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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.
1

Electrical connection for aluminium conductors in automotive applications : Prestudy of available solutions for electrical connection methods of aluminium cables

Hamedi, Emilia January 2017 (has links)
Due to increasing weight of electrical component and wiring harnesses in a vehicle contrary to the demand of light constructed vehicles as well as the constantly increasing and fluctuating price of copper compared to aluminium’s stable and far lower price, the use of aluminium conductors as an alternative have been promoted.  This thesis work lay theoretical research of the available methods used for electrical connection of aluminium conductors in order to increase the knowledge about the available termination techniques.  Due to aluminium’s characteristics such as lower conductivity and strength, tendency to form oxides and relax over time, differences in thermal expansion coefficient and high potential for galvanic corrosion, there is a risk of deterioration and degradation of the connection if the termination of aluminium conductors is not done correctly without being aware of the challenges when it comes to aluminium connection.  The founded solutions are different welding and soldering techniques such as friction welding, ultrasonic welding, resistance welding, plasma soldering and many other modifications of conventional crimp.  A robust termination system that faces all those challenges and ensure a reliable connection during the entire life length of the vehicle and in order to inhibit corrosion different type of sealing of the contact interface will be required.  In order to evaluate the performance of the founded connection method, testing with evaluation of, tensile strength of conductor to contact attachment, tightness demand, corrosion resistance, vibration and heat evolution at the contact attachment have to be conducted.
2

Making the Case for High Temperature Low Sag (HTLS) Overhead Transmission Line Conductors

January 2014 (has links)
abstract: The future grid will face challenges to meet an increased power demand by the consumers. Various solutions were studied to address this issue. One alternative to realize increased power flow in the grid is to use High Temperature Low Sag (HTLS) since it fulfills essential criteria of less sag and good material performance with temperature. HTLS conductors like Aluminum Conductor Composite Reinforced (ACCR) and Aluminum Conductor Carbon Composite (ACCC) are expected to face high operating temperatures of 150-200 degree Celsius in order to achieve the desired increased power flow. Therefore, it is imperative to characterize the material performance of these conductors with temperature. The work presented in this thesis addresses the characterization of carbon composite core based and metal matrix core based HTLS conductors. The thesis focuses on the study of variation of tensile strength of the carbon composite core with temperature and the level of temperature rise of the HTLS conductors due to fault currents cleared by backup protection. In this thesis, Dynamic Mechanical Analysis (DMA) was used to quantify the loss in storage modulus of carbon composite cores with temperature. It has been previously shown in literature that storage modulus is correlated to the tensile strength of the composite. Current temperature relationships of HTLS conductors were determined using the IEEE 738-2006 standard. Temperature rise of these conductors due to fault currents were also simulated. All simulations were performed using Microsoft Visual C++ suite. Tensile testing of metal matrix core was also performed. Results of DMA on carbon composite cores show that the storage modulus, hence tensile strength, decreases rapidly in the temperature range of intended use. DMA on composite cores subjected to heat treatment were conducted to investigate any changes in the variation of storage modulus curves. The experiments also indicates that carbon composites cores subjected to temperatures at or above 250 degree Celsius can cause permanent loss of mechanical properties including tensile strength. The fault current temperature analysis of carbon composite based conductors reveal that fault currents eventually cleared by backup protection in the event of primary protection failure can cause damage to fiber matrix interface. / Dissertation/Thesis / Fault current temperature relationship program in C / Current temperature relationship program in C / M.S. Electrical Engineering 2014

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