Stable Overload Operation of High-Temperature Superconductor Protective Resistors

The use of high-temperature superconductor (HTS) resistors to protect electrical equipment and ac networks from emergency short-circuit currents and single phase-to-ground faults has been considered. It has been proposed to use a stable overload operation in HTS composite wires to enhance the speed of response and thermal stability of HTS current-limiting devices. Design solutions for the use of stabilized low-resistance HTS wires in protective resistors for ac networks have been developed that increase the resistance inserted in the circuit by several orders of magnitude. The characteristics of first-generation HTS wires with high critical parameters in the resistive state have been measured in a wide current overload range. Prototypes of instantaneous thermally stable current-limiting devices with HTS protective resistors have been fabricated and tested. The design parameters of HTS protective resistors for use in electric power networks have been calculated.