The application of the wavelet analysis of analytic signals in mechanical fault diagnosis of circuit breakers

This paper introduces a fault diagnosis technique using mechanical vibration signals of circuit breakers. A new frequency-domain compact-support dyadic wavelet is constructed from the point of frequency domain. This wavelet has the characteristic of definite frequency-division. A method of wavelet transform to analytical signals has been presented. Using the constructed wavelet, not only the spread of signal in the frequency band corresponding to the scale is obtained, but also the signal envelope of amplitude, phase and instantaneous frequency at each scale are extracted. These characteristic parameters are used to diagnose faults. The mechanical vibration signals from closing operations of circuit breakers are discussed by using this method. Simulation results demonstrate that it is valid to use the wavelet transform of analytic signal in mechanic fault diagnosis of circuit breakers.