Automatic design of impedance in shell-form power transformer

Based on the computation of magnetic field forces subjected on current coils, a formula of partial derivatives of the percent impedance to the widths of the leakage magnetic channels in a shell-form power transformer is presented. By means of this formula, the leakage magnetic field, the percent impedance and its partial derivatives are calculated only through the finite element meshing and solution one time. The percent impedance of the shell-form power transformer is automatically designed by an optimization procedure based on the quasi-Newton optimization algorithm. Applying the above algorithm to the automatic design of the percent impedance of a large shell-form power transformer with four leakage magnetic channels, numerical result shows that the automatic design algorithm is very effective