HV-Freileitungsseile - Stand der Technik und Entwicklungsmöglichkeiten

Research output: ThesisMaster's Thesis

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Abstract

Since renewable energy is mostly generated locally, it often needs to be carried over long distances to the actual consumer centers. In addition, solar or wind energy is only available intermittently and produces local electricity surpluses, while elsewhere the peak loads cannot be covered by power-generation. In order to be able to integrate electricity effectively and economically into the power system, renewable energies are inevitably accompanied by increased grid expansion. It is necessary to develop new technologies along the entire value chain and to optimize existing systems efficiently. The aim of this master's thesis is to summarize the current technical status in the area of overhead line cables in the high-voltage segment and to offer an outlook on potential optimization directions. In this context, special attention is paid to the material and treatment processes to improve the same. The first chapter explains the motivation of the thesis and explains the possible consequences of a black out of the power system. Chapter 2 of this work includes research on the relevant basics in the high-voltage sector. In particular, the electrical conductivity is defined and comparisons are made between different conductor types and materials. This is made in terms of the electrical and thermal conductivity as well as thermal expansion and their interaction with one another. The following chapter 3 examines the technologies currently in use and compares different types of wires and their materials. A distinction is made between the conductor material for the transmission of electrical current and the supporting material, which mainly acts as reinforcement to carry the mechanical tension. Chapter 4 examines the requirement profile of the conductor wires in closer detail and defines the direction of optimization. A QFD analysis is embedded here to evaluate existing solutions and optimization options are set up. Even if a functional division is made into conductor and carrier wires, the conductor material should nevertheless have a certain strength and resistance to aging. The increase in strength of aluminum alloys can generally be achieved by grain refinement or by strain hardening without a drastic loss of electrical conductivity. Both solid solution hardening and precipitation hardening greatly reduce the conductivity. In order to increase the temperature-resistance of aluminum conductors and to protect them from recrystallization during operation, they can be alloyed with additives. In particular, zirconium alloys are already in use. To improve carrier wires and to minimize sag even at high temperatures, composite materials can be considered. Both PMCs and MMCs can be a high strength alternative with a lower density than steel. The disadvantage of these solutions is the uneconomical production and therefore the high price. Optical coatings and low-noise wires can be requested by customers and are therefore discussed in Chapter 4. Finally, options apart the material for minimizing the electrical losses are described. These include the use of direct current, overhead line monitoring and smart grids. The fifth chapter deals with applications that don’t seem to be associated with overhead line cables at first. For this purpose, analog requirement profiles were sought beyond the known industry. Finally, the results are discussed in a separate chapter and a summary with an outlook is provided.

Details

Translated title of the contributionHV-overhead power lines - state of the technology and development possibilities
Original languageGerman
QualificationDipl.-Ing.
Awarding Institution
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Publication statusPublished - 2020