Optimization Of The Three-electrode Spark Gap Characteristics

This paper presents results obtained in the development of the three-electrode spark gap. The requirements for correct operation of the spark gap were: 1) the ability of reliable triggering under operating voltages amounting to 50% of the spontaneous breakdown voltage value, 2) the low statistical dissipation of an random operating time and 3) the reversibility of spark gap characteristics under service conditions. Two kinds of three-electrode spark gaps with under-pressure gas insulator were considered: a spark gap with a third electrode within the main one, and a spark gap with a separate third electrode. We determined the parameters relevant for spark gap functioning (gas type, electrode material, triggering voltage amplitude and polarity, voltage polarity ratio and - for the spark gap having the third electrode within the main one, side of triggering). The gas type was selected among SF6, N2 and their mixture. The electrode material were: copper, tungsten and steel. We varied thevoltage from 30% to 90% of the spontaneous breakdown voltage. We determined and designed an optimal three-electrode spark gap with gas insulation for synthetic circuit control based on presented results.