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

Abstract

Experimental investigation of the effect of filling pressure on the post-arc dielectric recovery characteristics of nitrogen is reported in this paper. A half-cycle arc current duration of 540 µs followed by a 10 kV pulse with a rise rate of 150 V/µs is applied across the contact gap. The pulse is applied from 10 µs to 10 ms after the current zero. First, a free-burning arc is studied without any forced gas flow. The effect of the gap distance on the recovery process is studied by using two different inter-electrode gaps: 20 mm and 50 mm. The effect of arc current on the recovery process is investigated by using current amplitudes of 275 A and 425 A. Moreover, the effect of forced nitrogen flow near current zero is explored using two different arrangements: self-blast and puffer type. Four different nitrogen filling pressures are studied: 1, 20, 40, and 80 bar, the latter two being in the supercritical region. The experimental results show that, in the free-burning arc configuration, the breakdown voltage of the contact gap increases faster with the increase of the filling pressure. A gap of 50 mm recovers quicker than a 20 mm gap, whereas no strong current dependency is observed on the recovery characteristics in the investigated range. In the free-burning arc configuration, just after the current zero up to approximately 300 µs, the breakdown voltage at high filling pressure is found to be lower than at 1 bar. Forced gas flow, however, significantly enhances the dielectric recovery at a high filling pressure, also in the thermal phase.

Research on Discharge Characteristics in Ultra-high Pressure Gases (Supercritical Fluids): A Brief Review

“…The other sets of experiments, performed on ultrahigh pressure nitrogen exploring its applicability for current interruption purposes. The details of these experiments can be found in a series of earlier publications [12][13][14][15][16][17][18]. Different gas flow conditions, namely free burning arcs, arcs in tubular non-ablating nozzles (geometrically constricted arcs), arcs in ablating nozzles with different heating volume geometries (selfblast switch), arcs with forced gas flow (puffer switch), in a pressure range of 0.1 to 8 MPa at different current amplitudes, current frequencies exposed to different transient recovery voltage stresses are tested, see table 2.…”

“…Therefore, the experimental results relevant for current interruption are scarce; some are related to pulsed power application [9][10][11], where the supercritical fluid is used in a sort of plasma closing switch with almost no current interruption capability but fast dielectric recovery, enabling repetitive switching in a pulse power system. The only series of experiments [12][13][14][15][16][17][18] , which are to some extent relevant for switching applications in power grids, performed by one of the research groups, in ultra high pressure nitrogen for maximum current amplitudes of few hundred amperes.…”

Characterization of Ultrahigh Pressure Nitrogen Arc Using Black Box Arc Model

“…However, the arc characteristics at very high-pressure gas are limited [2,5,6]. Recently, a series of investigations have been carried out to study the ultrahigh pressure N 2 arc and its current interruption capability [7,8]. The arc voltage is found to rise with filling pressure, thus increasing arc energy deposition [5].…”

Arc extinction with nitrogen at 1-40 bar in a puffer-like contact configuration

“…The results showed that increasing the nitrogen filling pressure from 1 to 40 bar abs caused an almost threefold increase of the arc voltage. The arc-voltage characteristics for wall-restricted arcs, both thermal interruption capability and dielectric recovery rates in the contact gap after short (0.5-2.6 ms) current half-cycles, have also been published [4][5][6][7][8][9]. Moreover, dielectric recovery and arc characteristics in high-pressure (supercritical) CO 2 have been studied [10].…”

“…This paper reports on current-interruption experiments with a puffer-like contact configuration and nitrogen as the current interruption medium. In contrast to previous work [3][4][5][6][7][8], an upgraded test circuit with a current waveform close to 50 Hz is used. The current interruption capabilities at nitrogen filling pressures of 1, 10, 20 (subcritical) and 40 bar abs (supercritical state) were compared, using the same contact configuration and puffer design.…”