Mémoire (M. Sc.A.)-- Université du Québec à Chicoutimi, 1985. / Bibliogr.: f. [94]-99. Document électronique également accessible en format PDF. CaQCU

Mémoire (M.Eng.)--Université du Québec à Chicoutimi, 1996. / Document électronique également accessible en format PDF. CaQCU

Mémoire (M.Eng.)--Université du Québec à Chicoutimi, 1996. / Document électronique également accessible en format PDF. CaQCU

Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2003. / Bibliogr.: f. [145]-152. Document électronique également accessible en format PDF. CaQCU

Thèse (M.Eng.) -- Université du Québec à Chicoutimi, programme extensionné a l'Université du Québec à Rimouski, 2004. / Bibliogr.: f. 97-104. Document électronique également accessible en format PDF. CaQCU

Thèse (M.Eng.) -- Université du Québec à Chicoutimi, programme extensionné à l'Université du Québec à Rimouski, 2004. / Bibliogr.: f. 147-150. Document électronique également accessible en format PDF. CaQCU

Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2004. / Bibliogr.: f. [183]-197. Document électronique également accessible en format PDF. CaQCU

Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: Limited research results are available on the aging impacts of surface discharges for High Voltage Direct Current (HVDC) excitation on practical insulators using the Tracking Wheel Tester (TWT) methodology. This thesis gives details of an experimental investigation to compare the aging performance of insulator samples using the TWT for High Voltage Alternating Current (HVAC) and positive and negative polarity HVDC excitation. Two series of tests were performed. The first series of tests evaluated the aging of six insulator rods, namely three Room Temperature Vulcanized Silicone Rubber (RTV SR) coated glass samples and three uncoated glass samples. Three creepage distances were used for each of the test materials, namely 277 mm, 346 mm and 433 mm. The tests were conducted with HVAC excitation and the test methodology described in the IEC 61302 standard. The second series of tests involved the testing of actual insulator samples. The test voltage and conductivity of the salt water solution were also adapted. Six insulators from different manufacturers, representing different materials and specific creepage distances, were tested with HVAC and positive and negative polarity HVDC excitation. The test samples consisted of Ethylene Propylene Diene Monomer (EPDM), High Temperature Vulcanized Silicone Rubber (HTV SR), porcelain and SR coated porcelain insulators. The aging performance of the different test samples for the three types of excitation are compared in terms of peak leakage current, visual observations of surface degradation and hydrophobicity properties. The leakage current data for HVAC excitation shows that the insulators from the different manufacturers perform differently, even for the same type of material. The results also indicate differences in the way the surfaces degrade, as well as the rate of degradation. For insulators representing the same specific creepage distance, but different materials, it has been shown that the material does influence the aging performance. Comparison of the leakage current data for the HTV SR insulators from the same manufacturer, but with different specific creepage distances, shows that the specific creepage distance affect the aging performance significantly. In general, the test insulators showed higher peak leakage currents with HVDC excitation compared to HVAC excitation. The results for positive polarity HVDC excitation show that the dry band arcing, as well as the discharges, has the same form for all six insulators. The colour of the dry band discharges ranged from a blue-ish orange to a dark yellow, depending on the intensity of the leakage currents. The hydrophobic insulators, namely the HTV SR, EPDM and RTV SR coated porcelain insulators, had lost hydrophobicity within the first week of testing. The results for negative polarity HVDC excitation show severe surface degradation compared to the results for HVAC excitation. The effect of positive polarity HVDC excitation, however, seems to be more severe in terms of leakage currents and aging compared to negative polarity HVDC excitation.

Thesis. 1978. Ph.D.--Massachusetts Institute of Technology. Dept. of Electrical Engineering and Computer Science. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 248-250. / Ph.D.

The rapid development of organic electronics is leading to a number of promising devices in the area of energy sources and conservation (e.g., solar cells and solid-state lighting), while also advancing display technology, sensors, and thin-film transistors. One obstacle to this development is the susceptibility of these devices to water vapor and oxygen, which are well known to cause rapid degradation in many organic electronic devices. In order to guarantee the minimum lifetime needed for various applications, high barrier performance encapsulation materials and structures must be developed and has been the object of much experimental research. However, there is a dearth of comprehensive studies which link the characterization, modeling, and integration of ultra-high barrier films with organic electronics. Such studies are necessary in order to advance the understanding of thin-film encapsulation and to find methodologies which greatly improve its performance. The present work investigates the processing and development of high quality single-layer and multilayer encapsulation architectures for ultra-high barrier films. For compatibility with organic electronics, this study focuses on low temperature fabrication processes which can lead to poor film quality. To circumvent the issue of defects, multilayer encapsulation films with alternating inorganic and organic layers were used to provide ultra-low permeation films. By reducing the complexity of typical multilayer architectures, a new encapsulation processing procedure was developed which combines a plasma enhanced chemical vapor deposition fabricated inorganic film followed by a high quality film deposited by atomic layer deposition. The improvements that this hybrid film provided were through the quick coating of the device via plasma-based deposition followed by a short atomic layer deposition exposure to seal the defects in the first film. The barrier performance of all thin-film encapsulation was characterized in terms of the effective water vapor transmission rate (WVTR) by using Ca corrosion tests. A detailed study of the water vapor permeation mechanism through thin-film layers was presented. Finally, fully characterized encapsulation layers were integrated with organic solar cells to validate the effectiveness of the barrier layers. The compatibility of the encapsulation process with organic devices was investigated by comparing the performance parameters of organic device before and after encapsulation. The parameters of encapsulated organic devices with various encapsulation structures were compared with their initial values as a function of exposure time to atmosphere to provide a link between effective WVTR and shelf-lifetime of encapsulated organic devices.