Multiphysical Finite Element Modeling of Inductive Type Fault Current Limiters and Self Limiting Transformers

A coupled finite element model of inductive type fault current limiter was developed for transient calculations. The model includes two dimensional finite elements for magnetic field directly coupled with network elements and sequentially coupled three dimensional finite elements for thermal calculations. A computer simulation was developed for implementing the model. Both iron and HTS nonlinearity are handled. The HTS model takes the E-J characteristic into account that depends on flux density and its orientation as well as on the temperature. With 3D thermal calculation the model also handles material inhomogeneity along the perimeter. The simulation results were compared with measurements performed on experimental model of a self limiting transformer.