The Field-circuit Coupled Solution On DC Magnetic Biasing Of Transformer

It is studied that the power transformers'DC magnetic biasing in this dissertation. The DC bias magnetization of transformers in the power system is a complex problem, it involves power system simplifying, the three dimensional nonlinear electromagnetic fields numerical calculating.The main part of the dissertation is: when calculting the three dimensional electromagnetic fields of nonuniform media, it is proved that the result of the edge elements is more accurate than nodal elements'by solving a simple model, so we use the circuit-filed coupled solution based on solving the differential inductance of the transformer's model, by means of Runge-Kutta method compiled by Fortran program, doing a circular calculation of three dimensional nonlinear electromagnetic fields, the curve of the transformer's excitation current is solved, and a simulation of direct current magnetic bias on transformer is done; in the end,it is disscused that the relation of the length of the Runge-Kutta's step and the calculative result, simulation results provide a feasible way for analyzing the problem of transformers'family equipments in the power system.