Blar i NTNU Open på forfatter "Ellingsen, Rakel"

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    • Dynamic loads on Francis turbines 

      Valkvæ, Ingebjørg (Master thesis, 2016)
      New installations of unregulated power to the electrical grid have led to more fluctuations in the grid frequency. Hydropower plants with large reservoirs can provide services to balance the frequency by increasing or ...

    • Simulations of the dynamic load in a francis runner based on measurements of grid frequency variations 

      Ellingsen, Rakel; Storli, Pål-Tore Selbo (Journal article; Peer reviewed, 2015)
      In the Nordic grid, a trend observed the recent years is the increase in grid frequency variations, which means the frequency is outside the normal range (49.9-50.1 Hz) more often. Variations in the grid frequency leads ...

    • Stability Criteria of Reversible Pump Turbines 

      Ellingsen, Rakel (Master thesis, 2014)
      The objective in this Master's Thesis was to verify the stability criteria for a centrifugal pump. Operation of an unstable pump may lead to either exponential or oscillatory unstable behavior of both pressure and volume ...