Current limitation using high T/sub c/ materials

Abstract

The superconducting (SC) c u r r e n t limiter is one of the most attractive applications of superconductivity because it is an innovative device without any conventional equivalence. Following the emergence of ultra low a x . loss NtiTi strands in the eighties several devices have been designed and built using these superconductors. The discovery of high T, materials has crizated numerous potential applications such as particularly for current limiters. The operation a t higher temperatures and the very different nature of the SC oxides compared to low T, strands deeply modify the limitation process. We have carried out some experiments to study the transition of high T, samples fed by voltages with the objective of matking a resistive limiter. The quench behaviour of sintered and textured Bi compounds have been studied and compared. Grain boundaries play a very important p a r t in the limitation process. The resistive transition seems to begin a t the grain boundaries. The complete resistive transition of the sample has never been recorded. The propagation of the transition from the resistive part to the entire sample is very low. To overdrive the quench a magnetic field has been applied. In this paper, the results a r e reported to show the grain boundaries role in the transition.

Thermal recovery of inductive superconducting fault current limiters with weak zones in the secondary

“…the more abrupt the superconducting to normal transition), the lower the recovery time, because in this range of applied current densities (of the order of J c ), the maximum temperature reached is relatively low (similarly to what it is achieved for small samples). This does not occur, however, for samples with a higher J c , as is shown in the example displayed in figure 4(b), corresponding to the results of our simulation for a sample with a critical current density of the order of the ones commonly used in SFCL [21,22]. The values for the parameters used to carry out this calculation are the same as for the example of figure 4(a), except for J 0 (1) which is now 10 5 A cm −2 (i.e.…”

Quench in bulk HTS materials - application to the fault current limiter

“…For the same reason, those materials withstand overcurrents without developing a large electric field. The E(J ) curve is then run nearly without hysteresis (Tixador et al 1997). Magnetothermal runaway occurs with difficulty in sintered materials in the first alternation except when the current exceeds by a factor of 20 the critical one (Noudem et al 1997).…”

Development of Bulk Bi2+xSr3-yCa yCu 2O8+delta Superconductors by Partial-Melting Route for Fault Current Limiters Application

“…be an innovative device without a conventional equivalent 3 . Presently, the fault current interruption problem in high voltage transmission networks is solved with circuit breakers.…”