Topic
Liquid dielectric
About: Liquid dielectric is a research topic. Over the lifetime, 3702 publications have been published within this topic receiving 45150 citations.
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TL;DR: In this paper, the basic processes of electrical conduction in dielectric liquids are reviewed, attention being drawn to the similarities between conductive electrolytes and insulating liquids, and the concepts of the electronic amorphous solid state are employed to provide a framework for the review.
Abstract: The basic processes of electrical conduction in dielectric liquids are reviewed, attention being drawn to the similarities between conductive electrolytes and insulating liquids. The concepts of the electronic amorphous solid state are employed to provide a framework for the review. The conditions at metal electrodes can be incorporated naturally into the scheme, and it is known that the space charge layers occurring on them can control conduction. Although electrical breakdown itself is not considered, the underlying electronic processes which will develop when breakdown electrical fields exist in the liquid are considered. >
63 citations
Patent•
22 Aug 2001
TL;DR: In this paper, the authors describe a cable with recyclable covering, particularly for transporitng or distributing medium or high voltage energy, in which at least one covering layer is based on thermoplastic polymer material comprising a propylene homopolymer or a copolymer of propylene with ethylene or an.prop.-olefin other than propylene in mixture with a dielectric liquid.
Abstract: The invention describes a cable with recyclable covering, particularly for transporitng or distributing medium or high voltage energy, in which at least one covering layer is based on thermoplastic polymer material comprising a propylene homopolymer or a copolymer of propylene with ethylene or an .prop.-olefin other than propylene in mixture with a dielectric liquid. The cable of the invention possesses superior mechanical and electrical properties, including high dielectric strength, in particular enabling it to be used at high operating temperature.
63 citations
TL;DR: In this article, the authors examined the flow organization induced by charge injection from a needle of small radius of curvature into an insulating dielectric liquid, and the electrical current as a function of the point-plane distance and of applied voltage.
Abstract: We examine the flow organization induced by charge injection from a needle of small radius of curvature into an insulating dielectric liquid. Experimental results are presented for the electrical current as a function of the point-plane distance and of the applied voltage. Schlieren visualization reveals the existence of very thin plumes which are slightly vacillating. An approximate analysis of the laminar plume is developed which takes into account the finite but very thin axial region where charge is confined. A classical type of asymptotic treatment results in a set of ordinary differential equations, provided the current and the field distribution are known. A new expression for the order of magnitude of the liquid velocity is proposed which leads to estimates of the radius a of the charge core and the typical radial scale /spl delta/ of the velocity profile. For a gap spacing d, these estimates are of the order of 10/sup -3/ d and 10/sup -2/ d which confirm the thinness of such charge plumes.
63 citations
25 Oct 1998
TL;DR: In this paper, the authors reviewed the conventional diagnostics used on oil-paper insulation systems in large power transformers and proposed a method for the future dielectric testing of insulation in large transformers in service.
Abstract: The original research into the application of Recovery Voltage Measurement to diagnosis of oil-paper insulation is described in detail. The goal of this research was to thoroughly review the conventional diagnostics used on oil immersed paper insulation systems in large power transformers and, after fundamental laboratory measurements and on-site measurements of power transformers, to propose a method for the future dielectric testing of insulation in large transformers in service. The results of the basic research are further illuminated by examples drawn from the numerous tests since performed on actual test objects in the field, mostly large power transformers, which give insight into the strengths and limitations of the method. A few measurements on oil-paper insulated cables suggest a yet to be explored potential application to the diagnostic testing of cables.
63 citations
TL;DR: In this article, a finite element computational technique was developed for exactly calculating circulations inside and outside a dielectric drop suspended in another liquid under a uniform electric fifeld, which allows the prediction of not only the circulations but also drop deformation caused by electric and dynamic forces acting over the drop surface.
Abstract: A finite element computational technique has been developed for exactly calculating circulations inside and outside a dielectric drop suspended in another dielectric fluid under a uniform electric fifeld. This technique allows the prediction of not only the circulations but also drop deformation caused by electric and dynamic forces acting over the drop surface. Computed results show that the direction of the circulations and the drop deformation depend on physical properties of the fluids, especially the drop-to-medium ratios of electric conductivity and dielectric constant. These results are in good agreement with Taylor’s analytical solutions and authors’ experimental observations.
62 citations