Test and simulation of exciting current for single-phase transformers under DC bias

According to the nonlinear magnetization characteristics of transformer core, the 3D physical model and circuit model of the double-core column single-phase transformer are built by using the field-circuit coupling method in this paper. Exciting current is simulated and analyzed under different DC bias. The simulation results demonstrate that the exciting current becomes much more distort and will incline to half-circle saturation when the DC increases enough. The experiment on single-phase transformer with DC bias is performed to verify the accuracy of simulation result. The simulation result is consistent with the test result, thus the simulation model and the used method are approved to be correct and effective.