Experimental study on the effect of H₂O and O₂ on the degradation of SF₆ by pulsed dielectric barrier discharge

SF₆ has excellent insulation performance and arc extinguishing ability, and is widely used in the power industry. However, its global warming potential is about 23,500 times that of CO₂, it can exist stably in the atmosphere, it is not easily degradable and is of great potential harm to the environment. Based on pulsed dielectric barrier discharge plasma technology, the effects of H₂O and O₂ on the degradation of SF₆ were studied. Studies have shown that H₂O can effectively promote the decomposition of SF₆ and improve its degradation rate and energy efficiency of degradation. Under the action of a pulse input voltage and input frequency of 15 kV and 15 kHz, respectively, when H₂O is added alone the effect of 1% H₂O is the best, and the rate and energy efficiency of degradation of SF₆ reach their maximum values, which are 91.9% and 8.25 g kWh⁻¹, respectively. The synergistic effect of H₂O and O₂ on the degradation of SF₆ was similar to that of H₂O. When the concentration of H₂O and O₂ was 1%, the system obtained the best rate and energy efficiency of degradation, namely 89.7% and 8.05 g kWh⁻¹, respectively. At the same time, different external gases exhibit different capabilities to regulate decomposition products. The addition of H₂O can effectively improve the selectivity of SO₂. Under the synergistic effect of H₂O and O₂, with increase in O₂ concentration the degradation products gradually transformed into SO₂F₂. From the perspective of harmless treatment of the degradation products of SF₆, the addition of O₂ during the SF₆ degradation process should be avoided.