Over-Critical Current Analysis for Helical SFCL Coil

Superconducting fault current limiters (SFCLs) are foreseen to be critical and promising candidates in power system applications, due to their automatic fault current limiting performance, low loss, size compactness and light weight. A helical bifilar coil which is composed of one inner winding and one outer winding was developed, and these two windings were wound on the same coil bobbin with opposite directions and connected in parallel. Experiments were carried out to characterize the fault current limitation behavior of the helical bifilar coil in flux flow mode, when the prospective fault current falls in over-critical current regime yet still within 2 times of the coil's critical current. The current limiting performance of the helical bifilar coil in flux flow mode was demonstrated and discussed.