Sökning: "phase-resolved measurements"

Visar resultat 1 - 5 av 10 avhandlingar innehållade orden phase-resolved measurements.

  1. 1. 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. 2. Experimental investigation of the flow field in an aggressive intermediate turbine duct

    Författare :Lars-Uno Axelsson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; phase-resolved measurements; Intermediate turbine duct; flow visualization; vorticity dynamics; turbulence.; inter-turbine duct; hot-wire anemometry; experiment; 5-hole pressure probe;

    Sammanfattning : Intermediate turbine ducts are used for connecting thehigh-pressure turbine to the low-pressure turbine in turbofan engines. In order to meet the demands for more efficient and environmentally friendly jet engines, future intermediate turbine ducts need to have larger radial off-sets without increasing their length. LÄS MER

  4. 3. Modelling of cavity partial discharges at variable applied frequency

    Författare :Cecilia Forssén; Roland Eriksson; Hans Edin; Peter H.F. Morshuis; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; partial discharges; measurements; modelling; variable frequency; cavities; disc-shaped; polycarbonate; Electric power engineering; Elkraftteknik;

    Sammanfattning : The presence of partial discharges (PD) in high voltage components is generally a sign of defects and degradation in the electrical insulation. To diagnose the condition of high voltage insulation, PD measurements is commonly used. LÄS MER

  5. 4. Partial Discharges at Fast Rising Voltages

    Författare :Thomas Hammarström; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; short rise time; cavities; high dV dt.; measurements; Partial discharges; square like voltages; repetitive voltages;

    Sammanfattning : The present demand for higher efficiency and flexibility in the energy sector has led to an increased use of power electronic generated waveforms as these allow energy conversion between different frequencies including DC. The generated waveforms are usually synthesized by so called Pulse Width Modulation (PWM) techniques, where the desired waveform is approximated by a number of square shaped pulses with a short rise time. LÄS MER

  7. 5. Diagnostics of stator insulatin by dielectric response and variable frequency partial discharge measurements : a study of varied low frequencies in stator insulation, with particular attention to end-winding stress-grading

    Författare :Nathaniel Taylor; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical engineering; Elektroteknik;

    Sammanfattning : Stator insulation is a critical to the reliability of electrical generators and motors. It is common industrial practice to use electrical measurement of partial discharges (PD) and some form of current-voltage measurement as part of the condition assessment of stator insulation at maintenance times. LÄS MER