Vibration characteristics of ± 800 kV converter transformers part Ⅱ: Under load conditions

Abstract

As the second part of the investigation on vibration characteristics of ± 800 kV converter transformers, this part focuses on load conditions. A full-load thermal stability test is carried out on 12 YY and YD converter transformers in a converter station. Vibration, voltage, current, and other important information are collected by online monitoring devices. Vibration amplitude, vibration spectrum, dominant frequency, vibration power ratio of frequency band, vibration power entropy, and odd–even harmonic ratio under different load conditions are calculated and studied to evaluate the vibration state. Theoretical analyses of winding electromagnetic force and vibration acceleration are carried out and results show that the harmonic currents make the dominant frequency shift to 300 Hz or 400 Hz. Most vibration characteristics are sensitive to load rate changes. The odd–even harmonic ratio is sensitive to filter disconnection and reconnection. The results of this study reveal the vibration regularity and corresponding mechanism and can contribute to further study on vibration assessment of ± 800 kV converter transformers under load conditions.

Keywords

• Condition Assessments
• Converter Transformer
• Load Conditions
• Monitoring
• Vibration