WindVibraTransformer: A Foundational Model for Precise and Robust Wind Turbine Condition Monitoring via Vibration Signals

We aimed to develop WindVibraTransformer, a foundational model based on Transformers applied to vibration spectrograms, to derive precise and robust feature representations for wind turbine condition monitoring. In anomaly detection for wind turbine equipment, it is common to employ inlier modeling, where models are built solely on data from normal operation, with deviations classified as anomalies. Acquiring data for wind turbines, especially from the specific turbine being monitored, is challenging, often resulting in limited availability. However, this limitation can increase susceptibility to false alarms due to environmental variations. Thus, in this study, we explored the use of a vision Transformer trained with self-supervised learning to predict masked spectra conditioned on unmasked ones from vibration spectrograms, serving as the precise and robust feature extractor. Since this model aims to capture relationships within the context of the surroundings rather than solely the overview of the spectrogram, the resulting feature representations are expected to be complex yet less directly influenced by environmental variations. The complexity of these feature representations is addressed by constructing the normal state model using highly expressive normalizing flows. Experimental comparisons conducted on anomaly detection using real wind turbine vibration signals demonstrated that our approach enables highly reliable detection compared to existing unsupervised auto-encoder-based and supervised wind turbine classifier-based feature extraction methods.