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

Abstract

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.