Study of Dissociation Characteristic of SF₆-N₂ Mixture Under Corona Discharge with Pin-to-Plate Electrode

$\text{SF}_{6} / \text{N}_{2}$ mixed gas has the huge potential in high voltage power equipment for the sake of reduction of $\mathbf{S F}_{6}$. However, due to the inevitable fault conditions, $\text{SF}_{6} / \text{N}_{2}$ will decompose and react with the impurities in equipment generating various gaseous components, which ultimately endangers the safe operation of the equipment. The study on the decomposition of $\text{SF}_{6} / \text{N}_{2}$ mixture in corona discharge is of guiding significance to the timely detection of early failure of equipment and the insulation of diagnostic equipment. In this paper, the characteristics of $\text{SF}_{6} / \text{N}_{2}$ mixed gas decomposition products under typical corona discharge condition were studied. The experimental results show that the SF
6
mixture decomposition produces $\text{NF}_{3}, \text{SOF}_{2}$ and SO
2
F
2
characteristic products under the defect of the corona discharge of the needle plate electrode. The production rate of NF
3
is relatively low, while $\text{SOF}_{2}\gt\text{SO}_{2} \text{F}_{2}$. Decomposition products increase along with the discharge time increasing, the $\text{SF}_{6} / \text{N}_{2}$ pressure and the proportion of SF
6
reducing. The ratio of $\text{SF}_{6} / \text{N}_{2}$ mixture, and the total yield of decomposition products can be used as the characteristic parameters to distinguish the spark discharge and corona discharge of the needle plate electrode.