Arcing Time Analysis of Liquid Nitrogen in Asymmetrical Electrodes

Abstract

High density arcs were demonstrated in liquid nitrogen (LN 2 ) for the very first time and some important first hand investigations were previously witnessed. These investigations were based on electrodes that are geometrically symmetrical. The thorough study of arc behavior in LN 2 , also demands that asymmetrical analysis should be done in the same fashion. These new results would further our understanding of arcs in LN 2 and would be helpful for the future design of Liquid Nitrogen Insulated metal enclosed Switchgear (LNIS). The literature lacks the study on the arcing behavior of LN 2 with respect to asymmetrical electrodes condition. The objective of this work was to investigate the arcing time of stainless used steel (SUS) made, asymmetrical electrodes inside LN 2 and compare the results with air insulation. Experiments were carried out on a LC current source based DC system. The voltages considered were 200-500 VDC with a 100-volt step. Sphere-plane and rod-plane electrodes were tested. The tests were accounted on one atmospheric pressure for the LN 2 and air insulation, while strictly keeping the conditions same. The results are quite in agreement with the previous investigations done by the author. LN 2 has the shortest arcing time in comparison to air insulation and sphere-plane quenches arcs quicker than rod-plane type electrodes in most of the cases.