Study on the Current-Limiting Characteristics of Saturated Iron Core Superconducting Fault Current Limiter in MMC-HVDC System

Saturated iron core superconducting fault current limiter (SI-SFCL), which utilizes the saturation characteristics of iron core, has broad application prospects in handling with short circuit fault. SI-SFCL has the advantages of fast response speed, and the superconducting coils do not quench during the whole current limiting process. However, the research of SI-SFCL mainly focuses on AC systems, and there are few studies on its application in DC system. This paper analyzes the current-limiting mechanism of SI-SFCL in modular multilevel converter based high voltage direct current (MMC-HVDC) system. Based on PSCAD/EMTDC, the current-limiting characteristics of SI-SFCL in MMC-HVDC system are studied. The results show that SI-SFCL has strong limiting effect on the peak value of the short circuit current, but cannot limit steady-state current. Finally, the influence of magnetization current on the saturation of iron core and the current limiting effect of SI-SFCL is analyzed. The principle of selecting the appropriate magnetization current is given. © 2020, Electrical Technology Press Co. Ltd. All right reserved.