Current interruption performance of ultrahigh-pressure nitrogen arc

Abstract

In this paper, the influence of gas filling pressure on the current interruption performance of different switch configurations with electric arcs burning in nitrogen has been experimentally investigated. A synthetic circuit generating a current of 130 A at 190 Hz is used and the initial rate of rise of recovery voltage just after current zero is varied from 9.8 V/µs to 84.9 V/µs. To evaluate the effect of forced gas flow on current interruption performance, three different test arrangements are investigated: a simple contact configuration with a free-burning arc, a contact and a cylindrical nozzle setup (tube-constricted arc), and finally a self-blast arrangement where the arc is cooled by a gas flow near current zero. In each arrangement, three different filling pressures are mainly studied: 1, 20, and 40 bar, the latter being in the supercritical region. In all cases, the interelectrode gap is fixed at 50 mm. It is observed that the interruption performance deteriorates with increased filling pressure in the absence of forced gas flow. A higher post-arc current is observed for the arcs burning at high filling pressures (i.e. 20 and 40 bar) compared to at atmospheric pressure in cases with no or little forced cooling. On the other hand, a forced gas flow near the current zero reduces the post-arc current and improves the interruption performance also at high filling pressures. Little effect of the supercritical state on the interruption performance of nitrogen is observed. Under the above-mentioned test conditions, the majority of the failures at high filling pressure are observed to be of thermal re-ignition type.

Metal vapor content of an electric arc initiated by exploding wire in a model N2 circuit breaker: simulation and experiment

“…For instance, the current interruption performance at 20 bar for the tube constricted arrangements with 4 mm inner diameter, is observed to be worse than that at 1 bar, whereas 40 bar shows the best performance in the proposed N 2 CB model [50]. Compared with FB arcs, at higher pressures (5-30 bar), 3 cm nozzle length with 2 mm inner diameter in thc tot increases with p after 13 000 K, while decreases for temperatures less than 8 000 K in both 20 and 40 bar cases.…”

“…Figure 21 depicts the measured values of V, P (voltage multiplied by current), and R (voltage divided by current) for 20 µm EEW with a sampling rate of 1.25 Msamples per second, 40 µm and 100 µm EEW with a sampling rate of 500 Msamples per second in the logarithmic scale. In contrast to the well-known pulse with dwell (current pause), a single electrical pulse is produced [48], which is usual for relatively low resistive metals like copper [49] although it is also possible to have a current pause with 25 µm EEW, (for instance see figure 4 in [50]). The heating process changes to an explosion after 76, 116, and 529 µs from the current injection corresponding to 25, 40, and 100 µm, respectively, which results in the change of the voltage slope.…”

Rapid and Safe Arc Quench by Using External Magnetic Coil in Power Interruption

“…Accelerating the arc towards to the steel plates and forcing the arc evenly being cut and split can help to fulfill the efficient power interruption. Some techniques like imposing a gas flow [33] from the polymer dielectric polymer to interact with the thermal arc are proposed to expedite the power interruption.…”

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.…”