Browsing NTNU Open by Author "Eberg, Espen"
Now showing items 1-11 of 11
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Comparison of Offline VLF PD Measurements and Online PD Measurements on a 50-Year-Old Hydrogenerator Stator in Norway
Eberg, Espen; Aakre, Torstein Grav; Berg, Gunnar; Hvidsten, Sverre (Chapter, 2018)Stator winding insulation is the part of the hydrogenerator experiencing the highest number and the most damaging failures. Partial discharge (PD) measurement, both offline and online, are commonly used for condition ... -
Dielectric Characterization of Semi Conducting Field Grading Varnish for Hydro Generators
Sagøy, Olav Henry (Master thesis, 2021)Hovedformålet med dette arbeidet er å karakterisere en feltstyrende lakk som brukes i vannkraftgeneratorer. Lakken som er testet brukes i endeviklingene til generatorer. Den er laget for å utjevne feltkonsentrasjoner i ... -
Experimental study on the effect of soil moisture content on critical temperature rise for typical cable backfill materials
Rieksts, Karlis; Eberg, Espen (Peer reviewed; Journal article, 2022)The increased utilization of power grid requires operating power cables close to their thermal limit. Buried power cables in such condition experience thermal instability where thermal resistance increases as the moisture ... -
Fabrication by electron beam lithography and preliminary studies by high resolution electron microscopy techniques of perovskite nanostructures
Eberg, Espen (Master thesis, 2007)In order to study thin films of complex oxides deposited on discontinuous surfaces, necessary techniques to fabricate templates and analysis of templates and thin-film samples at atomic scale have been investigated. ... -
Forprosjekt - HighFlex
Eberg, Espen (HydroCen brief;Nr. 14, Report, 2023) -
HydroStator : hovedfunn og resultater i KPN-prosjektet HydroStator
Berg, Gunnar; Eberg, Espen; Aakre, Torstein Grav; Ildstad, Erling; Kantar, Emre; Nysveen, Arne (SINTEF Rapport;, Research report, 2022)Modeller som beskriver temperatur- og frekvensavhengighet til elektriske delutladninger er utviklet og viser at tilstandskontroll med den mer praktiske VLF-metoden som benytter 0,1 Hz høyspenning er representativ for 50 ... -
Influence of voltage frequency and rate of change on internal partial discharges
Johannessen, Magnus Normann (Master thesis, 2022)Interne, partielle utladninger i elektriske maskiner utgjør en betydelig kilde til degradering og havari. Høyspentmaskiner blir i økende grad utsatt for raske, repetitive spenningspulser forårsaket av transistor-switching ... -
Interface effects in PbTiO₃ thin films and anostructures : a transmission electron microscopy study
Eberg, Espen (Doktoravhandlinger ved NTNU, 1503-8181; 2011:220, Doctoral thesis, 2011)In the present work we have investigated ferroelectric PbTiO3 thin films grown on planar substrates and stepped surface templates. In order to probe the structural, electronic and chemical properties of the PbTiO3 thin ... -
Partial Discharge Activity in Rotating Machine Type II Insulation Systems as a Function of Temperature and AC Supply Frequency
Aakre, Torstein Grav; Kantar, Emre; Eberg, Espen (Peer reviewed; Journal article, 2023)The main purpose of this study was to investigate if the application of very low frequencies for PD measurements in type II generator bar insulation is relevant when compared to applying power line frequency at different ... -
Use of Data-Driven Approaches for Defect Classification in Stator Winding Insulation
Kantar, Emre; Cascallo, Jaume M.; Aakre, Torstein Grav; Thomsen, Nina Marie; Eberg, Espen (Peer reviewed; Journal article, 2022)Partial discharges (PD) in the high voltage insulation systems are both a symptom and cause of terminal and impending failures. The use of data-driven methods based on PD measurements will enable predictive strategies to ... -
Utilisation of Machine Learning in Power Transformer Asset Management
Ukkelberg, Martine (Master thesis, 2018)Ageing assets in the power system increase the need for maintenance and reinvestments. There is currently a shortage of adequate data and analysis systems available for estimation of condition and remaining lifetime, to ...