Voltage–Current Characteristic of Free Burning Arcs in SF₆ Alternative Gas Mixtures

Voltage–current characteristics of free burning arcs in SF6 and air have been known for decades. As the demand an SF6-free solution is increasing, there accompanying need to determine arc parameters alternative gases. An unblown experiment has established voltage–current gases, which not yet thoroughly studied. In this experiment, measurements were performed a number gases under consideration alternatives, including CO2 mixtures CO2/O2 with without C4F7N or C5F10O additives at concentrations up 10 %. Measurements also comparison. Arc voltage was measured each gas pressures ranging from 1- 5-bar absolute, electrode separations 20 $95 \mathrm {~mm}$ . characteristic show good agreement previously published results. A linear relationship length shown as well fourth root dependence on pressure. It that neither O2 nor fluorinated any significant influence characteristic. The minimum all slightly higher than SF6, but least stable had highest elongations resulting high-voltage peaks. similar value CO2-based much more stable, lower effective voltage, especially low currents.