Effect of Copper Vapor on Radiation Properties of C4F7N Gas Mixtures

C4F7N and its mixture with buffer gases are regarded as the most promising SF6-alternative gases in gas circuit breakers. The switching arc can severely ablate the electrodes, producing copper metal vapor that combine with the C4F7N gas mixture to chang radiation characteristics. This paper compares the net emission coefficient of C4F7N mixtures at various mixing ratios and assesses the effect of 20% copper vapor. It is found that adding copper vapor can greatly enhance radiation