Search for dissertations about: "impedance spectroscopy dielectric"

Showing result 1 - 5 of 14 swedish dissertations containing the words impedance spectroscopy dielectric.

2. 1. Arbitrary Waveform Impedance Spectroscopy for Characterization and Diagnostics of High Voltage Insulation

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

   Abstract : 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. READ MORE

4. 2. Partial discharges studied by dielectric response method

   Author : Xiangdong Xu; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; frequency domain spectroscopy; AWIS; partial discharge excess current; dielectric characterization; partial discharge; non-PD excess current;

   Abstract : The increasing demand of integrating various renewable energy recourses in power system requires extensive use of power electronic solutions, which allows energy conversion between different frequencies and stabilizes the system. Consequently, other than the traditional 50/60 Hz sinusoidal voltage stresses act on the high voltage insulation systems. READ MORE

5. 3. Enhancements in Dielectric Response Characterization of Insulation Materials

   Author : Xiangdong Xu; Chalmers tekniska högskola; []
   Keywords : 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;

   Abstract : 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. READ MORE

6. 4. Ionic transport of α-alumina below 1000°C : an in-situ impedance spectrosocpy study

   Author : Johan Öijerholm; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Materials science; α-alumina; in-situ impedance spectroscopy; molecular dynamics; spark plasma sintering; conductivity; microstructure; Materialvetenskap; Materials science; Teknisk materialvetenskap;

   Abstract : Ionic conductivity of metal oxides is critical for the function of a broad range of different components, such as electrolytes in solid oxide fuel cells and alloys designed for high temperature applications. In both cases the ionic conductivity can be studied by in situ impedance spectroscopy, which is also able to reveal information on the dielectric properties of the metal oxides, and in some cases the influence of their microstructure. READ MORE

7. 5. Electric Fields for Surface Design and Chemical Analysis

   Author : Christian Ulrich; Fredrik Björefors; Ingemar Lundström; Tautgirdas Ruzgas; Linköpings universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Electric fields; Surface design; Chemical analysis; Bipolar electrodes; Impedance spectroscopy; Electrochemistry; Elektrokemi; Chemical physics; Kemisk fysik; Physical chemistry; Fysikalisk kemi; Surface and colloid chemistry; Yt- och kolloidkemi;

   Abstract : This thesis deals with the use of electric fields for evaluation and control of chemical systems. An electric field can result in the flow of charge across an interface between a metal and a solution, by means of chemical reactions. This interplay between electricity and chemistry, i.e. READ MORE