The exciting current distortion and significant loss increment of transformer due to DC bias can result in overheating and insulation aging. To analyze the effect of DC bias on the core loss of transformer, the forecasting method of core loss under DC bias was proposed based on the Jiles Atherton(JA) hysteresis theory. Firstly, depending on the JA hysteresis theory and the Bertotti's field separation approach, the dynamic hysteresis model was established without DC bias considering the eddy current and the ...