The quench behavior of wires for superconducting fault current limiters at DC faults was simulated, with a focus on the effect of capacitor discharge on the quench. The behavior was also expressed in mathematical forms to facilitate a better understanding of the simulation results and for rough analytical estimations of the wire length suitable for the circuit voltage and capacitance. The quench resistance development behavior for various wire lengths and circuit capacitances was simulated using the model developed in the previous work. The quench behavior was expressed in mathematical forms, reflecting the concept of heat balance. During the quench, the wire temperature increased more slowly for longer wires, but was found to increase in a similar pattern. The wire length estimated by the mathematical formula was close to the one obtained by the simulation, with an error range of a few %. The calculations will be used to estimate effectively the length of wires needed to build superconducting fault current limiters for applications in DC power systems.

The quench behavior of coated conductors (CCs) was simulated with a focus on the initial stage of quenches, and the current limiting behavior of superconducting fault current limiters (SFCLs) at DC faults was calculated. Since the fault current reaches the peak in several ms in DC lines due to capacitor discharge, it is necessary to understand the initial quench behavior well. Considered in the simulation are characteristics of CCs in the flux-flow state, current sharing, non-uniform critical current distribution in CCs, and heat transfer to surroundings. The simulation fit data well. Using the CC model developed in the simulation, the current limiting behavior of SFCLs made of CCs at DC faults was calculated. Critical current distribution and heat transfer were found to affect the current limiting behavior of SFCLs less at DC faults. The calculation will contribute to the effective design of SFCLs for applications in DC lines.