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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Design optimisation of bare conductors for overhead line applications.

Munilall, Anandran. January 2009 (has links)
The South African economy is an emerging market and as such there is a continued and growing need for the efficient supply of cost effective electricity. The capital investment involved in the design, construction, installation and commissioning of overhead transmission line networks are high and so too are the subsequent maintenance and operation costs, incurred over their life cycle periods. The need to improve the electrical operating efficiency of existing and future electrical transmission networks, through the reduction of electrical losses, focused and motivated the research in this particular area. The results and findings produced by this research study show that the magnetic induction produced by the steel core in ACSR (Aluminium conductor, steel reinforced) conductors cause in increase in the ac power losses, associated ac-dc resistance ratio and the effective ac resistance of the conductor, whilst the conductor is energised during normal operation. More specifically, the key parameters that cause this increase in the effective ac resistance of the conductor, as a result of the magnetic induction produced by the steel core, are those of hysterisis and eddy current power losses in the steel core and an added power loss caused by the non-uniform redistribution of current in the layers of aluminum wires, due to the ‘transformer effect’. Therefore the addition of the conductor dc resistance value to the component resistances produced by the current redistribution and magnetic hysterisis & eddy current power losses, form the total effective ac conductor resistance. This is contrary to standard practice where assumption is made that the conductor ac and dc resistance values are equal. The factors which influence the magnetic induction, include amongst others; the ferromagnetic properties of the steel core, the physical construction of the conductor, the conductor operating/core temperature and the load current. In order to calculate the effective ac-resistance of multi-layer ACSR conductors a computer simulation program was developed, which was largely based on determining the impact of varying these key factors, by evaluating its effect on the ac resistance of the conductor. It was found through manipulation of these factors that the total effective ac resistance of the conductor could be reduced and significantly so with higher load currents. The conductor sample used in this research study is commonly known as TERN ACSR conductor in the South African market and it was shown that with practical changes in lay ratios or lay lengths, one is able to reduce the total effective ac resistance of the conductor and associated power losses. Several software simulation exercises were performed using the developed software simulation program, to ultimately produce a set of optimised lay-lengths (lay-ratios) for the TERN ACSR conductor, with the intention that these simulated parameters would be employed in the production of actual conductor samples. The intention going forward after the planned production trial runs would be to test these conductor samples to verify compliance, in meeting both electrical and mechanical performance requirements. It should be noted that the planned production trials and relevant conductor-testing processes did not form part of the scope of this research report but are processes that have been planned for in the near future. Although testing to IEC 61089 are post processes that are planned for outside of this research scope, the specification requirements of IEC61089 were incorporated into the various computer simulation exercises. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2009.
32

The work hardening of austenitic stainless steel, applied to the fabrication of high-strength conductors

Spencer, Kevin. Embury, J. D. January 2004 (has links)
Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: J. D. Embury. Includes bibliographical references (leaves 238-245).
33

A probability based unified model for predicting electrical, mechanical and thermal characteristics of stranded overhead-line conductors /

Filipovic-Gledja, Visnja January 1997 (has links)
Thesis (Ph. D.) -- McMaster University, 1997. / Includes bibliographical references (leaves 165-168). Also available via World Wide Web.
34

Efficient numerical modeling of random surface roughness for interconnect internal impedance extraction

Chen, Quan, January 2007 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available in print.
35

Efficient numerical modeling of random surface roughness for interconnect internal impedance extraction /

Chen, Quan, January 2007 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2008. / Also available online.
36

Étude de la phase d'accrétion de la glace atmosphérique sur des câbles /

Portaix, Christophe, January 2000 (has links)
Mémoire (M.Eng.)--Université du Québec à Chicoutimi, 2000. / Document électronique également accessible en format PDF. CaQCU
37

Exploration de différentes architectures de réseaux de neurones pour la prédiction de la glace atmosphérique sur les conducteurs des réseaux électriques /

Larouche, Éric, January 2002 (has links)
Thèse (M.Eng.)--Université du Québec à Chicoutimi, 2002. / Document électronique également accessible en format PDF. CaQCU
38

Transmission through an arbitrary aperture in an arbitrary three-dimensional conducting surface enclosing chiral material

Altunkilic, Fikret. January 2007 (has links)
Thesis (Ph.D.)--Syracuse University, 2007. / "Publication number: AAT 3295512."
39

Fast solution of large-body problems using domain decomposition and null-field generation in the method of moments

Killian, Tyler Norton, Rao, S. M. January 2009 (has links)
Thesis (Ph. D.)--Auburn University. / Abstract. Vita. Includes bibliographical references (p. 70-71).
40

Characterisation of proton conducting oxide materials for use in reverse water gas shift catalysis and solid oxide fuel cells /

De A. L. Viana, Hermenegildo. January 2008 (has links)
Thesis (Ph.D.) - University of St Andrews, January 2008.

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