Design aspects of transmission voltage superconducting fault current limiters with YBCO tapes in China

The design progress of superconducting fault current limiter (SFCL) for transmission voltage is presented, with a focus on the results of recent key experiments that have led to a state-of-the-art high-voltage high-capacity super-conducting current limiting techniques: the resistive alternating current (AC) SFCL, saturated iron cores AC SFCL, and resistive direct current (DC) SFCL. The main driving factors for designing SFCL in these projects are the preparation of high-performance superconducting materials, the development of large-scale superconducting current limiting winding, system testing, and operation technology. Based on the authors’ experience with both AC and DC SFCLs, this paper focuses on the main design aspects of resistive SFCL at transmission voltage. The relationship between the hot spot caused by the inhomogeneity of long superconducting tape and the overall parameter selection is presented. In addition, the thermal calculation based on the current limiting resistance and a real-time current curve is also proposed for the parameter design of the current limiting winding.