According to the characteristics of hydraulic operating mechanism of high voltage circuit breaker

a vibration signal analysis approach based on EMD （empirical mode decomposition） and envelope spectrum was proposed. First

the original signals were decomposed into a number of IMFs （intrinsic mode functions）; then

the characteristic vectors after the envelope spectra of some IMFs were obtained and used to identify the work conditions of operating mechanism. The experimental results show that the vibration signal analysis approach based on EMD and envelope spectrum can effectively extract the characteristics of hydraulic operating mechanism in time-domain.