746 / 2022-03-31 20:34:56

Surface Diacharge and Its Residual Charge Accumulaiton Characteristics in C4F7N/CO2 Under Negative Impulses

surface discharge,charge accumulation,C4F7N/CO2,impulse voltage

Many investigations have been carried out on C₄F₇N gas and its mixtures. However, the in-deep studies on the fundamental surface discharge characteristics of C₄F₇N/CO₂ mixtures are still scarce. Therefore, an investigation on surface discharge propagation and its residual charge distribution of C₄F₇N/CO₂ mixtures under negative impulses is conducted and analyzed.

Epoxy resin sheet is fixed on an insulating bracket with needle and plate electrodes to forming an electrode-sample configuration. The discharge image under negative impulse is captured by an ICCD camera, the discharge voltage signal is recorded by a resistance divider and the current signal is measured by a current sensor. After discharge, the dust figure is manufactured.

The surface discharge images and dust figures of C₄F₇N/CO₂ mixtures shows that the surface discharge in C₄F₇N/CO₂ mixture have more branches than CO₂ and SF₆. The backward discharge pattern could be found in current signal and dust figure. The residual charge distribution indicates that the propagation of surface discharge in C₄F₇N/CO₂ mixture is following a stepwise expansion development pattern.

The propagation pattern of surface discharge in C₄F₇N/CO₂ mixture is different from that in CO₂ and SF₆, which results in the difference in surface flashover properties.