Transient Behavior in Transformer Oils: Prebreakdown and Breakdown Phenomena

Rzad, Stefan J.; Devins, J. C.; Schwabe, R.J.

doi:10.1109/tei.1979.298184

Cited by 34 publications

(16 citation statements)

References 10 publications

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“…Discharge propagation may be, however, the result of ionization of gas included in discharge channel (development of slow 1st and 2nd mode discharges) or direct liquid ionization as a characteristic process of the development of 3rd or 4th mode discharges. This second type of ionization occurs when the voltage significantly exceeds (more than two times) the 50 % breakdown voltage for the given electrode gap [1][2][3][4][5][9][10][11][12]. Similar phenomena to these, observed in the setups of bare electrodes of point-plane arrangements, were recorded for electrode setups in which an HV electrode was covered by paper insulation.…”

Section: Introductionsupporting

confidence: 66%

“…These values, however, depend on the degree of field nonuniformity and type of liquid. In the setups of uniform and quasi-uniform electrical field distribution, inception electrical field stress is about 0.3-0.5 MV/cm (especially for the liquids of technical purity) while in the setups of non-uniform electrical field distribution and liquids of laboratory purity even few or 10 MV/cm [1][2][3][4][6][7][8]. In the first case, generally lower values of inception electrical field stress are the result of uniform electrical field distribution and the influence of surface and volume effect on the electrical strength of such setups.…”

Section: Discussionmentioning

confidence: 98%

“…Within the literature on this subject, there are many publications, serving such threshold values of inception electrical field stress both for the setups of non-uniform electrical field distribution (point-plane) and for setups of uniform and quasi-uniform field distribution [1,3,4,[6][7][8]. These data came from the theoretical considerations and experimental research, and also were supported by appropriate mathematical calculations.…”

Section: Discussionmentioning

confidence: 99%

“…In these studies, initiation has been considered both in pure hydrocarbon liquids and in transformer mineral oil of technical purity [1][2][3][4][5][6][7][8][9]. A new part of the experimental studies has been focused also B Pawel Rozga pawel.rozga@p.lodz.pl 1 Lodz University of Technology, Institute of Electrical Power Engineering, Stefanowskiego 18/22, 90-924 Lodz, Poland on environmentally friendly dielectric liquids such as the natural and synthetic esters [10][11][12]. The most often analyzed electrode setups have been the point-plane setups representing extremely non-uniform electrical field distribution.…”

Section: Introductionmentioning

confidence: 99%

“…The wide spectrum of research indicated that electrical discharge initiation and propagation are very complex processes involving different physical phenomena. Depending on the chemical composition and physical properties of the liquids, pressure and temperature, type of testing voltage as well as electrode geometry, the processes determining discharge initiation may be the bubble formation by Joule heating, cavity formation by electromechanical forces or electrostatic emission [1,3,4,7,8]. Discharge propagation may be, however, the result of ionization of gas included in discharge channel (development of slow 1st and 2nd mode discharges) or direct liquid ionization as a characteristic process of the development of 3rd or 4th mode discharges.…”

Section: Introductionmentioning

confidence: 99%

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Influence of volume effect on electrical discharge initiation in mineral oil in the setup of insulated electrodes

Rózga

Hantsz

2016

Electr Eng

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This article deals with the problem of electrical discharge initiation in mineral oil in the setup of insulated electrodes. The results of laboratory experimental studies were collated with the results of the numerical calculations of electrical field stress. Both kinds of the research methods were applied to analyze the two model electrode setups immersed in mineral oil: setup with insulated HV electrode and setup with bare HV electrode having the same outer dimensions as the insulated one. The obtained similarities in the values of maximum inception electrical field stress and the equality in the experimentally evaluated initiation delay indicated that the most stressed oil volume and weak points included in it may be responsible for discharge initiation in paper-oil insulation setups with oil of technical purity. The same number of weak points included in oil may be, in both the cases considered, an equally productive source of initiation sites.

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Section: Introductionsupporting

confidence: 66%

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Influence of volume effect on electrical discharge initiation in mineral oil in the setup of insulated electrodes

Rózga

Hantsz

2016

Electr Eng

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Streamers in Liquids

Tobazéon

1988

The Liquid State and Its Electrical Properties

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Propagation et génération des streamers dans les diélectriques liquides

Béroual¹,

Tobazéon²

1987

Rev. Phys. Appl. (Paris)

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2014 Cette étude concerne la génération et la propagation des streamers en géométrie pointe-plan sous créneau de tension. Un nouveau dispositif expérimental a permis de montrer qu'il existe une relation étroite entre la forme du streamer, sa vitesse de propagation, la forme du courant et la lumière qu'il émet qu'elles que soient la polarité de la pointe et la nature du liquide. Plus le streamer est filamentaire, plus il est rapide et réciproquement. La distribution de vitesse admet un minimum pour un très grand nombre de liquides isolants pur ou renfermant divers additifs. L'amplitude des vitesses dépend d'une manière importante des propriétés électroniques du liquide et des additifs. L'effet de la pression hydrostatique sur l'apparition des streamers dans les deux polarités, indique l'existence d'une phase gazeuse. Il semble que le mécanisme de cavitation induite par des mouvements électrohydrodynamiques résultant d'une injection unipolaire de charges ne soit pas à l'origine de cette phase gazeuse.Abstract. 2014 This study concerns the initiation and propagation of streamers in point-plane geometry. Our experimental set-up has permitted us to show the existence of a close correlation between the shape of the streamer, its propagation velocity, the current shape and the light it emits, whatever are the polarity of the point and the liquid nature. The more filamentary the streamer, the higher its velocity. The propagation velocity has a minimum for a large variety of insulating liquids wheter pure or containing different additives. The amplitude of the velocity depends strongly on the electronic properties of the liquid and additives. The effects of hydrostatic pressure on the streamer appearance for both polarities suggest the existence of a gas phase. It appears that electrohydrodynamically induced cavitation phenomena, resulting from unipolar charge injection, are not responsible for the gas phase.

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Transient Behavior in Transformer Oils: Prebreakdown and Breakdown Phenomena

Cited by 34 publications

References 10 publications

Influence of volume effect on electrical discharge initiation in mineral oil in the setup of insulated electrodes

Influence of volume effect on electrical discharge initiation in mineral oil in the setup of insulated electrodes

Streamers in Liquids

Propagation et génération des streamers dans les diélectriques liquides

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