Arc Voltage Distribution Measurement in Tube Constricted Ultrahigh-Pressure Nitrogen Arc

Abstract

This work contributes to the fundamental understanding of axial voltage distribution of the arc burning inside polytetrafluoroethylene (PTFE) tube at very high filling pressures of nitrogen. The arc peak current of 85 A at a frequency of 190 Hz with a fixed initial rate of rise of recovery voltage (IRRRV) of approximately 50 V/µs is used throughout the study. Arc burning at three different filling pressures are studied: 1 bar, 20 bar, and 40 bar. To examine the axial voltage distribution in the arc, the arc voltage at three different axial position of the arc is independently measured. For some cases, a 3 cubic centimeter heating volume is attached to the ring electrode, which produces a back flow. For the cases with a heating volume, the pressure rise in the heating volume is also measured. It is observed that the pressure rise in the heating volume increases with the filling pressure. In the presence of the heating volume at a high filling pressure (i.e., 20 bar, 40 bar), the voltage drop increases significantly near the vent due to the relatively cold gas flow.

Effect of filling pressure on post-arc gap recovery of N2

“…First, a freeburning arc and the influence of tube constriction on the arc have been investigated in the SC state and beyond, up to 80 bar filling pressure during the high current phase [12], [13]. Some further investigations were focused on the region near CZ, where the effect of N2 filling pressure on the thermal interruption performance is evaluated [14]- [16]. The arc voltage is reported to increase with the filling pressure, whereas no abrupt change in arc voltage is observed during the transition of N2 from gas to SC region [12].…”