Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2005. / The cause of the largest number of faults on the Eskom main transmission system is unknown. It is believed that a non-uniform pollution layer along an insulator string is the reason for these anomalous flashovers. This non-uniform pollution layer results in the highest electric field strength, and thus the highest voltage, across the cleanest and driest discs. There thus exists a strong possibility that the anomalous flashover phenomenon is caused by a combination of mechanisms involving the pollution and air breakdown flashover mechanisms. This research project attempted to prove that flashover of the insulators is possible in accordance with the above model. Various experiments were set up in the high voltage laboratory and at a natural test site with a low source impedance supply attempting to simulate the conditions that lead to flashover in accordance with the hypothesis. All the tests done have not proven the non-uniform light pollution flashover mechanism successfully. However, future research has proposed an air breakdown flashover mechanism in light pollution conditions where the polluted part of the insulator string has a specific non-uniform distribution. Full scale testing in conditions similar to the normal operating conditions is proposed to prove the validity of this new hypothesis.

Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 195-202).

University of Macau / Faculty of Science and Technology / Department of Electrical and Electronics Engineering

No description available.

The thesis discusses the findings of an investigation into the use of novel condition monitoring techniques for oil-paper insulated high voltage equipment as used on the Eskom Main Transmission System. This research into the monitoring of the condition of high voltage (RV) insulation was undertaken because of the high failure rate of high voltage current transformers (eT's) and transformer bushings on the Eskom Transmission National Grid. These failures reached unacceptably high levels in the 1990's. The extent of failures has been quantified and was the driving motivation behind this research. Techniques for the condition assessment and condition monitoring of oil-paper filled high voltage equipment have traditionally focused on off-line techniques, in particular off-line tan delta measurements. This requires that the equipment be removed from service temporarily, but at widely spaced intervals before a measurement may be taken (typically every 3 to 6 years). Such techniques will not be able to detect faulty equipment where the insulation integrity deteriorates rapidly, resulting in catastrophic failure with risk to both adjoining equipment and personnel. The need for an on-line technique for detecting deteriorating insulation prior to failure was identified in the early 1990's and various systems were developed. This research investigation has focussed on assessing the use of on-line relative tan delta monitoring of RV insulation and compares this to off-line monitoring. In particular, the ability of such a relative tan delta measurement system to detect deteriorating oil-paper insulation has been assessed. The investigation has included the design, construction and commissioning of a dedicated test facility located at Eskom's Tugela substation. This test facility is unique in the world. This test facility has resulted in a number of experiments that have provided invaluable insight into possible failure modes of oil-filled high voltage equipment and the ability of on-line techniques to detect rapid failure modes has been carefully assessed. Further assessment of the on-line monitoring systems was also undertaken at various Eskom operational installations. The results of these tests and operational monitoring are addressed in this research. The research work and its findings are assessed against published literature and global activity in this important area. / Thesis (M.Sc.-Eng.)-University of KwaZulu-Natal, Durban, 2004.

No description available.

Thesis (M.S.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed on March 18, 2008) Includes bibliographical references.

Thesis (M.Sc.) (Hons.) -- University of Western Sydney, 2002. / A thesis submitted to the University of Western Sydney in fulfillment of the requirements for admission to the [degree of] Masters of Science (Honours). Bibliography : leaves 156-163.

Thesis (M.S.)--Oregon State University, 1992. / Typescript (photocopy). Includes bibliographical references (leaves 82-85). Also available on the World Wide Web.

Thèse (D.Eng.) -- Université du Québec à Chicoutimi, 2007. / La p. de t. porte en outre: Thèse présentée à l'Université du Québec à Chicoutimi comme exigence partielle du doctorat en ingénierie. CaQQUQ Bibliogr.: f. 235-244. Document électronique également accessible en format PDF. CaQQUQ