Superconducting fault current limiter (SFCL), which is used in voltage source converter based high voltage direct current (VSC-HVDC) transmission systems to limit fault currents and protect the grid together with DC circuit breakers, could improve system safety and stability. The first transmission voltage DC SFCL is developed in China, and it has been applied in the 160 kV VSC-HVDC transmission system in Nan’ao. The electromagnetic design as well as insulation analysis of the current limiting unit is presented, where the current limiting unit is composed of 96 bifilar coils made of stainless steel reinforced YBCO tapes. The liquid nitrogen at the temperature of 77 K is used as the cooling and insulation medium, and the liquid nitrogen is cooled by a closed-loop cryogenic system consists of 3 G-M refrigerators. The 160 kV DC SFCL prototype has been fabricated, and the prototype has passed the steady-state current test of 1 kA, the DC withstand voltage test of 252 kV within 1 min, the lightning impulse test of 550 kV/1.2 µs/50 µs and the operating impulse test of 450 kV/250 µs/2500 µs. Power switching test results show that the developed SFCL could generate the desired limiting resistance, and the maximum fault current duration time could be as high as 60 ms. The developed prototype has been installed in the Nan’ao VSC-HVDC transmission system, and put into operation on August 17, 2020.

超导故障电流限制器（SFCL）用于基于电压源转换器的高压直流（VSC-HVDC）传输系统中，以限制故障电流并与直流断路器一起保护电网，可以提高系统安全性和稳定性。国内第一个输电电压直流SFCL研制成功，并已在南澳160 kV VSC-HVDC输电系统中应用。提出了限流单元的电磁设计以及绝缘分析，其中限流单元由96个由不锈钢增强YBCO胶带制成的双股线圈组成。温度为77 K的液氮用作冷却和绝缘介质，液氮通过由3个GM制冷机组成的闭环低温系统进行冷却。已制造出160 kV DC SFCL原型，该原型已通过1 kA的稳态电流测试，1分钟内的252 kV的直流耐压测试，550 kV / 1.2 µs / 50 µs的雷电冲击测试以及450 kV / 250 µs / 2500 µs的工作脉冲测试。功率开关测试结果表明，所开发的SFCL可以产生所需的极限电阻，并且最大故障电流持续时间可高达60 ms。开发的原型已安装在南澳VSC-HVDC输电系统中，并于2020年8月17日投入运行。功率开关测试结果表明，所开发的SFCL可以产生所需的极限电阻，并且最大故障电流持续时间可高达60 ms。开发的原型已安装在南澳VSC-HVDC输电系统中，并于2020年8月17日投入运行。功率开关测试结果表明，所开发的SFCL可以产生所需的极限电阻，并且最大故障电流持续时间可高达60 ms。开发的原型已安装在南澳VSC-HVDC输电系统中，并于2020年8月17日投入运行。