A study on the repeated breakdown field strength of compressed $SF_{6}$ in uniform field perturbed by protrusion

교란된 평등전계에서 고기압 $SF_{6}$ 가스의 연속절연 파괴강도에 관한 연구

For large gas-insulated systems, the conductor utilized possess some degree of surface roughness which locally enhances the applied field at highpressure in $SF_{6}$. In order to investigate the effect of field enhancement on the breakdown field strength, the spheric protrusion was employed which gives a quantitative analysis on field enhancement. For further investigations on the breakdown level and polarity effect in $SF_{6}$, the repeated breakdown tests were performed with d.c. voltage at pressures up to about 4 bar. The experimental results show that the breakdown level does vary noticeably due to successive voltage applications and the breakdown field strength measured for a test gap with the cathode protrusion is markedly lower than that determined from the identical anode protrusion.