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Atmospheric variations and apparatus flashover
Electrical Engineering, 1941I. Introduction IN practically all electrical apparatus use is made of the insulating properties of air. The electrical breakdown strength of air, for the electrode arrangements found in apparatus, depends upon air temperature, pressure and moisture content.
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On the theory of flashover development
Fire Safety Journal, 1995The characteristics of hot smoke layer development from ignition to flashover are obtained for a fire in a compartment with one opening. Flashover itself as a final stage of development is analysed using heat balance considerations for the developed hot layer (in direct contact with the external atmosphere through the opening) on the basis of a two ...
T.L. Graham +2 more
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1988
Remedies are called for, evidently, when the flashover frequency rises above acceptable levels. What is 'acceptable' depends on the importance of the line or substation and on the required quality of supply, in terms of outage time per year. Standards thus vary widely: for lines, a rate of about one flashover per 150 km per year is general for ...
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Remedies are called for, evidently, when the flashover frequency rises above acceptable levels. What is 'acceptable' depends on the importance of the line or substation and on the required quality of supply, in terms of outage time per year. Standards thus vary widely: for lines, a rate of about one flashover per 150 km per year is general for ...
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Journal of Applied Physics, 1967
Experiments on the vacuum flashover of dielectric frusta subjected to 35 and 75 nsec pulses show the strong influence of cone angle on insulation strength. A theory is presented to explain the formative process leading to flashover for one polarity. It is proposed that positive surface charge grows by emission of hot electrons during the application of
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Experiments on the vacuum flashover of dielectric frusta subjected to 35 and 75 nsec pulses show the strong influence of cone angle on insulation strength. A theory is presented to explain the formative process leading to flashover for one polarity. It is proposed that positive surface charge grows by emission of hot electrons during the application of
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Effects of soluble constituents on insulator flashover performance and flashover voltage prediction
2015 IEEE Conference on Electrical Insulation and Dielectric Phenomena (CEIDP), 2015Pollution materials affect insulator flashover performance, and there is long-term significance in researching it. In this paper, common kinds of nitrates were used as the soluble pollution, and the ac flashover tests of typical glass insulator were carried out. During the tests, the samples were polluted by dipping method. Also, up-and-down method was
Dongdong Zhang +4 more
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Surface flashover of insulators
IEEE Transactions on Electrical Insulation, 1989The author reviews surface flashover (i.e. voltage breakdown along the surface of insulators), primarily in vacuum. He discusses theories and models relating to surface flashover and pertinent experimental results. Surface flashover of insulators in vacuum generally is initiated by the emission of electrons from the cathode triple junction (the region ...
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Physics of pollution flashover
1988The apparent paradox in pollution flashover is that catastrophic electrical discharges are produced, spanning up to metres of air, by electrical potential differences capable, in ordinary circumstances, of being contained by air clearances of the order of a few centimetres.
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2013 Annual Report Conference on Electrical Insulation and Dielectric Phenomena, 2013
Atmospheric ice accretion, combined with pollution, has been identified as a significant risk factor in the reliability of line and station insulators in cold climate regions. Flashovers occurring on ice- and snow-covered insulators result from combinations of a number of factors.
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Atmospheric ice accretion, combined with pollution, has been identified as a significant risk factor in the reliability of line and station insulators in cold climate regions. Flashovers occurring on ice- and snow-covered insulators result from combinations of a number of factors.
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Flashover and boundary properties
Fire Safety Journal, 2010Abstract A non-linear model of flashover, FLASHOVER A1, which has been described in earlier work, has been used to explore the dependence of the critical heat release rate (Qfc) for flashover on the properties of the boundary of the enclosure.
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Flashover surface spectrometry
Conference on Electrical Insulation & Dielectric Phenomena - Annual Report 1972, 1972A bakeable, ultrahigh vacuum, time-of-flight mass spectrometer has been constructed in order to investigate, for the first time, the nature of the ion species formed prior to the flashover of a parallel plate diode.1 During operation, the field in the gap of the diode is maintained approximately 5% below that required for visible flashover.
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