosis criteria to reconstructing signal. Finally, the reconstruction signal is processed by using Hilbert transformation to obtain the marginal spectrum. The paper finally verifies the effectiveness of the proposed method through experiment.