中文摘要：

GIS隔离开关操作条件下SF6气体放电是GIS电磁暂态现象产生的根源。因此,SF6气体放电特性将直接影响GIS电磁暂态特性。为研究壳体地电位TEV升高的暂态特性,论文建立了新型SF6气体重燃模型。在分析SF6气体不同放电阶段阻抗变化规律的基础上建立了SF6单次高频放电模型;运用数据拟合的方法得到SF6气体击穿电压随时间变化的表达式,从而得到重燃判据;在此基础上结合单次放电模型建立了具有快速性、高频性和重复性的新型SF6重燃模型。采用该模型计算得到的VFTO值与实测值十分接近,证明了模型的正确性。完成上述工作后,在分析VFTO波传播机制的基础上建立了TEV的计算模型,讨论了SF6放电模型、VFTO激励源等效以及接地电网参数等对TEV暂态特性的影响。研究结果表明：①采用论文所建立的新型SF6重燃模型计算得到的TEV与实测值十分接近,其峰值误差为9%;②TEV具有幅值高、陡度大、频带宽等特性;③采用1：1变压器真实模拟VFTO比将其等效为指数模型更能反映TEV的暂态特性;④减小接地电感有助于抑制TEV。

英文摘要：

SF6 gas discharge is the basic cause of all the electromagnetic transient phenomenon occurring in GIS at disconnector operation. Therefore,the characteristic of SF6 discharging would have an important influence on GIS electromagnetic transient. In order to investigate the transient characteristics of TEV,a new SF6 reignition model is established in this paper. Based on analyzing the law of variation of SF6 impedance at different discharging stages,the segment model is adopted to set up the single discharge model of SF6. Besides,a thermal-fluid-electric coupling field model is built to calculate the breakdown voltage of SF6 when the disconnector contact opens slowly and then the reignition criterion can be obtained if the data fitting method is applied to express the reignition criterion as the function of time. According to this criterion,the new SF6 discharge model,which can describe the discharge characteristics of SF6 with rapidity,high frequency and repeatability,is established on the basis of the single discharge model. Moreover,to verify the validity of the new model,VFTO is calculated and the comparing results between the calculation and experimental measurement reveal that the simulation results show good agreement with experimental data. After that,the transmission mechanism of VFTO is researched,then on this basis the TEV model is established and the factors influencing on TEV such as SF6 discharge model,the equivalent methods of VFTO and grounding parameters are discussed as well.