Efficient Multiphysics Finite Element Simulation of a Transient Fault in a Bi-2223 HTS Power Cable
In this article, the problem of a high temperature superconducting cable (HTSC) response to and recovery from a transient short circuit fault is discussed and a finite element solution to the problem is presented. The full model consists of three subroutines, connecting together: 1) electromagnetic phenomena in HTSCs and associated Joule heat release; 2) heat transfer from the HTSC to the cooling circuit; 3) convective heat transport in liquid nitrogen. These subroutines are connected via geometric and variable couplings. The background of the real cable to be modeled is laid out together with its key properties. The most important parameter and variable calculations are explained in detail. In order to facilitate a computational speedup through manipulation of the active physics during selected intervals of time, the simulation is split in three distinct stages—steady state, transient fault, and recovery. Moreover, it was shown how the entire simulation may be performed over a moderately reasonable amount of time using low computational resources when certain approximations are exploited—namely, using the electromagnetic model only on a limited number of cross sections along the cable. This article shows that fairly accurate results can be achieved on an office PC using a commercial FEM software even without access to computing clusters, and that the same model can be used to examine both normal and transient operation.