INVESTIGATION ON SURFACE CHARGE ACCUMULATION CHARACTERISTICS OF C₄F₇N/CO₂ MIXTURE UNDER DIFFERENT ELECTRIC FIELDS

In this paper, the surface charge characteristics of C₄F₇N/CO₂ mixture under different electric fields was investigated. The electric fields with intense vertical component and intense horizontal component were established by needle-plane configuration and two semi-circle electrode configuration, respectively. The surface charging characteristics of pure SF₆ was also studied as a comparison group. The results show that in needle-plane configuration, the surface charge distribution of C₄F₇N/CO₂ mixture is hilltop-like with a certain randomness, while that of pure SF₆ is bell-like. Polarity effect is found that negative charges are easier to accumulated on sample surface than positive ones in both two gases. And the polarity effect of pure SF₆ gas is more remarkable than that of C₄F₇N/CO₂ mixture. The total amount of surface charge in C₄F₇N/CO₂ mixture is more than that in pure SF₆ gas.