Blar i Institutt for elkraftteknikk på tidsskrift "Proceedings of the Nordic Insulation Symposium"

Viser treff 1-13 av 13

    • AC Breakdown Voltage of 50-Year-Old Service Aged Hydro Power Generator Stator Bars 

      Aakre, Torstein Grav; Ildstad, Erling (Journal article; Peer reviewed, 2022)
      Randomly selected generator bars from a 50-year-old Norwegian hydro power generator were examined in this work. Typical non-destructive tests, as partial discharge and dissipation factor measurements were initially performed ...

    • Breakdown in short rod-plane air gaps under positive lightning impulse stress 

      Hygen Meyer, Hans Kristian; Mauseth, Frank; Pedersen, Per Atle; Martine, Husøy (Journal article; Peer reviewed, 2017)
      Prediction of withstand voltages in air-insulated systems are made on the basis of empirical models that are not sufficiently accurate for complex geometries. Bet-ter understanding of the spatio temporal ...

    • Breakdown Voltage of Polymeric HVDC Insulation at DC Stress and Superimposed Lightning Impulse Voltages 

      Ildstad, Erling; Mauseth, Frank; Olsen, Espen Torlei (Peer reviewed; Journal article, 2022)
      Space charge formation makes it difficult to predict the resulting electric field distribution within HVDC cable insulation. The main purpose of the work presented here has been to experimentally study how the lightning ...

    • Examination of Longitudinal AC Breakdown Strength of Dielectric Surfaces as a function of Elastic Modulus 

      Kantar, Emre; Hvidsten, Sverre; Ildstad, Erling (Journal article; Peer reviewed, 2017)
      This paper examines the influence of the elastic modulus of the polymer insulation on the tangential AC breakdown strength (BDS) of polymer interfaces theoretically and experimentally. In the experiments, four different ...

    • Limitations Regarding Use of the ABC-Model for Interpretation of Partial Discharge Measurements 

      Aakre, Torstein Grav; Skattenborg, Regina; Ildstad, Erling (Journal article; Peer reviewed, 2019)
      The main purpose of the work presented here is to facilitate use of partial discharge (PD) measurements as a diagnostic tool for condition assessment of hydropower generator bars. The main aim of the work is to clarify how ...

    • Local Electric Field in Mass-Impregnated HVDC Cables 

      Håkonseth, Gunnar; Ildstad, Erling; Furuheim, Knut Magne (Journal article; Peer reviewed, 2017)
      Detailed knowledge of the electric field in the insulation of mass-impregnated HVDC cables is important in order to understand their breakdown mechanisms and to improve their design. When calculating the local electric ...

    • Pre-Breakdown Phenomena in Technical Air with and without C5-Fluoroketone for a Rod-Plane Gap 

      Skirbekk, Fanny; Mauseth, Frank; Meyer, Hans Kristian Hygen (Journal article; Peer reviewed, 2022)
      alternatives to the potent greenhouse gas SF6 in medium voltage (MV) gas insulated switchgear. MV products using this gas mixture are already commercially available, but there is still a lack of knowledge about this gas ...

    • Review of Partial Discharge and Dielectric Loss Tests for Hydropower Generator Bars 

      Aakre, Torstein Grav; Ildstad, Erling; Hvidsten, Sverre; Nysveen, Arne (Journal article; Peer reviewed, 2017)
      Condition assessment of hydropower generators is important to ensure high serviceability of power stations. Many of the in-service generators are old and current load operation schemes demands more than the design load, ...

    • Review of Water Treeing in Polymeric Insulated Cables 

      Abideen, Amar; Mauseth, Frank; Hestad, Øystein Leif Gurandsrud; Faremo, Hallvard (Peer reviewed; Journal article, 2022)
      Since discovering the water treeing phenomenon (WT) in polymeric cables in the early 1970s, water treeing has been presumed to be the main cable degradation mechanism for polymeric cables and has been extensively researched ...

    • Streamer Propagation along Profiled Insulator Surfaces under Positive Impulse Voltages 

      Meyer, Hans Kristian Hygen; Marskar, Robert; Bilsbak, Henriette Graverholt; Mauseth, Frank; Schueller, Michael (Peer reviewed; Journal article, 2022)
      Controlling discharge growth on insulator surfaces is important in high voltage gaseous insulation systems. In this study, the effect of small-scale surface profiles on streamer discharge propagation is examined experimentally. ...

    • Time Development of Voltage Frequency Dependence of Partial Discharge Activity in Voids 

      Aakre, Torstein Grav; Ildstad, Erling; Hvidsten, Sverre (Journal article; Peer reviewed, 2019)
      Condition assessment of high voltage equipment based on partial discharge measurements is often performed after a voltage pre-conditioning period. The aim of this paper is to present results from experimental examinations ...

    • Time-Dependent Electric Field Distribution in Layered Paper-Oil Insulation 

      Håkonseth, Gunnar; Ildstad, Erling (Journal article; Peer reviewed, 2019)
      Layered 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 ...

    • 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 ...