Sökning: "dielectric spectroscopy"

Visar resultat 11 - 15 av 90 avhandlingar innehållade orden dielectric spectroscopy.

1. 11. Partial Discharges Studied with Variable Frequency of the Applied Voltage

   Författare :Hans Edin; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; diagnostic methods; partial discharges; phase resolved; variable frequency; dielectric spectroscopy; dielectric response; harmonics; insulation; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

   Sammanfattning : This thesis concerns partial discharge (PD) diagnostics withvariable frequency of applied voltage in the frequency range 1mHz - 400 Hz. The exploration of a new type of spectroscopythat combines partial discharge analysis and dielectricresponse is demonstrated. LÄS MER

3. 12. Enhanced Dielectric Response Methods for the Characterization of Dielectric Materials

   Författare :Jing Hao; Nathaniel Taylor; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; FDS; non-contact; dielectric response; combined AC and DC; space-charge polarization;

   Sammanfattning : Dielectric response measurement is widely used for condition assessment of high voltage equipment and for characterizing candidate materials. Measurement with high accuracy and reliability is important in all stages of the lifetime of high voltage equipment, from manufacture to replacement decision. LÄS MER

4. 13. Molecular Arrangement, Electronic Structure and Transport Properties in Surfactant Gel- and Related Systems Studied by Soft X-ray and Dielectric Spectroscopy

   Författare :Johan Gråsjö; Maria Strömme; Jan Swenson; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; surfactants; surfactant poly-ion gel; water; confined water; XAS; RIXS; dielectric spectroscopy; SAXS; pKa; transport; Fick’s law; Engineering Science with specialization in Nanotechnology and Functional Materials; Teknisk fysik med inriktning mot nanoteknologi och funktionella material;

   Sammanfattning : This thesis concerns studies of aqueous soft matter systems, especially surfactant micelle systems.The aim has been to study the molecular arrangement and electronic structure of the constituents of, as well as transport properties in such a system. LÄS MER

5. 14. 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

7. 15. 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