Resistive Type Superconducting Fault Current Limiter and Current Flowing Time

Superconducting fault current limiter (SFCL) is an alternative to solve the problems associated with the increasing fault current levels. For conventional resistive type SFCLs, the current flowing time of superconducting coil is usually more than 50 ms (depending upon the interruption time of circuit breaker). However, in an improved YBCO-type resistive SFCL, the current flowing time of superconducting coil is only 10 ms (current through superconducting coil can be interrupted by a fast opening switch). The difference of these two designs and the effect on the design of SFCLs are not investigated yet. This paper mainly compares the characteristics of the resistive type SFCL with different current flowing time. Experimental results showed that, with a 250 A current passing by, the resistance of superconducting tape with 10 ms-design and 50 ms-design are respectively 30 m Omega/m and 80 m Omega/m. Meanwhile, the current withstand ability (according to recovery time within 250 ms) are respectively 465 A for 10 ms-design and 272 A for 50 ms-design. Estimation about the demand of superconducting tapes between two types of resistive type SFCLs with different current flowing time was done. Calculation results showed that the improved resistive type SFCL with 10 ms-design only need 1/4th length of superconducting coil used in 50 ms-design.