Transient Eddy Current Loss and Magnetic Field Distribution of Single-phase Three-legged Transformer under DC Bias

In order to calculate eddy current loss and magnetic field distribution in iron core of single-phase three-legged transformer under DC bias, and to analyze local overheating problem, this paper puts forward to the coupling model of transient electric circuit and magnetic circuit considering core topology and nonlinearity of ferromagnetic materials. The transient distribution and variation of eddy current loss and magnetic field of single-phase three-Iegged transformer under different bias conditions are studied. The result shows that the waveform of transient eddy current loss and magnetic field in the iron core are shifted under DC bias. The amplitude of the eddy current loss and magnetic field grow nonlinearly with DC. The amplitude in B phase core column grows faster, which indicates the DC intrusion has greater influence on B phase core column.