Sökning: "torsional oscillation"

Hittade 3 avhandlingar innehållade orden torsional oscillation.

  1. 1. Wind Power - Added Value for Network Operation

    Författare :Nayeem Ullah; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; torsional oscillation; reactive power ancillary service; voltage stability; power system simulator.; STATCOM; non-minimum phase system; Variable speed wind turbine; frequency control; sensitivity analysis; transient stability; small-signal stability;

    Sammanfattning : This dissertation deals with the investigation on different value added properties of variable speed wind turbines (VSWT) that stem from the flexible controllability of converter interfaced wind turbines (WT). Improvements in voltage and transient stability of a nearby grid, small-signal stability improvement on the power system, frequency control support for the network operation, as well as thetechnical and the economic issues related to the reactive power ancillary service provision, are among the issues covered. LÄS MER

  3. 2. Hydropower generator and power system interaction

    Författare :Johan Bladh; Urban Lundin; Rafael Escarela-Perez; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Amortisseur windings; applied voltage test; automatic voltage regulators; damper windings; damping torque; empirical modelling; equivalent circuits; excitation control; finite element method; hydropower generators; power system restoration; power system stability; synchronous machines; self excitation; shaft torque amplification; short circuit test; single machine infinite bus; slip test; standstill frequency response test; subsynchronous oscillations; synchronising torque; synchronous generators; torsional interaction.; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : After decades of routine operation, the hydropower industry faces new challenges. Large-scale integration of other renewable sources of generation in the power system accentuates the role of hydropower as a regulating resource. LÄS MER

  4. 3. The bowed string

    Författare :Knut Guettler; KTH; []
    Nyckelord :Bowed string; violin; musical acoustics; musical transient; anomalous low frequencies; Helmholtz motion;

    Sammanfattning : Of the many waveforms the bowed string can assume, theso-called "Helmholtz motion" (Helmholtz 1862) gives the fullestsound in terms of power and overtone richness. The developmentof this steady-state oscillation pattern can take manydifferent paths, most of which would include noise caused bystick-slip irregularities of the bow-string contact. LÄS MER