Winding Technology and Experimental Study on 500 kV Superconductive Fault Current Limiter

500 kV saturated iron core superconductive fault current limiter (SFCL) has been built and tested successfully. The superconducting magnet consists of 88 high-temperature superconducting (HTS) double pancake coils with an inner diameter of 1940 mm and an outer diameter of 2040 mm. Double pancake coil plays an important role in 500 kV SFCL, the structure and the winding process have great influence on current carrying capability and reliability of the coil. In this paper, the key technology of winding process of the world's largest HTS coil was introduced, which included bending effect on critical current measurement of HTS tapes, insulation treatment of pancake coil and coil winding process. The V-I curve of the HTS coil was also investigated under the condition of liquid nitrogen in the self-magnetic field. The experimental results show that not only the pancake coil but also the superconducting magnet has good properties and the process is reliable and suitable for manufacturing 500 kV SFCL. The study will not only provide important references for large HTS coils fabrication but also accumulate experience and data for other similar engineering practices.