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dc.contributor.authorHåkonseth, Gunnar
dc.contributor.authorIldstad, Erling
dc.identifier.citationProceedings of the Nordic Insulation Symposium. 2019, 2019 (26), .nb_NO
dc.description.abstractLayered paper–oil insulation is used in several types of HVDC equipment. In order to better understand breakdown mechanisms and optimize the design, it is important to understand the electric field distribution in the insulation. In the present work, a test object with such insulation has been modeled as a series connection of oil and impregnated paper. The permittivity, conductivity, and the dielectric response function has been measured for impregnated paper and oil separately and used as parameters in a dielectric response model for the layered insulation system. A system of differential equations has been established describing the voltages across each material, i.e. across each layer of the test object. These equations have been solved considering a DC step voltage across the whole test object. Based on this, the time-dependent electric field in each material as well as the time-dependent polarization current density in the test object have been calculated. The calculated polarization current density was found to agree well with the measured polarization current density of the test object. This indicates that application of dielectric response theory gives a good estimate of the time-dependent electric field distribution in layered insulation systems. The results show that 90 % of the change from initial values to steady-state values for the electric fields has occurred within the first 35 minutes after the voltage step. This applies to the electric fields in both of the materials of the examined test object at a temperature of 323 K.nb_NO
dc.publisherNordic Insulation Symposiumnb_NO
dc.rightsNavngivelse 4.0 Internasjonal*
dc.titleTime-Dependent Electric Field Distribution in Layered Paper-Oil Insulationnb_NO
dc.typeJournal articlenb_NO
dc.typePeer reviewednb_NO
dc.source.journalProceedings of the Nordic Insulation Symposiumnb_NO
dc.description.localcoderoceedings of the Nordic Insulation Symposium licenses all content of the journal under a Creative Commons Attribution (CC-BY) licence.nb_NO
cristin.unitnameInstitutt for elkraftteknikk

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Navngivelse 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Navngivelse 4.0 Internasjonal