Vibration Signal Analysis of High Voltage Circuit Breakers System Based on Hybrid Model of Power Spectrum Estimation

Abstract

This paper discusses several methods of power spectrum estimation, respectively using the indirect method and Welch method to estimate power spectrum distribution through the acquisition of vibration signals of circuit breakers, and use the AR hybrid model to estimate different orders of power spectrum estimation. Under different length of data, the or- der selection method can be determined. Power spectrum estimation method is a power spectrum calculation method of vibration or random signal. It is an important link in the signal analysis, which can be used to detect the periodic component and the percentage of the sig- nal (1). And it is the great significance for the diagnosis of mechanical failure. Using a given set of sample data to esti- mate the power spectral density of a stationary random sig- nal is called power spectrum estimation. Power spectral den- sity is the discrete time Fourier transform of the random sig- nal autocorrelation sequence, it is used to characterize the statistical properties of random signals. The power spectrum of random signal reflects its frequency components and the relative strength of each component, it can reveal the signal rhythm from the frequency domain, and it is the important characteristic of random signals. Found in the study, statistical properties of CB vibration signal under different working conditions, the results show that when the circuit breaker is in normal working condition or state change is very small, the action of mechanical vibra- tion signal can be approximated at a stationary random pro- cess, which is consistent with the AR hybrid model assump- tion is usually described by. Therefore, the AR hybrid mod- el power spectrum estimation can achieve the desired effect of vibration signal.