Transient Quenching Properties of Vapor Arc Formed in Silica Sand: Contribution of Vaporized SiO₂ Mixture to DC Arc Extinction Performance

The current‐limiting fuse uses silica (SiO 2 )‐sand as arc quenching medium to increase a current‐limiting performance during the DC arc quenching process. In order to increase the current‐limiting performance of the fuse, a detailed understanding of an arc resistance rise process is necessary. This paper first carried out a 1000 A DC Cu arc quenching experiment using the silica‐sand to obtain transient change in , morphology of the arc, and arc temperature during the arc quenching process. As a result, a current decaying increased . The arc was maintained in the cavity surrounded by the fulgurite during the current decaying process. The temperature of Cu/SiO 2 arc was 25–8 kK at a current region of 950–400 A during the arc quenching process. Second, we theoretically calculated an electrical resistivity , and a thermal diffusivity as vapor properties for the Cu/SiO 2 vapor mixture. As typical results, the admixing of the SiO 2 vapor into the Cu arc less increased of the Cu/SiO 2 vapor mixture at between 25 and 5 kK. The of the Cu/SiO 2 vapor mixture drastically increased due to only decay in . In contrast, the admixing of the SiO 2 vapor into the Cu arc significantly increased at between 15 and 8 kK. The present results indicate that an increase in and consequent rise in thermal energy dissipation from the arc is the main role of the silica‐sand vapor mixed with Cu arc in the DC fuse during the arc quenching process. The increased thermal energy dissipation due to the SiO 2 vapor admixing further decreases to rapidly rise and during the arc quenching process.