1991 Volume 111 Issue 3 Pages 304-313
The model experimental apparatus for poor contact portion of the gas-insulated switchgear is assumed to a rod-to-plane gap with small arc current in SF6. The breakdown voltage in a gap at gas pressure of 0.1 MPa and small arc current of 1 A have been studied.
The effect of the small arc current on the breakdown in the gap was investigated experimentally, and the breakdown mechanism in the gap was studied. Also gas temperature and density were calculated by fluid analysis.
It was cleared that the small arc current played an important role on the breakdown in the rod-to-plane gap, and the hot gas produced by an arc was a principal factor of reduction of the breakdown voltage. The decomposition products produced by the arc were absorbed in an activated almina effectively, and the breakdown voltage in the gap increased by setting the activated almina in a chamber.
The time history of the breakdown voltage was characterized by six domains, and these breakdown mechanisms were explained by the development of the arc. The schematic diagram of the breakdown mechanism was proposed by the authors.