Fault Current Limitation Coordination in Power Transmission System With Superconducting Fault Current Limiting Cables (SFCLC)

We investigate a Superconducting Fault Current Limiting Cable (SFCLC), which is an HTS cable with fault current limiting function. From the viewpoint of the fault current limitation coordination in a power transmission system, it is necessary to investigate the interaction of current limiting functions between multiple SFCLCs introduced in the system. We constructed a numerical model to analyze electrical and thermal behaviors of SFCLC based on resistance generation characteristics of superconductors. In the model power system, two SFCLCs were connected in parallel and two fault points were assumed. We calculated the current limiting characteristics of each SFCLC in the model system, and evaluated the current limitation effect and temperature rise of SFCLCs on each fault point. Depending on the fault point, there are two types of substantial connection of SFCLCs, namely in series and in parallel during the fault. In the substantially parallel connection, each SFCLC operates as the case of single SFCLC introduction. In the substantially series connection, the current limiting effect is determined by SFCLC with the smaller critical current. These results imply that the efficiency and reliability of a power transmission system will be improved by the introduction of multiple SFCLCs, as well as the single SFCLC.