Testing of a Resistive Fault Current Limiter Component Based on Bi-2212 Bifilar Coil

A shunted bulk Bi-2212 bifilar coil was cooled with liquid nitrogen (77 K) and subjected to controlled fault current tests. Prospective currents achieving 11 kA were limited to about 5 kA (first peak) and to 3 kA (following peaks), under 200-300 V. The Bi-2212 coil was able to withstand several short circuits, showing a fast response and reproducible results. A recovery time of minutes was needed between two successive tests. Therefore, the bulk coil was damaged when the interval between subsequent short-circuits was reduced to 30-60 seconds. The critical current was severely reduced by those last tests and further thermal shock. The bulk coil was cut in transversal and longitudinal sections, in order to evaluate the damages.