Current-based eccentricity detection for direct-drive wind turbines via synchronous sampling

Current-based wind turbine generator (WTG) fault detection techniques have received more and more attention in academia and industry due to their nonintrusive character and economic advantages. This paper presents a novel broadband and highly accurate and efficient synchronous sampling method for eccentricity fault detection of direct-drive WTGs (i.e., no gearbox) only using generator stator current measurements. The proposed method resamples the WTG current measurements in a way such that the variable characteristic frequencies of the excitations generated by a WTG eccentricity fault are converted to constant values. Then, the excitations generated by WTG eccentricity fault can be easily extracted by using a traditional power spectrum density (PSD) method. Experimental results are provided to demonstrate the effectiveness of the proposed method for eccentricity fault detection of a direct-drive WTG operating with variable rotating speeds.