Study on resistance characteristics and operating conditions of YBCO thin-film wire for current limitation considering insulation layer

The YBCO thin-film wire has a high index value and a fast phase transition speed when a fault current is applied to it. Its critical properties are also superior to those of the existing Bi-Sr-Ca-O wire. Moreover, it can choose its stabilizing layers and control the magnitude of the resistance it generates in with the specific-resistance of the stabilizing layers. Thus, many researchers are studying the application of the Y-Ba-Cu-O(YBCO) thin-film wire to superconducting power machines. Being particularly studied are the properties of the YBCO thin-film wire as a current-limiting element material. In this study, to evaluate the basic properties of superconducting current-limiting elements that contain insulating layers, test samples were manufactured using the YBCO thin-film wire according to the absence and presence as well as the thickness of the insulating layers. Then a fault current was applied to the test samples to examine their quenching resistance trends and operational properties according to the fault angles. Towards those ends, a current was applied to various YBCO thin-film wires with different stabilizing layers to test their properties, and the YBCO thin-film wire that exhibited superior current-limiting performance was selected. Also, a fault current was applied to the selected YBCO thin-film wire with insulating layers to test their properties. Using the test results, the resistance occurrence trends were examined at the critical temperature of 90 K. the perfect quenching temperature of 250 K, and the middle temperature of 180 K. Also, to increase the current limiters' capacity, the element's operational properties, such as its maximum voltage, maximum current, initial limited current, and response time were observed at 90K, 180 K, and 250 K according to the fault angles. (C) 2010 Elsevier B.V. All rights reserved.