Blar i NTNU Open på forfatter "Hestad, Øystein Leif Gurandsrud"

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    • Cerman: Software for simulating streamer propagation in dielectric liquids based on the Townsend–Meek criterion 

      Madshaven, Inge; Hestad, Øystein Leif Gurandsrud; Åstrand, Per-Olof (Peer reviewed; Journal article, 2021)
      We present a software to simulate the propagation of positive streamers in dielectric liquids. Such liquids are commonly used for electric insulation of high-power equipment. We simulate electrical breakdown in a needle–plane ...

    • Conductivity and capacitance of streamers in avalanche model for streamer propagation in dielectric liquids 

      Madshaven, Inge; Hestad, Øystein Leif Gurandsrud; Unge, Mikael; Hjortstam, Olof; Åstrand, Per-Olof (Journal article; Peer reviewed, 2019)
      Propagation of positive streamers in dielectric liquids, modeled by the electron avalanche mechanism, is simulated in a needle–plane gap. The streamer is modeled as an RC-circuit where the channel is a resistor and the ...

    • Field dependent conductivity of n-pentane 

      Hestad, Øystein Leif Gurandsrud; Linhjell, Dag; Lundgaard, Lars Esben; Samseth, Jarl Ø.; Unge, Mikael (Chapter, 2017)
      A sensitive differential charge measurement technique was used to measure the conduction current from a sharp needle in a needle plane geometry in n-pentane. The current was measured at voltages up to the threshold for ...

    • Modeling the transition to fast mode streamers in dielectric liquids 

      Madshaven, Inge; Åstrand, Per-Olof; Hestad, Øystein Leif Gurandsrud; Unge, Mikael; Hjortstam, O. (Chapter, 2017)
      A simplified model for photoionization, modeling fast streamer propagation, is combined with an existing model for slow streamers, based on electron avalanches. Transitions from fast mode to slow mode, and from slow mode ...

    • Photoionization model for streamer propagation mode change in simulation model for streamers in dielectric liquids 

      Madshaven, Inge; Hestad, Øystein Leif Gurandsrud; Unge, Mikael; Hjortstam, Olof; Åstrand, Per-Olof (Journal article; Peer reviewed, 2019)
      Radiation is important for the propagation of streamers in dielectric liquids. Photoionization is a possibility, but the effect is difficult to differentiate from other contributions. In this work, we model radiation from ...

    • Prebreakdown phenomena in solids and liquids stressed by fast transients: The effect of additives and phase 

      Hestad, Øystein Leif Gurandsrud (Doktoravhandlinger ved NTNU, 1503-8181; 2010:243, Doctoral thesis, 2010)
      This study has been conducted to improve the knowledge of processes responsible for dielectric breakdown of liquid and solid insulation. This is important, as the electric power grid depends on reliable and cost effective ...

    • 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 ...