Performance Evaluation of Conductor on Round Core Cables Used in High Capacity Superconducting Transformers

Conductor on Round Core (CORC) cables with scalability, flexibility, strong mechanical strength and high current density are of large potential for different power applications. In this paper, CORC Cables are proposed to be the secondary winding for high capacity superconducting transformer. In order to evaluate the working performance of CORC cable in HTS (high temperature superconductor) transformer, firstly, fundamental parameters of short CORC samples including self-field critical current and room temperature resistance were measured by experiments. Then, to represent the real working condition, both rated current tests and overcurrent tests were carried out to the CORC cable, respectively. In rated current test, magnetization and transport AC loss were discussed by both experimental and numerical method. It is found that AC loss of the CORC cable with double layers is much smaller than that of the CORC cable with single layer. In overcurrent tests, when the maximum value of current is 3588 A, 3.44 times of I
_c
, resistance of CORC is 0.12 mΩ. The recovery time is used to evaluate the recovery-under-load capability, the peak-to-peak value of voltage becomes stable after 6 cycles. Conclusions obtained in this paper can verify the feasibility of this technique and also provide useful information for future design of HTS transformers.