Maximum permissible voltage of YBCO coated conductors

Abstract

Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (Ic) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the Ic degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100ms, the maximum permissible of SJTU CC, 12mm AMSC CC and 4mm AMSC CC are 0.72V/cm, 0.52V/cm and 1.2V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.