The discharge mechanism along the dielectric surfaces is still the subject of intense research [2, 3, 4] but
theoretical description suitable for engineering calculations is currently unavailable. Therefore it is necessary
to use different kind of simplification [5].
Based on presently-available calculation techniques, electric strength analysis of switching unit node under
high voltage with internal insulation was performed in the present study. General view of switching unit node
is given in Fig. 1 [6]. Nodes are numerated as follows: 1 - grounded casing; 2 - epoxy insulator; 3 - SF6
cleanup system (filter); 4- clamping element for current conductor 7 and insulator 2; 5 - screen in current conducting
system-filter gap; 6 - screen in current-conducting system-grounded casing gap; 7 - current
conductor. Gas flow is indicated by arrows.