Sökning: "Lightning Protection"

Visar resultat 1 - 5 av 12 avhandlingar innehållade orden Lightning Protection.

  1. 1. On the Attachment of Lightning Flashes to Grounded Structures

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Marley Becerra; Uppsala universitet.; [2008]
    Nyckelord :Engineering physics; Lightning; Lightning attachment; Positive leader discharges; Lightning protection; Thunderstorms; Numerical modeling; Teknisk fysik;

    Sammanfattning : This thesis deals with the physical modeling of the initiation and propagation of upward positive leader discharges from grounded structures during lightning strikes. It includes the analysis of upward leaders initiated under the influence of the electric field produced by a dominant negative cloud charge and due to the combined action of a negative thundercloud and a descending downward stepped negative leader. LÄS MER

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

    Detta är en avhandling från Uppsala : Institutionen för teknikvetenskaper

    Författare :Nelson Theethayi; Uppsala universitet.; [2005]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; EMC; Lightning; TECHNOLOGY Electrical engineering; electronics and photonics; TEKNIKVETENSKAP Elektroteknik; elektronik och fotonik; Electrical engineering; Electromagnetic Compatibility EMC ; Lightning Protection; Transmission Lines; Electromagnetic Wave Propagation; Underground Cables; Grounding; Electromagnetic Transients; Electromagnetic Interference; Shielding Effectiveness; Railway Systems; 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

  3. 3. Transient Response of Grounding Systems Caused by Lightning: Modelling and Experiments

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Yaqing Liu; Uppsala universitet.; [2004]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Grounding system; Lightning protection; Electromagnetic Compatibility; Transient analysis; Soil ionization; Transmission line approach; Elektroteknik; TECHNOLOGY Electrical engineering; electronics and photonics Electrical engineering; TEKNIKVETENSKAP Elektroteknik; elektronik och fotonik Elektroteknik;

    Sammanfattning : In order to achieve better lightning protection and electromagnetic compatibility (EMC) requirements, the needs for a proper grounding system and the knowledge of its transient behaviour become crucial.The present work is focused towards developing engineering models for transient analysis of grounding system with sufficient accuracy and simplicity for lightning studies. LÄS MER

  4. 4. The Effects of Lightning on Low Voltage Power Networks

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Raul Montaño; Uppsala universitet.; [2006]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Lightning induced effects; Lightning Electromagnetic fields; Electromagnetic Compatibility EMC ; Surge Protective Devices SPDs ; Low voltage power networks; Elektroteknik; elektronik och fotonik; TECHNOLOGY Electrical engineering; electronics and photonics; TEKNIKVETENSKAP Elektroteknik; elektronik och fotonik;

    Sammanfattning : The present society is highly dependant on complex electronics systems, which have a low damage threshold level. Therefore, there is a high risk of partial or total loss of the system’s electronics when they are exposed to a thunderstorm environment. LÄS MER

  5. 5. Studies of ground ionization and lightning protection of power lines

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Víctor M. Cabrera M.; Uppsala universitet.; [1992]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURAL SCIENCES; NATURVETENSKAP;

    Sammanfattning : .... LÄS MER