The load current in the operation of the converter transformer contains a large number of high harmonic components, which will generate harmonic leakage fields in the converter transformer and high harmonic losses in the windings, cores and metal structural parts. In order to solve the problem that the existing converter engineering calculations are unable to accurately calculate the eddy current loss of each metal structural component, as well as the simulation studies have seldom comprehensively considered the issues of converter stacked cores, shielding structures and winding skinning depth, which provide theoretical references for the design and manufacture of converter transformers. In this paper, a 800 kV converter transformer as a reference to establish a high degree of reduction of the three-dimensional model and simulation calculations, simulation results and measured in the error of about 4%, to meet the needs of the project, for the converter design to provide a theoretical basis.