This master’s thesis deals with the calculation of electrodynamic forces breaker BD250NE305. Main tasks in this semester project is to study the theoretical analysis of individual parts specified breakers. Processing theoretical analysis of these forces. Creating a 3D model current path and sheets quenching chamber single phase circuit breaker in Autodesk Inventor Professional 2012. Another challenge is the subsequent export the model into the simulation program ANSYS Maxwell. After simulation, the specified conditions must be processed and the results of the present work is to evaluate.

Thesis deal with design of drop-hammer and especially its carriage (frame) for direction equipment for driving various thin-walled profiles in civil engineering. The entire drop- hammer is used as an additional adapter for construction machine. The first part of thesis contains design options, description of chosen option, including principles of work with drop- hammer. It also contains the calculation which are important for design of parts of drop- hammer, frame strese analysis by computer software, the approximate production coast of drop-hammer and summary of the parameters of the final product. The annexes contains the specified drawings and examples of 3D models of assemblies.

The aim of this thesis is to simulate the action of electrodynamic forces on current carrying path and a movable contact of the circuit breaker OEZ Modeion BH 630NE. For the calculation there is used the simulation program Ansys Maxwell. The first part is devoted to theoretical analysis of electromagnetic forces on a conductor in a magnetic field. Further I discuss the constructional design of the circuit breaker itself, especially the current path and the contact mechanism. In the next part there is (with using program Autodesk Inventor) created a simplified 3D model of the current path including an arc chamber. With program Ansys Maxwell then there is performed simulation of the acting of forces in each mode. This is magnetostatic and transient analysis for symmetrical and asymmetrical flow of the fault current. In conclusion the results obtained are evaluated and processed in the tabular way.

Indiana University-Purdue University Indianapolis (IUPUI) / For women in patriarchal societies, life is stitched with silence and violence. This is especially true for women of color. In a world that has cast women as invisible and voiceless, to create from the margins is to demand to be seen and heard. Thus, women’s art has never had the privilege of being art for art’s sake and instead is necessarily involved in the work of articulating and (re)writing female experience. When women seek, through their work and art, to feel deeply and connect with other women, they tap into what Audre Lorde has famously termed “the power of the erotic.” Lorde suggests that to acknowledge and trust those deepest feelings within our bodies is a subversive power that spurs social change. In the following work, novels by Kate Chopin, Gayl Jones, and Edwidge Danticat are linked by their female characters who seek the erotic via their art of choice and, in doing so, resist disempowerment and explore the life-giving nature of female connection. Furthermore, because the authors themselves are engaged in rendering the female experience visible, the novels discussed actively converse with their respective waves of feminism and propel social activism and feminist discourse. Hence, this project provides both a close reading of The Awakening, Corregidora, and The Dew Breaker, and a broader contention on the role of women’s literature in social justice.

The aim of the present thesis is to improve and optimize a Thomson coil based actuatorfor medium voltage vacuum interrupters. The Thomson coil based actuator’s concept isdiscussed. The thesis presents analytical as well as finite element models of the actuatoralong with a comparison of their results. Several experimental setups have been built forthis degree project and they are described in the thesis. Measurements from these setupsare also compared to simulation results. The thesis concludes by drawing conclusionsfrom the compared results and proposes possible directions for additional work in thenear future. / Målsättningen för denna uppsats är att förbättra och optimera en aktuator för mellanspänningsvakuumbrytare baserad på en Thomsonspole. Aktuatorkonceptet analyserasoch diskuteras. Uppsatsen presenterar analytiska modeller såväl som numeriska modellerför FEM av aktuatorn, samt jämförelser av resultaten från simuleringar gjorda av dessa.Flera experimentuppställningar har byggts under detta examensprojekt och beskrivs idenna uppsatsen. Mätningar från dessa uppställningar jämförs också med resultaten frånsimuleringarna. Uppsatsen drar slutligen slutsatser utifrån resultaten och föreslår möjligavägar för ytterligare arbete på området inom en snar framtid.

The sustainable future in our already electrified world includes solar power generation, battery storage, and electric vehicles all which requires DC systems. DC breakers play a key role in operation and protection within the DC system. Current interruption in DC systems is more challenging than in AC systems due to the absence of natural zero crossing. Some existing interruption techniques are current injection, the use of semiconductors, and arc voltage increase. This thesis project investigates how ventilation geometry, radius, and current level affect the pressure and counterforce in a cylindrical design of a current interruption device based on arc squeezing technology that uses polymer ablation to increase the arc voltage. The purpose is to collect useful data for future product development in this relatively new technology area. The project consists of a pre-study about arc interruption, polymer ablation, and test circuit theory, the test object design phase, the experiments, and this report. The results experiments show that ventilation at the center of the cylindrical arc chamber reduces the pressure by three times compare to a non-ventilated center at the highest test current level. The radius variations did not affect the pressure, it was however seen that the thicker tube, with a higher mass, had a lower initial speed and a slightly higher counterforce. The pressure measurement implemented in the design allow for an additional quantity to analyze in relation to the previously available quantities. Further testing with other design parameter variations such as the length of the stroke, or size of the ventilation holes is the next step for future work. / Dagens samhälle strävar mot en hållbar framtid där elektrifiering är en stor del. Redan idag finns lösningar så som förnybara energikällor till exempel solenergi, smarta energilagringslösningar bland annat batterilager och elbilar. Fler och fler av dessa system är baserade på likström. Oavsett system är säkerhet, pålitlighet och manövrering av högsta prioritet. Systemen kräver strömbrytare som är säkra och effektiva. Likström är svårare att bryta jämfört med växelström som majoriteten av dagens apparater och system använder. Anledningen är att likströmmen saknar den naturliga nollgenomgången som växelströmmen har. Nollgenomgången måste skapas aktivt genom att exempelvis injicera ström, använda halvledare eller öka ljusbågsspänningen. Det här examensarbetet täcker en parameterstudie av hur ventilationsgeometrin och radien påverkar trycket och motkraften i en cylinderformad strömbrytare som använder sig av ljusbågssläckning skapad av ablerande polymermaterial som ökar ljusbågsspänningen. Syftet med studien är att samla in användbar data för framtida produktutveckling inom denna relativt nya brytningsteknik. Examensarbetet består av en förstudie om ljusbågsbrytning, polymerablation and provkretsteori, en designfas, en serie experiment och slutligen denna rapport. Resultaten från experimenten visar att ventilation av ljusbågskammarens centrum minskar trycket som byggs upp emellan kammaren och tuben. För den högsta testströmnivån är skillnaden tre gånger så högt tryck för ett oventilerat centrum jämfört med ett ventilerat centrum. Radien, och därmed tjockleken av tuben, har ingen tydlig påverkan på tryckuppbyggnaden i ljusbågskammaren. Däremot påverkar tjockleken vikten av tuben som i sin tur påverkar hastigheten tuben förs in i kammaren med. En tjockare tub har en lägre initial hastighet och även en något högre motkraft. Den implementerade tryckmätningen öppnar upp för ytterligare en mätstorhet att analysera och relatera till övriga tidigare mätta storheter. Framtida studier inom området är att variera andra parametrar så som tubens slaglängd and storleken på ventilationshålen.

This Master thesis is based on problems of force effects of the magnetic field of short-circuit current. Firstly, I analysed the force action of the three phase busbars during the three-pole short circuit. The analysis was performed in the Ansys Maxwell program and I verified the correctness of the analysis by numerical calculation. The second practical part was executed for ABB company. The main task was to analyse the force effects of the short-circuit current in the HV switchgear with focusing on the arms and contact system of the circuit breaker. The simulations of the following configurations were performed in more details: three configurations of the simplified VD4 circuit breaker, two types of VD4 circuit-breaker contact systems and a linear circuit breaker configuration model. The objective was to calculate the forces acting on the current path of the arms and contact system of the VD4 circuit breaker during the three-phase short-circuit and to simulate the effects of forces on these current parts. For modelling of individual assemblies, calculations and simulations I used: SolidWorks 2014, Ansys Maxwell 16.0 and Ansys Workbench 14.5 programs. With SolidWorks 2014 3D CAD software were modelled simplified assemblies of circuit breakers and contact systems. These systems were imported into the Ansys Maxwell software, where the force effects of the magnetic field of the short-circuit current were calculated. In Ansys Workbench programme was simulated the effect of forces on the current circuit breakers. Moreover, the final deformations of the materials (with respect to the mechanical properties of the structure) were plotted. The analysis of force effects of the magnetic field was performed for the specified static short - circuit current value.

Un modèle numérique d’un arc électrique diffus dans un disjoncteur à vide à champ magnétique axial (AMF) a été développé dans le but de mieux comprendre à terme la transition d’un mode de fonctionnement diffus de l’arc vers un mode plus concentré. Le comportement du plasma d’arc a été simulé depuis la sortie de la zone de mélange cathodique jusqu’à l’entrée de la gaine anodique. Le modèle bidimensionnel est basé sur un système d’équations hydrodynamiques à deux fluides non magnétisés (ions et électrons), incluant les équations de conservation d’énergie ionique et électronique. Il est démontré que les processus d’ionisation et de recombinaison et les effets visqueux sont négligeables. Les transferts radiatifs ne sont pas considérés en première approximation. Outre les forces dues au champ AMF, le modèle inclut les forces dues aux trois composantes du champ magnétique induit par l’arc. Deux régimes d’écoulement des ions, supersonique (aux faibles densités de courant) et subsonique (aux fortes densités de courant), sont considérés. Près de la cathode, les conditions aux limites sont spécifiées à partir de résultats de la littérature. A proximité de l’anode, elles sont basées sur une description simplifiée de la gaine anodique. Les résultats de simulation présentés mettent en évidence une constriction du courant et un comportement différent des ions aux faibles et aux fortes densités de courant, et renseignent sur l’influence de divers paramètres (intensité du courant, distance interélectrode). Ce travail présente également une étude expérimentale, basée sur des visualisations par vidéo rapide de l’arc et des mesures pyrométriques de la température de la surface de l’anode / A model of a diffuse arc in a vacuum circuit breaker with an axial magnetic field (AMF) has been developed with the ultimate aim to better understand the transition of the arc from a diffuse mode to a more confined mode. The interelectrode plasma is simulated from the exit of the mixing region on the cathode side to the entrance of the anode sheath. The two-dimensional model is based on the solution of a system of two-fluid (ions and electrons) hydrodynamic equations, including in particular the energy balance equations relative to both the ions and the electrons, which are treated as non-magnetized particles. It is demonstrated that ionisation and recombination processes, as well as viscous effects, can be neglected. Radiation losses are not taken into account in a first approximation. In addition to the forces due to the AMF, the model considers the forces created by the three components of the magnetic field induced by the arc current. The possibility of both supersonic (at low current density) and subsonic (at high current density) ionic flow regimes is considered. On the cathode side, the boundary conditions are specified using results from the literature. On the anode side, they are based on a simplified description of the anode sheath. The simulation results presented show a constriction of the current lines, emphasize the differences in the behaviour of the ions at low and high current densities, and provide some insight on the influence of various operating parameters (arc current, gap length). The present work comprises also an experimental study, based on high-speed camera visualisations of the arc and measurements of the temperature at the anode surface

This thesis overviews my experience during graduate school making tangible,object oriented sculpture. I have been working formally to compose space in a way that develops a narrative between parts. The work is also a bridge between the fields of painting and sculpture, in terms of drawing with form and both painted and local, material color. My palette has mostly consisted of bronze casting, steel fabrication, fiberglass and epoxy resin, paint, the found object, woodworking, and mold making. This work is also conceptually based in showing the hand worked qualities of the materials, the transfer of meaning through casting, and my emotional relationship with the various parts of the sculptures. The three major themes of the work are: divine love and the complex of the apocalypse, the complexities and psychology concerning the relationship between a man and a woman, and the intrigue, potential energy, and beauty of the systems mankind hasinvented to harness the atom. The major artistic influences for this body of work have been: Jasper Johns, Marcel Duchamp, Constantine Brancusi, Alberto Giacommetti, Reg Butler, Henry Moore, Lynn Chadwick, Kenneth Armitage, Jeff Koons, Terry Winters, William DeKooning, Richard Diebenkorn, David Smith and Charles Long. I retain a strongrelationship with the movements of Dada, Surrealism, Futurism, and Assemblage, and amalso currently involved in solidifying the Manifesto of Raubeaux with a small group ofesteemed colleagues.

Actuellement, il y a une baisse du prix des ressources énergétiques distribuées, en particulier l'énergie solaire photovoltaïque, conduisant à la croissance significative de leur capacité d'installation dans de nombreux pays. D'autre part, les politiques encourageant l'efficacité énergétique ont favorisé le développement de charges DC dans les zones domestiques, telles que l'éclairage LED, les ordinateurs,, les téléphones, les téléviseurs, les moteurs DC efficaces et les véhicules électriques. Grace à ce changement, le système de distribution de microgrid DC devient plus attractive que le système de distribution à courant alternatif traditionnel. Les avantages principaux du microgrid DC sont l'efficacité énergétique plus élevée, plus facile à intégrer avec les sources d'énergie distribuées et le système de stockage. Alors que de nombreuses recherches se concentrent sur les stratégies de contrôle et la gestion de l'énergie dans le microgrid DC, sa protection reçoit une attention insuffisante et un manque de réglementation et d'expériences. La protection dans les réseaux DC est plus difficile que dans le réseau AC en raison de l'arc continu, de la valeur plus élevée du courant de courtcircuit et du taux de défaut de montée. En outre, dans les réseaux distribués à courant continu sont composés de nombreux dispositifs de commutation électroniques et semi-conducteurs, qui ne supportent le courant de défaut que quelques dizaines de microsecondes. Les disjoncteurs mécaniques, qui ont un temps de réponse de quelques dizaines de millisecondes, ne semblent pas satisfaire aux exigences de sécurité du microréseau à courant continu. L'absence d'un dispositif de protection efficace constitue un obstacle au développement du microgrid DC dans le système distribué. Cette thèse propose un disjoncteur DC auto-alimenté à courant continu utilisant normalement JFET SiC, qui offre un excellent dispositif de protection pour les microgrids DC grâce à son temps de réponse rapide et ses faibles pertes à l'état passant. La conception du disjoncteur DC à semi-conducteurs vise à répondre à deux objectifs: temps de réponse rapide et fiabilité. Les spécifications conçues et les énergies critiques qui entraînent la destruction du disjoncteur sont identifiées sur la base des résultats mesurés d'un JFET populaire dans le commerce. Un pilote de protection très rapide et fiable basé sur une topologie à convertisseur flyback avant est utilisé pour générer une tension négative suffisante pour tourner et maintenir le JFET SiC. Le convertisseur sera activé chaque fois que le disjoncteur détecte des défauts de court-circuit en détectant la tension de drain-source de JFET et crée une tension négative s'applique à la porte de JFET. Pour éviter une défaillance de la porte par surtension au niveau de la grille du JFET, la tension de sortie du convertisseur de retour vers l'avant est régulée à l'aide de la mesure coté primaire. Les résultats expérimentaux sur le prototype du disjoncteur DC ont validé les principes de fonctionnement proposés et ont confirmé que le disjoncteur DC à semi-conducteurs proposé peut interrompre le défaut en 3 μs. D'un autre côté, un modèle du JFET normalement activé dans l'environnement Matlab/Simulink est construit pour étudier les comportements du SSCB pendant une durée de court-circuit. L'accord entre la simulation et les résultats expérimentaux confirment que ce modèle JFET peut être utilisé pour simuler le fonctionnement d'un disjoncteur DC et dans l'étude du fonctionnement du microgrid DC pendant le processus de défaut et de compensation / Currently, there is a drop in the price of distributed energy resources, especially solar PVs, which leads to a significant growth of the installed capacities in many countries. On the other hand, policies encouraging energy efficiency have promoted the development of DC loads in domestic areas, such as LEDs lighting, computers, telephones, televisions, efficient DC motors and electric vehicles. Corresponding to these changes in sources and loads, DC microgrid distribution system becomes more attractive than the traditional AC distribution system. The main advantages of the DC microgrid are higher energy efficiency, easier in integrating with distributed energy sources and storage systems. While many studies concentrate on the control strategies and energy management in the DC microgrid, the protection still receives inadequate attention and lack of regulations and experiences. Protection in DC grids is more complex than AC grids due to the continuous arc, higher short circuit current value and fault rate of rising. Furthermore, the DC distributed grids are composed of many electronic and semiconductor switching devices, which only sustain the fault currents of some tens of microseconds. Mechanical circuit breakers, which have a response time in tens of milliseconds, seem not to meet the safety requirement of DC microgrids. The lack of effective protection devices is a barrier to the development of DC microgrids in the distributed systems. This thesis proposes a self-power solid state DC circuit breaker using normally-on SiC JFET, which offers a great protection device for DC microgrids due to its fast response time and low on-state losses. The design of the solid state DC circuit breaker aims to meet two objectives: fast response time and high reliability. The designed specifications and critical energies that result in the destruction of the circuit breaker are identified on the basis of the experiments of a commercial normally-on JFET. In addition, a very fast and reliable protection driver based on a forward-flyback converter topology is employed to generate a sufficient negative voltage to turn and hold off the SiC JFET. The converter will be activated whenever short-circuit faults are detected by sensing the drain-source voltage, then creating a negative voltage applied to the gate of JFET. To avoid gate failure by overvoltage at the gate of JFET, the output voltage of the forward-flyback converter is regulated using Primary Side Sensing technique. Experimental results validated the working principle of the proposed solid state DC circuit breaker with fault clearing time less than 3 μs. Additionally, a model of the normally-on JFET in Matlab/Simulink environment is built for exploring the behaviors of the solid-state DC circuit breaker during short-circuit faults. The agreement between the simulation and experimental results confirms that this JFET model can be appropriately used for the investigation of solid state DC circuit breaker operations and DC microgrids in general during fault evens and clearing fault processes