Sökning: "PD measurement"
Visar resultat 6 - 10 av 40 avhandlingar innehållade orden PD measurement.
6. Partial Discharge Signatures of Defects in Insulation Systems Consisting of Oil and Oil-impregnated Paper
Sammanfattning : Partial discharge measurement is a common method for monitoring and diagnostics of power transformers, and can detect insulation malfunctions before they lead to failure. Different parameters extracted from the measured PD activity can be correlated to the PD source, and as a result it is possible to identify the PD source by analyzing the PD activity. LÄS MER
7. Measurement and Analysis of Partial Discharges at Semi-Square Voltages
Sammanfattning : Insulation is today being exposed to voltages having considerably higher frequency components than the conventional power frequency AC 50 Hz or 60 Hz, for example in motors supplied by adjustable speed drives based on pulse width modulated converters. This has in many cases caused unexpected behaviour of the insulation systems. LÄS MER
8. Experimental tooth clenching : a model for studying mechanisms of muscle pain
Sammanfattning : “I felt like I’d done three rounds with Mike Tyson…all becauseI was grinding my teeth in my sleep”, så beskrev en patient somintervjuades av Daily Mail i en artikel där det ökade problemet medöverbelastning i käkarna beskrevs, vilket kan leda till tandslitage,muskelsmärta, och frakturer på tandmaterial. Det personliga lidandet,och de ekonomiska kostnaderna för både individ och samhälle ärstort. LÄS MER
9. Characterization of Electrical Insulation Exposed to Arbitrary Voltage Waveforms
Sammanfattning : The extensive use of power electronics in power systems today gives rise to other voltage waveforms than the conventional 50/60 Hz sinusoidal and consequently other types of electric stress act on high voltage insulating materials. Previous studies has shown that Pulse Width Modulated (PWM) voltages and similar waveforms increase stress in Adjustable Speed Drives (ASD) as compared with sinusoidal waveforms and it has also been shown that partial discharge (PD) activity is intensified during PWM voltages and that rise time of square like pulses affect PD inception voltage. LÄS MER
10. Unveiling catalytic species in suspension/solution-based reactions by in situ X-ray absorption spectroscopy
Sammanfattning : The palladium (Pd) and ruthenium (Ru) species in several attractive catalysts have been probed using X-ray absorption spectroscopy (XAS). The study of catalyst evolution in suspension- and solution-based reactions was the primary aim. It was achieved by performing in situ XAS experiments on Pd and Ru over the course of the reactions. LÄS MER