Dissertations / Theses on the topic 'Cables lines'
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1
Bernardin, Sylvie. "Étude et analyse du délestage de glace atmospherique sur les cables /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1989. http://theses.uqac.ca.
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Teo, Yu Xian. "Modelling of interconnects including coaxial cables and multiconductor lines." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13832/.
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In recent years, electromagnetic compatibility (EMC) problems associated with high frequency and high speed interconnects are becoming of increasing concern. Coaxial cables are a popular form of interconnect. In this thesis, the crosstalk coupling between two parallel coaxial cables in free space and above a ground plane is investigated. The degree of coupling is usually formulated analytically in the frequency domain. In this thesis, a method for time domain simulation is proposed using the TLM technique. Results are compared with frequency domain solutions and experimental results. Also; the standard model has been improved by including the skin depth effect in the coaxial cable braid. The crosstalk between the two coaxial cables is observed through the induced voltages on the loads of the adjacent cable, which is deemed to be the usual measureable form of cable coupling. The equivalent circuit developed for the coupling path of two coaxial cables in free space takes account of the differential mode (DM) current travelling in the braids of the cables. As for the coupling path of the cables via a ground plane, the equivalent circuit is developed based on the flow of differential mode (DM) and common mode (CM) currents in the braid, where the coaxial braid’s transfer impedance is modelled using Kley’s model. The radiated electric (E) field from the coaxial cable above a ground plane is also deduced from the predicted cable sheath current distribution and by the Hertzian dipoles’ approach. Results are validated against the radiated electric field of a single copper wire above ground. Both the simulated and experimental results are presented in the time and frequency domains and good agreement is observed thus validating the accuracy of the model.
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Rajasekaran, Vinod. "Power delivery in systems with lossy cables or interconnects." Diss., Available online, Georgia Institute of Technology, 2003:, 2003. http://etd.gatech.edu/theses/available/etd-11252003-095456/unrestricted/rajasekaranvinod200312phd.pdf.
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Thesis (Ph. D.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2004.Dr. Bonnie S. Heck, Committee Chair; David G. Taylor, Committee Member; Thomas. G. Habetler, Committee Member; Linda M. Wills, Committee Member; Eric Johnson, Committee Member. Includes bibliography.
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Sellers, Sally M. "Caculation of ampacity for underground electrical cables." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/18973.
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Akinnikawe, Ayorinde. "Investigation of broadband over power line channel capacity of shipboard power system cables for ship communications networks." Thesis, [College Station, Tex. : Texas A&M University, 2008. http://hdl.handle.net/1969.1/ETD-TAMU-3155.
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Li, Quan. "AC loss characteristics of monolayer and multilayer superconducting power transmission cables." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609500.
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Aslan, Y. "Accurate fault location on overhead distribution lines using superimposed components." Thesis, University of Bath, 1996. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.321843.
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Marti, Luis. "Simulation of electromagnetic transients in underground cables with frequency-dependent modal transformation matrics." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/27442.
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This thesis presents a new model to simulate the behaviour of underground cable systems under transient conditions. The new cable model belongs to the class of time-domain, frequency-dependent models, and it is directly compatible with the solution algorithm of the EMTP (Electromagnetic Transients Program).
The most important feature of the new model is that it takes into account the frequency dependence of the modal transformation matrices and cable parameters, thus overcoming the main limitation of currently-used transmission line and cable models, which assume that the modal transformation matrices are constant
Conceptually, the new model is relatively simple. The system parameters which define the behaviour of an underground cable (namely the modal characteristic admittance matrix, the modal propagation matrix, and the modal transformation matrix), are expressed in closed form by approximating them with rational functions in the frequency domain. Therefore, in the time domain, all numerical convolutions can be expressed recursively. The host transients program (to which the model is interfaced) sees the new model as a constant, real admittance matrix, in parallel with a continuously-updated vector current source.
The accurate approximation by rational functions of the modal transformation matrix is possible when its elements are continuous and smooth functions of frequency. Standard eigenvalue/eigenvector algorithms are not well suited for this purpose. Therefore, a new procedure to generate eigenvalues and eigenvectors has been developed. This procedure is based on the Jacobi method, and it produces the desired smooth functions of frequency. This manuscript presents a number of simulations where the performance of the new cable model is compared with exact analytical solutions. These simulations show an excellent agreement between analytical and numerical answers. The effects of not taking into account the frequency dependence of the modal transformation matrices is illustrated with the simulation of a line-to-ground fault on a three-phase cable. The response of the new cable model is also compared with results measured in a field test
The new cable model is numerically stable. Its computational speed is comparable to that of frequency-dependent line models with constant transformation matrices.
The new cable model is general. Its extension to the simulation of multiple-circuit overhead transmission lines should also be of considerable practical importance.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Farmer, Anthony Lee. "Investigation Into Snap Loading of Cables Used in Moored Breakwaters." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/35854.
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A two-dimensional, nonlinear dynamic analysis is conducted on a moored breakwater
configuration to investigate snap loads in mooring lines. Breakwaters are structures used
to attenuate or eliminate waves and protect shorelines, harbors, and other natural and
man-made marine structures from wave damage. The breakwater in this investigation is
modeled both as a point mass and as a rigid body. Both models are subjected to free
undamped motions and forced undamped wave motion. Energy is dissipated through the
use of a coefficient of restitution applied when a mooring line becomes taut (i.e., reaches
its natural length). The mooring line is modeled as an inextensible cable with no axial or
bending resistance when slack. Snap loading arises when a mooring line transitions
suddenly from a slack condition to a taut condition. The analysis was conducted on a
breakwater configured upside down and hanging by two mooring lines. The length of the
mooring lines, coefficient of restitution, size and shape of the breakwater, initial position
of the breakwater, amplitude of wave forcing, ratio of vertical to horizontal forcing, and
frequency of forcing were all varied in the analysis. The results show that the rotations of
the rigid body and the wave forcing have a significant role in the analysis, indicating that
a rigid-body model for a moored breakwater under wave forcing is the more accurate model.Master of Science
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Yin, Yanan. "Calculation of frequency-dependent parameters of underground power cables with finite element method." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/31119.
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In this thesis, the finite element method (FEM) is applied to the calculation of frequency-dependent series impedances and shunt capacitances of underground power cables. The principal equations describing the quasi-magnetic fields and static electric fields are solved with FEM based on the Galerkin technique. The Js method and the loss-energy method are derived to calculate the impedances of a multiconductor system from its field solution, and the energy method and the surface charge method are derived to calculate the capacitances. With a single-core (SC) coaxial cable, the suitability of quadratic isoparametric elements and high-order simplex elements are studied, and a suitable division scheme is suggested for the auto-mesh program.
The conventional FEM with a field truncation boundary is applied to the impedance calculation of buried SC cables. Suitable locations for the field truncation boundary and division schemes in the earth are studied. The results show that rb ≥ 12[symbol omitted] is required to obtain accurate impedances of shallowly buried cables with the conventional FEM. This requires a large solution region in the earth at low frequencies. A new technique based on the perturbation concept is proposed to reduce the solution region in the earth. Comparisons between the results from the conventional FEM and from the proposed technique with a significantly reduced solution region in the earth show good agreement.
In the case studies, the FEM is applied to the parameter calculation of multiphase SC cables, PT cables, sector-shaped cables, and stranded conductors. The numerical results are compared with those from analytical formulas.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Gouzy, Sophie. "Analyse de la phase de maintien de différents types de glace atmosphérique sur des cables /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2002. http://theses.uqac.ca.
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Wood, Sandra Jean. "Determination of effective thermal conductivity of media surrounding underground transmission cables." Thesis, Georgia Institute of Technology, 1993. http://hdl.handle.net/1853/17390.
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Hayakawa, N., A. Ishiyama, N. Amemiya, T. Hasegawa, T. Saitoh, M. Yagi, S. Mukoyama, et al. "Development of 66 kV and 275 kV Class REBCO HTS Power Cables." IEEE, 2013. http://hdl.handle.net/2237/20737.
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Makhkamova, Irina. "Numerical investigations of the thermal state of overhead lines and underground cables in distribution networks." Thesis, Durham University, 2011. http://etheses.dur.ac.uk/866/.
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As part of extensive activities on the reduction of CO2 emissions, a rapid expansion of power generation using new more fuel efficient technologies (large, medium and embedded scale with combined heat and power (CHP) projects) and renewable energy (wind, biomass, solar PV) is currently taking place in numerous European countries, including the UK. The research presented in this thesis is a part of a UK government funded project, which aims to find answers to how to accommodate increased renewable energy into the distribution network. Current ratings, which are limited by the temperature of the conductors used in the distribution network, are based on worst case scenario conditions and are conservative. The temperature limits can be lifted if one takes into consideration the dynamic changes in the surrounding environmental conditions of the conductors. Implementation of real-time thermal rating of existing power systems could result in greater installed capacities of distributed generation (DG). This research aims to provide new insights into the thermal state of overhead line conductors (OHL) and underground cables (UGC) by using Computational Fluid Dynamic methods. An algorithm consists of building the geometry of the calculation domain, meshing, choosing a model, inputting initial conditions, initiation of the calculation, and analysing results. A part of the UK power system was chosen by Scottish Power Energy Networks for monitoring essential data of OHL conductors in order to validate results of the temperatures of the conductors.
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Siegel, Thomas A. "Magnetic fields of an underground coaxial cable caused by return currents in the earth." Ohio : Ohio University, 1989. http://www.ohiolink.edu/etd/view.cgi?ohiou1182517321.
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Djaziri, Leila. "Diagnostic de défauts d'isolement dans des lignes de transmission électriques : application aux cables de signalisation SNCF." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112134/document.
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Ces travaux de thèse portent sur la détection de défauts d'isolement dans des lignes de transmission de grandes longueurs. Il s'agit de détecter des défauts non francs liés à l'isolant entre les conducteurs d'un câble de grande longueur qui sont représentés par le paramètre de conductance de fuite. Détecter ces défauts, signes d'un possible futur court-circuit, est un enjeu important mais nécessite une méthode non invasive. Par exemple, dans le cas des câbles de signalisation SNCF, il s'agit de développer une méthode de diagnostic de très faibles conductances de fuite dans les câbles de signalisation le long des voies ferrées compatible avec la circulation des trains. Il faut savoir estimer, à partir de mesures en un seul point du câble, de fortes résistances distribuées sur plusieurs centaines de mètres sans perturber la bande de fréquences du continu à 40 kHz, réservée aux signaux de service. En effet, les câbles de signalisation de la SNCF qui nous intéressent ont une longueur moyenne de 1500 m et sont utilisés dans la bande de fréquence 0-40 kHz. Nous proposons donc une méthode fréquentielle permettant d'estimer de faibles défauts à moyenne fréquence dans des lignes de transmission uniformes avec pertes. Elle repose sur deux idées principales : une analyse fine des effets conjoints de la dissipation et de la dispersion et une méthode de comparaison de deux lignes ayant les mêmes caractéristiques et ne différant que du paramètre de conductance de fuite. Cette méthode de comparaison a été généralisée dans le cas de lignes multiconducteurs en adoptant une démarche statistique.\\Cette thèse a apporté de nouveaux résultats : des formules d'estimation de pertes découlant de l'analyse fine d'une part des effets conjoints de la dissipation et de la dispersion et d'autre part de la méthode de comparaison de deux lignes. Des simulations numériques ont été faites dans les deux cas afin de valider la méthode fréquentielle proposée. Des expériences ont été réalisées afin de valider l'analyse statistique développée dans le cas de lignes multiconducteursThis thesis work focuses on the detection of insulation faults in very long transmission lines. This is detecting soft defects related to the insulation between the conductors of a long cable which are represented by the leakage conductance parameter. Detect these faults, signs of a possible future short-circuit, is an important issue but requires a noninvasive method. For example, in the case of railway signaling cables, it is to develop a method of diagnosis of very low leakage conductances in signaling cables along railways compatible with the movement of trains. Be aware estimate from measurements in one point of the cable, strong resistance distributed over several hundred meters without disturbing the continuous frequency range to 40 kHz, reserved for service signals. Indeed, the signal cables from the train that interest us have an average length 1500 m and are used in the frequency band 0-40 kHz.We propose so a frequency method for estimating low defects to medium frequency in uniform transmission lines with losses. It is based on two main ideas : a detailed analysis of joint effects of dissipation and dispersion and a method of comparing two lines having the same characteristics and differing only leak conductance parameter. This method of comparison was widespread in the case of multiconductor lines by adopting a statistical approach.This thesis has brought new results : losses estimation formulas resulting from the detailed analysis of a share of joint effects of dissipation and dispersion and also the method of comparing two lines. Numerical simulations were made in both cases to validate the proposed frequency method. Experiments were performed to validate the statistical analysis in the case of multiconductor lines
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Kermani, Koosheh Majid. "Ice shedding from cables and conductors : a cracking model of atmospheric ice = Délestage de glace des câbles et des conducteurs : un modèle de rupture fragile de la glace atmosphérique /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 2007. http://theses.uqac.ca.
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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 au doctorat en ingénierie. CaQQUQ Bibliogr.: f. [211]-220. Document électronique également accessible en format PDF. CaQQUQ
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Filipovic-Gledja, Visnja. "A probability based unified model for predicting electrical, mechanical and thermal characteristics of stranded overhead-line conductors." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp02/NQ30086.pdf.
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Lang, Ian Dewi. "The degradation of all-dielectric self supporting cables installed in high potential electro-magnetic fields : a theoretical and practical evaluation of optical fibre cables strung independently on overhead power transmission lines." Thesis, University of South Wales, 2001. https://pure.southwales.ac.uk/en/studentthesis/the-degradation-of-alldielectric-self-supporting-cables-installed-in-high-potential-electromagnetic-fields(5a7dee38-9f9b-40f8-8259-2e3d5386e292).html.
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The operational life of all-dielectric self supporting (ADSS) optical fibre cables installed on high voltage over-head power transmission lines is limited by sheath degradation caused by induced electrical activity on the cable's surface. The work presented in this thesis describes research completed to quantify this degradation. This has resulted in a novel analysis method being developed and used to associate product testing with field trial results. The analysis is based on evaluating the magnitude of recorded electrical activity and fitting an appropriate distribution to the data to describe relative electrical arcing power. This innovation was possible due to the completion of a comprehensive review of the theories dealing with the generation of the electrical activity, followed by a detailed analysis. Where appropriate, worked examples are given in the thesis to demonstrate these theories. As a result of this work three proposals have been made to simplify future analyses. They are: approximating the relevant variables to span related polynomial functions, relating capacitive coupling to the space potential, and the superposition of assumed functions. The work is supported by results presented of extensive practical testing and simulations carried out by the author. These include analyses of the resulting cable damage, some of which has not been discriminated between in previous work. The completed analysis of tested products has also identified, previously not quantified, degradation accelerants. The work classifies these accelerants into extrinsic installation and intrinsic product factors. The thesis presents and reviews the implication of the electrical degradation resistance of sheaths applied to slotted-core and advance multi-loose tube (MLT) optical fibre cable designs. This has lead to the evaluation of three generations of sheath technology, which varied from low smoke compound technology, through to bimodal polyethylene. The work also identifies specific methods to limit risk to products. They include the use of pre-blended materials and the need to assure both sheath surface finish quality and cable longitudinal water blocking. Finally, the thesis summarises the development of new and previously investigated proposed degradation mitigation systems. Selected possible solutions were then evaluated using tests and analysis methods developed by the author, and compared with those of other notable works. This has resulted in the filing of two patents. As a result of this research a solution has been trialed and proposed to the collaborating company. This will allow optical fibre cable to be installed in high potential fields for the prescribed lifetime, overcoming previous limitations.
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Almeida, Geraldo Roberto de. "Tecnologia para linhas de transmissão instaladas diretamente enterradas em solos sujeitos a instabilidade térmica e hidrológica: novos materiais para backfill; sistema de controle de temperatura." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-04112011-134718/.
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Este trabalho é um conjunto de conhecimentos sistematizado, alguns já disponíveis através da engenharia e/ou da tecnologia, e outros desenvolvidos durante este trabalho para solução de problemas que freqüentemente se apresentam na modalidade de instalação de linhas de transmissão subterrânea enterradas diretamente no solo. Nas linhas de transmissão diretamente enterrada, a corrente máxima circulante nos condutores depende do salto térmico entre o condutor e a temperatura máxima do solo em um ponto remoto onde os cabos estão instalados. Duas variáveis além da corrente teem um papel de extrema relevância: A resistência elétrica do condutor e blindagens que define as perdas joules geradas pelos condutores e capas metálicas, respectivamente e a resistência térmica externa do solo circunstante ao cabo enterrado. A parte devido às perdas joules já foi exaustivamente estudada e sistematização atual é suficiente para a solução da maioria dos problemas de engenharia, mas a parte do conhecimento da resistência térmica externa tem ainda muitos pontos que ainda não foram totalmente esclarecidos: sejam na modelagem, sejam nos materiais sejam no controle da fenomenologia. O escopo deste trabalho é dar uma contribuição no papel da resistência térmica externa aos cabos enterrados através de uma engenharia simultânea (Elétrica, Mecânica e Civil) assistida por tecnologia de desenvolvimento de materiais (Backfill).The present work is a set of systematized knowledge, some of them available in the engineering and technological literature and others developed during this work to solve problems which presents in direct buried cables modalities. In direct buried transmission lines the current carrying in the conductors depends on the temperature rise of the conductor in respect of the temperature of remote soil. Two variables beyond the electrical current on the conductor play a paramount role: The electrical resistance of the conductor and sheaths which define the Joules losses upon the conductor and sheath and the thermal resistance between cable and soil. The role of Joule losses has been sufficiently studied providing solutions for large class of engineering problems, but the available knowledge regarding external thermal resistivity has several points under considerations yet: Even in modeling, materials and phenomenology control. The scope of this work is to present a short contribution on the role of external thermal resistance between cables and soil through the simultaneous frame work (Electrical, Mechanical and Civil engineering) and Technological development of materials (Backfill).
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Giardinetto, Rosemary Boettger. "Repotencialização de linhas de transmissão localizadas em áreas de severas restrições ambientais." Universidade de São Paulo, 2014. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-23032017-150255/.
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Os cerca de 107.000 km de linhas de transmissão existentes no Brasil, nas tensões de 138/230/345/440/500/750 kV (corrente alternada), e 600 kV (corrente continua), atravessam parques nacionais ou estaduais, estradas, rios e parte se encontra com sobrecarga. O aumento da capacidade de carregamento das linhas de transmissão, se feito da forma tradicional, com a substituição ou reforço nas estruturas e fundações, em faixas que cruzam áreas consideradas de preservação ambiental permanente, exige obras adicionais que alteram o meio ambiente e desta forma, com os rigores da atual legislação ambiental, torna inviável tais alterações ou substituição. Uma das formas encontradas é a utilização de novas tecnologias em cabos condutores aéreos. Este trabalho tem a finalidade de pesquisar as necessidades do recondutoramento da linha de transmissão, com a minimização/eliminação dos danos ao meio ambiente. Uma das alternativas encontradas é a utilização de cabos especiais, que por se tratar de nova tecnologia em cabos, e considerando o desconhecimento de seu desempenho efetivo em condições reais, surge a necessidade da verificação de seu comportamento. Este trabalho apresenta a análise de casos no Brasil e o desenvolvimento piloto de um sistema de monitoramento em tempo real, através de medições diretas e indiretas, no trecho de linha de transmissão onde foi instalado um condutor de nova tecnologia, a fim de acompanhar o desempenho das características elétricas e mecânicas do novo condutor. Como resultado final foram validados os valores de projeto da ampliação da capacidade da linha de transmissão, sem impactos ao meio ambiente.The approximately 107,000 km of transmission lines existing in Brazil, operating at 138 kV, 230 kV, 345 kV, 440 kV, 500 kV, 750 kV(ac) and 600 kV(dc), regularly encounter and cross state or national parks as well as highways, rivers and parks. Due to the ever increasing demand of power most of these transmission lines are at present overloaded. Increasing the loading capacity of these transmission lines in the traditional way (i.e. by substituting or reinforcing the structures and foundations in areas of permanent preservation) require additional works that may alter the environment; thus, making unfeasible the application of such alterations in view of the current strict environmental regulations. One way to cope with such a problem is through the utilization of new technologies applied to cables. Therefore, the objective of this work is to investigate the alternative of reconductoring a transmission line causing a minimum damage (and if possible eliminating this damage) to the environment. One of the alternatives found is the use of special cables which due to its relatively new introduction and technology to the power industry demands a thorough study on issues like the performance and verification of its behavior under real conditions. This work presents the development of a real-time monitoring system through direct and indirect measurements performed on a transmission line segment where a special conductor was installed. During the course of the research the performance of the new conductor regarding its electrical and mechanical characteristics was monitored. The measurements performed showed to be coherent with those obtained during the design of the transmission line.
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Жила, Віталій Юрійович. "Режим роботи розподільної мережі напругою 20 кВ." Master's thesis, КПІ ім. Ігоря Сікорського, 2019. https://ela.kpi.ua/handle/123456789/31660.
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Магістерська дисертація складається з пояснювальної записки та графічної частини. Пояснювальна записка виконана на 154 сторінках формату А4, яка включає в себе 79 рисунків, 49 таблиць, 8 джерел використаної літератури. Графічна частина містить 8 аркушів технічних креслень форматом А1. В дисертації розглянуто режим роботи розподільної мережі напругою 20 кВ в порівнянні із напругою 10 кВ.
Актуальність теми. У даний час розподільні електричні мережі знаходяться у важкому стані, що обумовлено високим ступенем фізичної і моральної зношеності електроустаткування, високим відсотком технічних втрат, низьким рівнем автоматизації. Тема режиму роботи електричних мереж напругою 20 кВ є актуальною до впровадження її в реалізацію. Мета магістерської дисертації полягає в розрахунку районної електричної мережі напругою 10 кВ та переведення її на напругу 20 кВ, та виконання аналізу порівняння 10 кВ та 20 кВ.
Обєктом дослідження є ПЛ 10 кВ від ПС 110/35/10 кВ «Березань».
Предмет дослідження : режим роботи розподільної мережі 20 кВ.
Методи дослідження – в магістерськй дисертації використовувалися методи теоретичних основ електротехніки та електричних систем при розрахунках параметрів елементів електричних мереж.
Публікації за тематикою досліджень:
Жила В.Ю. Енергетична незалежність // збірник «Направления научной мысли» – 2019/2020.
Жила В.Ю., Кирик В.В. Аварійність в електричних мережах // збірник «Направления научной мысли» – 2019/2020.The master's thesis consists of an explanatory note and a graphic arts. The explanatory note is made on 177 A4 pages, which includes 79 drawings, 49 tables, 8 sources of used literature. The graphic part contains 8 sheets of technical drawings in A1 format In dissertation mode, a large number of voltages of 20 kV in comparison with a voltage of 10 kV Actuality of theme. Currently, distribution networks are in a difficult state, due to the high degree of physical and moral deterioration of electrical equipment, a high percentage of technical losses, low level of automation. The theme of the mode of operation of 20 kV electrical networks is relevant before its implementation. The purpose of the master's thesis is to calculate the district electrical network with a voltage of 10 kV and transfer it to a voltage of 20 kV, and to perform a comparison analysis of 10 kV and 20 kV. The object of the study is 10 kV power line from 110/35/10 kV "Berezan". Subject of study: operating mode of the 20 kV distribution network. Research Methods - The methods of theoretical foundations of electrical engineering and electrical systems were used in the master's thesis in calculating the parameters of elements of electrical networks. Research publications: Zhyla V.Y. Energy independence // the collection "Directions of scientific thought" - 2019/2020. Zhyla V.Y., Kyryk .V.V. Accidents in electrical networks // the collection "Directions of scientific thought" - 2019/2020.
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Oliveira, Fábio Gabriel de. "Estudo de instalações de linhas subterrâneas de alta tensão com relação a campos magnéticos." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-20102010-165349/.
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Atualmente, a intensidade de campo elétrico, campo magnético e campo eletromagnético é um fator determinante não só para a implantação de novas instalações, mas também, para as instalações existentes no sistema elétrico. Apesar de não existir nenhum estudo conclusivo que comprove a evidência direta entre a exposição a estes campos e os efeitos nocivos na saúde das pessoas, muitos países, inclusive o Brasil, definiram em suas legislações limites básicos à exposição de campos elétrico e magnético provenientes dos sistemas elétricos. Este trabalho tem como objetivo contribuir para análise de campo magnético de linhas subterrâneas de alta tensão existentes ou linhas em fase inicial de projeto, visando atender os limites de exposição vigentes na legislação local. Nele é apresentada a metodologia de cálculo de campo magnético baseada na Lei de Biot-Savart e no princípio da superposição. Estudos analíticos para verificação da influência dos parâmetros de instalação e elétricos de linhas sobre o campo magnético são apresentados para linhas subterrâneas de alta tensão compostas por um e dois circuitos com diferentes tipos de instalação e aterramentos. Comparações entre valores analíticos e valores de medições de campo magnético de linhas subterrâneas de alta tensão existentes em operação também são abordadas neste trabalho. As principais técnicas de mitigação de campo magnético utilizadas em linhas subterrâneas de alta tensão, tais como técnicas de compensação envolvendo laços de cabos e técnicas de blindagens com materiais metálicos externos aos cabos, também são apresentadas. Devido ao campo elétrico externo ao cabo isolado ser praticamente zero, assuntos referentes a este campo não são abordados neste trabalho. Por simplicidade, campo magnético refere-se à densidade de fluxo magnético neste documento.Nowadays, the intensity of electric field, magnetic field and electromagnetic field is a determining factor, not only for implantation of new installations, but also for existing installations in the power system. Although no exist conclusive study that proves the direct evidence between exposure to these fields and adverse effects on human health, many countries, including Brazil, have defined in their laws basic limits for exposure to electric and magnetic fields produced by the electric system. This work aims to contribute to analysis of magnetic field for both existing high voltage underground lines and lines in initial stage of project, aiming the actual exposure limits of the local legislation. In it, is shown the magnetic field calculation methodology based on the Biot-Savart\'s law and the superposition principle. Analytical studies to verify the influence of installation and electrical parameters of lines on the magnetic field are presented for high voltage underground lines consist of one and two circuits with different types of installation and earthing. Comparisons between analytical and measurement values of magnetic field of existing high voltage underground lines in operation are also addressed in this work. The main mitigation techniques of magnetic field used in high voltage underground lines, such as compensation techniques by loop of cables and shielding by metallic materials, are also presented. Due the electric field outside the insulated cable be practically zero, issues related to the electric field are not addressed in this work. For simplicity, the magnetic field refers to the magnetic flux density in this document.
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White, Ashley. "Novel High Frequency Electromagnetic Shielding Measurements Within Functional Geometries Using Non-Metal and Fatigued Conductors." University of Dayton / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1501765571693941.
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Hobdell, Stephen Barry. "Thermally stimulated current and electrokinetic investigations of HV cable models." Thesis, Bangor University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.311421.
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Lwana, Mkuseli. "Investigation of 3 terminal differential protection using standard-based numerical relays." Thesis, Cape Peninsula University of Technology, 2017. http://hdl.handle.net/20.500.11838/2578.
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Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2017.Transmission lines are a vital part of the electrical distribution system, as they provide the path to transfer power between generation and load. Factors like de-regulated market environment, economics, etc. have pushed utilities to operate transmission lines close to their operating limits. Any fault, if not detected and isolated quickly will cascade into a system wide disturbance causing widespread outages for a tightly interconnected system operating close to its limits. Current differential criterion is used with success to protect various elements in power systems, i.e. transmission lines, power transformers, generators and busbars. The alpha plane differential relaying system provides sensitive protection for transmission lines, security and dependability for external faults. This thesis focuses on three terminal alpha plane differential protection with the aim to develop a complete test method using OMICRON test universe software essentially defining security, dependability and sensitivity of the alpha plane characteristic. The research analyses the three terminal alpha plane characteristic and existing primitive test methods and develops an improved test method using IEC 61850 standard. The primitive methods are time consuming and result in unnecessary prolonged outages. These methods have been discussed and improved in the thesis by implementing IEC 61850 standard. First the standard IED Capability Description (ICD) file is modified by developing new logical nodes using AcSELerator Architect and XML Maker software. Then the developed logical nodes, three terminal differential protection alpha plane characteristic with its additional infeed/outfeed check logic, and the developed test method are tested simultaneously using Test Universe software. A laboratory test bench is built using three SEL311L relays, two CMC 356 Omicron injection devices, PC, MOXA switch, CMIRIG-B time synchronising unit, SEL 2407 satellite synchronised clock, and a DC power supplier. The test method developed in this research vindicates benefits of IEC 61850 standard over hard wired systems. Prolonged outage times due to test set preparation using hard wires are drastically reduced. The thesis findings and deliverables will be used as a solution to industrial problems, postgraduate studies of other students and research project.
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Mokeretla, Molungoa Samuel. "Self-damping characteristics of transmission line conductors subjected to free and forced vibration." Thesis, Bloemfontein : Central University of Technology, Free State, 2011. http://hdl.handle.net/11462/15.
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Thesis (M. Tech.) - Central University of Technology, Free State, 2011The objectives of this research were to investigate and establish a procedure to determine the self-damping characteristics of transmission line conductors subjected to free and forced vibrations. The TERN and Aero-Z IEC62219-REV240609 conductor cables were the transmission line conductors that were readily available at the Vibration Research and Testing Centre (VTRC) of the University of KwaZulu-Natal (UKZN). The question to be answered was whether the self-damping characteristics of the TERN and Aero-Z IEC62219-REV240609 conductors were adequate to suppress Aeolian or wake-induced vibrations. In other words, is it necessary for external damping mechanisms to be used with these conductors? This study confirmed that the self-damping characteristics of conductors are not adequate to suppress Aeolian or wake-induced vibrations. Governing partial differential equations describing the characteristics of the catenary and parabolic cable conductors were developed to validate the experimental results. The experimental tests involved both conductors being subjected to an impulse function (a free vibration method) and also to a harmonic function (a forced vibration method). Measurements were carried out using accelerometers, and the recording equipment consisted of oscilloscopes and the PUMA system. With both the free and forced vibration methods, the damping factor of the TERN conductor was confirmed to be ζ ≤ 0.05, whereas the damping factor of the Aero-Z IEC62219-REV240609 was confirmed to be ζ ≤ 0.2. A procedure for determining the self-damping characteristics of the TERN and Aero-Z IEC62219-REV240609 conductors was developed, with the damping factor found to be ζ ≤ 0.2 for both conductors. These methods can assist in the implementation of procedural analysis of the self-damping behaviour of different types of transmission conductors and in finding the most suitable mass absorber (damper) to use in reducing the rate of failure of transmission line conductors. The results of this study can be used to improve the mathematical modelling of Aeolian and wind-induced vibrations where both self-damping properties and a mass absorber are incorporated.
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Dawood, Sami. "Etude du couplage d'une onde electromagnetique avec des cables souterrains (antennes et cables)." Clermont-Ferrand 2, 1987. http://www.theses.fr/1987CLF2D197.
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Etude de la reponse d'un cable enterre infini a une impulsion electromagnetique. Determination de la repartition du courant induit par une methode modale. Etude du cas des cables de longueur finie par la theorie des lignes. Etude des impulsions exponentielle et en echelon
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Navaratnam, Srivallipuranandan. "Series impedance and shunt admittance matrices of an underground cable system." Thesis, University of British Columbia, 1986. http://hdl.handle.net/2429/26726.
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This thesis describes numerical methods for the evaluation of the series impedance matrix and shunt admittance matrix of underground cable systems. In the series impedance matrix, the terms most difficult to compute are the internal impedances of tubular conductors and the earth return impedance. The various formulae for the internal impedance of tubular conductors and for the earth return impedance are, therefore, investigated in detail. Also, a more accurate way of evaluating the elements of the admittance matrix with frequency dependence of the complex permittivity is proposed.
Various formulae have been developed for the earth return impedance of buried cables. Using the Pollaczek's formulae as the standard for comparison, the formula of Ametani and approximations proposed by other authors are studied. Mutual impedance between an underground cable and an overhead conductor is studied as well. The internal impedance of a laminated tubular conductor is different from that of a homogeneous tubular conductor. Equations have been derived to evaluate the internal impedances of such laminated tubular conductors.Applied Science, Faculty of
Electrical and Computer Engineering, Department of
Graduate
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Theethayi, Nelson. "Electromagnetic Interference in Distributed Outdoor Electrical Systems, with an Emphasis on Lightning Interaction with Electrified Railway Network." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis : Univ.-bibl. [distributör], 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5889.
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Tian, Yuan. "Partial discharge detection in cable systems." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.342750.
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Roberge, Mathieu. "A study of wet snow shedding from an overhead cable /." Thesis, McGill University, 2006. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99790.
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Wet snow accumulating and shedding from overhead transmission lines can lead to a number of serviceability, safety and mechanical reliability issues. An innovative and inexpensive method to reproduce wet snow accretions on a cable in a controlled environment is explained. Wet snow sleeves were experimentally reproduced by using this technique to study their shedding mechanism. A numerical modeling technique using nonlinear finite element analysis is proposed to evaluate the dynamic response of an overhead cable subjected to any snow-shedding scenario. A time function is associated to the mass and weight of each snow element, which enables its virtual removal from the model at the time prescribed by the user. The response of a single span of overhead ground wire subjected to total and partial snow shedding scenarios is evaluated.
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Franek, Lešek. "Vícevodičový model komunikace po venkovním elektrickém vedení." Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2017. http://www.nusl.cz/ntk/nusl-256566.
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PLC - power line communication is not new. It has been known for many years. But It never be used in massive scale. There were only sporadic applications, for example ripple control system HDO used in the Czechoslovakia. PLC currently experiencing a renaissance thanks to the advent of Smart Grid. PLC offering relatively low bit rates and relatively unreliable transmission, but these disadvantages compensates very low costs to build a communication infrastructure and it offers specific functionalities for Smart Grid. The question is whether the declared parameters will be met in the real world. This thesis tries to find an answer.
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Bibby, Ian Paul. "Theoretical database for the prediction of rime-ice and wet-snow overload on overhead transmission lines." Thesis, University of Hull, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322337.
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Vo, Van Huy Hoang. "Optimisation des techniques de mise à la terre des écrans des cables haute et très haute tension." Grenoble INPG, 1999. http://www.theses.fr/1999INPG0169.
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Des liaisons souterraines par câbles isolés seront à court terme insérées dans le réseau aérien THT de transport d'électricité. Diverses évolutions technologiques des câbles, de leurs matériels de raccordement et de leurs conditions de pose ont été initiées afm de réduire le coût de ces liaisons. L'optimisation des techniques de mise à la terre des écrans des câbles s'inscrit également dans cette démarche. La thèse donne les bases théoriques pour la défmition de spécifications de réalisation des techniques de mise à la terre des écrans des câbles dites de connexions spéciales d'écran (mise à la terre en un point et permutation d'écrans) et propose des règles pratiques de dimensionnement. Les études ayant permis d'obtenir ce résultat portent sur la détermination des surtensions sollicitant les matériels. Dans la première partie, on a établi une méthode de calcul des contraintes d'une part en régime permanent et d'autre part dans les régimes de défaut, consécutifs soit à une avarie externe à la liaison souterraine soit à un claquage de câble. Dans la deuxième partie, on a analysé les contraintes dans les régimes transitoires, calculées à l'aide du logiciel Electromagnetic Transient Program (EMTP). La synthèse de ces deux types d'étude permet d'optimiser le choix du type de limiteur de surtension à mettre en oeuvre pour protéger les matériels vis-à-vis des contraintes transitoires subies par les gaines des câbles; elle permet également de déterminer les longueurs maximales réalisables pour les liaisons à mise à la terre en un point ou les distances maximales entre permutations en fonction des contraintes à la fréquence industrielleUnderground links with insulated cables will be introduced in close future in the overhead grid for VHV electricity transmission. Various technological developments of the cables, their connecting equipments and their installation conditions were initiated in order to reduce the cost of these links. The optimization of the sheath grouding techniques also fits in this step. The thesis gives the theoretical bases for the definition of specifications to realize specially bonded underground links techniques (single point bonding and cross bonding) and proposes practical ru les for the design of cables sheath grounding. The studies having made it possible to obtain this result relate to the determination of overvoltages affecting the equipements. In the first part, a general method of calculation of stresses is established, on the one hand, in steady state and on the other hand during faults, consecutive either with an external fault or with a cable breakdown. In the second part, the stresses during transients, calculated using the Electromagnetic Transient Program (EMTP) are analyzed. The synthesis of these two kinds of studies leads to optimize the choice of the type of surge arresters to be implemented to protect the equipements with respect to the transients undergone by the cable sheaths " it also makes if possible to determine the maximum possible lengths for single point bonding underground links or the maximum lengths between cross-bondings, according to the stresses at power frequency
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Goodwin, Stephen. "Investigation of cable emissions within a screened room environment." Thesis, University of York, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329646.
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Centeno, Luis E. "Application of demand flow technology to cable assembly production line." Online version, 2002. http://www.uwstout.edu/lib/thesis/2002/2002centenol.pdf.
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Sun, Ruiwen. "Detecting Faulty Tape-around Weatherproofing Cables by Computer Vision." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-272108.
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More cables will be installed owing to setting up more radio towers when it comes to 5G. However, a large proportion of radio units are constructed high in the open space, which makes it difficult for human technicians to maintain the systems. Under these circumstances, automatic detections of errors among radio cabinets are crucial. Cables and connectors are usually covered with weatherproofing tapes, and one of the most common problems is that the tapes are not closely rounded on the cables and connectors. This makes the tape go out of the cable and look like a waving flag, which may seriously damage the radio systems. The thesis aims at detecting this flagging-tape and addressing the issues. This thesis experiments two methods for object detection, the convolutional neural network as well as the OpenCV and image processing. The former uses YOLO (You Only Look Once) network for training and testing, while in the latter method, the connected component method is applied for the detection of big objects like the cables and line segment detector is responsible for the flagging-tape boundary extraction. Multiple parameters, structurally and functionally unique, were developed to find the most suitable way to meet the requirement. Furthermore, precision and recall are used to evaluate the performance of the system output quality, and in order to improve the requirements, larger experiments were performed using different parameters. The results show that the best way of detecting faulty weatherproofing is with the image processing method by which the recall is 71% and the precision reaches 60%. This method shows better performance than YOLO dealing with flagging-tape detection. The method shows the great potential of this kind of object detection, and a detailed discussion regarding the limitation is also presented in the thesis.Fler kablar kommer att installeras på grund av installation av fler radiotorn när det gäller 5G. En stor del av radioenheterna är dock konstruerade högt i det öppna utrymmet, vilket gör det svårt för mänskliga tekniker att underhålla systemen. Under dessa omständigheter är automatiska upptäckter av fel bland radioskåp avgörande. Kablar och kontakter täcks vanligtvis med väderbeständiga band, och ett av de vanligaste problemen är att banden inte är rundade på kablarna och kontakterna. Detta gör att tejpen går ur kabeln och ser ut som en viftande flagga, vilket allvarligt kan skada radiosystemen. Avhandlingen syftar till att upptäcka detta flaggband och ta itu med frågorna. Den här avhandlingen experimenterar två metoder för objektdetektering, det invändiga neurala nätverket såväl som OpenCV och bildbehandling. Den förstnämnda använder YOLO (You Only Look Once) nätverk för träning och testning, medan i den senare metoden används den anslutna komponentmetoden för detektering av stora föremål som kablarna och linjesegmentdetektorn är ansvarig för utvinning av bandbandgränsen. Flera parametrar, strukturellt och funktionellt unika, utvecklades för att hitta det mest lämpliga sättet att uppfylla kravet. Dessutom används precision och återkallande för att utvärdera prestandan för systemutgångskvaliteten, och för att förbättra kraven utfördes större experiment med olika parametrar. Resultaten visar att det bästa sättet att upptäcka felaktigt väderbeständighet är med bildbehandlingsmetoden genom vilken återkallelsen är 71% och precisionen når 60%. Denna metod visar bättre prestanda än YOLO som hanterar markering av flaggband. Metoden visar den stora potentialen för denna typ av objektdetektering, och en detaljerad diskussion om begränsningen presenteras också i avhandlingen.
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Klovas, Darius. "10 KV kabelinių linijų būklės Šiaulių mieste analizė." Master's thesis, Lithuanian Academic Libraries Network (LABT), 2013. http://vddb.laba.lt/obj/LT-eLABa-0001:E.02~2013~D_20130618_155001-31917.
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Magistro darbe ištirta ir iš dalies įvertinta 10 kV kabelinių linijų Šiauliuose būklė: nustatytas bendras šio tipo kabelinių linijų ilgis, kabelių tiesimo metų ir kabelių tipų santykis, movų skaičius ir jų tipai, pateikta prognozė, kokių gedimų gali kilti ateityje.The aim of the master's paper is to investigate and evaluate the 10 kV cable line state in Šiauliai city.The LESTO Šiauliai unit has provided information about the 10 kV cable lines used in Šiauliai city: common length of this type of cable lines, cable laying year and cable types, numbers of couplings numbers and their types. The information obtained was processed using Excel and Matlab, a cable length and installation year ratio and coupling types reflective graphics were prepared.
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Guerrab, Mohamed Arezki. "Validation expérimentale de la théorie des lignes couplées appliquées à des faisceaux de cables simulant un site industriel." Lille 1, 2000. https://pepite-depot.univ-lille.fr/RESTREINT/Th_Num/2000/50376-2000-212.pdf.
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L'application de la theorie des lignes couplees pour la prediction des tensions et des courants induits aux extremites d'un reseau de lignes multifilaires agresse par une onde electromagnetique, est basee sur des hypotheses s'eloignant souvent des situations qu'on peut rencontrer sur sites industriels. Notre these traite de la fiabilite de ces predictions theoriques basees sur la theorie des lignes de transmission sous le formalisme de la topologie electromagnetique exploitant sur le plan experimental des eprouvettes proches de celles qu'on peut rencontrer sur sites industriels. La premiere partie de notre travail traite de la caracterisation des lignes multifilaires par la determination de leurs parametres lineiques primaires, inductances et capacites. La connaissance de ces parametres lineiques est necessaire pour toute tentative de prediction des signaux parasites induits aux extremites de ces lignes. Nous avons ensuite etudie le couplage diaphonique entre conducteurs d'une meme ligne. Plusieurs cas de figures ont ete consideres a savoir ; une ligne a disposition parallele des conducteurs, une ligne a disposition aleatoire des conducteurs, une ligne presentant une fourche, ainsi qu'une ligne disposant de 25 conducteurs. La deuxieme partie de notre travail porte sur l'effet d'une agression de type onde electromagnetique plane sur une ligne au-dessus d'une reference de masse dont la geometrie est choisie de sorte a s'apparenter a des situations susceptibles d'etre rencontrees sur les installations electriques rencontrees sur sites industriels. La derniere partie de ce travail traite des resultats obtenus en chambre reverberante a brassage de modes lorsque la dimension transversale de la reference de masse est du meme ordre de grandeur que la longueur d'onde du signal electromagnetique incident.
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Lebedka, Serhii Mykolaiovych, Сергей Николаевич Лебедка, Сергій Миколайович Лебедка, and И. И. Борзенко. "Современные методы поиска мест повреждения в кабельных линиях." Thesis, Изд-во СумДУ, 2008. http://essuir.sumdu.edu.ua/handle/123456789/4139.
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Mansour, Tony, and Majdi Murtaja. "Applied estimation theory on power cable as transmission line." Thesis, Linnéuniversitetet, Institutionen för fysik och elektroteknik (IFE), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-46583.
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This thesis presents how to estimate the length of a power cable using the MaximumLikelihood Estimate (MLE) technique by using Matlab. The model of the power cableis evaluated in the time domain with additive white Gaussian noise. The statistics havebeen used to evaluate the performance of the estimator, by repeating the experiment fora large number of samples where the random additive noise is generated for each sample.The estimated sample variance is compared to the theoretical Cramer Raw lower Bound(CRLB) for unbiased estimators. At the end of thesis, numerical results are presentedthat show when the resulting sample variance is close to the CRLB, and hence that theperformance of the estimator will be more accurate.
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Han, Junyu. "Fault location on mixed overhead line and cable network." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/fault-location-on-mixed-overhead-line-and-cable-network(1a911a42-ddfa-4592-8365-badc8d5c45f3).html.
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Society is increasingly concerned about the environmental impact of energy systems, and prefers to locate power lines underground. In future, certain socially/environmentally sensitive overhead transmission feeders will need to include underground cable sections. Fault location, especially when using travelling waves, become complicated when the combined transmission line includes a number of discontinuities, such as junction points, teed points and fault points. Consequently, a diverse range of fault locators were developed in this thesis, and the performance of the proposed fault locators investigated. For a combined transmission line (CTL), consisting of one or more overhead line sections and one or more underground cable sections, a hybrid fault location scheme is proposed. This utilises the robustness of an impedance based distance algorithm and the accuracy, but stability concerns, of a travelling wave based fault locator, to determine the faulted section. The distance algorithm can determine the approximate fault location, but if the fault is located near an “underground-overhead” junction point, the accuracy is not sufficient to decide whether the fault is located on the overhead or the underground section. This thesis proposes utilizing a single end travelling wave fault locator to improve the accuracy of the fault location decision. The single end travelling wave fault locator can determine the fault section according to the permutation of the polarity of the “special surges”, which is especially important when the fault is close to a junction point. However, this single end fault locator fails in certain “blind” areas, wand these require the use of a distance relay to help determine fault section. Simulation results demonstrated that this hybrid fault locator can reliably determine which section of the feeder is faulty. For all types of CTL, including teed networks, the multiple-end travelling wave fault locator, utilising the arrival time at the feeder ends of the first fault instigated surges, can estimate the fault location. One of the main features of the proposed fault locator is the classification of the time difference between the arrivals of a fault instigated surge at the feeder ends as standard values, when the fault is located at each of the junction points or teed points. Comparing the time differences measured during an actual fault with these standard values allows the faulted feeder section to be estimated. The simulation results show this multiple-end travelling wave fault locator is highly reliable and suitable for application on combined overhead and underground transmission lines.
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Kane, Mamadou. "Modeles analytiques originaux pour la determination des parametres lineiques des lignes et cables multifilaires parcourus par des signaux large bande." Ecully, Ecole centrale de Lyon, 1994. http://www.theses.fr/1994ECDL0029.
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La présence d'ondes électromagnetiques perturbatrices au voisinage des lignes et cables peut occasionner une altération des signaux émis et quelques fois la destruction des appareils connectés aux extremités. Pour prévoir les niveaux des signaux parasites et dans le but de les reduire, il est important d'envisager une modélisation fine des structures filaires et ceci avec un temps de calcul acceptable. Pour y repondre, des modèles analytiques de simulation plus ou moins detaillés ont été mis au point. Nous verrons tout au long du chapitre I que les modèles existants n'envisagent pas, dans des configurations générales, la prise en compte de la proximité des conducteurs les uns par rapport aux autres. Ceci pose un sérieux problème alors que l'on assiste de plus en plus à un besoin soutenu d'intégration des circuits et systèmes. Notre travail s'inscrit dans la correction de ces défauts et propose des modèles de type circuit caractérisant les lignes et cables blindés en tenant compte des effets de peau et de proximité intervenant dans les milieux conducteurs. Les hypothèses quasi-tem sont adoptées et des matrices d'impédances et d'admittances des structures filaires sont determinées sur une large gamme de fréquences (fréquences pour lesquelles les courants de déplacements dans les conducteurs restent négligeables). Après une analyse critique des méthodes et modèles existant dans le chapitre I, nous proposons dans le chapitre II un modèle original de calcul des paramètres des lignes multifilaires (avec effets de peau et de proximité). Enfin, le chapitre III propose un modèle de détermination des paramètres des cables multifilaires blindés. Les modèles proposés sont de type circuits équivalents et sont valides par des méthodes utilisant la technique des éléments finis ou par une comparaison avec des mesures, sur une gamme de fréquences allant de 0 a 10 mhzThe coupling of incident fields (plan wave, lightning stroke, nuclear electromagnetic pulse, current injection,. . . ) with lines or cables gives rise to over voltage which can damage electrical and electronic apparatus connected at the ends of these lines or cables. Accurate line or cable models are needed to solve these problems. Most of existing models suppose losseless lines or take account only of the skin effects in conductors. Nowadays most of electrical and electronic systems are very integrated, so the skin and the proximity effects cannot be neglected. The analytical modelling of shielded or unshielded multiwire telecommunication and power cables proposed in this PhD report involved the calculation of cable parameters in a frequency range covering (o Hz, 10 MHz). These calculations include the skin and the proximity effects considerations in conducting materials. In chapter I we point out the weakness of the existing models. A new multiwire closely line parameters is proposed in the chapter II. In the chapter III, a new multiwire shielded cable primary parameters is given
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Атаманський, А. В. "Дослідження пошкоджуваності обладнання локальних електричних систем." Thesis, ВНТУ, 2016. http://conferences.vntu.edu.ua/index.php/all-feeem/all-feeem-2016/paper/view/351.
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Кардинальна зміна економічних відносин, формування енергоринку, поява змішаної приватно-державної форми власності потребують докорінного реформування енергетичного сектору України.Більше 50% експлуатованого в галузі обладнання вимагає заміни, оскільки фізично і морально застаріло. В енергетиці України розвиваються нові технології, впроваджуються інформаційні і діагностичні системи, сучасні засоби вимірювань і управління, які дозволяють визначити поточний стан обладнання та здійснювати керування режимів з урахуванням стану обладнання.Radically change economic relations, the formation of the energy market, the emergence of mixed private and stateowned require radical reform of the energy sector of Ukraine.
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Monzani, Rafael Cuerda [UNESP]. "Análise de transitórios eletromagnéticos utilizando matrizes de transformação reais-sistemas trifásicos com a presença de cabos pára-raios." Universidade Estadual Paulista (UNESP), 2013. http://hdl.handle.net/11449/87144.
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Este trabalho apresenta um método para determinação de matrizes reais de transformação em sistemas trifásicos considerando a presença de cabos pára-raios. Assim, para as matrizes Z e Y que representam a linha de transmissão, considera-se que os cabos pára-raios não estão implícitos nos valores das fases. Como proposta, usa-se uma matriz de transformação real por toda faixa de frequência de análise. Essa matriz de transformação é uma aproximação da matriz de transformação exata. Para os elementos relacionados com a fase do sistema considerado, a matriz de transformação é composta a partir dos elementos da matriz de Clarke. Nas partes relacionadas com os cabos pára-raios, os elementos da matriz de transformação devem estabelecer uma relação com os elementos das fases considerando o estabelecimento de uma referência homopolar única no domínio dos modos. No caso de linhas de transmissão trifásicas com a presença de dois cabos pára-raios, não é possível obter a diagonalização completa das matrizes Z e Y no domínio dos modos. Isso leva a aplicação de uma matriz média-antimédia com o objetivo de minimizar os erros da composição da matriz de transformação obtida a partir da primeira matriz proposta. Uma segunda proposta de matriz de transformação ainda é aplicada. Os resultados obtidos são analisados por meio de gráficos e condensados em tabelas. Por fim, é aplicada uma rotina de correção com o objetivo de minimização dos erros obtidos para os autovalores e os valores relativos fora da diagonal principal
This paper presents a method for determining real transformation matrices in three-phase systems considering the presence of ground wires. Thus, for the matrices Z and Y represent the transmission line, it is considered that the ground wires are not implied in the phases values. As a proposal, it uses a transformation matrix throughout the frequency range for analysis. This transformation matrix is an approximation of the exact transformation matrix. For items related to the phase of the considered system, the transformation matrix is composed by elements from Clarke’s matrix. In parts related to ground wires, the elements of the transformation matrix must establish a relationship with the elements of the phases considering the establishment of a unique homopolar reference in mode domain. In the case of three phase transmission lines in the presence of ground wires, it is not possible to obtain complete diagonalization of the Z and Y matrices in the mode domain. This leads to the application of a media-antimedia matrix in order to minimize errors in the composition of the transformation matrix obtained from the first proposal. A second proposal of transformation matrix is still applied. The results are analyzed by using graphs and condensed tables. Finally, it is applied a correction routine with the goal of minimizing errors obtained for the eigenvalues and relative values outside the main diagonal
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Mohnsam, Luciana De Almeida. "Simulação numérica do comportamento de cabos viscoelasticos." reponame:Repositório Institucional da FURG, 2008. http://repositorio.furg.br/handle/1/3626.
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Dissertação(mestrado)-Universidade Federal do Rio Grande, Programa de Pós-Graduação em Engenharia Oceânica, Escola de Engenharia, 2008.Submitted by Lilian M. Silva (lilianmadeirasilva@hotmail.com) on 2013-04-24T21:57:46Z No. of bitstreams: 1 Simulação numérica do comportamento de cabos viscoelasticos.pdf: 4203728 bytes, checksum: 7ceef8d6df53ec7479e4f8c76d03d32c (MD5)
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Atualmente, há muito interesse em estudar e criar novos materiais sintéticos que apresentem alta resistência à ruptura. Um exemplo disto é o avanço na construção de linhas de ancoragem para plataformas em operações offshore, que são preferencialmente constituídas, além de outros componentes, por cabos de fibra sintética, como a de poliéster. O objetivo principal deste trabalho foi efetuar a simulação numérica do comportamento de cabos viscoelásticos submetidos a esforços externos até que ocorra a ruptura. Este trabalho é importante para compreender melhor o comportamento de cabos sintéticos utilizados na ancoragem de plataformas, ajudando assim, a estimar de forma mais adequada a durabilidade dos mesmos. No programa construído, considerou-se que o comportamento do cabo é uma sobreposição dos movimentos dos multifilamentos que o constitui. Um modelo viscoelástico foi usado para representar o comportamento de cada multifio e sua dinâmica foi analisada resolvendo numericamente as equações de movimento. Os parâmetros do modelo foram determinados mediante análise de dados obtidos em ensaios dinâmicos e de tração com multifios de poliéster, realizados no Laboratório de Análises de Tensões - POLICAB. Os resultados numéricos foram comparados aos encontrados na literatura e posteriormente aos resultados experimentais, que permitiram também validar o modelo para a simulação do comportamento de um multifilamento de poliéster até a ocorrência de ruptura.
Currently, there has been much interest in studying and creating new synthetic materials with high breaking strength. The advances in construction of anchorage lines designed for operating offshore platforms are, beyond other components, for synthetic fiber ropes, as of polyester. The main goal of this study was to elaborate the numerical simulation of the behavior of viscoelastics ropes submitted the external efforts until the rupture occurs. This study is important to better understand the behavior of synthetic ropes used in platforms anchorage helping, to estimate more adequate form and durabilities of them. In the elaborated program, it was considered that the behavior of the rope is an overlap of the movements of the multi-wires that constitutes it. A viscoelastic model was used to represent the behavior of each multi-wire and its dynamics was analyzed using the numerical solutions of the motion equations. The parameters of the model had been determined by the analysis of data gotten in dynamic assays and tractive with multi-wires of polyester, carried through in the Laboratory of Analyses of Tensions - POLICAB. The results have been compared with ones in the literature and later with the experimental results, that had also validate the model for the simulation of the behavior of a multi-wire of polyester until the imminence rupture.
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Kaplanová, Klára. "Výpočet ustáleného chodu sítě 22 kV v zadané oblasti." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219415.
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Master's thesis proposes a new operation state of distribution network 22kV in Prostějov district after connection of the new Prostějov – Západ substation. The PASS DAISY OFF-LINE Bizon program is used to calculate power losses, optimal network possibilities, as well as to create a new model of Prostějov district's distribution network and to design a modification of a current state of given location. A description of this calculating and simulation program is also included in this paper. The theoretical part describes calculating methods of distribution network’s condition, with emphasis on mathematical method used by PASS DAISY OFF-LINE Bizon program, the modified Newton-Raphson method. The aim of this paper is to prepare technical documentation for E.ON company, with respect to new operation disconnection, planned overhead and cable lines of corresponding parameters. These changes in network's configuration will cause a new distribution of feeding areas. As a result, related changes of provided power from individual feeding points and changes of power currents in electric lines will occur. Due to new operation connection, a reduction of losses and, simultaneously, an improvement of voltage ratios are expected. One of the aims of this paper is to update network's model in PASS DAISY OFF-LINE Bizon program to match the current network’s state of a given area. The outcome of this work is a comparison between the current condition and the new operation condition, with new Prostějov – Západ substation connected, from perspective of distribution network's operator.
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Nedoma, Jakub. "Vliv samonosného optického kabelu na mechaniku venkovního vedení VN." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442472.
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This thesis is focused on assessing the impact of retrofitting dielectric All Dielectric Self-Supporting Cable (ADSS) to existing MV overhead line. This type of optical cable is a means of future strengthening of the communication infrastructure of the distribution network. However, its mechanical properties are significantly different from the properties ACSR cable, due to which its installation can be problematic in terms of meeting the requirements of the PNE 33 3301 standard. In practical part, this work deals with the design of the ADSS installation on the existing MV line and the determination of its impact based on the assessment of the results of this design.
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Chafik, Aymene. "Modélisation haute fréquence des effets électromagnétiques induits dans les câblages aéronautiques." Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0143/document.
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La modélisation numérique des réseaux de câbles est devenue une étape indispensable dans la phase de conception d’un projet afin de prédire les disfonctionnements dans les moyens de transport issus de l’augmentation des couplages électromagnétiques. La majorité des modèles repose sur des méthodes analytiques, qui sont certes rapides en comparaison avec les méthodes numériques 3D, mais en contrepartie sont limitées aux basses fréquences et aux géométries uniformes. De plus, des hypothèses concernant les conditions aux limites des conducteurs, comme les plans de masse infinis, sont souvent appliqués dans le but d’obtenir des formules analytiques simples C’est dans ce contexte, que nous avons envisagé l’amélioration de ces modèles en réduisant ces simplifications et ces hypothèses imposées au départ. A cet égard, nous avons développé dans un premier temps un modèle de ligne de transmission filaire qui consiste à prendre en compte les pertes par rayonnement en haute fréquence, la longueur finie et la géométrie non uniforme. Lors de cette étude, nous avons utilisé la théorie des lignes et deux méthodes numériques en l’occurrence les méthodes PEEC et TLST. Nous avons démontré pour le cas des risers que les coefficients de la méthode PEEC peuvent être obtenus analytiquement. Concernant notre deuxième axe de recherche, on s’est intéressé à la modélisation des conduits métalliques notamment les plans de masse finis et les goulottes. Ces derniers ont été modélisés avec un ensemble de câbles. Une étude expérimentale a été menée sur les effets induits par la goulotte sur la propagation des ondes électromagnétiques. Finalement, les résultats de nos modèles ont été validés expérimentalement avec des mesures. Une attention particulière a été portée sur l’effet des extrémités des lignes de transmissionConsidering the increasing awareness of the EM coupling issues inside aircraft and automotive engines, numerical modeling of cable harness networks is currently one of the most important steps in the design process of an engineering project. Most of the relevant softwares that deals with the cable topology simulation relies on the well-known analytical models such as the multiconductor transmission line theory. These techniques are better than the fullwave ones regarding the time calculation and the memory requirement. However, they are available only in the low frequency range because of the assumptions taken into account such as the uniform geometry and the infinite length of the wires. To overcome these restrictions and improve the existing solutions, we come up with a new high frequency model which is based on the transmission line theory and two numerical methods: PEEC and TLST. To keep the analytical approach of our model, we managed to get the analytical expressions of the PEEC’s partial elements. In this thesis, we were also interested by the cable raceways and cable trays. First of all, we developed a raceway model based on transmission line wires. Comparing our results with the FDTD ones, we noticed some differences especially in the high frequency range when the wire ends with the risers. Through an experimental study, we explained the behavior and the impact of these cables trays on the EM wave propagation. Finally, the results of our models have been validated with the measurements. Thanks to these experiments, we highlighted the fact that the termination of a wire has an important impact on the wave propagation