Effects of Unevenly Distributed Critical Currents and Damaged Coated Conductors to AC Losses of Superconducting Power Transmission Cables

Two groups of superconducting power transmission cables composed of two layers of coated conductors with 4 mm width and 2 mu m superconductor-thickness have been designed. In one group, four styles of unevenly distributed critical currents (I(c)) are applied, while in the other group there is one damaged coated conductor in each cable. Trapezoidal critical current density (J(c)) distribution with a sloping shoulder of 0.3 mm is assumed while calculating the AC losses of these cables numerically by using a one dimensional FEM model. Numerical results show that unevenly distributed I(c) increase AC losses along with the increasing variance ratio which defines the difference between individual I(c) and the average I(c). Even only one damaged coated conductor can dramatically increase AC losses no matter which layer it locates at. The detailed AC loss distributions among coated conductors are presented and the reasons for different influences of unevenly distributed as well as damaged coated conductor are discussed.