Sökning: "power grids"

Visar resultat 1 - 5 av 144 avhandlingar innehållade orden power grids.

  1. 1. Distributed Control of HVDC Transmission Grids

    Författare :Davood Babazadeh; Lars Nordström; Oriol Gomis; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; co-simulation; cyber-physical system; DC slack bus; distributed control; HVDC grids; power injection; topology processor; wind farms; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Recent issues such as priority access of renewable resources recommended by European energy directives and increase the electricity trading among countries lead to new requirements on the operation and expansion of transmission grids. Since AC grid expansions are limited by legislative issues and long distance transmission capacity, there is a considerable attention drawn to application of HVDC transmission grids on top of, or in complement to, existing AC power systems. LÄS MER

  3. 2. Main Circuits, Submodules, and Auxiliary Power Concepts for Converters in HVDC Grids

    Författare :Stefanie Heinig; Hans-Peter Nee; Staffan Norrga; Kalle Ilves; Rainer Marquardt; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ac–dc power conversion; energy storage; fault tolerance; HVDC converters; HVDC grid; isolated power supply; modular multilevel converter MMC ; power system faults; silicon carbide; submodules; voltage source converter VSC ; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : In order to enable the massive introduction of renewable energies the need for high-voltage direct current (HVDC) grids is anticipated. Large, globally interconnected HVDC networks will likely be the most cost-efficient means to balance electricity demand and available generation. LÄS MER

  4. 3. Fundamental Control Performance Limitations for Interarea Oscillation Damping and Frequency Stability

    Författare :Joakim Björk; Karl H. Johansson; Lennart Harnefors; Joe H. Chow; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Power system control; HVDC transmission control; interarea oscillations; power oscillation damping; small-signal stability; fundamental control limitations; frequency stability; hydro power; wind power; non-minimum phase; zero dynamics; eigenvalue analysis; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : With the transition towards renewable energy and the deregulation of the electricity markets, the power system is changing. Growing electricity demand and more intermittent power production increase the need for transfer capacity. Lower inertia levels due to a higher share of renewables increase the need for fast frequency reserves (FFR). LÄS MER

  5. 4. Voltage Support of Transmission Grids Using Resources Located in the Underlying Lower Voltage Networks : Unlocking the Potential of Distributed Generation Reactive Power Capabilities

    Författare :Stefan Stanković; Lennart Söder; Andrew Keane; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; reactive power support; voltage control; voltage stability; reactive power planning; inverter-based generation; active distribution networks; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : The path to sustainable, fossil-free future leads to inevitable energy transition towards renewable energy sources. A part of this transition includes replacement of conventional transmission system connected power plants with distributed renewables plants such as wind power. LÄS MER

  7. 5. Large Scale Solar Power Integration in Distribution Grids : PV Modelling, Voltage Support and Aggregation Studies

    Författare :Afshin Samadi; Lennart Söder; Olof Samuelsson; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Photovoltaic systems; PV system modelling; reactive power control; droop control; voltage sensitivity analysis; German Grid Codes; relative gain array RGA ; singular value decomposition SVD ; load modeling; system identification; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Long term supporting schemes for photovoltaic (PV) system installation have led to accommodating large numbers of PV systems within load pockets in distribution grids. High penetrations of PV systems can cause new technical challenges, such as voltage rise due to reverse power flow during light load and high PV generation conditions. LÄS MER