Research on magnetostrictive characteristics of threephase transformer under DC bias

Abstract The primary cause of vibration and noise in transformers is the magnetostrictive behavior of the core. A transient electric-magnetic circuit coupling model of the three-phase five-pillar transformer under DC bias is developed by using the duality principle to investigate this phenomenon more thoroughly. In the model, the Jiles-Atherton ferromagnetic hysteresis theory is employed to describe the magnetization process. The variations of magnetic flux density, magnetic field intensity, and the magnetostriction curve under different DC conditions are analyzed through simulations of the three-phase transformer. The results indicate that DC bias causes the waveforms of magnetic flux density and magnetic field intensity to shift and become distorted, magnetostrictive deformation intensifies, and the curves depicting the connection between deformation and magnetic field (Δ l-B , Δ l-H ) are also distorted, showing an asymmetric butterfly shape, and the level of distortion is directly related to the size of DC. The research findings confirm that the proposed transient model can precisely reflect the magnetostrictive characteristics of a three-phase five-pillar transformer under DC bias.