Finite Element Analysis of Three-Phase Three-Limb Power Transformers Under DC Bias

A finite element method for the analysis of three-phase, three-limb power transformers under dc bias is presented. The phase voltages and the dc components of the phase currents are assumed to be given. Using parallel algorithms, the steady-state periodic solution is obtained without stepping through the transients using a fixed-point method to solve the nonlinear equations. A novel technique to obtain the starting solution for the fixed-point iterations to ensure fast convergence is introduced. The solution to a large, real world problem is presented.