Subproblem Methodology for Progressive Finite Element Modeling of Transformers

Model refinements of transformers are performed via a subproblem finite element method. A complete problem is split into subproblems with overlapping meshes, to allow a progressive modeling from ideal to real flux tubes, 1-D to 2-D to 3-D models, linear to nonlinear materials, perfect to real materials, wired to volume inductors, and homogenized to fine models of cores and coils, with any coupling of these changes. Its solution is the sum of the subproblem solutions. The procedure simplifies both meshing and solving processes, and quantifies the gain given by each refinement on both local fields and global quantities. Efficient ways to chain the refinements are proposed and tested.