Impact of volume breakdown on surface flashover in high pressure SF 6

A. A. Neuber, J. T. Krile, G. Rogers, H. Krompholz

Research output: Contribution to journalArticlepeer-review


We investigate the pulsed flashover voltage of dielectric samples at up to 4 bar SF6 in the simultaneous presence of a high current (> 10 kA, ∼ 20 microsecond pulse) volume discharge nearby. The chosen distance, ∼ 7 cm, between surface and volume breakdown is consistent with conditions found in the Sandia-Z-machine type rimfire switch. For a flashover gap distance of 24 mm and a simultaneous excitation within ∼ 5 microseconds, we observe an average reduction in the flashover voltage from 164 kV to 142 kV at 3.7 bar when the volume discharge is turned on. The test setup utilizing a magnetic switching scheme operating at 320 kV and 10 kA is briefly discussed along with the breakdown properties and the spectral characterization of the volume/surface flashover discharge plasma. In general, UV light propagates relatively unattenuated for wavelengths > 160 nm in the high pressure SF6 from the volume discharge to the dielectric surface, setting up conditions which are conducive to photoelectron emission from the dielectric.

Original languageEnglish
Pages (from-to)995-997
Number of pages3
JournalActa Physica Polonica A
Issue number6
StatePublished - Jun 2009


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