In-Liquid Streamer Characterization and Fractal Analysis

Dirnberger, Abraham; Kovaleski, Scott D.; Norgard, Peter; Thagard, Selma Mededovic; Franclemont, Joshua

doi:10.1109/tps.2017.2778710

Cited by 5 publications

(3 citation statements)

References 20 publications

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“…However, a high luminescence can take place under a large gap (tens of millimeters) and a high applied voltage (hundreds of kilovolts) in water or oil [34][35][36]. Furthermore, for positive streamers, an intense light signal was captured during their development [37][38][39], or at their initiation [40][41][42].…”

Section: Streamer Induced Breakdown In Lnmentioning

confidence: 99%

Prebreakdown negative streamers in liquid nitrogen: propagation characteristics and their influence on microsecond breakdown

Yan

Wang

Zhou

et al. 2021

J. Phys. D: Appl. Phys.

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Further clarification of streamer-induced breakdowns in liquid nitrogen has been attracting increasing attention owing to their potential applications in superconducting systems and cryoplasmas. In this work, negative streamers in microsecond discharges were investigated using a high-speed multiple-frame imaging technique. Different external voltages, gap lengths, hydrostatic pressures, and pin tips were employed to initiate various streamers, namely bush-like streamers, single pinecone-like streamers, dendritic streamers, and filamentary streamers. Furthermore, abundant hybrid streamers involving streamer transition and combination were observed. The diversity of negative streamers may be related to the pin morphology. Generally, it was found that thinner streamers, especially filamentary streamers, could take place more frequently with higher breakdown probability under stronger filed and lower pressure. However, bush-like streamers gradually played a more dominant role upon increasing the pressure, and they were unable to cause breakdown. Moreover, several intermittent weak discharges were recorded during the growth of streamers, which might be responsible for the streamer transition and propagation. Additionally, given the evolution of streamers branches after breakdown and the influence of pressure on streamers characteristics, it was speculated that high-pressure gas could be involved inside the streamers. The possible mechanism of streamer propagation and resultant breakdown were further explored based on the analysis of streamer protrusions.

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Section: Streamer Induced Breakdown In Lnmentioning

confidence: 99%

Prebreakdown negative streamers in liquid nitrogen: propagation characteristics and their influence on microsecond breakdown

Yan

Wang

Zhou

et al. 2021

J. Phys. D: Appl. Phys.

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“…Among them, fractal analysis is considered to deal with the selfsimilarity of discharge image with acceptable result which was first introduced to analyze Energies 2021, 14, 8253 2 of 13 the discharge phenomenon in SF 6 [14]. In past years, fractal analysis has already been applied to investigate the discharge at the dielectric interface or inside the transparent dielectric [15][16][17]. A.…”

Section: Introductionmentioning

confidence: 99%

Improved Image Analysis Method to Evaluate Tracking Property under Successive Flashover Based on Fractal Theory

Cao

Lin

2021

Energies

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Successive flashover would result in carbonized tracking on insulator surface and cause deterioration to the insulation. Thus, investigation of the tracking can be beneficial in understanding flashover characteristics during long-term operation. In this paper, DC flashover was operated on the insulator, and the image of tracking after successive discharge were captured. Improved differential box-counting method (IDBM) was applied to analyze these images based on fractal theory. Weighted item was suggested during the counting procedure for rectangle image with margin covered by cut-size box. Fractal dimension of the tracking was calculated according to the suggested method. It is claimed that the suggested method could estimate the discharge propagation property and deterioration characteristics on the insulator surface. Moreover, IDBM showed advantages in image pre-processing and deterioration property revealed compared to traditional box-counting method attributing to the consideration of color depth. This image analysis method shows universality in dealing with tracking image and could provide additional information to flashover voltage. This paper suggested a potential approach for the investigation of discharge mechanism and corresponding deterioration in future research.

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“…These disparities in the breakdown voltage of ester liquids and mineral oils are also seen to worsen under high field inhomogeneity and in longer inter-electrode gaps. Polarity has also been shown to affect breakdown voltage of esters, with typical values for negative impulse breakdown voltages being higher than for positive impulsive stresses [4], [6]. The breakdown voltage of an insulating liquid will also be affected by the amount of moisture contained within the liquid.…”

Section: Introductionmentioning

confidence: 99%

Breakdown Characteristics of Natural and Synthetic Ester Liquids When Containing Varying Levels of Moisture

Williamson

Timoshkin

MacGregor

et al. 2019

2019 IEEE Pulsed Power &Amp; Plasma Science (PPPS)

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Ester insulating liquids provide a number of benefits when compared with conventional naphthenic oils. To increase acceptance of esters as a long term replacement for mineral oils in high voltage/pulsed power systems, it is of paramount importance that their dielectric properties are well known. This paper examines the breakdown voltage, and time to breakdown, of MIDEL 7131 synthetic ester, the natural ester Envirotemp FR3 and a mineral oil: Shell Diala S4 ZX, at varying levels of moisture saturation, when exposed to HV impulses of both positive and negative polarity. No statistically significant difference in the breakdown voltage of the ester liquids with increasing relative humidity for either polarity was observed. Noticeable polarity dependence in breakdown voltage values was observed with Envirotemp FR3 liquid, which possesses the highest breakdown strength under positive impulses, but the lowest under negative impulses. Inversely, MIDEL 7131 exhibits the lowest breakdown voltage for positive impulses, and the highest breakdown voltage under negative impulsive energisation.

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In-Liquid Streamer Characterization and Fractal Analysis

Cited by 5 publications

References 20 publications

Prebreakdown negative streamers in liquid nitrogen: propagation characteristics and their influence on microsecond breakdown

Prebreakdown negative streamers in liquid nitrogen: propagation characteristics and their influence on microsecond breakdown

Improved Image Analysis Method to Evaluate Tracking Property under Successive Flashover Based on Fractal Theory

Breakdown Characteristics of Natural and Synthetic Ester Liquids When Containing Varying Levels of Moisture

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