Arc Energy Evaluation in Liquid Nitrogen

Abstract

Power loss in switchgear can possibly be minimized to a very tolerable value by using cryogenic dielectrics. Research in the past have shown that Liquid Nitrogen (LN 2 ) is an economical alternative to Liquid Helium (LHe). It is a good coolant with tremendous dielectric properties and is widely preferred for the high temperature superconducting (HTS) equipment. Yet there is no literature to refer on the evaluation of arc energies in LN 2 . The objective of this paper is to compute the arc energy in LN 2 and compare the aftermaths with the arc energy in open air insulation. Experiments were carried out on different DC voltage levels. Different kinds of electrodes were subjected to high luminance arcs under 1 atmospheric pressure of LN 2 and Air. Arc voltages, Arc currents and Arcing times were measured and the Arc energies were calculated for both the cases. It was observed that LN 2 extinguished arcs in almost half of the time required by air insulation. This quick quenching action resulted in reduced power loss and improved efficiency. Hence the results approved that the LN 2 as an insulation medium, may serve as a promising substitute for the future metal enclosed switchgear system. This novel approach of using the environment friendly LN 2 to extinguish low current arcs, may possibly be a better alternative to the Sulphur hexafluoride (SF 6 ) gas.