Patent ID: 6215408
Filing Date: 2001-04-10
Classification: G01R,H01H

Abstract:
A method of processing a vibro-acoustic signal emitted by a high-voltage switching system, comprising the steps of:(a) converting the vibro-acoustic signal into a digital signal;(b) rectifying the digital signal to produce a rectified signal;(c) applying a convolutional filter with a spectral window on the rectified signal to produce a smoothed signal;(d) decimating the smoothed signal according to a predetermined decimation factor to produce a decimated signal representing an envelope of the vibro-acoustic signal;(e) carrying a time realignment of the decimated signal with respect to a reference signature to produce a realigned signal;(f) 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;(g) 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 step (e) for initial factor;(h) calculating variances of the realigned signal with respect to the reference and actualized signatures; and(i) 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.