| Title |
Impulse Breakdown Characteristics of Nonuniform Field Gap in SF_6-N_2 Mixtures |
| Authors |
이복희(Lee, Bok-Hee) ; 이경옥(Lee, Kyoung-Ok) ; 김정일(Kim, Jung-Il) |
| Keywords |
SF_6-N_2 혼합기체 ; 뇌 임펄스전압 ; 진동성 임펄스전압 ; 절연파괴 ; V-t 곡선 ; 전구방전전류 ; |
| Abstract |
Lightning impulse (1.2/44[μs]) and damped oscillating impulse (Osc./44[μs]) : 0.83[MHz]) breakdown characteristics in sulphur-hexafluoride/nitrogen (SF6-N2) mixtures were investigated. The predischarge currents were observed to clarify the breakdown mechanism. th experiments were carried out under nonuniform electric fields disturbed by a needle-shaped protrusion whose length and diameter are 10[mm] and 1[mm] at total gas pressure up to 0.5[MPa] with nitrogen concentrations varying from 5 to 20[%] in the mixture. The electrical breakdowns of SF6-N2 mixtures for both the positive and negative polarities develop with steplike pulses in leader mechanism and the breakdown voltage -time (V-t) characteristics were affected by the space charge. The voltage-time curves for the negative oscillating impulse voltage were extended over the longer time range. The minimum breakdown voltages for the negative lightning and oscillating impulse voltage were higher than those for the positive ones. in particular the positive breakdown voltages were independent of the gas pressure. |