Sökning: "dielectric properties"

Visar resultat 21 - 25 av 266 avhandlingar innehållade orden dielectric properties.

  1. 21. Enhancements in Dielectric Response Characterization of Insulation Materials

    Författare :Xiangdong Xu; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; harmonic limited waveform; air reference method; contact-free electrode; geometric corrections.; frequency domain spectroscopy; Dielectric characterization;

    Sammanfattning : The increasing demand of integrating various renewable energy recourses in power system requires extensive use of power electronic solutions, such as HVDC and FACTS, as these techniques allow energy conversion between different frequencies and serves to stabilize the network. Consequently, electric stresses other than traditional 50/60 Hz sinusoidal voltage stress are acting on high voltage insulation materials. LÄS MER

  3. 22. Computer Modelling of Electrophysical Phenomena in High Voltage Insulation

    Författare :Yuriy Serdyuk; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dielectric properties; discharge plasma; composite material; computer model; numerical simulations; electrical discharge;

    Sammanfattning : Different kinds of dielectrics are used for high voltage insulation. In most of the cases, they are combined into complex insulating systems forming macro- and micro-scale composite structures. LÄS MER

  4. 23. Arbitrary Waveform Impedance Spectroscopy for Characterization and Diagnostics of High Voltage Insulation

    Författare :Björn Sonerud; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; insulation testing; aging; monitoring; discrete Fourier transforms; Dielectric measurements; dielectric materials;

    Sammanfattning : In high voltage engineering the dielectric response technique is a widely used tool both for characterization of insulation materials and for diagnostics of components such as transformers and cables. Currently available techniques are not capable of measuring on-line which would be advantageous; when characterizing a material and evaluating the effect of different voltage magnitudes, waveforms and temperatures it is desirable to be able to observe the continuous development of the dielectric properties. LÄS MER

  5. 24. Material Properties of Starch and Cereal Protein Films and Foams

    Författare :Thomas Gillgren; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; foam; avenin; oxygen permeability; amylopectin; water vapour permeability; plasticization; mechanical properties; zein; film; glass transition temperature; kafirin; prolamin; cereal protein; amylose; starch;

    Sammanfattning : Materials that are renewable and biodegradable are demanded for environmental reasons. Biopolymeric materials, such as materials from starch and cereal proteins, are both renewable and biodegradable. However, starch and cereal protein materials are generally rather brittle and therefore need to be plasticized to become more flexible. LÄS MER

  7. 25. Analysis of dielectric response measurement methods and dielectric properties of resin-rich insulation during processing

    Författare :Anders Helgeson; KTH; []
    Nyckelord :;

    Sammanfattning : The dielectric diagnostic methods ofpolarisation/depolarisation currents and recovery voltage,which are time domain methods, and capacitance and tandmeasurements at different frequencies, which is a frequencydomain method, have been studied here. In the first part of thethesis, these measurement methods are analysed and evaluated. LÄS MER