Analysis of No-Load Vibration and Noise Characteristics of Transformers Under Power Frequency Superimposed Harmonics

With the influx of a large number of harmonics caused by the popularization of power electronic devices, transformers suffer from excitations generated by harmonics, resulting in the increased vibration and noise levels. Therefore, it is of great significance to investigate the vibration and noise response of transformers under power frequency superimposed harmonic excitation. In this paper, a vibration and noise test platform for transformers under multi-frequency excitation is built. The vibration and noise response characteristics of transformers under different power frequency superimposed harmonic excitation are analyzed. It is found that under the surface vibration velocity in the frequency band of 40–600 Hz is approximately proportional to the noise intensity of the transformer. Then, a semi-linearized synthesis method for the vibration and noise response of transformers is proposed, and verification experiments are carried out under the excitation of power frequency superimposed with third- and fifth-order harmonics.