Description: Das Projekt "Alternative Gases for dielectric insulation" wird vom Umweltbundesamt gefördert und von Eidgenössische Technische Hochschule ETH Zürich, High Voltage Laboratory durchgeführt. Introduction: The United Nations Framework Convention on Climate Change classified SF6 as greenhouse gas, and the Annex I countries are obliged to publish the inventory of SF6 and to reduce emissions. However, survey data show an increasing concentration of SF6 (1), and recent evaluations demonstrate that only 30 Prozent of SF6 emissions are reported (2). Novel regulations and technical development must aim at decreasing SF6 emissions below the natural decomposition rate. For dielectric insulation applications, i.e. in situations where discharges are exceptional, it might be possible to replace SF6 by a different gas or gas mixture. No alternative gas is established, despite an extensive study of the dielectric strength of electron attaching gases in the past (3), (4). As many of the well investigated gases are covered by the Kyoto protocol, new options must be provided by fundamental research. In the present research project, the dielectric strength of alternative gases will be evaluated. There is general agreement, that mixtures of two or more gases are most suitable for replacing SF6 in dielectric insulation applications. Due to 'synergistic effects' the dielectric strength of a mixture can be higher than of pure gases (5), or at least the dielectric strength of a mixture can be higher than the linear combination of the strength of the constituents (6). Various types of synergistic effects have so far been described on the basis of the electron velocity distribution function or on the basis of ion-neutral collisions. Methods: The methods developed for investigating electron attaching gases may be classified to three groups: Phenomenological, macroscopic and microscopic methods. The research strategy of the project at hand is a combination of two established methods. In a Pulsed Townsend Discharge (PTD) experiment the macroscopic parameters of electron-ion swarms in attaching gases are measured. Synergistic effects in gas mixtures will be investigated microscopically by Monte Carlo (MC) simulations. The PTD is a traditional method and considerable experience has been gained at the HVL during the years 1980-1990 (7,8). The group of de Urquijo (Mexico) lately used a PTD for studying the alternative gas CF3I (9). In figure 1 the principle of the PTD setup is given. The swarm parameters are obtained from a fit of the analytical expression of the displacement current to the recorded current. Refer to (10) for more details on our swarm parameter experiment SParX. Recently satisfying agreement was achieved between MC simulations and data from PTD experiments (11, 12). The critical issue of these simulations is the availability of a consistent set of cross sections of electron-neutral and ion-neutral collisions. In the present study the output of SParX serves for calibrating the cross sections and the simulations. usw.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Synergistische Wirkung ? Technische Vorschrift ? Kyoto ? Zürich ? Treibhausgasemission ? Kalibrierung ? Gewächshaus ? Brunnen ? Kyoto-Protokoll ? Gasgemisch ? Abfluss ? Kataster ? Schwefelhexafluorid ? Wirkung ? Klimarahmenkonvention ? Gasförmiger Stoff ? Forschungsprojekt ? Bewertung ? Daten ? Emission ? Emissionsminderung ? Geodäsie ? Ionen ? Simulation ? Stoffgemisch ? Studie ? Vertrag ? Verwitterung ? Wertermittlung ? Wirkung ? Messung ? Abdeckung ? Forschung ? Kenngröße ? Klimawandel ? Übereinkommen ? Strategische Aspekte ? FUNKTION ? GRUNDSAETZE ? BEREICH ? NEU ? NICHTOEFFENTLICH ? PROJEKT ? UNTER ? VERFUEGBARKEIT ? VERTEILUNG ? Vermehrung ? Verwertung ? EINFUEHRUNG ? ENTWICKLUNG ? GRUNDSATZ ? GRUPPE ? EXPERIMENT ? Isolation [benutze Unterbegriffe] ? Konzentrat ? Kreuzung [biologisch] ? Elektronen ? LAENDER ? LAND ? ANALYTISCH ? GEBRAUCHT ? GEGENWART ? ABNAHME ? METHODE ? GRUNDLAGE ? MISCHUNG ?
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 2010-02-01 - 2014-02-01
Webseite zum Förderprojekt
http://www.eeh.ee.ethz.ch/de/power/hochspannungstechnik/forschung/projekte-prof-dr-christian-m-franck/view/detail/project/alternative-gases-for-dielectric-insulation.html (Webseite)Accessed 1 times.