LIMITATOR SUPRACONDUCTOR HTS REZISTIV PENTRU CURENȚI DE AVARIE

The present work refers to the realization of some applications of HTS superconductors in alternating current, of significant importance for the protection of electrical networks and, respectively, the transport of electrical energy: fault current limiter and superconducting cable, realized in ICPE-CA within the Applied Superconductivity Laboratory. The fault current limiter is of resistive type and is made with HTS superconducting material of YBCO type in the form of a strip of 6 mm width and 0.11 mm thickness [1]. The experimental model realized was tested for currents of 200 A AC, its operating temperature is -196 ºC, immersed in liquid nitrogen. The operating principle is based on the superconductor exiting, under the influence of fault currents higher than the nominal current IA> IN, from the superconducting state and its transition to the resistive state, at which point the current is bypassed through an alternating circuit [2], thus protecting the primary circuit. The HTS superconducting cable is designed to transport intense currents (102 – 103 A), presenting very low Joule losses compared to conventional conductors [3]. The cable is made with HTS superconducting material of the YBCO type with a critical temperature of 92 K used in the form of a strip with a width of 12 mm and a thickness of 0.11 mm [1]. The cryogenic cooling of the superconducting material is performed with liquid nitrogen at a temperature of -196 ºC.