Analysis of acoustic fingerprint characteristics of a low-frequency transformer under diverse test conditions

Abstract

The acoustic signal of a low-frequency transformer can provide insights into its working condition and abnormal states. Therefore， it is essential to analyze its acoustic fingerprint characteristics. A 20 Hz low-frequency transformer was chosen， and its acoustic fingerprint signals were collected during no-load， short-circuit， and temperature-rise tests. Through time-domain and frequency-domain analyses， characteristic values such as the root mean square （RMS） value and the high-low frequency ratio were derived. The analysis results show that the core’s acoustic fingerprint signal mainly consists of harmonic components at multiples of 40 Hz， while the winding’s acoustic fingerprint signal is predominantly at the fundamental frequency of 40 Hz. The sound intensity resulting from the vibration of the core and winding intensifies with the increase in voltage or current. Moreover， an elevation in oil temperature exacerbates transformer vibration and amplifies noise. Additionally， compared to power-frequency transformers， low-frequency transformers exhibit lower noise levels and greater complexity in acoustic fingerprint frequencies. These research findings demonstrate that the acoustic fingerprint characteristics of low-frequency transformers can effectively mirror their internal states， providing a practical foundation for operating condition identification and fault diagnosis.

Keywords

• low-frequency power transmission
• transformer
• acoustic fingerprint characteristics
• rms value
• core vibration
• winding vibration
• transformer temperature rise