Theoretical modeling and experimental verification analysis of mechanical vibration characteristics of converter transformer winding and bushing accessories

The domestic UHVDC transmission lines are developing rapidly, among which the converter transformer and its bushing accessories are typical electrical equipment. This paper focuses on theoretical modeling and experimental verification analysis of mechanical vibration characteristics of key electrical equipment under 6300A high current and 800kV high voltage. The band-pass filter is used to analyze the dynamic signal time series, which shows that the band-pass filter limits the frequency to 0~2000Hz, and the passable frequency is 2000~5000Hz. After Fourier decomposition, it is found that the peak value of signal amplitude appears near 1000Hz and 2000Hz. Furthermore, the analysis of the electromagnetic force of the short circuit of the converter transformer winding and its bushing accessory structure and the on-site accident shows that the maximum short circuit current occurs at 0.01s, and SVM identification accuracy is 91.3%. The research in this paper has guiding significance for the fault diagnosis of converter transformer and its bushing accessories based on the vibration signals for typical power equipment.