The application of high-temperature superconductor resistors (HTSC resistors) in ac electrical equipment and networks has been considered to protect them from fault currents and single-phase to earth faults. To improve the response speed and thermal withstand capability of HTSC fault current limiters the use of a stable overloaded regime in composite HTSC wires has been proposed. Basic circuits has been developed for the application of stabilized HTSC wires of low-ohmic value in protective resistors for ac networks that enables to increase the apparent resistance in the circuit by few orders of magnitude. The results are given of measurements of characteristics of first generation HTSC wires with high critical parameters in resistive state in a wide range of overcurrent. Prototype instantaneous current limiters with high thermal capability using the HTSC protective resistors have been manufactured and tested. The estimated values are given for the design parameters of the HTSC protective resistors applicable in electrical networks.