Sökning: "laboratory discharges"

Visar resultat 6 - 10 av 21 avhandlingar innehållade orden laboratory discharges.

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

    Författare :Marley Becerra; Vernon Cooray; Rajeev Thottappillil; Mats Boman; Ivo Gallimberti; Uppsala universitet; []
    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

  3. 7. Partial Discharges in Large Rotating Machines - Continuous On-line Monitoring and Localisation, Based on a New Developed Technique (InTech)

    Författare :Abkar Kheirmand; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; InTech; detection; on-line monitoring; insulation; stator; condition control; PD measurement; Powerformer; winding; rotating machine; partial discharge;

    Sammanfattning : Partial discharges (PD) that originate from dielectrically defective parts of the insulation system result in its degradation, which may ultimately lead to a failure of high voltage apparatus. This has resulted in development of numerous PD measuring techniques. One of the most widespread applications of PD measurement is in rotating machines. LÄS MER

  4. 8. Estimation of hydrophobicity of insulating surfaces by studying sessile water drops

    Författare :Marcus Berg; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; hydrophobicity; contact angle; insulator; water; silicone; image processing; image analysis; Young-Laplace equation; droplet; axisymmetric; Materialvetenskap; Materials science; Teknisk materialvetenskap; Electricity; Esp The Study Of Transients and Discharges; elektricitetslära; ssk studiet av transienter och urladdning;

    Sammanfattning : Today, the traditional insulator materials for high voltage powerlines, i.e. glass and porcelain, are gradually being replaced with new materials, most notably silicone rubber. LÄS MER

  5. 9. Characteristic of Surge Transfer Through Transformers : Study of Conventional Distribution Transformer and XLPE Cable Winding Transformer (Dryformer)

    Författare :Mighanda Manyahi; Vladmiir Rakov; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Fysik; Physics; Fysik; Electricity; Esp The Study Of Transients and Discharges; elektricitetslära; ssk studiet av transienter och urladdning;

    Sammanfattning : Wide spread application and dependence on microelectronics based equipment in modern society has necessitated the study of power supply quality problems in low voltage power installations. In spite of improvements in surge protection, sensitive equipment connected to low-voltage side of distribution transformer has continued to fail due to transient voltages that are transferred through distribution transformer from high voltage circuits. LÄS MER

  7. 10. Morphology of Tigris River inside Baghdad City

    Författare :Ammar Adel Ali; Govand H. M. Sherwani; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Soil Mechanics; Geoteknik;

    Sammanfattning : Tigris and Euphrates rivers represent the artery of life in Iraq. Tigris River rises from Turkey and flows toward the southeast to enter Iraq. It drains a catchment area of 473 100 km² of which about 58% lies in Iraq. In this study the reach, about 50 km long, of the river inside Baghdad was been studied. LÄS MER