Search for dissertations about: "frequency domain reflectometry"

Showing result 1 - 5 of 10 swedish dissertations containing the words frequency domain reflectometry.

  2. 1. An FRA Transformer Model with Application on Time Domain Reflectometry

    Author : Hanif Tavakoli; Göran Engdahl; Jonas Ekman; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; complex permeability; lumped circuit model; frequency response analysis; time domain reflectometry; high frequency modeling; transformer diagnosis; reluctance network method.;

    Abstract : Frequency response analysis (FRA) is a frequency-domain method which is used to detect mechanical faults in transformers. The frequency response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. READ MORE

  4. 2. A High Frequency Transformer Winding Model for FRA Applications

    Author : Hanif Tavakoli; Göran Engdahl; Jonas Ekman; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; complex permeability; frequency response analysis; time domain reflectometry; high frequency modeling; transformer diagnosis; Electrical engineering; Elektroteknik;

    Abstract : Frequency response analysis (FRA) is a method which is used to detect mechanical faults in transformers. The FRA response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. READ MORE

  5. 3. Time and Frequency Domain Measurement Methods for High Frequency Characterisation of Power Cables

    Author : Ruslan Papazyan; KTH; []
    Keywords : Attenuation measurement; XLPE insulation; Power cables;

    Abstract : Time Domain Reflectometry (TDR) has been used forlocalisation of transmission line discontinuities in variousapplications. One of the challenges when applying TDR on powercables is to obtain knowledge of the high frequencycharacteristics of both the degraded and the undegradedsections of the cable. READ MORE

  6. 4. On-line time domain reflectometry diagnostics of medium voltage XLPE power cables

    Author : Valentinas Dubickas; Roland Eriksson; Tord Bengtsson; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Elektroteknik;

    Abstract : Degradation of XLPE insulated power cables by water-trees is a primary cause of failure of these cables. The detection of water-trees and information about the severity of the degradation can be obtained with off-line measurement using dielectric spectroscopy. In many situations only a limited part of the cable may be degraded by the water-trees. READ MORE

  7. 5. Techniques for Localization of Insulation Degradation along Medium-Voltage Power Cables

    Author : Ruslan Papazyan; Roland Eriksson; Fred Steennis; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical power technology; Attenuation measurement; cross-linked polyethylene insulation; discontinuities; localization; mass-impregnated insulation; numerical analysis; parameter estimation; power cable metallic screen; scattering parameters; time domain reflectometry; velocity measurements; water treeing; Elkraftteknik; Electric power engineering; Elkraftteknik;

    Abstract : Time Domain Reflectometry (TDR) has been used for localization of transmission line discontinuities in diverse applications. Various challenges have to be addressed when applying TDR for localization of insulation degradation in power cables. READ MORE