Vibro-Acoustic Analysis for Transformer under DC Bias Based on Electromagnetic Coupling

Aiming at the operational stability of DC-biased transformer, a multi-parameter correlation method based on electromagnetic coupling is presented in this paper. The mode-state analysis scheme is designed, and the feature parameters of electromagnetic, mechanical, and acoustic fields in internal components are simulated and analyzed. The electromagnetic properties under DC bias are simulated by the electromagnetic model, thus the winding current and magnetic flux density are extracted as the feature parameters. Then the vibration and stress distribution can be solved by the mechanical model, which are treated as the feature parameters of the mechanical field. By utilizing the computed mechanical information as excitation, the spatial-temporal distribution of sound pressure can be obtained in the acoustic model. Taking three-phase three-limb transformer and three-phase group transformer as examples, the electromagnetic, mechanical, and acoustic parameters of components are analyzed under different conditions. The variations of feature parameters are summarized and contrasted. Furthermore, actual vibration and noise parameters are measured through dynamic experimental platforms. The effectiveness of the multi-parameter correlation method is verified by the consistency between simulation and experiments, and the unobservable abnormal physical features can be represented by observable electrical information. © 2024, Electromagnetics Academy. All rights reserved.