446 / 2022-03-15 22:19:47

Bubble Behavior and Its Influence on DC Breakdown Characteristics of Liquid Nitrogen During the Quenching-recovery-re-quenching of Resistive Superconducting Fault Current Limiters

Superconducting fault current limiters,HVDC,bubble,quench,insulating strength

Resistive-type superconducting Fault current limiters (R-SFCLs) can limit short-circuit fault currents and have good prospects in HVDC systems. When the superconducting tape in the R-SFCLs is quenched to limit the short-circuit fault current, it gradually returns to the superconducting state, and the system can be reclosed at this time. If the short-circuit fault is a permanent fault, the R-SFCLs will be quenched for the second time after the system is reclosed. At this time, the superconducting tape still continues to generate bubbles locally, and the temperature of the tape has not dropped to the initial bath temperature, so the bubbles generated by the second quenching may be more violent and seriously affect the insulating properties of R-SFCLs. In order to obtain the quenching bubble characteristics of R-SFCLs during the quenching-recovery-re-quenching of the superconducting tapes and its influence on the insulating properties of R-SFCLs, this paper uses the method of two current impulses to investigate the characteristics of the bubbles generated by the quenched superconducting tape during the quenching-recovery-re-quenching. The results show that the second quenching resistance of the superconducting tape is larger, the recovery time is longer, and the quenching bubbles are more intense, which reduces the dielectric strength of R-SFCLs.