Impact mechanism and regularity of trace H2O on SF6 decomposition characteristic under PD

H₂O is one of the most important factors that affect the final SF₆ decomposition products, the products concentration, and the production rate, and so on, under partial discharge (PD). However, the mechanism and regular pattern of SF₆ decomposition haven´t been figured out completely. This paper had made several experiments, as long as 48h, research SF₆ PD decomposition in different H₂O contents, all experiments utilize the test platform of SF₆ PD decomposition, and then detect the concentration of SF₆ decomposition products in different H₂O contents. It had obtained the regular pattern of the effects of H₂O on SF₆ PD decomposition. The results indicate: increasing H₂O contents can restrain the generation of CF₄, and the generation of CO₂ is more than CF₄. Moreover, H₂O will firstly promote the generation of both SO₂F₂ and SOF₂, and then inhibit them as time goes on. Discriminatively, the promotion and inhibition leaded by H₂O of SOF₂ are stronger than that of SO₂F₂. Therefore, when diagnoses facilities faults through using the SF₆ decomposition products, the effect of H₂O should be taken into account.