Speaker
Mr
Can Guo
(Xi'an Jiaotong University)
Description
In recent years, SF6/N2 gas mixtures especially with low SF6 mixing ratio was getting used as insulating medium in gas-insulated equipment for replacing pure SF6 which causes greenhouse effect. For the application of SF6/N2 gas mixtures in power equipment such as GIL, the breakdown characteristics of SF6/N2 gas mixtures in different electric field non-uniformity under lightning impulse were studied in this paper based on a fully enclosed steep-front impulse test device. The research indicates that the breakdown voltage of SF6/N2 gas mixtures increases linearly with increase of gas pressure in slightly non-uniform electric field, and the saturated trend appears with increase of the electric field non-uniformity. The reversal of polarity effect was found in SF6/N2 gas mixtures. The breakdown voltage under negative lightning impulse is higher than that under positive lightning impulse in low gas pressure, but when pressure exceeds a critical value, the result converses. The increase of SF6 mixing ratio or decrease of electric field non-uniformity would both lead to the decrease of the critical value of gas pressure. Meanwhile the change of polarity effect in SF6/N2 gas mixtures is later than that in pure gas with the increase of electric field non-uniformity. In addition, the synergistic effect of SF6/N2 gas mixtures weakens obviously with the increase of electric field non-uniformity, and the negative synergistic effect even appears with strongly non-uniform electric field.
Primary author
Mr
Can Guo
(Xi'an Jiaotong University)
Co-authors
Mr
Haoyang You
(Xi'an Jiaotong University)
Mr
Jingtan Ma
(Xi'an Jiaotong University)
Prof.
Qiaogen Zhang
(Xi'an Jiaotong University)
Mr
Tao Wen
(Xi'an Jiaotong University)
Mr
Yifan Qin
(Xi'an Jiaotong University)
