Sökning: "Overvoltages"

Visar resultat 1 - 5 av 9 avhandlingar innehållade ordet Overvoltages.

  1. 1. Managing uncertainties through efficient calculation of transients and harmonic propagation in power systems

    Författare :Oscar Lennerhag; Math Bollen; Jan Lundquist; David Thomas; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Overvoltages; harmonics; uncertainties; stochastic methods; Electric Power Engineering; Elkraftteknik;

    Sammanfattning : The electric power system is undergoing changes including large-scale introduction of renewable energy sources together with HVDC/FACTS, changes in the network such as increased amount of high voltage cables, industrial electrification, and changes in the load composition. These changes will impact the system in different ways and lead to challenges that must be addressed to facilitate planning, dimensioning, and operation of the system in a secure and economical way. LÄS MER

  3. 2. Simulation of lightning electromagnetic fields and their interaction with low voltage power installations : By Arturo Galván Diego

    Författare :Arturo Galván Diego; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Lightning electromagnetic field; electromagnetic interaction; low voltage power installation; lightning induced voltage; transient response; Fysik; Physics; Fysik; Electricity; Esp The Study Of Transients and Discharges; elektricitetslära; ssk studiet av transienter och urladdning;

    Sammanfattning : An increasing number of damages of electric nature are being observed on modem electronic sensitiveequipment connected to low voltage power installation (LVPI) networks when they are exposed tolightning electromagnetic fields (LEMPs), or indeed, any other electromagnetic pulse (EMP). The wayin which these fields affect the electronic equipment depends on the properties of the interferencesource, the electromagnetic interaction and the hardness of the device. LÄS MER

  4. 3. Homogenization of some linear and nonlinear partial differential equations

    Författare :Niklas Wellander; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Sammanfattning : In this thesis is studied two-scale convergence for sequences of linear and nonlinear evolution problems. In particular homogenization procedures, correctors and a numerical algorithm for such problems are studied. The main results are the following: We prove a crucial compactness results of two-scale convergence type. LÄS MER

  5. 4. System Aspects and Modulation Strategies of an HVDC-based Converter System for Wind Farms

    Författare :Stephan Meier; Hans-Peter Nee; Boon-Teck Ooi; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Isolated AC DC Converter; Mutual Commutation; Soft Switching; Voltage Source Converter; Cycloconverter; Modulation Strategies; Medium-Frequency Transformer; HVDC Transmission; Wind Power; Wind Farms; Electric power engineering; Elkraftteknik; Electrical engineering; Elektroteknik;

    Sammanfattning :   In this thesis, a new HVDC-based converter system for wind farms is investigated. It is based on a mutually commutated soft-switching converter system and provides a unique integrated solution for the wind turbine generator drive systems, the wind turbine interconnection, and the power conversion for HVDC transmission. LÄS MER

  7. 5. Electromagnetic Interference in Distributed Outdoor Electrical Systems, with an Emphasis on Lightning Interaction with Electrified Railway Network

    Författare :Nelson Theethayi; Rajeev Thottappillil; Farhad Rachidi; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Electromagnetic Compatibility EMC ; Lightning; Lightning Protection; Transmission Lines; Electromagnetic Wave Propagation; Underground Cables; Grounding; Electromagnetic Transients; Electromagnetic Interference; Shielding Effectiveness; Railway Systems; Elektroteknik; elektronik och fotonik; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : This thesis deals with the electromagnetic compatibility (EMC) problems of distributed electrical networks, especially that caused by lightning to electrified railway. Lightning transients were found to damage important devices that control train movements, causing traffic stoppage and delays. LÄS MER