Prebreakdown phenomena in hydrocarbon liquids

Yamashita, H.; Amano, Hiroshi

doi:10.1109/14.7347

Cited by 68 publications

(18 citation statements)

References 8 publications

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“…This is attributed to π bonds, which have lower bond strength than σ bonds in CC double bonds. This result is consistent with previous reports [4,5]. (3) Features (1) and (2) are also seen for both cyclic and straight-chain hydrocarbon liquids.…”

Section: Discussionsupporting

confidence: 94%

The effect of molecular structure on prebreakdown phenomena in dielectric liquids under a nonuniform field

Nakao

Yamazaki

Miyagi

et al. 2002

Electrical Engineering Japan

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In the present work, prebreakdown phenomena in dielectric liquids which have various molecular structure, especially those with chlorine or fluorine atoms and some double bonds included in their molecular formula, are observed in detail for positive and negative point polarities, under the application of an impulse voltage (1.1/225 µs) to the point electrode. As test liquids, cyclic hydrocarbon liquids such as cyclohexane, benzene, chlorocyclohexane, monochlorobenzene, hexafluorobenzene, and cyclohexene are used. Results obtained in these liquids are compared with those obtained in straight‐chain hydrocarbon liquids.As a result, the propagation of negative streamers, especially in dielectric liquids with chlorine or fluorine atoms in their molecular formula, is promoted, whereas the propagation of positive streamers in dielectric liquids with some double bonds is promoted. The former is related to a large electron affinity, the latter is due to π electrons, for both cyclic and straight‐chain hydrocarbon liquids. © 2002 Scripta Technica, Electr Eng Jpn, 139(1): 1–8, 2002; DOI 10.1002/eej.1140

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Section: Discussionsupporting

confidence: 94%

The effect of molecular structure on prebreakdown phenomena in dielectric liquids under a nonuniform field

Nakao

Yamazaki

Miyagi

et al. 2002

Electrical Engineering Japan

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“…From Fig. Thus, it appears that these features are due to π bonds, which have smaller bond energy and are more chemically reactive than σ bonds, which agrees with results of studies by Yamashita and Amano [7] and Yamada and colleagues [9]. 3, reach the Teflon plate (t = 3.7 µs) and that the currents seen after that time correspond to positive surface streamers propagating on the Teflon plate.…”

Section: Resultssupporting

confidence: 88%

“…Yamashita and Amano have reported the essential properties of density changes (streamers) generated in liquids (insulating oils) [5,6], the relation between the molecular structure of liquids (saturated-unsaturated, straight chain-cyclic) and insulation breakdown phenomena [7], and the relation between prebreakdown phenomena and chain length in straight-chain hydrocarbon liquids [8]. Yamashita and Amano have reported the essential properties of density changes (streamers) generated in liquids (insulating oils) [5,6], the relation between the molecular structure of liquids (saturated-unsaturated, straight chain-cyclic) and insulation breakdown phenomena [7], and the relation between prebreakdown phenomena and chain length in straight-chain hydrocarbon liquids [8].…”

Section: Introductionmentioning

confidence: 99%

“…In particular, since studies of the influence of molecular structure on the insulation breakdown of liquids are of great importance to an understanding of their breakdown mechanism, many studies that are relevant to this have been carried out. Yamashita and Amano have reported the essential properties of density changes (streamers) generated in liquids (insulating oils) [5,6], the relation between the molecular structure of liquids (saturated-unsaturated, straight chain-cyclic) and insulation breakdown phenomena [7], and the relation between prebreakdown phenomena and chain length in straight-chain hydrocarbon liquids [8].…”

Section: Introductionmentioning

confidence: 99%

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Influence of molecular structure on propagation of positive streamer discharge in dielectric liquids

Nakao¹,

Hamano²,

Naito³

et al. 2004

Electrical Engineering Japan

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In this paper, streamer discharges in dielectric liquids which have various molecular structures, such as a double bond or a triple bond in the molecular formula, are observed in detail for positive point polarity under the application of an impulse voltage to the point electrode. As test liquids, four straight-chain hydrocarbon liquids-n-hexane, n-heptane, n-octane, and n-decane-are selected and in addition the influence of a double or triple bond included in their molecular formula on the propagation of positive streamers is investigated in detail by simultaneously using a highspeed schlieren method and an LED current measurement system. Some differences in the mean propagation velocity and the propagation shape of positive streamers are evident. Their shape is mainly filamentary in test liquids including a double or triple bond. Also, positive streamer propagation is promoted in these liquids. It is thought that this is due to the effect of π bonds which have smaller bond energies than σ bonds.

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“…The bubbles or cavities generated by the initiating steamers have been determined to range in size from 2 to 10 μm [7][8][9][10][11]. In this context the cavities referred to are the prebreakdown cavities, which are initiated by the first streamer which, after undergoing expansion and partial discharge, collapse before any subsequent breakdown streamers can develop.…”

Section: Introductionmentioning

confidence: 99%

Partial discharge measurements in dielectric liquids

Pompili

2008

2008 IEEE International Conference on Dielectric Liquids

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PD measurements in dielectric liquids have been normally performed in the past only using conventional narrow bandwidth detectors. The more recent use of ultra-wide bandwidth instruments has permitted to support once again the thesis that the PDs in oils are the consequence of the streamer (vapor phase) formation and its development. In the paper simultaneous PD measurements in insulating liquids using both narrow and ultra-wide bandwidth detectors are presented. Whilst PD detection with narrow bandwidth instruments gives only integrated signals, the use of ultra-wide bandwidth techniques permits to have much more precise information on PD phenomena, which appear to be in the form of pulses (bursts) of ascending magnitude as the bubble within the liquid expands in volume. As reported in the paper, the use of the ultra-wide bandwidth instruments permits also to distinguish the PD pulses occurring in regular voids of oil-paper insulations and PD pulses formed directly in the liquids as consequence of the streamer development. Also in the paper the meaning of the PDIV in oils is discussed, showing its dependence with the definition used, the unpredictable level of the background noise as well as the randomness of the PD initiation process

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Prebreakdown phenomena in hydrocarbon liquids

Cited by 68 publications

References 8 publications

The effect of molecular structure on prebreakdown phenomena in dielectric liquids under a nonuniform field

The effect of molecular structure on prebreakdown phenomena in dielectric liquids under a nonuniform field

Influence of molecular structure on propagation of positive streamer discharge in dielectric liquids

Partial discharge measurements in dielectric liquids

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