Rapidity

high frequency and repeatability are the remarkable characteristics of SF

6

gas discharge

which have important influneces on the transient characteristics of VFTO such as the rise time

amplitude and etc. Therefore

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 SF

6

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 Toepler model

Barannik model and Vlastos model show the similar discharge impedance change tendency with that of SF

6

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 Toepler 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 SF

6

discharge model

VFTO is calculated by employing these SF

6

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.