1. Xi’an Superconducting Magnet Technologies Co., Ltd., Xi’an 710016, China
2. School of Electrical Engineering, Beijing Jiaotong University, Beijing 100871, China
3. Guangdong Power Grid Development Research Institute Co., Ltd.,Guangzhou 510080, China
The superconductive fault current limiter (SFCL) is an innovative electric power equipment designed to rapidly and effectively mitigate short circuits in high voltage transmission systems. With the rapid economic development of our country, there has been a growing demand for increased power load and reliability. Consequently, this has led to the generation of larger short circuit currents within the electric grid, surpassing the capacity of existing switch equipment which poses a significant constraint on safe and stable operation. As the most advanced electric power equipment available, the SFCL not only detects and interrupts power flow during short circuits but also effectively mitigates the magnitude of the short circuit current. In this study, we have designed, fabricated, and experimentally evaluated a superconducting magnet specifically tailored for a high voltage SFCL. The magnet features a roomtemperature bore with dimensions of 1660 mm in diameter and 1960 mm in length, incorporating a liquid nitrogen vessel with a capacity of 2000 L.Notably, the central peak field within the roomtemperature bore reaches an impressive value of 0.45 T. The magnet consists of 88 high temperature superconducting (HTS) double pancake coils, with 468,000 ampere turns.These coils are strategically divided into three segments operating at distinct currents: namely, 220 A for YBCO coils followed by Bi2223 coils operating at 1000 A and concluding with another set of YBCO coils operating at 220 A. After undergoing multiple processes, including winding, terminal wire installation, welding, and assembly, the magnet is subjected to a rigorous test at 72 K. The results of the test align with the theoretical design specifications and exhibit an insulation grade exceeding 10 kV. Additionally, meticulous investigation reveals that the nitrogen evaporation rate remains below 70 L/d, Moreover, it has been determined that the cryostat leakage is less than 10-6(Pa·L)/s, thereby confirming the resounding success of this superconducting magnet.