Vibro-acoustic signature treatment process in high-voltage electromechanical switching system

An apparatus for processing a vibro-acoustic signal emitted by a high-voltage switching system, comprising:

• a converting means for converting the vibro-acoustic signal into a digital signal;
• a rectifying means for rectifying the digital signal and producing a rectified signal;
• a filtering means for applying a convolutional filter with a spectral window on the rectified signal and producing a smoothed signal;
• a decimating means for decimating the smoothed signal according to a predetermined decimation factor and producing a decimated signal representing an envelope of the vibro-acoustic signal;
• a realigning means for performing a time realignment of the decimated signal with respect to a reference signature and producing a realigned signal;
• a first calculating means for adding the realigned signal as a factor of a mean to produce the reference signature, the mean having a predetermined reference signal for initial factor;
• a second calculating means for adding the realigned signal as a factor of a mean to produce an actualized signature, the mean having the first realigned signal produced by the realigning means for initial factor;
• a third calculating means for calculating variances of the realigned signal with respect to the reference and actualized signatures;
• and
• a comparing means for comparing the realigned signal with the actualized and reference signatures to detect a gradual behavior change or a sudden defect, taking the variances into consideration.