Transient Electromagnetic-Thermal FE-Model of a SPICE-Coupled Transformer Including Eddy Currents with COMSOL Multiphysics 4.2

Operation of a transformer is charac- terised by strong dynamic interactions between the electrical subsystems on the primary and secondary sides and the magnetic subsystem. Transient finite element (FE) analysis of a trans- former together with SPICE-coupled external electrical sources and loads is a powerful tool for the analysis and design of transformers. This paper describes electromagnetic and thermal 3D FE modelling and transient simulation of a cur- rent transformer with focus on the non-linear characteristic of the ferromagnetic transformer core, the coupling of the transformer windings to external circuitry, and the effects of eddy cur- rents and self-heating.