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First‐mode of negative streamers:Inception at liquid/solid interfaces

High Voltage 2021年第6期6卷 1069-1078页

作者： David Ariza abderrahmane beroual Ralf Methling Sergey Gortschakow Harold R.Chamorro School of Electrical Engineering KTH Royal Institute of TechnologyStockholmSweden Ecole Centrale de‐Lyon Ampère CNRS UMR 5005EcullyFrance Leibniz Institute for Plasma Science and Technology INP GreifswaldGermany

An experimental study of the inception of the first‐mode negative streamer at liquid/solid interfaces is presented in this article.The study is performed with a point‐plane configuration under square high voltage pulses.The electrode configuration is immersed in mineral oil and the liquid/solid interface is assembled in contact with the point electrode or in its vicinity.Four polymers and two impregnated papers have been tested as solids of the liquid/solid interface.Thus,it is possible to compare the influence of different parameter of the solid and the interface on the streamer inception.For example:Permittivity,solid surface roughness,chemical composition,etc.It has been observed that streamer inception voltages at interfaces with solids of higher permittivity to that of the mineral oil are statistically similar.Additionally,streamer inception voltages of streamer initiated free in the oil(no liquid/solid interface)are similar to that of the inception voltage of cases with solids with high permittivity.In contrast,the inception voltage of streamers initiated at permittivity matched interfaces are shown to be highest of the cases.The streamer inception voltage is also studied for different distances be-tween the liquid/solid interface and the point electrode with a permittivity matched interface.The results show a dependency of the inception voltage and the distance be-tween the point electrode and the interface.Finally,an analysis of the observation is performed to show that the Townsend‐Meek criterion cannot predict the obtained results.

关键词： solid liquid electrode

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Verification of Insulation Oil Reclamation by Turbidity and Spetrophotometry Measurements

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Journal of Energy and Power Engineering 2012年第5期6卷 703-712页

作者： Janvier Sylvestre N'cho Issouf Fofana abderrahmane beroual Thomas Aka-Ngnui John Sabau AMPERE Laboratory CNRS UMR 5005 Ecole Centrale de Lyon Ecully 69134 France Canada Research Chair on Insulating Liquids and Mixed Dielectrics for Electrotechnology (ISOLIME) University of QuebecChicoutimi G7H 2B1 Quebec Canada R&D Department Insoil Canada Ltd. Calgary T3A 4Y7 Alberta Canada

Oil reclamation with Fuller's earth is known to have an improved effect on conditioning aged oil. In this paper it is shown that aged oil reclamation effectiveness can be monitored with turbidity and spectrophotometry measurements. These low cost testing techniques offer a useful tool to quantify the effect of Fuller's earth. Experimental investigations performed in laboratory conditions have shown that the quality of properly reclaimed aged oil can compete with that of new oils. Thus, in addition to extending the life cycle of this non-renewable resource, on-line reclamation of liquid might also prevent the premature ageing of paper insulation. Studying the stability of reclaimed service aged oil samples emphasized the important role played by Fuller's earth absorption capability.

关键词：填海工程浊度绝缘油光度法实验室条件核查测量不可再生资源

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Comparative Study of Streamers＇ Characteristics in Different Seed Based Insulating Oils under Lightning Impulse Voltages

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Journal of Energy and Power Engineering 2014年第4期8卷 735-740页

作者： abderrahmane beroual1 Viet-Hung Dang Essam Al-Ammar Muhammad Iqbal Qureshi Laboratoire Ampere-CNRS UMR 5005 Ecole Centrale de Lyon University of Lyon Ecully 69130 France Saudi Aramco Chair in Electrical Power Department of Electrical Engineering King Saud University Riyadh 11421 Saudi Arabia

This paper is aimed at the streamers in natural esters (vegetable oils) in point―plane electrode arrangement under lightning impulse voltage. The shape, stopping length, velocity and current of streamers are investigated. Six untreated commercial oils extracted from grape seeds, sunflower and rape seeds, corn, rice and sesame that could constitute potential liquids for high voltage applications are tested. A naphthenic mineral oil is also tested for comparison. It"s shown that the streamers are filamentary for both polarities. For a given voltage, the stopping lengths (L f ) of streamers are longer when the point is positive than when it is negative; also, except mineral oil when the point is negative, the values of L f are very close in all tested oils. The streamers" velocities are in the same range for all vegetable oils and they vary between 0.4 km/s and 1.2 km/s for positive polarity and 0.2 km/s and 0.8 km/s for negative polarity.

关键词：雷电冲击电压绝缘油基础特性平面电极植物油矿物油葡萄籽

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Recovery and Use of Blast Furnace Slag in the Field of Road Construction in Algeria

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Open Journal of Civil Engineering 2013年第2期3卷 113-118页

作者： Kamel Rouabah Abdesselam Zergua Ahmed beroual Mohamed Nacer Guetteche Department of Civil Engineering Constantine 1 University Constantine Algeria

Waste and industrial by-products represent a significant percentage of the industrial landfill. The evaluation of these products has a dual effect: it avoids both the landfill (risk of environmental pollution) and limits the use of natural aggregates (depletion of natural resources and landscape fragmentation and the imbalance of the ecosystem). In recent years, applications for industrial waste have been taken into account in the construction of roads with a great interest in many industrialized countries and developing countries. The use of these materials in the construction of the road is a decision based on technical, economic and ecological criteria. In Algeria, the steel plant of El-Hadjar (Annaba), due to its activity generates a significant industrial waste (slag) which creates a storage problem and pollution. For industrialized countries, this product is an abundant raw material at low cost that must be used on a large scale public works. Our study implies the use of slag in the preparation of the subgrade and surface course (as coated). The results of chemical, physical and mechanical analyses of El-Hadjar slag and materials developed, compared to those of natural aggregates, can be used as aggregate in road construction.

关键词： Bitumen Road Platform Mechanical Testing Blast Furnace Slag

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放电对变压器油特性的影响(英文)

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高电压技术 2011年第11期37卷 2793-2799页

作者： J.S.N'Cho I.Fofana T.Aka-Ngnui A.beroual Ecole Centrale de Lyon AMPERE CNRS UMR 500536Avenue Guy de Collongue69134EcullyFrance Canada Research Chair on Insulating Liquids and Mixed Dielectrics for Electrotechnology(ISOLIME) Universite du Quebec d ChicoutimiQcCanada

Petroleum based oils,the so-called mineral oils,are used for impregnating solid insulations or filling products of very large number of electric materials:transformers,reactors,cables,bushings,circuit breakers,tap changers, etc.In these equipments,oil is exposed to electrical stress and may experience electrical discharges under certain circumstances.Since the electrical stress is unavoidable in power equipments,the ability of oil to resist decomposition under electrical stress is of great importance for the safety of these devices.Electrical stress together with heat and moisture,in the presence of oxygen,oxidises the oil producing free radicals,acids and sludge that are deleterious to the transformer.In this paper,the effect of electrical discharges on oil properties is reported.The results indicate that quality of oil is considerably affected with increasing voltage stress.Comparing oil properties before and after voltage application allows assessing the outcome of random secondary chemical reactions between large oil born free radicals.

关键词： electrical discharge oil transformer dielectric dissipation factor(DDF) conductivity dissolved decay products turbidity interfacial tension total acid number water content

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Self Compacting Concrete under Local Conditions

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Open Journal of Civil Engineering 2013年第2期3卷 119-125页

作者： Abderahmane Seddik Ahmed beroual Abdesselam Zergua Mohamed Nacer Guetteche Department of Civil Engineering Constantine 1 University Constantine Algeria Department of Civil Engineering Ferhat Abbas University Setif Algeria

This paper presents the results of experimental investigations on mechanical properties of self compacting concrete made with local materials. The used materials were cement, aggregate and super plasticizer. Limestone powder, silica fume and blast furnace slag have been used as adjuvant in self compacting concrete (SCC). Self compacting concrete properties in fresh and hardened state are characterized and analyzed. The test results indicate the possibility to manufacture SCC with good rheological and mechanical properties using local materials.

关键词： Self Compacting Concrete (SCC) Mineral Additions Super Plasticizer Workability Compressive Strength and Tensile Strength

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