Surface Charging on Epoxy Spacer at DC Stress in Compressed SF₆ Gas

Micro discharges in HVDC gas insulated systems

“…This saturation effect limits the total charge accumulated on an insulator surface. The effect of micro discharges at low fields in real HVDC components could be reduced by these accumulated charges for electrode surfaces close to the insulator like shown in [12]. For larger distances this effect is of limited influence as screening of the rough metal surface by accumulated charges on the insulator becomes less effective.…”

“…There are in principle three different charge sources in the gas: Natural ionization due to cosmic background radiation and radioactive elements in the ground [6], micro discharges from microscopic protrusions (roughness) on the electrodes [6][7][8][9], and field emission at highly stressed cathodes or macroscopic protrusions [6][7][8][9]. 7,8,9 In the literature [10][11][12][13] it was shown that in arrangements where partial discharge cannot be detected by classical measurement methods, additional charges due to micro discharge can nevertheless be present. The aim of this contribution is to analyze these micro discharges and quantify the resulting discharge currents and their impact on the charging of HVDC insulator surfaces.…”

Surface fluorinated epoxy resin for high voltage DC application

“…In another study conducted by Nakanishi et al [9], they stated that heterocharges that accumulate on the spacer surface at the time of abrupt polarity reversal reduce the flashover voltage along the spacer surface. On top of that, Okabe et al [10] reported that charges on the spacer model may have opposite or same polarity depending on the ratio of the insulating gas resistance and spacer resistance.…”

Approche physique du développement de streamers positifs sur une surface de glace =

“…Le premier suggère que les charges produites autour d'une électrode diffusent dans le gaz de remplissage à travers les lignes de champ pour s'accumuler vers le centre de la surface diélectrique [103,104,113]. Le second préconise la circulation de charges sur la surface par l'effet du courant de faite [102,114,115], tandis que le dernier propose la migration vers l'extérieur de la surface, de charges produites à l'intérieur du diélectrique [73,100].…”