  High temperature superconductor (HTS) (RE)Ba2Cu3Ox (REBCO) conductor on round
core cable (CORC) has high current carrying capacity for high field magnet and
power applications. In REBCO CORC cables, current redistribution occurs among
tapes through terminal contact resistances when a local quench occurs.
Therefore, the quench behaviour of CORC cable is different from single tape
situation, for it is significantly affected by terminal contact resistances. To
better understand the underlying physical process of local quenches in CORC
cables, a new 3D multi-physics modelling tool for CORC cables is developed and
presented in this paper. In this model, the REBCO tape is treated as a thin
shell without thickness, and four models are coupled: T-formulation model,
A-formulation model, a heat transfer model and an equivalent circuit model. The
current redistribution, temperature and tape voltage of CORC cable during hot
spot induced quenches are analysed using this model. The results show that the
thermal stability of CORC cable can be considerably improved by reducing
terminal contact resistance. The minimum quench energy (MQE) increases rapidly
with the reduction of terminal contact resistance when the resistance is in a
middle range. When the terminal contact resistance is too low or too high, the
MQE shows no obvious variation with terminal contact resistances. With a low
terminal contact resistance, a hot spot in one tape may induce an over-current
quench on the other tapes without hot spots. This will not happen in a cable
with high terminal contact resistance. In this case, the tape with hot spot
will quench and burn out before inducing a quench on other tapes. The modelling
tool developed can be used to design CORC cables with improved thermal
stability.
