Influence of the Normal Zone Propagation Velocity on the Thermal Performance of HTS Coated Conductors Under DC Over-current Impact

The voltage source converter (VSC)-based DC distribution system that uses self-turnoff power electronic devices is getting attractive, and the cooperation of resistive superconducting fault current limiters (R-SFCLs) and DC circuit breakers has become a practical strategy to isolate the DC fault. However, high temperature coated conductors (HTS-CCs) widely used in R-SFCLs are prone to generate localized resistive zones and have a very low normal zone propagation velocity (NZPV). Therefore, it is meaningful to investigate the effect of different NZPV values on the thermal performance of HTS-CCs used in the R-SFCLs of VSC-based DC distribution systems. This paper developed a prototype of the VSC-based DC distribution system and a model of the HTS-CC in software, PSCAD and COMSOL respectively. The results showed that the increase of the NZPV could improve the superconductor's uniformity of temperature distribution after the DC over-current impact.