GIS隔离开关操作条件下SF_6气体高频放电模型的研究

GIS隔离开关操作时,触头间SF_6气体放电具有快速性、高频性和重复性特征。上述特性会对VFTO的陡度、幅值等暂态特性产生重要影响。因此,建立隔离开关操作条件SF_6气体高频放电模型对VFTO的精确仿真而言十分重要。在已有试验研究结果基础上,论文分析了SF_6气体放电不同阶段的阻抗变化规律,对比了火花放电和开关操作条件下SF_6气体放电之间的差异,发现Toepler模型、Barannik模型和Vlastos模型所描述的阻抗变化规律与SF_6气体放阻抗变化规律十分相似。为此,论文借鉴了火花放电模型的数学表达式。在此基础上,根据采用SF6气体放阻抗变化规律,采用分段思想对火花放电模型的数学表达式进行改进,从而建立了3种不同的SF_6气体高频放电模型。为验证模型的正确性,将其应用于VFTO的仿真。结果表明仿真计算值与VFTO的实测波形基本重合、幅值几乎相等,证明了模型的正确性。

Investigation on the High-frequency Model of SF_6 Gas Discharge Caused by Disconnector Operation in GIS

Rapidity, high frequency and repeatability are the remarkable characteristics of SF6 gas discharge,which have important influneces on the transient characteristics of VFTO such as the rise time, amplitude and etc. There fore, it is very important to set up the high frequency model of SF6 gas discharge for calculating VFTO accurately. Base on the exsiting experimental research, the impedance variation characteristics of SF6 gas discharge in different stage are anlayzed. The difference between spark discharge and SF6 gas discharge are compared as well. Further research and study indicates that Toepier model, Barannik model and Vlastos model show the similar discharge imped ance change tendency with that of SF6 discharge under the condition of GIS disconnector operation. Then, the mathematical expression of spark models are used for reference. According to the impedance change tendency of SF6 gas discharge in different stage, the time segment method is adopted to improve the mathematical expression of Toepier model, Barannik model and Vlastos model respectively. Therefore, three high frequency SF6 discharge models are established, which can describe the SF6 discharge characteristics perfectly and completely. Moreover, to verify the validity of SF6 discharge model, VFTO is calculated by employing these SF6 discharge model respectively. And the results reveal that the waveform and amplitude of VFTO obtained by using these models almost coinciding with each other. Comparing these simulation results with the measurement data, it can be found that the calculated results show good agreement with experimental data.