Three-electrode gas switches with electrodynamical acceleration of a discharge channel

Abstract

High voltage, high current, and high Coulomb transfer closing switches are required for many high power pulsed systems. There are a few alternatives for closing switches, for example, ignitrons, vacuum switches, solid-state switches, high pressure gas switches (spark gaps), and some others. The most popular closing switches up to date are spark gaps due to relatively simple design, robustness, easily field maintenance, and repair. Main drawback of spark gaps is limited lifetime, which is related directly or indirectly to erosion of the electrodes. Multichannel switches and switches with moving arc have been proposed to prevent the electrodes erosion. This study investigates switches, where a spark channel is initiated in a three-electrode layout and then the spark accelerates due to electrodynamic force and moves along the extended electrodes. At a given current amplitude, the diameter of the extended electrodes allows to control the spark velocity and hence, the erosion of the electrodes providing the required lifetime. The first switch is designed for 24 kV charging voltage and approximately 4 C total charge transfer. This spark gap was tested at 25 kA peak current in 40 000 shots in a single polarity discharge and in 20 000 shots in bipolar discharge. Second spark gap is designed for 24 kV charging voltage and approximately 70 C total charge transfer. It was tested in 22 000 shots, at a current of 250 kA with a pulse length of 360 mus. In this paper, we present design of these spark gaps and trigger generator, describe the test bed, and present the results of the tests.

Investigation of a two-electrode gas switch with electrodynamical acceleration of spark channel in oscillatory regime of discharge

“…Measured capacitance of the bank is 39.9 µF. The bank is connected with HV electrode of the switch SW1 by HV connector (5). HV power supply UV-50-50 (maximum voltage 50 kV, maximum current 50 mA) is used for charging of the bank.…”

“…Spark gaps are often used to commute energy on a load. Triggered spark gaps with electrodynamical acceleration of spark channel were developed and investigated by Kovalchuk and colleagues [5,6]. Later two-electrode spark gap with inductive coupling in a triggering circuit [7] was introduced with sharp extension in operation range and charging voltage.…”

Capacitor bank module for multi megajoule energy storage

“…2) Switches for the pre-ionization and main circuits were developed and tested earlier by IHCE and ITHPP [3]. These switches are rail type spark gaps, where the spark is initiated in a three electrode layout and then accelerates due to electro-dynamical force and moves along the two extended electrodes.…”

Effect of metal-submicron-particle accumulation on the stability of consecutive high-pulse-power breakdowns in compressed N2

“…The breakdown stability of SGSs is crucial for the reliability of pulsed-power systems. Various factors determine their stability, for example, airflow disturbance [4], switch structure [5], and the contact materials [6]. However, the effects of metallic particles could be particularly important.…”