The Influence of Electric Field Inhomogeneity on Repetitive Performance of a Corona-Stabilized Switch

Abstract

The corona-stabilized switch has a great potential in pulsed power systems where high pulse repetition frequencies are required. Corona discharge in SF 6 in highly inhomogeneous electric field is utilized to improve repetitive performance of this kind of switch. To clarify how the repetitive performance (insulation recovery and repetitive breakdown stability) of the switch depends on the field inhomogeneity, the insulation recovery and repetitive breakdown stability of a corona-stabilized switch are experimentally investigated and theoretically analyzed. An innovative double-pulse method combining breakdown voltage and discharge channel images is used to measure the insulation recovery of the switch. For different electrodes, their voltage jitters at pulse repetition frequencies of 1-2000 Hz are measured to illustrate the stability of repetitive breakdown. The experimental results are theoretically analyzed from the memory effect and behavior characteristics of the residual plasma, the critical volume and its dynamic characteristics. The results reveal the corona stabilization enhancement effect during the repetitive breakdown in SF 6 in extremely inhomogeneous field. The influence of electrode profile on the propagation of discharge channel shock wave, the decay of residual plasma and the recovery of neutral gas density are clarified. Effect of the electrostatic conditions, including the critical volume and its dynamic characteristics, and the intensity of corona discharge, on the repetitive performance of the switch are also clarified. INDEX TERMS Corona stabilization, electric field inhomogeneity, gas discharge devices, insulation recovery, memory effect.

Development and Test of a 500-kV Compact Marx Generator Operating at 100-Hz PRF

“…As mentioned in [21], the application of the corona stabilized electrode reduces the breakdown delay. It also reduces the jitter of the generator.…”

“…Since the corona phenomena occur before the complete breakdown of the gap, the corona stabilization effect will act on any of the subsequent breakdowns during the PRF operation. Therefore, an improvement in the insulation recovery performance of the interelectrode gas and a reduction of the breakdown voltage jitter are both expected, as detailed in [21]. Preliminary testing of the 13-stage Marx generator proved that, after setting the optimum positions for all the corona-stabilized electrodes, it has a very stable operation even in atmospheric air.…”

“…To overcome this disadvantage, corona-stabilized electrodes were installed in the SGSs in stages from 2 to 10. The application of this technique allows to improve the stability of the SGS operation and increases the PRF of the generator [21].…”

“…A few electrons can hardly cause an electron avalanche when their position is too far from the corona stabilizing electrode to be accelerated enough to obtain sufficient kinetic energy. A critical volume is defined here as a region close to the highly stressed corona stabilized electrode, where the presence of just a few electrons will lead to an electron avalanche [21]. Ionization in atmospheric air starts when the field strength exceeds 26 kV/cm [23].…”

Investigating the characteristics of internal discharge shock waves in gas‐insulated switchgear under varied gap configurations

“…Numerous studies have explored gas discharge shock waves, investigating the attributes of shock waves generated by various gases such as air and argon [12][13][14]. Extensive research has been conducted on the shock waves produced by SF 6 gas discharges in SF 6 circuit breakers [5,[15][16][17], primarily aimed at informing the internal structure design of these circuit breakers. For instance, in [15], simulations were employed to analyse the propagation characteristics of shock waves resulting from arc discharges in SF 6 circuit breakers.…”