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1
Lukowiaks, Jakub. „Vision-based Cable Parameters Identification“. Thesis, Umeå universitet, Institutionen för datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-167766.
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Industrial robots have increased their presence on the market in recent years increasing the importance of smart maintenance. Unexpected downtime due to robot cable damage is the main cause for production downtime in manufacturing plants. There is also a strong trend towards consolidating tools for computer aided design and engineering of manufacturing processes and plants. This thesis provides a machine learning implementation in a simulated environment using a Gaussian process for determining dynamic cable parameters such as Young’s modulus and damping in order to increase cable simulation value. Better simulations will result in more confident programming measures of avoiding dangerous motions and thereby increasing cable lifetime. Results obtained from simulations show that it is possible to obtain dynamic cable parameters in certain error margin using just a few markers.
2
Hoshmeh, Abdullah, und Uwe Schmidt. „A Full Frequency-Dependent Cable Model for the Calculation of Fast Transients“. Universitätsbibliothek Chemnitz, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-228649.
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The calculation of frequency-dependent cable parameters is essential for simulations of transient phenomena in electrical power systems. The simulation of transients is more complicated than the calculation of currents and voltages in the nominal frequency range. The model has to represent the frequency dependency and the wave propagation behavior of cable lines. The introduced model combines an improved subconductor method for the determination of the frequency-dependent parameters and a PI section wave propagation model. The subconductor method considers the skin and proximity effect in all conductors for frequency ranges up to few megahertz. The subconductor method method yields accurate results. The wave propagation part of the cable model is based on a cascaded PI section model. A modal transformation technique has been used for the calculation in the time domain. The frequency-dependent elements of the related modal transformation matrices have been fitted with rational functions. The frequency dependence of cable parameters has been reproduced using a vector fitting algorithm and has been implemented into an resistor-inductor-capacitor network (RLC network) for each PI section. The proposed full model has been validated with measured data.
3
Kavan, Pavel. „Parametry silnoproudých vedení“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-218979.
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At the beginning is diploma thesis focused on a distribute power line parameters measurement and examination changes of this parameters depending on using of various power line cables. On the basis of measurements is made a transmission channel in Matlab & Simulink, where are executed simulations with power transmission line. The simulated power line is based on measured distribute parameters or physical proportions of cabels. By changing different parts of simulated communication channel is a symbol error rate expressed on the lenght of transmission line.
4
Váša, Lukáš. „Parametry kabelových vedení“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2021. http://www.nusl.cz/ntk/nusl-442551.
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In recent years, the development trend of power grids character shows increased demand for using cables of both current overhead and newly constructed lines. In order to preserve reliable operation and to predict the maintenance requirements, it is crucial to regard not only the parameters certified by manufacturers, but also externalities induced by real environment and incorporate these externalities into cable models in simulation software. The diploma thesis deals with determining of characteristic parameters of single core cables in real environment, which are affected by real grounding methods of metal shielding. The emphasis is put on analysis of current cable models in simulation software PSCAD and its evaluation using two-step experiment 1) measurement of shunt parameters in laboratory using electronic bridge model and 2) on field measurement of cable series parameters in real environment.
5
Theed, Justin Edward. „Environmental parameter for cable ratings“. Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287344.
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Mrákava, Petr. „Realizace počítačových modelů vedení pro PLC“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218227.
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The subject of this thesis is to become familiar with the different parameters describing the lines, and the possibility of modeling data and power models. The thesis also outlined the difference in the mechanical structure of different types of cables. The practical part focuses only on the power cables and measure their basic parameters. Then is created computer model which describes the behavior of cable lines at higher frequencies than are primarily intended. The final section is an experimental network created by the PLC for remote reading of electricity meters, and it measured different transmission properties.
7
Stølan, Ronny. „Losses and Inductive Parameters in Subsea Power Cables“. Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9992.
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Four samples of galvanized steel armour for sub sea power cables are tested with an electric steel tester. The samples exhibit different remanence magnetization and permeability. The effects of permeability on loss in sub sea cables is found to be insignificant. Slight increase of conductor inductance due to increase in permeability of armour wires is observed. Mutual cancellation of inductance between circuits that are twisted opposite to each other, or with respect to one circuit, is confirmed with laboratory tests and measurements on full scale sub sea power cables. The parameters of one cable is calculated using IECs analytical approach and found to be inaccurate for conductor resistance. The Calculations places 22% of total cable loss in the armour. Measurements on two sub sea cables and analysis using finite element method contradict the calculated armour loss. Parameters for two sub sea power cables are calculated based on measurements performed on the actual cables. The calculated values are compared with values computed using finite element analysis. Derived physics from laboratory experiments and measurements on the cables is applied in finite element analysis and found to be accurate compared with calculated values from measurements and computed values using Flux 2.5D.
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Luong, David, und Ibrahim Salloum. „Investigation of electromagnetic compatibility (EMC) of low-voltage (<60V) DC electric motors in construction machinery application“. Thesis, Linköpings universitet, Fysik och elektroteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162160.
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The brushed DC motor is a source of electromagnetic emission that may cause interference. The main issues with brushed DC motor are arcing, which occurs between the brushes and commutator, and inrush current. It is possible to decrease the electromagnetic emissions by addressing the source (brushed dc motor) and the installation. The source may be addressed by using filters in the form of X2Y-capacitors on the terminals or ferrites on the cables. The installation does not produce any emission, but it is possible to lower its contribution. This is done by altering the installation like changing the placement of cables and provide good coupling. An effective way of decreasing inrush currents is by using negative-thermal-coefficient (NTC) thermistors. Another measure to improve the EMC properties of the brushed DC motor is to design the motor so that it can trap EM emissions. Some of these parameters are motor house material, end-cap material, vent holes or slots on motor housing, placement of power terminals, crimping tabs and motor enclosure.
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Anniballi, Giulio. „Analysis of superconducting Rutherford cables through a lumped parameter circuit“. Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.
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The upgrade of the LHC, High Luminosity Large Hadron Collider requires more powerful bending magnets. Four of the 1232 dipoles based on Nb-Ti technology will be replaced with magnets made of Nb3Sn in order to create space for collimators.
This technology will allow the induction magnetic field of the magnets to pass from 8 to 11 Tesla. In this way, shorter magnets are needed for the same integrated field.
Nb3Sn has never been used in magnet technology and its use represents a technological challenge. One of the main characteristic of Nb3Sn is its fragility. This feature could damage one or more of the forty strands of the Rutherford Cable during cool down and assembling phase, creating a breakage. The current flow will be interrupted in correspondence to the breakage and in order to preserve the transport current, it has to flow from the broken strand to others (current distributions).
The aim of this thesis focuses on the analysis of a Rutherford superconducting cable with a breakage through lumped parameter circuits.
In the first phase, a steady state model has been developed to allow us to calculate the values of the adjacent and crossing strands as a function of the spatial coordinate during current plateau.
In order to reduce the complexity of the problem, the developed circuit is made of only three strands. Each of these strands represent a typology in which the forty strands of the cable have been divided : broken, adjacent and crossing strands.
The model has been validated by a comparison with numerical software THEA (Thermal, Hydraulic and Electric Analysis of a generic superconducting cable).
Subsequently of the validation, some parametric studies have been carried out in order to understand which physical parameters of the cable play a key role in the current distribution.
In the second phase, the time dependence of the model has been implemented by adding dynamic components.
The circuit under exam has been solved through state space representation.
10
La, Voie Scott Lewis. „Parameter estimation for a modified cable model using a Green's function and eigenvalue perturbation“. [Johnson City, Tenn. : East Tennessee State University], 2003. http://etd-submit.etsu.edu/etd/theses/available/etd-0331103-140715/unrestricted/LaVoieS04162003a.pdf.
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Thesis (M.S.)--East Tennessee State University, 2003.Title from electronic submission form. ETSU ETD database URN: etd-0331103-140715. Includes bibliographical references. Also available via Internet at the UMI web site.
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Hernandez, Erika Lyn. „Parameter Estimation in Linear-Linear Segmented Regression“. Diss., CLICK HERE for online access, 2010. http://contentdm.lib.byu.edu/ETD/image/etd3551.pdf.
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Evans, Katie Allison. „Reduced Order Controllers for Distributed Parameter Systems“. Diss., Virginia Tech, 2003. http://hdl.handle.net/10919/11063.
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Distributed parameter systems (DPS) are systems defined on infinite dimensional spaces. This includes problems governed by partial differential equations (PDEs) and delay differential equations. In order to numerically implement a controller for a physical system we often first approximate the PDE and the PDE controller using some finite dimensional scheme. However, control design at this level will typically give rise to controllers that are inherently large-scale. This presents a challenge since we are interested in the design of robust, real-time controllers for physical systems. Therefore, a reduction in the size of the model and/or controller must take place at some point. Traditional methods to obtain lower order controllers involve reducing the model from that for the PDE, and then applying a standard control design technique. One such model reduction technique is balanced truncation. However, it has been argued that this type of method may have an inherent weakness since there is a loss of physical information from the high order, PDE approximating model prior to control design. In an attempt to capture characteristics of the PDE controller before the reduction step, alternative techniques have been introduced that can be thought of as controller reduction methods as opposed to model reduction methods. One such technique is LQG balanced truncation. Only recently has theory for LQG balanced truncation been developed in the infinite dimensional setting. In this work, we numerically investigate the viability of LQG balanced truncation as a suitable means for designing low order, robust controllers for distributed parameter systems. We accomplish this by applying both balanced reduction techniques, coupled with LQG, MinMax and central control designs for the low order controllers, to the cable mass, Klein-Gordon, and Euler-Bernoulli beam PDE systems. All numerical results include a comparison of controller performance and robustness properties of the closed loop systems.Ph. D.
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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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Rasuli, Abdol Rasul. „Dynamic modeling, parameter identification, payload estimation, and non-contact arm geometry sensing of the mining cable shovel“. Thesis, University of British Columbia, 2012. http://hdl.handle.net/2429/43648.
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This thesis presents the application of the least squares estimation technique in identification of the cable shovel parameters and monitoring its payload. Both detailed and simplified dynamic models of the cable shovel are derived by modeling the DC motors and analyzing such nonlinear effects as inertia, Coriolis, centripetal, and friction. Mathematical methods, including the interactive Newton-Euler technique, have been used to obtain the kinematic and dynamic equations of the shovel, and establish the relationship between the shovel parameters and the payload inside the bucket. The cable shovel bucket is also referred to as “dipper”. An on-line parameter identification scheme was developed and experimentally verified in order to estimate the cable shovel parameters. A data acquisition system was installed on a P&H2100 cable shovel in the Sarcheshmeh Copper mine, located in Iran, where it logged the cable shovel data for several loading cycles. The payload was dynamically estimated using the simplified dynamic cable-shovel model developed in this thesis. The accuracy and repeatability of the algorithm has been verified based upon the cable-shovel data logged during its normal operation at the mine.
In the course of this thesis project, I also devised a novel approach for non-contact sensing of the dynamic arm-geometry of the cable-shovel. A prototype sensor apparatus was designed and assembled that measures the dipper handle angle, the swing angle, and the dipper handle length. Different sensors such as gyroscopes, magnetometers, accelerometers, and a laser sensor are integrated into Arm Geometry Sensor (AGS) apparatus. The AGS apparatus is installed on the saddle block and measures all cable shovel joint variables without having direct physical contact with the links or joints. The AGS apparatus was employed during field trials on the on P&H2100 cable shovel and verified to effectively sense the shovel joint variables with acceptable accuracy.
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Hrubý, Radek. „Analýza vyvedení elektrického výkonu v městské zástavbě“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2012. http://www.nusl.cz/ntk/nusl-219418.
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The work focuses on outlet of the electrical power from power plants operating in urban areas. After a short analysis of the general possibility of leading out electric power from power plants of various types, thesis continues to describe of outlet electrical power from PPC Červený Mlýn. Subsequently, are calculated short-circuit conditions in the main switching station. It follows an analysis of power lines. The last part dealt with the issue of reliability of sources in connection with random transition processes in the electrical network and the light of the operational reliability of electrical power equipment.
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Lewis, S. L. „The influence of geotechnical parameters on the efficiency of water jetted burial of underwater cables in cohesive sediments“. Thesis, Bangor University, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.245853.
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Riechel, Andrew T. „Force-Feasible Workspace Analysis and Motor Mount Disturbance Compensation for Point-Mass Cable Robots“. Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/5243.
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Cable-actuated manipulators (or 'cable robots') constitute a relatively new classification of robots which use motors, located at fixed remote locations, to manipulate an end-effector by extending or retracting cables. These manipulators possess a number of unique properties which make them proficient with tasks involving high payloads, large workspaces, and dangerous or contaminated environments. However, a number of challenges exist which have limited the mainstream emergence of cable robots. This thesis addresses two of the most important of these issues-- workspace analysis and disturbance compensation.
Workspace issues are particularly important, as many large-scale applications require the end-effector to operate in regions of a particular shape, and to exert certain minimum forces throughout those regions. The 'Force-Feasible Workspace' represents the set of end-effector positions, for a given robot design, for which the robot can exert a set of required forces on its environment. This can be considered as the robot's 'usable' workspace, and an analysis of this workspace shape for point-mass cable robots is therefore presented to facilitate optimal cable robot design. Numerical simulation results are also presented to validate the analytical results, and to aid visualization of certain complex workspace shapes.
Some cable robot applications may require mounting motors to moving bases (i.e. mobile robots) or other surfaces which are subject to disturbances (i.e. helicopters or crane arms). Such disturbances can propagate to the end-effector and cause undesired motion, so the rejection of motor mount disturbances is also of interest. This thesis presents a strategy for measuring these disturbances and compensating for them. General approaches and implementation issues are explored qualitatively with a simple one-degree-of-freedom prototype (including a strategy for mitigating accelerometer drift), and quantitative simulation results are presented as a proof of concept.
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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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Dlouhý, Lukáš. „ANALÝZA NÁVRHOVÝCH PARAMETRŮ PŘEDPJATÝCH BETONOVÝCH KONSTRUKCÍ POMOCÍ OPTIMALIZAČNÍCH ALGORITMŮ“. Doctoral thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-392296.
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During recent years more and more emphasis has been put on saving and ecological aspects of the civil engineering industry. As the total volume of concrete being produced on our planet is immense (ca 1010 tons per year), the possibility of decreasing it by even a small percentage can bring large savings in material costs, transport and other costs and reduction of CO2 production and other pollution. Therefore, optimal analysis of design variables of concrete structures appears to be of high importance. Optimization is finding the best solution to a given problem. Many disciplines define different optimization problems and it is typically the minimum or maximum value of the objective function that is searched. It is known that mathematical procedures and algorithms to find an optimal structural design are used in practice in mechanical engineering, but the use of these tools in civil engineering is rather exceptional. Generally, scientific works deal with the optimal design of structures only. Finding of an optimal shape and dimensions is usually a question of the engineer’s experience and good “guess”, which is then verified by calculation. There are many reasons explaining why optimization in common practise is used only occasionally. One of them is the absence of proper user friendly software tools which could help within relatively short time available for structural design. Another reason is the complexity of optimization tasks as well as a lot of constraints in civil engineering design codes. Last but not least, the change of design variables of buildings, bridges and structures of special types do not express regular response. This issue is discussed in the submitted work.
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Berrabah, Nassif. „Problèmes inverses pour le diagnostic de câbles électriques à partir de mesures de réflectométrie“. Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S140/document.
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Les câbles électriques sont présents dans de nombreux produits et systèmes où ils sont utilisés pour transmettre des données ou transporter de l'énergie. Ces liaisons sont la plupart du temps installées pour des durées d'exploitation longues au cours desquelles elles doivent subir l'usure du temps, ainsi que celle résultant d'un environnement parfois agressif. Alors que les câbles électriques assurent des fonctions essentielles et dans certains cas critiques, ils sont aussi sujets à des défaillances qui découlent des contraintes qu'ils endurent. Ceci explique la nécessité de surveiller leur état, afin de détecter au plus tôt les défauts naissants et d'intervenir avant qu'ils ne dégénèrent en dommages dont les conséquences peuvent être préjudiciable et économiquement lourdes. L'entreprise EDF est particulièrement concernée par cette problématique dans la mesure ou elle exploite des longueurs considérables de câbles pour le transport et la distribution d'électricité sur tout le territoire bien sûr, mais aussi au sein des centrales qui produisent l'électricité, pour alimenter les différents organes, et acheminer commandes et mesures. L'entreprise, attentive à ce que ces câbles soient en bon état de fonctionnement mène plusieurs travaux, d'une part pour étudier leur vieillissement et modes de dégradation, et d'autre part pour développer des méthodes et outils pour la surveillance et le diagnostic de ces composants essentiels. Le projet EDF CAIMAN (Cable AgIng MANagement) commandé par le SEPTEN (Service Etudes et Projets Thermiques Et Nucléaires) traite de ces questions, et les travaux présentés dans cette thèse ont été conduits dans ce cadre et sont le fruit d'une collaboration avec Inria (Institut National de Recherche en Informatique et Automatique). Partant du constat que les méthodes de diagnostic de câbles existantes à l'heure actuelle ne donnent pas pleine satisfaction, nous nous sommes donné pour objectif de développer des outils nouveaux. En effet, les techniques actuelles reposent sur différents moyens dont des tests destructifs, des prélèvements pour analyse en laboratoire, et des mesures sur site mais qui ne permettent pas de diagnostiquer certains défauts. Parmi les techniques non destructives, la réflectométrie, dont le principe est d'injecter un signal électrique à une extrémité du câble et d'analyser les échos, souffre aussi de certaines de ces limitations. En particulier, les défauts non-francs restent encore difficiles à détecter. Toutefois les travaux qui se multiplient autour de cette technique tentent d'en améliorer les performances, et certains obtiennent des résultats prometteurs. Les chercheurs de l'Inria qui travaillent sur le sujet ont développé des algorithmes pour exploiter des mesures de réflectométrie. En résolvant un problème inverse, les paramètres d'un modèle de câble sont estimés et servent alors d'indicateurs de l'état de dégradation du câble testé. L'objectif de cette thèse est d'étendre ces méthodes pour répondre aux besoins spécifiques d'EDF. Un des principaux défis auquel nous avons apporté une solution est la prise en compte des pertes ohmiques dans la résolution du problème inverse. Plus spécifiquement, notre contribution principale est une méthode d'estimation du profil de résistance linéique d'un câble. Cette estimation permet de révéler les défauts résistifs qui produisent souvent des réflexions faibles dans les réflectogrammes habituels. Une seconde contribution vise à améliorer la qualité des données utilisées par cette méthode d'estimation. Ainsi, nous proposons un pré-traitement des mesures dont le but est de gommer l'effet de la désadaptation des instruments aux câbles ou celui des connecteurs. Ces travaux apportent de nouveaux outils pour l'exploitation des mesures de réflectométrie et des solutions pour le diagnostic de certains défauts encore difficiles à détecter aujourd'huiElectric cables are ubiquitous in many devices and systems where they are used for data or power transmission. These connection links are most often installed for long periods of operation during which they are subject to aging and sometimes exposed to harsh environments. While electric cables fulfill important and sometimes even critical functions, they might fail due to the hard constraints they have to endure. This motivates the need for monitoring tools, in order to detect early faults and to intervene as soon as possible, before they mutate into heavier damage whose consequences can be detrimental and expensive. EDF company is very affected by this problematic insofar as it operates significant lengths of cables for energy distribution, but also in power plant for power supply of the diverse apparatus, to route data and to transmit measurement. The company has been leading several studies regarding cable aging, cable faults, and wire diagnosis methods. The CAIMAN project (Cable AgIng MANagement), sponsored by the Engineering Department of Nuclear and Thermal Projects (SEPTEN), deals with these questions. The work presented in this dissertation were led in this context and results from a collaboration with Inria (French National Institute for Research in Applied Mathematics and Computer Sciences). Starting from the observation that existing cable diagnosis methods do not offer full satisfaction, we targeted the goal of developping new tools to improve the state of the art. Existing techniques rely on a range of tests, some of which are destructive or involve in-lab investigations, but these still cannot detect some kind of faults. Among major techniques, reflectometry has the most promising results. This technique consists in the same principle as a radar. One sends a wave down a cable from one end. Then the reflected signal is analysed searching for signs of faults. Yet, this method also suffers some limitations and soft faults remain hard to detect. Researchers and industries multiply the investigations in the domain of reflectometry-based techniques, and some get interesting results. Scientists from Inria developped algorithms for cable parameter estimation from reflectometry measurements, following an inverse-problem approach. The goal of our work was to extend these methods to meet the specific needs of EDF. One of the main challenges we coped with was to take into account electric losses in the resolution of the inverse problem. Our main contribution is a method to estimate the per unit length resistance profile of a cable. This estimation reveals resistive faults that most often only produce weak reflections in reflectometry measurements. Other contributions concerns the improvement of the method based on pre-processing of the data whose role is to erase the effect of impedance mismatches. This work breaks new grounds in the domain of reflectometry-based wire diagnosis techniques
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Cottanceau, Emmanuel. „Simulation numérique du processus d’assemblage de câbles flexibles en grands déplacements“. Thesis, Paris, ENSAM, 2018. http://www.theses.fr/2018ENAM0011/document.
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Avec l’essor de l’électronique embarquée, les câbles électriques constituentune part importante des pièces automobiles tandis que l’espace à bord n’a cessé de diminuer. Leur flexibilité requiert la prédiction de leur déformation durant leur montage afin d’éviter le contact avec d’autres pièces du véhicule et leur endommagement. Les outils actuels ne permettent pas une prédiction assez réaliste et précise de leur comportement, nécessaire dans un volume de travail très restreint. Les étapes de montage sont donc validées via la réalisation de maquettes réelles coûteuses. Cette thèsea pour but d’améliorer la simulation numérique de ces pièces souples. Nous proposonsici un code de simulation 3D basé sur un modèle de poutre géométriquement exact résolu par la méthode des éléments finis. Son originalité tient dans le couplage des quaternions pour modéliser les rotations 3D et de la méthode asymptotique numérique pour la continuation du système non linéaire qui lui confère une grande robustesse. Un banc d’essai permettant l’identification des paramètres homogénéisés nécessaires au modèle numérique et sa validation par comparaison de la géométrie finale et du chemin d’équilibre est présenté. Combinés à des développements analytiques sur les modèles de poutres avec cisaillement, les essais mènent à une évaluation critique du modèle deTimoshenko 3D pour la représentation des torons de câblesWith on-board electronics expansion, electrical cables are an essential partof automotive pieces and the space on board has plummeted. Their flexibility requires to predict their deformation during vehicle assembly in order to avoid the contact with other pieces and damaging. Current numerical tools do not allow a realistic and accurate prediction, which is necessary in the obstructed car space. Assembly steps thus are validated on costly physical mock-ups. This thesis aims at improving numerical simulation of these flexible pieces. We herein propose a 3D algorithm based on a geometrically exact beam model solved by the finite element method. This work’s originality stands in coupling quaternions as rotational parameters and the asymptotic numerical method as nonlinear solver which results in a very robust algorithm. A test bench designed to identify the homogenized beam parameters of the numerical model and to validate it by offering a comparison on the final geometry and the equilibrium path is presented. Analytical developments on shear beams and the results of these experimental tests lead to a critical evaluation of the 3D Timoshenko model for representing stranded cables
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Cholachue, Ngounou Christel. „Caractérisation des blindages électromagnétiques des câbles et faisceaux aéronautiques“. Thesis, Normandie, 2020. http://www.theses.fr/2020NORMR025.
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Ces dernières années, la multiplication des loisirs à bord des nouveaux avions a connu une croissance exponentielle. Dans un appareil comme l’A380, chaque siège intègre plusieurs fonctions (jeux vidéo, musique, etc. ..) et chaque fonction est connectée à l’aide d’au moins un câble électrique. Ce qui nécessite un nombre important de kilomètres de câbles pour établir toutes les connexions électriques à bord d’un tel appareil. En plus l’électrification progressive pour des raisons de sécurité des fonctions auparavant mécaniques, hydrauliques ou pneumatiques, a augmenté les exigences de câblage notamment en compatibilité électro- magnétique (CEM). La cohabitation de tous ces kilomètres de câbles dans un espace aussi réduit a accru les exigences en termes de blindage électromagnétique (EM). Les nombreuses méthodes d’analyse du blindage des câbles et faisceaux sont limitées en termes de rapidité, d’analyse des systèmes multiports. Les outils de simulations eux sont très onéreux (prévoir environ18Ke pour une licence), et nécessitent des compétences avancées et beaucoup de temps pour la caractérisation du blindage des câbles et faisceaux de câbles. Avec un outil de simulation EM 2D/3D comme HFSSR d’ANSYSR, il faut prévoir environ trois heures pour créer le modèle d’une gaine de blindage tressé, et également prévoir un temps de simulation moyen de 20 minutes en utilisant un PC équipé d’un processeur mono-cœur Intel RXeon RCPUE5-1620v4@ 3,50 GHz et 32 Go de RAM physique avec 64 bits Windows 10. En plus, les méthodes et techniques de caractérisation du blindage des câbles et faisceaux de câbles aéronautiques ont montré leurs limites à l’instar du banc triaxial avec lequel il est difficile d’effectuer des mesures d’impédance de transfert au-delà de 100 MHz. Les travaux effectués dans cette thèse ont pour but de dépasser ces limites. Nous avons développé une nouvelle méthode d’extraction rapide des paramètres S des systèmes multiports. La connaissance analytique des paramètres S permet de remonter à des caractéristiques intrinsèques des structures de blindage tubulaire. Par exemple, nos calculs des paramètres S d’une structure de câble coaxial sont prometteurs pour déterminer l’impédance de transfert par rapport à la géométrie et d’autres paramètres physiques des gaines. L’originalité de ce travail de recherche consiste à se familiariser à une méthode analytique et semi-hybride de modélisation des structures de blindage tubulaire en exploitant le formalisme de l’Analyse Tensorielle des Réseaux (ATR) à base de la méthode de Kron. Ce formalisme offre un avantage notable pour l’analyse rapide avec une précision relativement importante des systèmes électriques et électroniques complexes comme le cas des éléments de blindage. La rapidité de la méthode a été évaluée avec différentes structures sur une bande de fréquence allant de 0 Hz à quelques gigahertz en menant à des expressions dont les applications numériques se font sur un temps de calcul ne dépassant pas les millisecondes. D’autre part, nous avons aussi développé nos savoir-faire sur l’analyse des blindages électromagnétiques des câbles et faisceaux de câbles. Une approche a été élaborée pour déterminer l’efficacité de blindage (EB) d’une gaine via une configuration de couplage entre un câble coaxial blindé et une sonde boucle. Une méthode de modélisation innovante a été développée à l’aide de la théorie des circuits pour déterminer l’efficacité de blindage en étudiant le couplage entre un câble nu (conducteur interne) et un câble tressé en parallèle par la méthode de Kron. Nous avons également développé un banc de caractérisation des structures tubulaire de blindage électromagnétique dans le but de fonctionner jusqu’à 300 MHz. Les résultats dans ces études ont été confirmés par des simulations 3D et des mesuresDuring the last decade, the proliferation of on-board leisure activities in the new aircrafts have been growing exponentially. In the airplane like A380, each seat integrates several functions (video games, music, etc. ..) Additionally, each function must be connected using at least one electric cable. This system requires a significant number of kilometers of cables to establish all the on-board electrical connections. Furthermore, for reasons of safety and security related to mechanical, hydraulic or pneumatic functions, the wiring EMC requirements associated to the massive progressive electrification becomes considerably stricter. The coexistence of kilometer lengths of cables system in such a small space has increased the requirements in terms of electromagnetic (EM) shielding. Most of existing numerous methods for analyzing the shielding of cables and harnesses are limited in terms of computation speed, design process and in accuracies for the multiport systems analysis. Moreover, most of popular simulation and commercial tools are very expensive (for example with license cost can be more than 18K€). The use of commercial tools requires advanced skills and a lot of time to characterize the shielding of cables and harnesses. For example, with a simulation tool like HFSSR from ANSYSR , the computation time may cost approximately 3 hours to create a design model of a braided shields heath. Then, the computed results can be generated during an average simulation time of 20 minutes using a PC equipped with an Intel single-core processor RXeon RCPU E5-1620 v4 @ 3.50 GHz and 32 GB of physical RAM with 64-bit Windows 10. Most of available methods and techniques for characterizing the shielding of aeronautical cables and cable harnesses have shown their limits. For example, most of existing triaxial benches are particularly difficult to deploy for the transfer impedance measurements and they cannot operate beyond 100 MHz. The present PhD thesis aims to overcome these technical limits. Doing this, an original analytical method is developed for extracting S-parameters from multiport systems under fast computation speed and design process. An innovative methodology of EMC modelling was proposed. The knowledge of S-parameters is helpful to determine the broadband EM intrinsic parameters of the cabling as coaxial system. The developed analytical and semi-hybrid model is based on the unfamiliar formalism using tensorial analysis of networks (TAN) based on the Kron’s method. The model offers an outstanding possibility to analyze complex systems with deep knowledge of physical phenomenal behind the EM shielding. Thanks to the TAN formalism, an innovative method of circuit theory has been developed to determine the shielding efficiency (SE) of shielded cable. The feasibility of this multiport S-parameter approach was verified with the consideration of EM coupling between a nude cable constituting an internal conductor and a braided cable placed in parallel. More importantly, an advanced study of shielding efficiency (SE) with respect to the EM coupling configuration between a shielded coaxial cable and a loop probe is performed. Substantially, it was noteworthy that the TAN formalism provides an illuminating know-how on the theoretical, numerical and experimental analyses of cables and bundles EM shielding, and transfer impedances of the shielding sheath. Moreover, the TAN modelling effectiveness was confirmed with different applications with computation time which does not exceed milliseconds. Finally, the TAN model was also used to develop a SE characterization bench for tubular EM shielding structures up to 300 MHz. Emphatically, broadband SE and transfer impedance results in good correlation between 3D simulations and measurements were obtained
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Prudík, Jiří. „Model metropolitní optické sítě“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217666.
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The purpose of this master’s thesis is foremost to provide a simple guide how to build elements of optical metropolitan area network. The basic model consists to sequence of construction, network topology, passive and active parts. The collection contains examples of alternative technology such as Wireless LAN with different frequency. The optical network construction based on optical cable, fibres, splices, trays, adapters, connectors and active parts for example a lot of media convertor models. After that there are demonstrating type of wavelength division multiplexer used in metropolitan area network – passive planar PCL splitter. One of the passive planar splitter are used to increase optical fibre channel. At the end of the collection a simplified examples of used measurements – optical time domain reflectometry and optical fibre transmission. Contains standard protocols or reflectogram. The conclusion of this thesis summarizes costs of FTTb (Fibre To The Building) model of optical metropolitan area network in Czech republic and future contribution for society.
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MacNeill, Aaron. „Submarine Power Cable Transmission Line Parameters and Performance“. 2012. http://hdl.handle.net/10222/15470.
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Submarine power production installations use the power of the ocean to generate
renewable energy for the population to use. To bring this electricity back to land, use of
electrical cables is required. The choice of cable will affect both the quality of received
power and the security of the transmission line. To find the inductance and capacitance of these submarine transmission lines, a study of the electric and magnetic fields that are produced due to the power flow on these cables must be performed. The armor that is used to protect the cable from underwater hazards is significant in determining the cable losses and finding the equivalent inductance and capacitance. Finding the inductance and capacitance of the submarine cable will allow for the determination of the two port parameters of the cable. These parameters will allow for the analysis of the transient and steady state performance of the cable.
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Chen, Ting-Yu, und 陳亭伃. „Cable Parameters and Ionic Conductances of Oligodendrocyte Precursor Cells“. Thesis, 2014. http://ndltd.ncl.edu.tw/handle/64212769508550484235.
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碩士國立陽明大學
神經科學研究所
102
Abstract of Part I Oligodendrocyte precursor cells (OPCs) are one of the major glial cells, which were discovered about twenty years ago. Unlike the other types of glia cells, OPCs receive directly excitatory synaptic transmission from neurons, and form synapses with neurons. Synaptic integration is critical for neuronal function, and synaptic potential propagation in neurons are well studied. However, little is known about the synaptic potential processing in OPCs. In the present study, we used whole-cell patch-clamp recordings to investigate electrical signals in OPCs and two-photon laser scanning imaging to reconstruct the morphology of recorded OPCs. Furthermore, we developed realistic OPC models for synaptic integration, based on passive membrane responses of OPCs obtained by simultaneous whole-cell patch-pipette recordings. The results showed that the value of specific membrane resistance (Rm) was 4.1 ± 1.1 kΩ-cm2, specific membrane capacitance (Cm) was 1.2 ± 0.1 microF/cm2 and specific axial resistance (Ri) was 146.0 ± 21.5 Ω-cm. Compared with neurons, the value of Rm in OPCs was relatively low. The low Rm suggested that OPCs had a leaky membrane property, which was largely mediated by Ba2+-sensitive background K+ conductances. The low Rm is not only critical for sharpening excitatory postsynaptic potential (EPSP) and but also limit the temporal window for summation of synaptic inputs. Abstract of Part II Acid-sensing ion channel 4 (ASIC4) is a member of the ASIC family, which is widely expressed in the mammalian nervous system. Previous studies have demonstrated that ASICs are implicated in pain, ischemia stroke, seizures and many other neurological diseases. Most of our knowledge about the function of ASICs is concluded from the conventional ASIC1a-null mice. However, the role of ASIC4 subunit remains poorly understood. This study identified that OPCs, a type of glial cells, were one of the ASIC4-expressing cells. A previous study suggests that the hippocampal OPCs express high density of Ca2+-permeable ASIC1a channels compared with several types of hippocampal neurons. Here, using a combination of genetic and electrophysiological approaches, we found that the density of ASIC currents in hippocampal OPCs was relatively high in ASIC4-null mice as compared with wild-type mice, suggesting that ASIC4 may downregulate ASIC current density. In addition, both input resistance (RN) and membrane time constant (τm) in ASIC4-null mice were significantly smaller than those in wild-type mice, suggesting that ASIC4 may also downregulate resting conductance of OPCs.
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Cao, Jun, und 曹駿. „Study of Kao Ping Hsi Cable-Stayed Bridge Health Monitoring from Changes in Modal Parameters“. Thesis, 2004. http://ndltd.ncl.edu.tw/handle/92209770563918045751.
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碩士國立雲林科技大學
營建工程系碩士班
92
The Kao Ping Hsi Bridge is the longest cable-stayed bridge in Taiwan. Although there was no damage to this bridge during the 921 earthquake, the Kao Ping Hsi Bridge is possible to be damaged in the future. In case that the damage is not found and accumulated, abrupt collapse of the bridge could happen and result in sever life and financial losses. Therefore it is necessary to carry out routine structural health monitoring of the Kao Ping Hsi Bridge. This study conducts a series of structural analyses of the Kao Ping Hsi Bridge using the SAP2000 program. First, the critical sections of the bridge when subjected to various overloading cases are found. Then the XTRACT program is used to analyze these critical sections and determine their cracking moment, yielding moment, and ultimate moment. After identifying the locations of damage for various overloading cases, the natural frequencies and mode shapes for the original and damaged structures are calculated to study whether it is possible to detect these damages from the changes in modal parameters of the Kao Ping Hsi Bridge. The results of this study show that the prestressed concrete girder of the Kao Ping Hsi Bridge would be damaged in the overloading cases of live load and settlement. However, the modal parameters of the damaged bridge are almost unchanged, which demonstrates that it is impossible to detect this kind of damages from the changes in modal properties. Comparatively, in the cases of overloaded axial and lateral earthquake forces, the damages in the pylon result in apparent changes in vibration periods. Therefore it should be feasible to detect if the pylon of the Kao Ping Hsi Bridge is damaged due to large seismic loadings by measuring modal data of the bridge.
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Chang, Chun-Hsu, und 張君旭. „Study on Identification of Parameters for Cable-Stayed Bridge Deck Buffeting Response Analyses and on Related Numerical Simulations“. Thesis, 2007. http://ndltd.ncl.edu.tw/handle/00616831865851633967.
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博士國立臺灣科技大學
營建工程系
96
As the main spans of bridges become longer, engineers have to assess the wind induced vibration of bridge decks for safety and serviceability. Generally, either the full bridge model wind tunnel test or section model wind tunnel test with analytical procedure is used to evaluate buffeting responses of bridges. Modal parameters, including modal frequencies and damping ratios, are usually obtained by finite element models; aerodynamic parameters, including aerodynamic coefficients and flutter derivatives, are obtained by section model wind tunnel test. In this research, modal and aerodynamic parameters are obtained by identifying filed measurement results and numerical simulations respectively. This study proposes a method, combing empirical modal decomposition, random decrement technique with Hilbert transform, for identification of modal parameters in time domain from modally coupled response time histories. Aerodynamic and aeroelastic phenomena of blunt sections are simulated by numerical simulations; the associated aerodynamic coefficients are evaluated; flutter derivatives are identified by stochastic subspace identification method. Vortex shedding and reattachment phenomena are observed in the simulated results. The obtained aerodynamic parameters are compared with those of the wind tunnel test in the literature, and indicated that aerodynamic coefficients approach to the average of wind tunnel test results, flutter derivatives are higher estimated slightly. Finally, numerical simulations are conducted for a bridge section; the interaction effect of fluid-bridge section is accounted by an arbitrary Lagrangian-Eulerian strategy. Finally, the root mean square values of bridge buffeting responses are evaluated by an approximate analytic formula using the obtained parameters. These results can be used to assess safety and serviceability of the bridge. The effects of modal parameters, aerodynamic coefficient and flutter derivatives on buffeting responses are also investigated.
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Su, Jiun-Shiang, und 蘇俊祥. „Measurement of resistance ohm value parameters at both ends of a nickel-based alloy (INCONEL601) cable wire connector using crimping and argon welding“. Thesis, 2017. http://ndltd.ncl.edu.tw/handle/hwy9zg.
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碩士元智大學
機械工程學系
105
The function of the cable conductor, the importance of the relevant industry, like the blood vessels in the human body, is a transport organ. For electrical, electrical, telecommunications, mechanical and industrial engineering industry, as long as the need to use the place to live, the cable is a cable can not be missing transmission [1]. Cable wires are roughly divided into two categories: the first type of classification, the second to the classification of the composition of the wire. The first type of appearance can be divided into four categories: a bare wire, insulated wire, cable, special wire, which in turn the most widely used cable and special wire; the second composition can be divided into five: , Single line, white flat wire, stranded wire, cable. The cable class is subdivided into 1. Power cable class 2. Communication cable class 3. Fiber optic cable class 4. Control cable type. This article explores the parts of the power cable. The part of the cable wire material used in this study is the material of INCONEL601. The prominent feature of INCONEL alloy is the high temperature oxidation resistance. It is generally used in high temperature environment above 540 ℃, and it is different according to its use. Alloy design, and more for special corrosion resistance, high temperature corrosion environment, to be equipped with high temperature mechanical strength of the equipment [2]. It is resistant to oxidation at 2200 ° F (1200 ° C). Can be used for high temperature long-term use, and not oxidation. In this study, different crimp methods and argon welding were used to measure the ohmic values of the electrical leads in different states and to find the best parameters. The results show that, with different crimping methods and different welding methods, with the instrument after the test will indeed have an ohmic value of the cable lead to different aspects of the impact.
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Liou, Jien-Mieng, und 劉謹銘. „Ambient Vibration Analysis and Modal Parameter Identification for Cables of Chi-Lu Cable-Stayed Bridge“. Thesis, 2004. http://ndltd.ncl.edu.tw/handle/63811325616396140045.
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碩士國立雲林科技大學
營建工程系碩士班
92
Chi-Lu cable-stayed bridge was the first cable-stayed bridge in the world damaged by earthquake. Due to the complexity of restoring the corresponding cable system, the associated research and repairing work are still under way. Focused on the cables of Chi-Lu bridge, this study applies the techniques of ambient vibration measurement to investigate various fundamental engineering properties of cable including the estimation of Young's modulus, the effects of temperature and the centralizing device, and the long-term monitoring of cables. Moreover, the random decrement method together with Ibrahim time-domain system identification method are applied to identify all the modal parameters of those cables. Based on the experimental and analytical results, it is observed that temperature difference can moderately affect the axial force of cable and the elastic modulus of cable should be taken as around ninety percent as that of steel in analysis. Besides, the status of the cables are found stable from long-term monitoring. As to the identification of modal parameters, it is proved that the dynamic parameters for each modal can be efficiently and accurately identified taking advantages of the characteristic of cables that each modal frequency is equally spaced and well separated.
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Liau, Jau-an, und 廖釗銨. „Modal Parameter Identification for the Cables and Body of the Cable-Stayed Bridge by the Way of Multiple Random Decrement Method with Dates of Cable Ambient Vibration Measurement“. Thesis, 2007. http://ndltd.ncl.edu.tw/handle/39471809419002820718.
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碩士國立雲林科技大學
營建工程系碩士班
95
The bridge cable is the primary member which transmits the strength in cable-stayed bridge overall construction system, so it can reflect the dynamic performance and the healthy condition of the overall bridge system directly. At the same time, the cable’s geometry shape can regard as the pure dimensional structure which makes it relatively simple to carry the measurement and analysis of the dynamic response on. Therefore ambient vibration measurement and following dynamic parameter identification of cable are the best shortcut to carry on the health monitor to the whole cable-stayed bridge. But the dynamic response of the bridge cable which occupies by higher frequencies occupies the composition proportion is high because of lower lateral-stiffness, we usually must distinguish the more model parameters above. The ways about the system-identification of the cable-stayed bridge most carry on the ambient vibration measurement by the mobile and simple establishment in the last few years. We must apply the system-identification skill which is only according to the output signals to decide the model parameters, because the ambient vibration measurement of the bridge cable only can obtain the output signals. And we don’t easily carry on the multi-spot even distributive measurement for the identical cable because of field work limit. In addition, the signals of the ambient vibration measurement are usually minimum. The questions of signals often create the puzzle in the practice application such as noises and so on. We carry on the preliminary analysis through the ambient vibration measurement record of cables of the Chi-Lu cable-stayed bridge. The paper inspires the frequency of every cable respectively first; moreover, the conspicuous model frequencies of the bridge body are pointed out by the overlapping and compared way. Before developing the new method, we first aim at the tradition random decrement method and Ibrahim time domain identification to conduct the detailed parameter research. Above these foundations, the most important achievement of this research is to combine the innovative mode parameters with multiple random decrement method to develop the effective method distinguishing multiple mode parameters of cables by using ambient vibration measurements from single station. This set of method fully uses the dynamic performance of bridge cable. On the one hand, it improves many complex questions about distinguishing multiple mode parameters simultaneously to decide mode parameters separately by way of the mode separation. Meanwhile, it filters thoroughly influence of the external force’s noise and the bridge body’s mode frequencies and so on to compute mode damping ratios accurately by way of the multiple random decrement method. Taking the dates of the Chi-Lu cable-stayed bridge cables’ speed ambient vibration measurement as an example, its identification result clearly confirms this method sufficiently provides the precise identification to the multiple mode parameters of bridge cables.
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Lu, Bing Luongo Cesar A. „Electrical parameters in multi-strand superconducting cables and their effect on stability“. 2006. http://etd.lib.fsu.edu/theses/available/etd-03172006-173643.
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Thesis (Ph. D.)--Florida State University, 2006.Advisor: Cesar Luongo, Florida State University, FAMU-FSU College of Engineering, Dept. of Mechanical Engineering. Title and description from dissertation home page (viewed July 28, 2006). Document formatted into pages; contains xiii, 126 pages. Includes bibliographical references.
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Wang, Ming-Chieh, und 王銘杰. „Cost Reduction of Cable Material Based on Parameter Design of Taguchi Method“. Thesis, 2009. http://ndltd.ncl.edu.tw/handle/55036602280134082783.
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碩士國立高雄應用科技大學
工業工程與管理系
97
The wire and cable (WC) industry in Taiwan has reached its mature period. To sustain in intensive market competitions of the WC, companies have to reduce the cost of WC materials by improving the formulas of making WC products. The low smoke free-halogen (LSFH) formula is one of critical recipes for making WC products. In this research, the parameter design of Taguchi method is used to improve LSFH formula. Certain key parameters contained in the LSFH formula, such as ethylene-vinyl acetate, magnesium hydroxide, aluminum hydroxide, flame retardant, polyethylene, filler, and plasticizer are experimented on different levels based on Taguchi’s orthogonal array table. The experimental results show that designing the proper parameters in the LSFH formula the cost of the WC materials can be reduced with a certain degree of robustness.
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„Parameter Estimation for a Modified Cable Model Using a Green's Function and Eigenvalue Perturbation“. East Tennessee State University, 2003. http://etd-submit.etsu.edu/etd/theses/available/etd-0331103-140715/.
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34
Chen, Chi-Hong, und 陳智泓. „APPLICATION OF DIGITAL PHOTOMETRY TECHNIQUES IN IDENTIFYING THE MODAL PARAMETERS OF STAY CABLES“. Thesis, 2010. http://ndltd.ncl.edu.tw/handle/49617379054777273617.
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碩士雲林科技大學
營建工程系碩士班
98
Conventional sensors, such as the accelerometers and velocimeters, have been generally adopted to conduct the vibration measurements of stay cables for the identification of their dynamic parameters. Even though these contact sensors are able to obtain accurate measurements, the installation of such devices may require substantial efforts. A simple digital videogrammetric technique with or without using artificial target is developed in this study to perform the ambient vibration measurements of stay cables for the subsequent identification of cable dynamic-parameter, including frequencies, damping ratio and mode shapes. Demonstrated by the on-site measurements for three different cables selected from Chi-Lu Bridge, it is shown that this technique equipped with a customer grade camcorder and an ordinary tripod placed on the bridge deck can attain the same order of accuracy for cable dynamic-parameter identification as that of high-resolution velocimeters. Based on this study, it is proved that the practical application of a videogrammetric technique to the cables of long-span cable-stayed bridges is not only feasible but also advantageous in many aspects.
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Rivas, Richard A. „Calculation of frequency-dependent parameters of power cables with digital images and partial subconductors“. Thesis, 2001. http://hdl.handle.net/2429/13827.
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This thesis work presents the development of a general-purpose cable-parameter algorithm
which uses digital images to discretize the cable geometry and the partial subconductor
equivalent circuit method to estimate the cable parameters.
The idea of the proposed geometry discretization technique is to draw the cable geometry,
or scan its photograph, and to use this digital image (pixel map) to automatically
identify the spatial coordinates of the square-shaped (pixel-shaped) partial subconductors
into which the different conductors can be subdivided. Image resolution, penetration
depth, edge detection, as well as area and geometric mean distance error reduction techniques
are then used to reduce the dimensions of the problem and improve the accuracy
of the results.
The idea of the partial subconductors method is to transform the system of conductors
into an equivalent network of subconductors. A set of coupled circuit equations represents
the equivalent network, and "bundling techniques" are used to obtain the parameters of the
cable system. These "bundling techniques" transform the equations of the subconductors
into the equations of the conductors by row and column operations.
Since the number of subconductors increases noticeably with the frequency, an algorithm
to partition the impedance matrices is proposed. The proposed methodology adapts
itself to the physical memory of the computer, thus allowing the program to partition the
partial subconductor impedance matrices when their sizes exceed the available physical
memory.
Coaxial cables, buried cables, and sector-shaped cables are studied with the proposed
technique, and the results are compared with those obtained from the analytic method,
the finite element method, and Ametani's approximate method.
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Zhou, Dan H. „Numerical methods for frequency dependent line parameters with applications to microstrip lines and pipe-type cables“. Thesis, 1993. http://hdl.handle.net/2429/1949.
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Signal lines such as microstrip lines have recently assumed increased importance in VLSI circuit design and computer package design. Their behavior has become a key factor in system performance. As the circuit implementation size or area reduces almost to its physical limits, the circuit speed is so high that devices can react in less than nanoseconds. Under these conditions, the trans-mission line characteristics of microstrip lines become dominant compared to their simple function for signal linkage.
Many numerical methods have been introduced to simulate these signal lines. To employ these models, the transmission line characteristics must be determined first. With signal transients containing the frequency of interest, traditional formulae are inappropriate to calculate line parameters because of skin and proximity effects. A common strategy is to apply the subdivision principle — to subdivide the line conductors into smaller parts so that the traditional formulae may be used. Based on this strategy, new numerical methods have been developed in this thesis to determine microstrip line parameters including skin and proximity effects. The developed techniques include a Linear Current Subconductor Technique (LCST), and an advanced method of subareas (ANS). These methods are derived from the traditional subconductor method and the traditional method of subareas, respectively. LCST combines the simplicity of the traditional subconductor method with the accuracy of finite element methods. AMS avoids the procedures of optimization and recursion of traditional subareas methods. To generate the LCST, the conductors of microstrip lines are firstly divided into subconductors by a 26 rule (6 is the skin depth at the considered frequency). For the subconductors system, an impedance matrix is then built using Ohm's law and the concept of Geometric Mean Distances (GMD). Secondly, the current distributions in the subconductors are solved from the telegrapher's equations. Thirdly, a linear current distribution is evaluated from the results of the previous step. After substituting linear currents back into the telegrapher's equations, correction factors are obtained for the subconductor's impedance matrix. Finally, the corrected
impedance matrix is reduced to an equivalent line impedance matrix by a bundling procedure. Another important application of the proposed sub conductor technique is in the calculation of the parameters of underground cables in electric power systems. Due to the irregular arrangement of the conductors in the cable no analytical formulas are available for these calculations. As an example, the LCST technique is ap-plied to pipe-type cables and the results are compared to those of previously published work using a finite element technique. In the case of ANS, after a similar subdivision procedure, the Maxwell coefficients matrix of subareas is setup from Green's functions. A bundling procedure is then used to convert the Maxwell coefficients matrix of the subareas into the Maxwell coefficients matrix of the line conductors. The inverse of the resultant matrix is the line capacitance matrix. In simulations of microstrip lines and pipe-type cables, the proposed LCST and ANS techniques proved to be efficient and accurate. Compared to the traditional uniform current density technique, the LCST results in savings of up to 99% and 98% in memory requirement and CPU cost, respectively, while the ANS technique results in savings of up to 80% as compared to the conventional uniform charge distribution technique. In comparisons with a finite element method and a traditional subconductor method, the results from LCST presented an average difference of about 4.0%. The resulting average difference was of 6.31% for the ANS technique as compared with two finite element methods and a software package from A. Djordjevic et al, ("Analysis Of Arbitrarily Oriented Microstrip Transmission Lines...", IEEE Trans. on MTT, vol.MTT-33,no.10, Oct.1985). Yet to be researched is the extension of LCST and ANS into otherline structures with open boundaries. Other potential applications are in telecommunications and computer high speed networking, as well as supercomputer packaging.
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Smith, Rodriguez Edison Manuel. „Full-space conformal mapping for the calculation of the parameters of overhead transmission lines and underground cables“. 2016. http://hdl.handle.net/1993/31733.
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This thesis presents a method to obtain the per-unit-length electrical parameters of a given overhead transmission line or underground cable in an unbounded space considering the effect of the ground. This is achieved using a two-dimensional conformal mapping technique, which consists of a modified bilinear transformation to map a semi-open half-space problem into a unit circle. The Helmholtz equations describing the quasi-stationary approximation for the electromagnetic field behaviour are solved using finite element method, with the aid of commonly used commercial software program, COMSOL Multiphysics. The per-unit-length resistance, inductance and capacitance are calculated using the proposed mapping method, the truncation of the original space method and then compared with the analytical solution obtained from Carson's approximation for the overhead lines and Wedepohl's formulation for the underground cables.October 2016
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„An Online Monitoring and Fault Location Methodology for Underground Power Cables“. Master's thesis, 2016. http://hdl.handle.net/2286/R.I.38467.
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abstract: With the growing importance of underground power systems and the need for greater reliability of the power supply, cable monitoring and accurate fault location detection has become an increasingly important issue. The presence of inherent random fluctuations in power system signals can be used to extract valuable information about the condition of system equipment. One such component is the power cable, which is the primary focus of this research.
This thesis investigates a unique methodology that allows online monitoring of an underground power cable. The methodology analyzes conventional power signals in the frequency domain to monitor the condition of a power cable.
First, the proposed approach is analyzed theoretically with the help of mathematical computations. Frequency domain analysis techniques are then used to compute the power spectral density (PSD) of the system signals. The importance of inherent noise in the system, a key requirement of this methodology, is also explained. The behavior of resonant frequencies, which are unique to every system, are then analyzed under different system conditions with the help of mathematical expressions.
Another important aspect of this methodology is its ability to accurately estimate cable fault location. The process is online and hence does not require the system to be disconnected from the grid. A single line to ground fault case is considered and the trend followed by the resonant frequencies for different fault positions is observed.
The approach is initially explained using theoretical calculations followed by simulations in MATLAB/Simulink. The validity of this technique is proved by comparing the results obtained from theory and simulation to actual measurement data.Dissertation/Thesis
Masters Thesis Electrical Engineering 2016
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Peng, Yi-Yan, und 彭一晏. „Modal Parameter Identification of Stay Cables Based on Vibration Measurements with the Application of Wavelet Transform Techniques“. Thesis, 2008. http://ndltd.ncl.edu.tw/handle/uq853u.
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碩士國立雲林科技大學
營建工程系碩士班
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The ambient vibration signal of a stay cable is commonly adopted to estimate its cable force for a long-term health monitoring. The significant change in cable force induced by passing heavy vehicles in a short period, on the other hand, is an important factor to cause fatigues and also requires a reliable method for effective evaluation. However, the conventional Fourier analysis is developed to transform the signal from the time domain into the frequency domain and consequently would fail the need to trace the corresponding time-varying information for such a non-stationary signal. It is aimed in this research to apply the wavelet transform technique covering both the time and frequency domains for investigating the time-varying modal parameters of a stay cable. The primary results of this research are presented in this paper by developing the fundamental methodology and conducting the parameter study. Simulated numerical examples and measured vibration signals from Chi-Lu Bridge are also used to verify the effectiveness of the proposed method.
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Coulson, Adam Lee. „Investigation of the Pre to Post Peak Strength State and Behaviour of Confined Rock Masses Using Mine Induced Microseismicity“. Thesis, 2009. http://hdl.handle.net/1807/19183.
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As hard rock mining progresses into higher stress mining conditions through either late stage extraction or mining at depth, the rock mass is driven not just to the peak strength, but often well into the post-peak until complete ‘failure’ occurs and easier mining conditions become evident. Limited research has been accomplished in identifying the transition of the rock mass and its behaviour into the post-peak and this research investigates this behaviour in detail. As the rock mass progressively fails, fractures are initiated through intact rock and extension and shear failure of these and pre-existing features occurs. Associated with this failure are microseismic events, which can be used to give an indication of the strength state of the rock mass. Based on an analogy to laboratory testing of intact rock and measurement of acoustic emissions, the microseismicity can be used to identify, fracture initiation, coalescence of fractures (yield), localization (peak-strength), accumulation of damage (post-peak) and ultimate failure (residual strength) leading to aseismic behaviour. The case studies presented in this thesis provide an opportunity to examine and analyse rock mass failure into the post-peak, through the regional and confined failures at the Williams and the Golden Giant mines, both in the Hemlo camp in Northern Ontario, Canada. At the Williams mine, the progressive failure of a sill pillar region into the post-peak was analysed; relating the seismic event density, combined with numerical modelling and a spatial and temporal examination of the principal components analysis (PCA), to characterize the extent, trend and state of the yielding zone, which formed a macrofracture shear structure. Observations of conventional displacement instrumentation, indicates regional dilation or shear of the rock mass occurs at or prior to the point of ‘disassociation’ (breakdown of stable PCA trends) when approaching the residual strength. At the Golden Giant mine, the complete process from initiation to aseismic behaviour is monitored in a highly stressed and confined pendent pillar. The PCA technique, numerical modelling and focal mechanism studies are used to define significant stages of the failure process, in which a similar macrofracture structure was formed. Temporal observations of key source parameters show significant changes prior to and at the point of coalescence and localization.