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

Abstract

To develop cost-efficient subsea switchgear for large sea depths, the extinction of arcs under high filling pressures must be understood. In this work, arc-extinction experiments have been performed with a puffer-like contact configuration using nitrogen at different filling pressures as the current interruption medium. The main finding is that, for the given contact configuration, the currentinterruption capability was lower at 20 and 40 barabs than at 1 and 10 barabs. While higher pressures result in higher cooling flow rates and longer flow times given the same puffer volume, compression spring and nozzle geometry; it does not necessarily improve the arc-extinction capability. This is probably because higher filling pressures increase the arc voltage and total energy dissipated in the arcing zone. Because the filling pressure greatly influences the flow characteristics, the puffer design should be optimized for each pressure level.

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.…”