Influence regularity of trace H₂O on SF₆ decomposition characteristics under partial discharge of needle-plate electrode

摘要

SF decomposition characteristics under partial discharge (PD) are not only associated with insulation fault type and its severity but also closely related to the HO content of in the equipment. This paper studies the decomposition characteristics of mixture gas SF/HO with six different gradients of trace HO under the same PD energy, selects SOF, SOF, CO, and CF as the characteristic components, and analyzes the influence regularity of trace HO on each of the component concentration, effective formation rate and characteristic ratio. Results show that HO creates favorable conditions for generating SOF and SOF owing to the capacity to capture F atom and inhibit low fluorine sulfides from recombining into SF. As a result, the concentration and effective formation rate of SOF and SOF is positively related with HO. Whereas HO has no evident influence on CO, it can consume intermediate by-products CF and CF which restrain CF generation. Each characteristic ratio decreases sharply and then becomes stable with increment of HO. The defined effective characteristic ratio effectively reflects its relationship with HO, whereas obtained mathematical expression between each effective characteristic ratio and trace HO lays solid foundation for fault diagnosis of SF insulated equipment based on SF decomposition characteristics.