bulkiorew.blogg.se

Structural health monitoring (SHM) has been employed for internal or surface damage detection in real time and early diagnosis and prediction, ultimately to avoid catastrophic accidents.

Hence, timely and accurate detection of stator insulation damage can provide effective and reliable reference information for an early damage diagnosis. The stator insulation structure gradually deteriorates because of the combined effect of electricity, heat, mechanical vibration, and environmental factors during its long-term operation, leading to various types of internal or surface damage and eventually causing insulation failure and fault shutdown. The insulation condition of the stator largely determines the life and operating reliability of such generators. Stator winding is a core component of large generators. This study extends the applicability of Lamb wave-based non-destructive detection of stator insulation damage in complex environments. The results show that the VMD and wavelet transform methods can significantly improve the signal-to-noise ratio of Lamb wave detection signals and the accuracy with which the damage is located under strong background noise. The proposed method is experimentally tested and verified under various noise environments. First, considering that the characteristics of VMD are sensitive to noise, the Lamb wave detection signal is decomposed, denoised, and reconstructed the reconstructed signal is then wavelet-transformed to extract the time of flight (TOF) of the damage-scattered wave as the damage location feature finally, the damage location is determined using the TOF features. This paper proposes a method based on variational mode decomposition (VMD) and wavelet transform to enhance and extract the location features of stator insulation damage signals of large motors. However, it is difficult to extract the features of Lamb wave signals in a strong background noise environment, thus significantly reducing the accuracy with which the damage is located. Lamb waves are used to locate any damage in the stator insulation structure of large generators.