Sökning: "vattenkraft"

Visar resultat 11 - 15 av 25 avhandlingar innehållade ordet vattenkraft.

  1. 11. Numerical modelling considerations for analysis of concrete hydraulic structures subjected to high-frequency seismic loads

    Författare :Roghayeh Abbasiverki; Anders Ansell; Erik Nordström; Richard Malm; Peter Folkow; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Betongbyggnad; Concrete Structures;

    Sammanfattning : Concrete hydraulic structures are of great importance in today's society. When situated in areas with hard bedrock, these structures may become extra vulnerable to seismic excitations as these here are dominated by high-frequency vibrations which can have disastrous consequences for slender structures. LÄS MER

  3. 12. 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

  4. 13. Optimal regulating power market bidding strategies in hydropower systems

    Författare :Magnus Olsson; Lennart Söder; Terje Gjengedal; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electricity market; stochastic optimization; bidding strategy; time series analysis; Electrical engineering; Elektroteknik;

    Sammanfattning : Unforeseen changes in production or consumption in power systems lead to changes in grid frequency. This can cause damages to the system, or to frequency sensitive equipment at the consumers. The system operator (SO) is the responsible for balancing production and consumption in the system. LÄS MER

  5. 14. Fundamentals of Polyethylene Composites for HVDC Cable Insulation – Interfaces and Charge Carriers

    Författare :Mattias E. Karlsson; Richard Olsson; Mikael Skrifvars; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; polyethylene; nanocomposites; HVDC; conductivity; metal oxide; nanoparticles; surface functionality; polyeten; nanokompositer; HVDC; konduktivitet; metalloxider; nanopartiklar; ytfunktionalitet; Fiber- och polymervetenskap; Fibre and Polymer Science;

    Sammanfattning : Power transmission over long distances by using high voltage direct current (HVDC) cables is important for the transition from fossil energy to using renewable energy sources, e.g. wind, solar and water. LÄS MER

  7. 15. Durability evaluation of PEM fuel cell components

    Författare :Live Mølmen; Peter Leisner; Lars Fast; Frode Seland; Jönköping University; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Proton exchange membrane fuel cell; bipolar plate; corrosion; interfacial contact resistance; electrocatalysis; Polymermembranbränsleceller; bipolära plattor; korrosion; kontaktresistans; katalys;

    Sammanfattning : Proton exchange membrane fuel cells (PEMFCs) are used to convert hydrogen and oxygen to electricity, heat, and water. There are no greenhouse gas emissions, given that the hydrogen is produced from renewable sources, such as water electrolysis from wind, hydro or solar energy. LÄS MER