Flashover of insulators in vacuum: the last twenty years

Miller, H. Craig

doi:10.1109/tdei.2015.004702

Cited by 190 publications

(69 citation statements)

References 175 publications

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“…The initial increase of is a well-known effect of conditioning of the insulator surface which is associated with removal of surface gas, removal of surface contaminants, or removal of emission sites [30,31]. One can see that continued to increase slowly in the following flashover events ( >1000) and reached about 14.5 kV after about 10 6 breakdowns.…”

Section: Resultsmentioning

confidence: 99%

Low energy surface flashover for initiation of electric propulsion devices

Zhang

Dary

Shashurin

2019

Plasma Res. Express

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An approach to utilize Low Energy Surface Flashover (LESF) for triggering the discharge in electric propulsion systems has been demonstrated. LESF uses conventional surface flashover mechanism with limited duration of high-current stage of the flashover below <100-200 ns. This eliminates the damage to the LESF assembly and allows robust operation of the same assembly for >1.510 6 consecutive flashovers. The amount of the seed plasma created in the individual LESF event was demonstrated to be sufficient to trigger a moderate current arc which models a discharge in an electric propulsion system.

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Section: Resultsmentioning

confidence: 99%

Low energy surface flashover for initiation of electric propulsion devices

Zhang

Dary

Shashurin

2019

Plasma Res. Express

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“…Epoxy resin is widely used in gas insulated switchgear and gas insulated transmission line as insulating and strutting parts due to its excellent electrical and mechanical properties [1][2][3][4][5]. However, in DC electric field, a large amount of electric charges are likely to accumulate on the interface between the epoxy resin and gas, which distort electric field and provide charges, and finally cause surface discharge.…”

Section: Introductionmentioning

confidence: 99%

Deposition of SiC_xH_yO_zthin film on epoxy resin by nanosecond pulsed APPJ for improving the surface insulating performance

Xie¹,

Lin²,

Zhang³

2017

Plasma Sci. Technol.

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Non-thermal plasma surface modification for epoxy resin (EP) to improve the insulation properties has wide application prospects in gas insulated switchgear and gas insulated transmission line. In this paper, a pulsed Ar dual dielectrics atmospheric-pressure plasma jet (APPJ) was used for SiC x H y O z thin film deposition on EP samples. The film deposition was optimized by varying the treatment time while other parameters were kept at constants (treatment distance: 10 mm, precursor flow rate: 0.6 l min −1 , maximum instantaneous power: 3.08 kW and single pulse energy: 0.18 mJ). It was found that the maximum value of flashover voltages for negative and positive voltage were improved by 18% and 13% when the deposition time was 3 min, respectively. The flashover voltage reduced as treatment time increased. Moreover, all the surface conductivity, surface charge dissipation rate and surface trap level distribution reached an optimal value when thin film deposition time was 3 min. Other measurements, such as atomic force microscopy and scanning electron microscope for EP surface morphology, Fourier transform infrared spectroscopy and x-ray photoelectron spectroscopy for EP surface compositions, optical emission spectra for APPJ deposition process were carried out to better understand the deposition processes and mechanisms. The results indicated that the original organic groups (C-H, CC , C=O, C=C) were gradually replaced by the Si containing inorganic groups (Si-O-Si and Si-OH). The reduction of C=O in ester group and C=C in p-substituted benzene of the EP samples might be responsible for shallowing the trap level and then enhancing the flashover voltage. However, when the plasma treatment time was longer than 3 min, the significant increase of the surface roughness might increase the trap level depth and then deteriorate the flashover performance.

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“…[1][2][3][4] Generally, the flashover process can be divided into three stages, i.e., the initiation stage, the development stage, and the last breakdown stage. It is considered that the surface discharge in vacuum initiates with field emission of electrons from the cathode triple junction (CTJ), where the cathode, dielectric and vacuum meet and is finally breakdown in the desorbed gas from insulator surface.…”

Section: Introductionmentioning

confidence: 99%

“…It is considered that the surface discharge in vacuum initiates with field emission of electrons from the cathode triple junction (CTJ), where the cathode, dielectric and vacuum meet and is finally breakdown in the desorbed gas from insulator surface. 4,5 However, it is still under debate about the development process, and the secondary electron emission avalanche (SEEA) 3 model maybe the one of the most acceptable theories. To clarify the development process, the accompanying luminescence behaviors during flashover are of great help to find out the physical mechanisms governing the discharge.…”

Section: Introductionmentioning

confidence: 99%

Luminescence evolution from alumina ceramic surface before flashover under direct and alternating current voltage in vacuum

Wang

Song

et al. 2016

AIP Advances

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The luminescence evolution phenomena from alumina ceramic surface in vacuum under high voltage of direct and alternating current are reported, with the voltage covering a large range from far below to close to the flashover voltage. Its time resolved and spatial distributed behaviors are examined by a photon counting system and an electron-multiplying charge-coupled device (EMCCD) together with a digital camera, respectively. The luminescence before flashover exhibits two stages as voltage increasing, i.e., under a relative low voltage (Stage A), the luminescence is ascribed to radiative recombination of hetero-charges injected into the sample surface layer by Schottky effect; under a higher voltage (Stage B), a stable secondary electron emission process, resulting from the Fowler-Nordheim emission at the cathode triple junction (CTJ), is responsible for the luminescence. Spectrum analysis implies that inner secondary electrons within the surface layer of alumina generated during the SSEE process also participate in the luminescence of Stage B. A comprehensive interpretation of the flashover process is formulated, which might promote a better understanding of flashover issue in vacuum.

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Flashover of insulators in vacuum: the last twenty years

Cited by 190 publications

References 175 publications

Low energy surface flashover for initiation of electric propulsion devices

Low energy surface flashover for initiation of electric propulsion devices

Deposition of SiC_xH_yO_zthin film on epoxy resin by nanosecond pulsed APPJ for improving the surface insulating performance

Luminescence evolution from alumina ceramic surface before flashover under direct and alternating current voltage in vacuum

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Flashover of insulators in vacuum: the last twenty years

Cited by 190 publications

References 175 publications

Low energy surface flashover for initiation of electric propulsion devices

Low energy surface flashover for initiation of electric propulsion devices

Deposition of SiCxHyOzthin film on epoxy resin by nanosecond pulsed APPJ for improving the surface insulating performance

Luminescence evolution from alumina ceramic surface before flashover under direct and alternating current voltage in vacuum

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Product

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Deposition of SiC_xH_yO_zthin film on epoxy resin by nanosecond pulsed APPJ for improving the surface insulating performance