Technical Requirements of the DC Superconducting Fault Current Limiter

The dc fault current increase rapidly and reach an unbreakable value when a fault occurs. Cutting off dc fault current directly cost enormous energy and cause voltage stresses for the dc converters, dc circuit breakers, etc. It is expected to use the dc superconducting fault current limiter (SFCL) to limit dc fault current. In this paper, different types of dc SFCLs are introduced at the beginning. Then the current-limiting requirements of the dc SFCL are analyzed. In order to satisfy these requirements, some essential technical indicators of the dc SFCL are proposed. The dc SFCL shall not only limit the peak value of dc fault current to reduce the requirement of the maximum interrupting capacity of the dc circuit breaker, but also limit the rising rate of fault current to realize the coordination among the converter, dc circuit breaker and dc SFCL. Besides, the response time, recovery time and other issues of the dc SFCL should be guaranteed as well. Simulation results indicate the significance and necessity of the proposed indicators. A prototype is designed and experimental tests are carried out.