Abstract
It was reported that breakdown might be caused by the small arc current at the poor contact between conductors in GIS.
The effect of a small arc current on the breakdown was investigated experimentally. In the experimental apparatus, a poor contact portion of GIS was arranged by a rod-to-plane gap with the arc current.
It was clear that the arc current played an important role on the breakdown in the gap at gas pressure of 0.3_??_0.4MPa. The hot gas produced by the arc and the deforming of the contacts due to the arc were the main factors of the reduction of the breakdown voltage. The breakdown voltage was dependent on the arc current, and its reduction ratio increased with arc current. When the arc stopped, the breakdown voltage recovered to the level determined by the deforming of the contacts in a short time. The effects of the contact deforming and the hot gas on the breakdown voltage reduction could be separated by renewing the filled SF6 gas after the duration of small arc current.
