Description
As an indispensable part of GIS (Gas Insulated Switchgear), the cone-type insulator supports the transmission bus and separates SF6 gas chambers, which is as well the weakest link of insulation of the switchgear. The existence of metal particles, which is possibly produced during the fabrication, installation or maintenance of GIS, can lead to the tremendous distortion of local electric field, and consequently the decrease of surface flashover voltage of the insulator. In order to study the flashover characteristics of a 220kV cone-type insulator with metal particle contamination, metal particles of different lengths varying from 6mm to 12mm are stuck to the insulator surface near the bus, with the pressure of SF6 gas varying from 2 bar to 6 bar. The result shows that under DC voltage, the flashover voltage of the insulator decreases as the length of the metal particle grows, and decreases more slowly when the particle length exceeds 10 mm. For a certain particle length, the flashover voltage shows a typical “hump effect” as the SF6 gas pressure augments, while under higher gas pressure, the flashover voltage is more sensitive to the metal particle than that under lower pressure. From the perspective of charge accumulation on the insulator surface, analyses are made to explain the experimental phenomenon.
Primary author
Qiandong DU
(Xi'an Jiaotong University)
Co-authors
Ms
Jie HE
(China Electric Power Research Institute)
Jingtan Ma
(Xi'an Jiaotong University)
Mr
Junping ZHAO
(Xi'an Jiaotong University)
Mrs
Pengfei ZHANG
(China Electric Power Research Institute)
Prof.
Qiaogen ZHANG
(Xi'an Jiaotong University)
Tao Wen
(Xi'an Jiaotong University)
Yifan Qin
