• A Method to Estimate the Necessary Twist Pitch in Multi-filamentary Superconductors 

      Lindau, Sandra Madeleine; Magnusson, Niklas; Taxt, Henning (Journal article; Peer reviewed, 2014)
      Twisting of multi-filamentary superconductors is an important step in the development of wires with AC losses at an acceptable level for AC applications. The necessary twist pitch depends on wire architecture, critical ...
    • AC Loss in MgB2 Superconductors: Calorimetric Loss Measurement 

      Taxt, Henning (Master thesis, 2012)
      Ever since the phenomenon of superconduction was discovered, and especially after the discovery of high-temperature superconductors (HTS) in the mid-80s, there has been high expectations to what could be achieved by this ...
    • AC loss measurements multi-filamentary MgB2 wires with non-magnetic sheath material 

      Taxt, Henning; Magnusson, Niklas; Runde, Magne; Brisigotti, S (Journal article; Peer reviewed, 2012)
      The MgB2 superconductor is an attractive choice for many high-current DC applications, particularly for its low cost compared to e.g. YBCO, and the higher operating temperature than the low-temperature superconductors. To ...
    • AC losses in MgB2 superconductors 

      Giljarhus, Sigrid Anne (Master thesis, 2007)
      This Master thesis studies losses in superconductors. Losses arise when the superconductor carries alternating current or is placed in an alternating magnetic field. As most power applications involve at least one of the ...
    • AC-tap i MgB2-superleder: Effekt av simulert slaglende 

      Lindau, Sandra Madeleine (Master thesis, 2013)
      Superconductive materials can conduct DC currents without energy losses when cooled down below their critical temperature. However, under AC conditions, energy losses appear in the superconductor. In 2001 the new and ...
    • Apparatus for calorimetric measurements of losses in MgB2 superconductors exposed to alternating currents and external magnetic fields 

      Taxt, Henning; Magnusson, Niklas; Runde, Magne (Journal article; Peer reviewed, 2013)
      Inexpensive superconducting wires with low AC losses would open up for a large superconductor market in AC electrical power applications. One candidate for this market is the MgB2 conductor. In the development of an AC ...
    • Apparatus for loss measurements under multidirectional and dc-bias flux in electrical steel laminations 

      Wang, Wei; Nysveen, Arne; Magnusson, Niklas (Peer reviewed; Journal article, 2020)
      Conventional standardized power loss measurements for electric steels are performed at flux densities with a single sinusoidal and unidirectional excitation. However, the flux inside electrical steel laminations can deviate ...
    • Assembly and Testing of Superconducting Field Winding 

      Paulsen, Morten Ellingsen (Master thesis, 2016)
      Superconducting rotor windings are considered for large offshore wind turbines to reduce weight, size and cost. The European project INNWIND.EU utilize various national projects in different European countries to accelerate ...
    • Common and differential mode of dc-bias in three-phase power transformers 

      Wang, Wei; Nysveen, Arne; Magnusson, Niklas (Peer reviewed; Journal article, 2022)
      Dc magnetization due to the geomagnetically induced currents (GICs) and HVDC (High Voltage Direct Current) systems may cause core saturation and result in serious destruction in the transformer performance as well as the ...
    • Coupling currents and hysteresis losses in MgB2superconductors 

      Magnusson, Niklas; Lindau, Sandra Madeleine; Taxt, Henning; Runde, Magne (Journal article; Peer reviewed, 2014)
      MgB2 multi-filamentary superconductors are widely considered for use in dc applications. To expand the possible application range to ac apparatuses, the development of a low ac loss wire is needed. This development involves ...
    • Eddy Current Loss in Grain-Oriented Steel Laminations due to Normal Leakage Flux 

      Wang, Wei; Nysveen, Arne; Magnusson, Niklas (Peer reviewed; Journal article, 2021)
      Leakage flux penetrating laminated iron cores in power transformers and large generators induces eddy current and local loss. Due to the strong magnetic anisotropy of the lamination structure, the penetrating flux tends ...
    • Experimental Determination of Losses in MgB2 Superconductors for Wind Turbine Applications 

      Moslått, Lars-Erik (Master thesis, 2017)
      Superconducting generator field windings are suggested for the next generation of wind turbines. The foreseen wind turbines with power ratings greater than 10 MW give raise to technical challenges. Superconducting field ...
    • Fabrication of a scaled MgB2 racetrack demonstrator pole for a 10 MW direct drive wind turbine generator 

      Magnusson, Niklas; Eliassen, J. C.; Abrahamsen, Asger B; Hellesø, Svein Magne; Runde, Magne; Nysveen, Arne; Moslått, Lars-Erik; Bjerkli, Jarle; King, Patrick (Journal article; Peer reviewed, 2018)
      Field windings made of MgB2 wires or tapes are considered for their potential to reduce volume, weight and cost of large offshore wind turbine generators. To gain experience of how to use this relatively new material in ...
    • Fourier-based effective permeability for transformer iron losses computation under saturation 

      Wang, Wei; Nysveen, Arne; Magnusson, Niklas; Nilssen, Robert (Journal article; Peer reviewed, 2020)
      Computation of iron losses in transformers requires significant numerical efforts, particularly under magnetic saturation when the magnetic non-linearity needs to be considered. This study proposes a Fourier method to ...
    • The influence of multidirectional leakage flux on transformer core losses 

      Wang, Wei; Nysveen, Arne; Magnusson, Niklas (Peer reviewed; Journal article, 2021)
      In a power transformer, the leakage flux enters the laminations of the iron core in different directions. Depending on the orientation of the leakage flux, it can add eddy current and hysteresis losses to the well-documented ...
    • Large Superconducting Wind Turbine Generators 

      Abrahamsen, A.B.; Magnusson, Niklas; Jensen, B.B.; Runde, Magne (Journal article; Peer reviewed, 2012)
      To realize large (>10 MW) direct-driven off-shore wind turbines, a number of steps are needed to reduce weight and cost compared to on-shore technologies. One of the major challenges is to provide drive trains which can ...
    • Power losses in the three-phase three-limb transformer due to common and differential mode of dc-bias 

      Wang, Wei; Nysveen, Arne; Magnusson, Niklas (Peer reviewed; Journal article, 2021)
      Geomagnetically induced currents (GICs) and the converter modulation effect are the two main causes for dc magnetisation in power transformers. It is well known that a small dc-bias can saturate a large transformer and ...
    • Testing av superledende spoler 

      Engebrethsen, Eivind (Master thesis, 2009)
      Tradisjonelle induksjonsovner bruker vekselstrøm for å indusere strømmer og varme opp større aluminiumsdeler. Effektiviteten til ovnene ligger normalt mellom 55-60%, noe som gir et stort forbedringspotensial. Ved å erstatte ...
    • Testing of an MgB2 coil for a wind turbine generator pole 

      Magnusson, Niklas; Hellesø, Svein Magne; Mikkonen, R.; Abrahamsen, A.B.; Runde, Magne; Berg, Gunnar; Nysveen, Arne (Peer reviewed; Journal article, 2021)
      We report on the testing of a 1 m long and 0.5 m wide racetrack coil wound from 4.5 km of MgB2 tape-shaped superconductors with a copper strip soldered to the nickel matrix. The cross-section of the coil corresponds to ...
    • Winding and Testing of Superconducting Coils 

      Eliassen, Jan Christian (Master thesis, 2015)
      Superconducting rotor windings are considered for future large offshore wind turbines for their low weight, volume and their possibility to reduce costs. In a joint European project, INNWIND.EU, a superconducting small ...