Sökning: "electrical discharges"
Visar resultat 1 - 5 av 71 avhandlingar innehållade orden electrical discharges.
1. Physics of Electrical Discharge Transitions in Air
Sammanfattning : Electrical discharges with a variety of different forms (streamers, glow corona, leaders, etc.) broadly exist in nature and in industrial applications. Under certain conditions, one electrical discharge can be transformed into another form. LÄS MER
2. Mechanisms of Electrical Ageing of Oilimpregnated Paper due to Partial Discharges
Sammanfattning : In this thesis, partial discharge (PD) phenomenon in oil-impregnated paper (OIP) is investigated under accelerated electrical stress. The thesis is mainly focused on the characteristic of PD activity and the influence it has on the insulation properties of OIP. LÄS MER
3. Detection of Partial Discharges at Fast Rising Voltages
Sammanfattning : The present demand for higher efficiency and flexibility in the energy sector has ledto an increased use of power electronic generated waveforms as these allow energyconversion between different frequencies including DC. The generated waveformsare usually synthesized by so called Pulse Width Modulation (PWM) techniques,where the desired waveform is approximated by a number of square shaped pulseswith a short rise time. LÄS MER
4. Numerical modelling of positive electrical discharges in long air gaps
Sammanfattning : This dissertation deals with research on the numerical modelling of electrical discharges in laboratory long air gaps excited with positive switching impulses. It begins with the preliminary work of several scientists during the last decades, making a detailed analysis of different approaches for modelling all the stages in a full discharge. LÄS MER
5. Partial Discharges at Fast Rising 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