Design and Tests of a 160-kV/1-kA DC Superconducting Fault Current Limiter

DC Superconducting fault current limiter (SFCL) can be used to reduce the fault current of voltage source converter-based high-voltage direct current (VSC-HVdc) transmission systems, thereby significantly reducing the manufacturing difficulty and cost of dc circuit breakers. The authors aim to develop a 160-kV/1-kA resistive type dc SFCL, and apply it in the VSC-HVdc transmission system in Nan'ao of China. In order to verify the feasibility of the transmission voltage dc SFCL, the research is divided into two stages, and the results of the first stage are presented. The rated voltage and current of the developed dc SFCL is 160 kV and 1 kA, respectively, and the current limiting resistance is no less than 2 Ω within 10 ms, which is 1/4 of the second stage prototype. The used superconducting material is stainless steel reinforced yttrium barium copper oxide (YBCO) conductor produced by Shanghai Superconductor. A three terminal structure is presented to meet the different operation parameters. A 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. The average operating thermal loss of the device at rated current is 652 W. Power switching test results show that the developed SFCL could generate the desired limiting resistance of about 2.2 Ω in less than 10 ms, and the maximum fault current duration time could be as high as 60 ms.