Numerical analyses of the electromagnetic force acting on high-temperature superconducting power cables due to fault current

Abstract

In Japan, the development of the 66 kV class REB2C3O7−x (RE123; RE stands for rare earth) high-temperature superconducting (HTS) power cable was begun in 2008 as a national project. 66 kV class RE123 HTS power cables may be subjected to a fault current of 31.5 kArms for 2 s. Therefore, the electromagnetic and thermal characteristics of HTS power cables have to be determined under fault conditions to ensure stability and feasibility. In this study, numerical analyses were performed using a computer program on the basis of the finite element method and an equivalent circuit model to evaluate the electromagnetic and thermal behaviors of a 66 kV class HTS model cable resulting from the fault current. The electromagnetic forces acting on coated conductors that are assembled in the HTS model cable were also numerically simulated under the fault condition. The result found was that the maximum electromagnetic force acting on the coated conductor in the peeling and compression direction was less than 20 kPa. However, the irreversible Ic degradations caused by the peeling and compression stress were above several MPa in previous studies. Thus, the results of this study indicate a low probability of Ic degradation of the 66 kV class HTS power cable being caused by the electromagnetic force due to the fault current.