A CO2/O2 Mixed Gas DC Circuit Breaker With Superconducting Fault Current-Limiting Technology

Researchers have investigated the interruption properties of CO2gas, including CO2and O2mixed gas. However, there has been no research on the passive resonance DC interrupting characteristics of CO2/O2mixed gas. The objective of this paper is to learn the passive resonance DC interrupting properties of CO2/O2mixed gas with superconducting fault current-limiting technology. A proposed passive resonance DCCB that includes a superconducting current-limiting module (SCLM) and a DC interrupting module (DCIM) connected in series was tested for DC voltages of 1.3, 3 and 10 kV and DC currents from 50 A to 10 kA. The experimental results show that the DCCB could successfully interrupt a 10 kA current in a 10 kV DC system. The response time of the DCCB was only 0.3 ms. After interruption, there was no overvoltage. The arcing time and the arc voltage of the SF6gas and the CO2/O2mixed gas were also compared experimentally. Experimental results show that CO2/O2mixed gas may be a good substitute for the SF6gas in passive resonance interruption. The CO2/O2mixed gas passive resonance DCCB combined with the SCLM is an effective way to interrupt high short-circuit fault currents in medium-voltage and high-voltage DC systems.