气压对SF6局部过热分解的影响特性

Influence Characteristics of Pressure on the Partial Over-thermal Decomposition of SF6

为获取气压对SF6局部过热分解的影响特性,通过实验研究了故障温度为400℃、气压为0.2-0.5 MPa的SF6局部过热分解特性,并结合粒子反应碰撞理论分析了气体压强对SF6分解特征组分生成过程的影响作用机制及影响规律。研究结果表明：随着气压的增加,单位体积内的各种分子的有效碰撞频次增加,进而提高了生成CO2、SO2F2、SOF2、H2S和SO2的化学反应的速率,使得各特征分解组分的摩尔浓度均随着气压的升高而增长;气压的升高对不同分解组分有不同程度的促进作用,其中对SO2F2生成的促进作用最为显著;气压对特征组分的有效产气速率的影响规律明显,同时,SO2F2/SOF2和SO2F2/（SO2＋SOF2）两组有效特征组分比值均与气压呈正线性相关。以上研究结果可为将来采用SF6气体组分分析法（DCA）对SF6气体绝缘装备进行绝缘状态监测提供支撑。

In order to obtain the influence characteristics of gas pressure on the partial over-thermal decomposition of SF6, we researched the decomposition characteristics of SF6 under partial over-thermal fault based on the statistics from lab experiments and further analysis. The gas pressure value settings of the experiments were selected within the range between 0.2 MPa and 0.5 MPa. The simulated fault temperature of heating source was set to be 400 degrees Celsius. With the help of particle collision theory, we analyzed the impact mechanisms of gas pressure on the generation process of SF6 decomposition characteristic components. The experimental results show that, as the pressure increases, the effective collision frequency of various molecules within unit volume increases correspondingly. And the aforementioned process further promotes the generation rate of the components of CO2, SO2F2, SOF2, H2S, and SO2, respectively. As a consequence, the concentrations of each decomposed component increase along with the rise of gas pressures. A conclusion can be drawn from our experimental results that the gas pressure has varying levels of promoting effects on different decomposition components. Specifically, the promotion level on the formation of SO2F2 is most remarkable among all decomposed components. Moreover, it is found that there are significant patterns of the influence of pressure on the effective formation rate of characteristic components. Meanwhile, we have also discovered a close linear relation between both effective ratios of characteristic components, SO2F2/SOF2 and SO2F2/（SOF2＋SO2）, with respect to the gas pressure inside the insulating device. The above results can provide theoretical support for SF6 decomposition component analysis（DCA） to monitor the insulation status of SF6 gas insulation equipment in the future.