Lamination of T-joints in the transformer core

The paper presents a new method of taking into account overlapping zones in stacked transformer cores for magnetic field calculations. The method has been worked out with the use of homogenization technique under the assumption that the distribution of magnetic flux between the layers of overlaps results from the tendency to reach the minimum of the magnetic field energy. This enables replacement of a heterogeneous 3-D overlap structure with a simpler homogeneous 2-D one. The method has been used to calculate the equivalent homogenized reluctivity of the whole structure and the flux density vectors in its layers. The family of equivalent anisotropic magnetizing curves of an overlap has also been determined. To discuss the method, a classical overlap of a transformer core has been chosen. Calculation results and the results of measurements taken in two adjacent sheet layers of an overlap situated in a T-joint of a 3-limb 3-phase transformer core are compared and presented