Browsing NTNU Open by Author "Lundgaard, Lars Esben"

Now showing items 1-7 of 7

    • Currents in AC stressed liquid insulated needle plane gap 

      Grav, Torstein; Lundgaard, Lars Esben (Chapter, 2014)
      Currents and space charge phenomena in 8 different dielectric liquids have been investigated for an ac stressed needle plane gap. Applied frequencies ranged from 0.1 Hz to 100 Hz. A high resolution analogue-digital converter ...

    • 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 ...

    • Field-dependent molecular ionization and excitation energies: Implications for electrically insulating liquids 

      Davari, Nazanin; Åstrand, Per-Olof; Unge, Mikael; Lundgaard, Lars Esben; Linhjell, Dag (Journal article; Peer reviewed, 2014)
      Themolecular ionization potential has a relatively strong electric-field dependence as compared to the excitation energies which has implications for electrical insulation since the excited states work as an energy sink ...

    • Influence of fast rise voltage and pressure on partial discharges in liquid embedded power electronics 

      Abdelmalik, Abdelghaffar Amoka; Nysveen, Arne; Lundgaard, Lars Esben (Peer reviewed; Journal article, 2015)
      Initiation of partial discharges at the highly stressed regions of an Insulated Gate Bipolar Transistor (IGBT) can lead to degradation of the insulation and eventual total breakdown of the system. In this work, an experimental ...

    • Investigation of Partial Discharges in AlN Substrates under Fast Transient Voltages 

      Semenov, Ivan; Gunheim, Ingrid Folkestad; Niayesh, Kaveh; Meyer, Hans Kristian Hygen; Lundgaard, Lars Esben (Peer reviewed; Journal article, 2022)
      The objective of this paper is to characterize partial discharge (PD) inception voltages and patterns at sinusoidal and square voltages in insulating ceramic substrates with generic manufacturing defects. PD tests were ...

    • Partial Discharges in Narrow Gaps on Power Electronic Converter 

      Abdelmalik, Abdelghaffar Amoka; Nysveen, Arne; Lundgaard, Lars Esben (Chapter, 2014)
      The quest for power electronic converters to operate in a subsea pressurized environment that is completely filled with appropriate dielectric liquid brings about the need to study the insulation performance of liquid in ...

    • Time to breakdown studies for liquids of different physico-chemical nature 

      Aakre, Torstein Grav; Lundgaard, Lars Esben; Unge, Mikael (Chapter; Peer reviewed, 2017)
      An automated setup for testing dielectric performance of liquids in a small point-to-plane gap is presented. It provides step voltages with rise times around 30 ns, with amplitudes up to 90 kV. Breakdown studies of thirteen ...