Comparisons of the AC and DC Magnetization Characteristics of Transformer Models with Single-Phase Four-Limb Core Composed of Different Grades of Steel Sheets

The AC and DC magnetization characteristic test platforms are built, respectively. By analyzing the mechanism of magnetization process of ferromagnetic materials, the differences between AC and DC magnetization characteristics of single-phase four-limb transformer are compared. It is found that the AC and DC magnetization characteristics of single-phase four-limb transformer present similar laws. At the same magnetic field strength level, the magnetization curve has a good degree of coincidence in the linear segment. The degree of AC magnetization in the knee-point segment is slightly higher than that in DC magnetization. Meanwhile, the AC magnetization characteristics of the saturation segment are similar to the DC magnetization characteristics, but under DC conditions, it is easier to make the core into deep saturation.