Sökning: "Power flow simulations"

Visar resultat 1 - 5 av 187 avhandlingar innehållade orden Power flow simulations.

  1. 1. Fluid Mechanics of Vertical Axis Turbines : Simulations and Model Development

    Författare :Anders Goude; Olov Ågren; Carlos Simão Ferreira; Uppsala universitet; []
    Nyckelord :Wind power; Marine current power; Vertical axis turbine; Wind farm; Channel flow; Simulations; Vortex model; Streamtube model; Control system; Graphics processing unit; CUDA; Fast multipole method; Engineering Science with specialization in Science of Electricity; Teknisk fysik med inriktning mot elektricitetslära;

    Sammanfattning : Two computationally fast fluid mechanical models for vertical axis turbines are the streamtube and the vortex model. The streamtube model is the fastest, allowing three-dimensional modeling of the turbine, but lacks a proper time-dependent description of the flow through the turbine. LÄS MER

  3. 2. Aspects on Dynamic Power Flow Controllers and Related Devices for Increased Flexibility in Electric Power Systems

    Författare :Nicklas Johansson; Hans-Peter Nee; Göran Andersson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Adaptive Control; Controlled Series Compensator; Dynamic Power Flow Controller; Frequency Scanning; Phase-Shifting Transformer; Power Controller Plane; Power Flow Control; Power Oscillation Damping; Subsynchronous Resonance; Thyristor Controlled Series Compensator; Thyristor Switched Series Compensator; Transient Stability; Electrical engineering; Elektroteknik;

    Sammanfattning : This thesis studies different aspects of Flexible AC Transmission System (FACTS) devices which are used to improve the power transfer capability and increase the controllability in electric power systems. In the thesis, different aspects on the usage and control of Dynamic Power Flow Controllers (DPFC) and related FACTS devices are studied. LÄS MER

  4. 3. Modeling, Control and Protection of Low-Voltage DC Microgrids

    Författare :Daniel Salomonsson; Lennart Söder; Brian K. Johnsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; circuit transient analysis; dc power systems; dispersed storage and generation; load modeling; power conversion; power distribution control; power distribution faults; power distribution protection; power electronics; Electric power engineering; Elkraftteknik;

    Sammanfattning : Current trends in electric power consumption indicate an increasing use of dc in end-user equipment, such as computers and other electronic appliances used in households and offices. With a dc power system, ac/dc conversion within these loads can be avoided, and losses reduced. LÄS MER

  5. 4. Power Electronics for Mitigation of Voltage Sags and Improved Control of AC Power Systems

    Författare :Marcio Magalhães de Oliveira; KTH; []
    Nyckelord :power electronics; power quality; voltage sags; voltage-source converters; Custom Power; FACTS; real-time simulations; solid-state devices;

    Sammanfattning : The thesis deals with the application of compensators andswitches based on power electronics in AC transmission anddistribution systems. The objective of the studieddevices/equipment is the power flow and voltage control intransmission systems and the mitigation of voltage sags andmomentary interruptions to critical loads in distributionsystems. LÄS MER

  7. 5. Numerical investigation of the flow and instabilities at part-load and speed-no-load in an axial turbine

    Författare :Jelle Kranenbarg; Michel Cervantes; Lisa Prahl Wittberg; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Speed-no-load; vortical flow structures; flow instabilities; rotating stall; mitigation; independent guide vanes; axial turbine; swirling flow; off design operation; URANS; parametric study; blade clearance; head losses; diffusor; GEKO model; flow separation; hydraulic turbine; Strömningslära; Fluid Mechanics;

    Sammanfattning : Global renewable energy requirements rapidly increase with the transition to a fossil-free society. As a result, intermittent energy resources, such as wind- and solar power, have become increasingly popular. However, their energy production varies over time, both in the short- and long term. LÄS MER