| Title |
Analysis Of Dielectric Recovery Characteristics for SF_6 Gas-Blast AFC |
| Authors |
송기동(Song, Gi-Dong) ; 이병윤(Lee, Byeong-Yun) ; 박경엽(Park, Gyeong-Yeop) ; 박정후(Park, Jeong-Hu) |
| Keywords |
가스차단기 ; 절연회복 ; 열적회복 ; 전류영점 ; 아크채널 ; 스트리머 기준 gas circuit breakers ; dielectric recovery ; thermal recovery ; current zero ; arc channel ; streamer criterion |
| Abstract |
In this paper, computer simulations of the physical Phenomena occurring in the arc region before and after current zero were carried out to evaluate the dielectric recovery characteristics of two types of double-flow nozzles. A commercial CFD Program "PHOENICS" is used for the simulation and the user-coded subroutines to consider the arcing phenomena were added to this program by the authors. The computed results were verified by the comparison with the test results presented by the research group of BBC. In order to investigate the state of the arc region after current zero, the simulation was carried out with four steps. They are cold gas flow analysis, steady state arc simulation, transient arc simulation before current zero, transient hot gas flow simulation after current zero. The semi-experimental arc radiation model is adapted to consider the radiation energy transport and Prandtl′s mixing length model is employed as the turbulence model. The electric field and the magnetic field were calculated with the same grid structure used for the simulation of the flow field. The streamer criterion was introduced to evaluate the dielectric recovery characteristics after current zero. Compared with the results obtained by assuming the current zero state in the former studies, it has been found that the results obtained by considering the state before current zerowere more accurate. |