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Dissertations / Theses on the topic 'Transformeur'
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1
Liew, Ming Chuen. "Reverse design transformer modelling technique with particular application to partial core transformers." Thesis, University of Canterbury. Electrical and Electronic Engineering, 2001. http://hdl.handle.net/10092/2123.
Full textAbstract:
This thesis first describes the conventional transformer design method used for design
iron-core transformers. Limitations associated with this design method is highlighted.
In this thesis, an alternative transformer design method is presented. It is called the
reverse design method. This new design technique is compared against the conventional
design method, and validated with experimental results.
The reverse design method is applied to partial core transformers. Modifications made
to accommodate full-core equivalent circuit components to partial core transformers
are discussed. Particular attention is given to the derivation of core loss resistance,
core magnetising reactance and winding leakage reactances. The new reverse design
partial core model is applied at 50Hz normal operating temperature applications. The
model is verified with experimental results.
Next the reverse design model is applied to transformers when immersed in liquid nitrogen.
The accuracy of the model derived previously for normal operating temperatures
is investigated. Necessary modifications are made to the model. The corrected model
is again justified with experimental results.
Finally, the model is used for the harmonic frequency analysis of partial core transformers.
Capacitive components are included as part of the analysis. Frequency responses
of transformers with relatively low turn ratio are analysed, followed by high voltage
partial core transformers with large turn ratio. Comparisons are made between the
model calculated and test results.
2
Lapthorn, Andrew Craig. "High Temperature Superconducting Partial Core Transformers." Thesis, University of Canterbury. Electrical and Computer Engineering, 2012. http://hdl.handle.net/10092/7130.
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The thesis begins by providing an introduction to transformer theory. An ideal transformer is examined first, followed by full core transformer theory. The partial core transformer is then introduced and compared to the full core design. An introduction to superconductors is then presented where a simplified theory of superconductivity is given. High temperature superconductors are then examined including their physical structure, superconducting properties and the design of the superconducting wire.
The early development of high temperature superconducting partial core transformers at the University of Canterbury is then examined. Early partial core development is discussed followed by some material testing at cryogenic temperatures. This work lead into the development of the first high temperature superconducting partial core transformer. This transformer failed during testing and an examination of the failure mechanisms is presented. The results of the failure investigation prompted an alternative winding insulation design which was implemented in a full core superconducting transformer.
The modelling used to design a high temperature superconducting partial core transformer is then presented. Based upon the reverse design method, the modelling is used to determine the components of the Steinmetz equivalent transformer circuit. The modelling includes a combination of circuit theory and finite element analysis. An ac loss model for high temperature superconductors is also presented.
A new 15 kVA, 230-230V high temperature superconducting partial core transformer was designed, built and tested. The windings are layer wound with first generation Bi2223 high temperature superconductor. The modelling was used to predict the performance of the transformer as well as the ac losses of the high temperature superconductor. A series of electrical tests were performed on the transformer including open circuit, short circuit, resistive load, overload, ac withstand voltage and fault ride through tests. The test results are compared with the model. The transformer was found to be 98.2% efficient at rated power with 2.86% voltage regulation.
3
Bergsåker, Claudia. "Impact of transformer core size on the reactive power requirement of power transformers due to GIC." Thesis, KTH, Elektroteknisk teori och konstruktion, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-157347.
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Geomagnetically induced currents (GIC) are a natural phenomenon which arises due to solar storms. During a solar storm, large amounts of magnetized plasma are ejected from the surface of the sun. When this plasma reaches earth, it causes fluctuations in the geomagnetic field. Such fluctuations may induce DC over-currents in long transmission lines. These currents affect the transmission system several dierent ways; In particular high voltage transformers are sensitive to GIC. When the over-current flows through the transformer windings the reactive power absorption of the transformer increases, which may lead to voltage instability in the power system. For this project, the main issue has been to determine whether or not an increase in the size of the transformer core leads to the reactive power absorption being less sensitive to GIC. In order to investigate this issue a recently developed transformer model has been used; the Hybrid transformer model. This model combines the principle of duality with a matrix representation of the transformer. The Hybrid transformer model, which has recently been implemented in the power system simulations software PSCAD, has been used to simulate GIC events in transformers of varying core sizes. The results from these simulations indicate that a larger transformer core is associated with a smaller increase in reactive power absorption during a GIC event. It is also clear that the reactive power absorption as a function of GIC magnitude is a non-linear function when the Hybrid transformer model is applied. This function has previously been considered a linear function.Geomagnetiskt inducerade strömmar (GIC) är ett naturfenomen som uppstår till följd av solstormar. Vid en solstorm kastas stora mängder magnetiserad plasma ut från solens yta, och när denna plasma når jorden uppstår uktuationer i det jordmagnetiska fältet. Detta kan leda till att DCstr ömmar induceras i långa transmissionsledsningar. Dessa överströmmar påverkar kraftsystemet på era olika sätt, bland annat har de en stor påverkan på transformatorer. Då överströmmen yter genom transformatorlindningarna ökar det reaktiva eektuttaget för transformatorn, vilket kan leda till spänningsinstabilitet i systemet. En fråga som legat till grund för detta projekt är huruvida en ökning av transformatorkärnans storlek gör transformatorns reaktiva eektuttag mindre känsligt för GIC. För att undersöka detta har en ny transformatormodell använts; den såkallade hybridmodellen som kombinerar dualitetsprincipen med en matrisrepresentation av transformatorn. Denna modell, som nyligen implementerats i simuleringsprogrammet PSCAD, har använts för att simulera GIC i transformatorer med kärnor av olika storlekar. Resultaten från dessa simuleringar indikerar att större transformatorkärna medför mindre förändring av det reaktiva eektuttaget när transformatorn utsätts för GIC. Det är även tydligt att det reaktiva eektuttaget som funktion av GIC är en icke-linjär funktion när hybridmodellen används. Denna funktion har tidigare ansetts vara linjär.
4
Bell, Simon Colin. "High-voltage partial-core resonant transformers." Thesis, University of Canterbury. Electrical and Computer Engineering, 2008. http://hdl.handle.net/10092/2161.
Full textAbstract:
This thesis first describes the reverse method of transformer design. An existing magnetic model for full-core shell-type transformers, based on circuit theory, is summarised. A magneto-static finite element model is introduced and two sample transformers are analysed. The magnetic model based on finite element analysis is shown to be more accurate than the model based on circuit theory.
Partial-core resonant transformers are then introduced and their characteristics are explained using an equivalent circuit model. A method of measuring the winding inductances under resonant operation is developed and used to investigate the characteristics of two different tuning methods. A finite element model of the partial-core resonant transformer is developed by adopting the model for full-core shell-type transformers.
The model results accurately match the measured inductance variation characteristics of three sample transformers and predict the onset of core saturation in both axial-offset and centre-gap arrangements. A new design of partial-core resonant transformer is arrived at, having an alternative core and winding layout, as well as multiple winding taps. The finite element model is extended to accommodate the new design and a framework of analysis tools is developed. A general design methodology for partial-core resonant transformers with fixed inductance is developed. A multiple design method is applied to obtain an optimal design for a given set of specifications and restrictions. The design methodology is then extended to devices with variable inductance.
Three design examples of partial-core resonant transformers with variable inductance are presented. In the first two design examples, existing devices are replaced. The new transformer designs are significantly lighter and the saturation effects are removed. The third design example is a kitset for high-voltage testing, with the capability to test any hydro-generator stator in New Zealand. The kitset is built and tested in the laboratory, demonstrating design capability. Other significant test results, for which no models have yet been developed, are also presented. Heating effects in the core are reduced by adopting an alternative core construction method, where the laminations are stacked radially, rather than in the usual parallel direction. The new kitset is yet to be used in the field.
5
Leplus, François. "Sur la modélisation numérique des transformateurs monophasé et triphasé : Application aux montages redresseurs et gradateurs." Lille 1, 1989. http://www.theses.fr/1989LIL10073.
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Méthode de résolution des équations du système modélisé, indépendante de son environnement électrique, donnant un programme modulaire, utilisable dans un ensemble plus complexe. Extension de la méthode et procédure d'identification des paramètres. Expérimentation en fonctionnement redresseur et gradateur
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Siebrits, F. B. (Francois Bart). "Field implementation of a transient voltage measurement facility using HV current transformers." Thesis, Stellenbosch : Stellenbosch University, 2003. http://hdl.handle.net/10019.1/53426.
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Thesis (MScEng)--University of Stellenbosch, 2003.ENGLISH ABSTRACT: The bandwidth of standard HV measurement devices such as capacitive voltage transformers is too limited in order to measure wideband phenomena. This thesis is concerned with the investigation into a non- intrusive HV transient voltage measurement facility using standard substation HV current transformers (CI's) configured in a transconductance topology. The sensing, summation and integration of the CT capacitive earth currents are investigated. This thesis also reports on the development of a optically isolated link using optical fibre for signal transfer and a computer based data acquisition system.
AFRIKAANSE OPSOMMING: Standaard hoogspannings (HS) meettoerusting soos kapasitiewe spannmgs transformators het beperkte bandwydte vir die meet van wyeband verskynsels. Hierdie tesis handel oor die implementering van 'n HS meetstelsel wat op meinbrekende wyse oorgangsverskynsels meet deur middel van HS stroomtransformators wat in 'n transkonduktansie topologie gekonfigureer is. Die meet, sommasie en integrasie van kapasitoewe grondstrome word ondersoek. Hierdie tesis doen ook verslag aangaande die ontwikkeling van 'n optiese geisoleerde koppelvlak wat gebruik word vir seinoordrag en 'n rekenaar gebasseerde data versamelaar.
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7
Makowski, Nathanael Jared. "Proposal and Analysis of Demagnetization Methods of High Voltage Power System Transformers and Design of an Instrument to Automate the Demagnetization Process." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/431.
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Present demagnetization methods for large power system transformers are time consuming and can be dangerous to persons performing demagnetization. The work of this thesis was to develop improved demagnetization methods and to construct an automated instrument that would implement the methods developed. One previously developed method was analyzed for effectiveness. Then, two new methods for demagnetization were developed and also analyzed for effectiveness. An automated test instrument prototype was redesigned to be able to accommodate these methods and to improve the safety of the user. The previously developed method attempts demagnetization based on current flow behavior characteristics. The first new method is a magnetic flux estimation based on saturation time. The second new method is also based on measuring saturation time, modified to account for the variable voltage loss due to wire resistance. The second of the two new methods developed proved to be the most effective for demagnetization and was able to demagnetize a transformer within an error margin of 2%. The instrument designed to perform the demagnetization with this new routine is now in early production stages for an expanded field trial with transformer maintenance teams.
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Messaoud, Kaouther. "Deep learning based trajectory prediction for autonomous vehicles." Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS048.
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La prédiction de trajectoire des agents avoisinants d'un véhicule autonome est essentielle pour la conduite autonome afin d'effectuer une planification de trajectoire d'une manière efficace. Dans cette thèse, nous abordons la problématique de prédiction de trajectoire d'un véhicule cible dans deux environnements différents ; une autoroute et une zone urbaine (intersection, rond-point, etc.). Dans ce but, nous développons des solutions basées sur l'apprentissage automatique profond en mettant en phase les interactions entre le véhicule cibles et les éléments statiques et dynamiques de la scène. De plus, afin de tenir compte de l'incertitude du futur, nous générons de multiples trajectoires plausibles et la probabilité d'occurrence de chacune. Nous nous assurons également que les trajectoires prédites sont réalistes et conformes à la structure de la scène. Les solutions développées sont évaluées à à l'aide de bases de données de conduite réellesThe trajectory prediction of neighboring agents of an autonomous vehicle is essential for autonomous driving in order to perform trajectory planning in an efficient manner. In this thesis, we tackle the problem of predicting the trajectory of a target vehicle in two different environments; a highway and an urban area (intersection, roundabout, etc.). To this end, we develop solutions based on deep machine learning by phasing the interactions between the target vehicle and the static and dynamic elements of the scene. In addition, in order to take into account the uncertainty of the future, we generate multiple plausible trajectories and the probability of occurrence of each. We also make sure that the predicted trajectories are realistic and conform to the structure of the scene. The solutions developed are evaluated using real driving datasets
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Mahamat, Ahmat Taha. "Conception, réalisation et caractérisation d'un transformateur de commande." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSES011.
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Ce travail concerne la conception, la réalisation et la caractérisation d’un transformateur de commande pour interrupteurs de puissance à grille isolée, le transformateur assurant l’isolation galvanique entre étage de commande et circuit de puissance. L’objectif du travail n’était pas de répondre à un cahier des charges précis mais de développer une nouvelle voie technologique pour la réalisation de transformateur planaire intégrable. Les principales caractéristiques d’un tel transformateur sont : - une inductance élevée (rapport inductance/surface occupée le plus grand possible) ; - des résistances séries faibles ; - un couplage capacitif entre primaire et secondaire le plus faible possible. Ces contraintes nous ont conduits à étudier un transformateur planaire à couches magnétiques dont les enroulements primaire et secondaire sont enterrés dans le matériau magnétique afin de réduire l’entrefer. La structure Face to Face a été retenue avec un décalage de 45° entre enroulements primaire et secondaire. Après une étude en simulation, chaque enroulement enterré dans un matériau ferrite a été réalisé séparément puis assemblé pour donner naissance au transformateur. De très nombreuses étapes technologiques : micro usinage laser femtoseconde, dépôts de cuivre par pulvérisation cathodique, photolithographie, planarisation, gravure chimique … ont été mises en oeuvre. Le transformateur ainsi réalisé est constitué d’un empilement de couches magnétiques, conductrices et isolantes. Il a été caractérisé des très basses fréquences jusqu’à plusieurs dizaines de MHz. Les résultats de mesure obtenus sont proches des résultats de simulation, la bande passante du transformateur s’étendant de 20kHz à 7MHzThis work concerns the design, realization and characterization of a control transformer for insulated gate power switches, the transformer providing galvanic isolation between driving stage and power circuits. The aim of the work was not to respond to a precise specification but to develop a new technological path for the realization of an integrable planar transformer. The main characteristics of such transformer are: - high inductance (ratio of inductance / area occupied as large as possible); - low series resistances; - a capacitive coupling between primary and secondary as small as possible. These constraints guided us to study a planar transformer with magnetic layers whose primary and secondary windings are buried in the magnetic material in order to reduce the air gap. The Face to Face structure was chosen with a 45 ° offset between primary and secondary windings. After a numerical study, windings buried in a ferrite material were fabricated separately and then assembled to give rise to the transformer. Many technological steps: femtosecond laser micromachining, copper deposits by sputtering, photolithography, planarization, chemical etching ... have been implemented. Thus, the transformer produced consists of a stack of magnetic, conductive and insulating layers. It has been characterized from very low frequencies up to several tens of MHz. The measurement results obtained are close to simulation results, the bandwidth of the transformer extending from 20 kHz to 7 MHz
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Fouineau, Alexis. "Méthodologies de Conception de Transformateurs Moyenne Fréquence pour application aux réseaux haute tension et réseaux ferroviaires." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1256/document.
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Les Transformateurs Moyenne Fréquence (TMF) sont une technologie innovante par rapport aux transformateurs basse fréquence, avec la promesse d’une réduction de volume et d’une augmentation du rendement. Cette thèse s’intéresse en particulier à leur conception pour des applications haute tension forte puissance, telles que les réseaux haute tension et moyenne tension à courant continu, ainsi que les réseaux ferroviaires. Dans ces applications, les TMF sont utilisés au sein de convertisseurs pouvant générer des contraintes spécifiques à prendre en compte durant leur conception : signaux non-sinusoïdaux, tension de polarisation, valeurs d’inductances cibles. De plus, les choix technologiques actuellement disponibles pour la réalisation des TMF sont nombreux, et aucun de ces choix ne fait actuellement consensus quelle que soit l’application visée. Des tendances ont pu être identifiées à l’aide d’un outil de classification des designs de TMF issus de la littérature. Ainsi, les technologies les plus prometteuses ont été sélectionnées et retenues pour la suite. A partir de ces technologies, une méthodologie de conception permettant de concevoir et comparer rapidement et ce de façon semi-automatique des TMF avec différents choix technologiques a été mise en place. Elle est constituée de trois étapes : pré-design, design analytique et validation. Le design analytique complet du TMF avec différents choix technologiques est réalisé à l’aide d’un outil de conception automatisée développé durant cette thèse, que nous avons nommé SUITED (SUpergrid Institute TransformEr Design). Cette méthodologie requiert des modèles et données pour chacun des composants et phénomènes du TMF. Concernant le noyau magnétique, une revue et une sélection de modèles issus de la littérature ont été effectuées pour l’évaluation de l’inductance magnétisante et des pertes magnétiques. De plus, des caractérisations magnétiques ont permis de mettre en évidence l’impact de certains procédés technologiques sur les niveaux de pertes de noyaux magnétiques en matériau nanocristallin, qui est un excellent candidat pour les TMF. Au niveau des bobinages, des modèles analytiques pour calculer le champ magnétique, l’inductance de fuite et les effets de peau et de proximité ont été développés et comparés avec ceux de la littérature ainsi que des simulations. Ces nouveaux modèles s'avèrent obtenir une meilleure précision sur les géométries de TMF considérées que ceux de la littérature. De plus, une nouvelle méthode d’évaluation des capacités parasites de bobinages à spires rectangulaires a été mise en place et validée avec succès. Des schémas thermiques équivalents ont été identifiés pour différentes géométries de TMF. Les résistances thermiques de conduction, convection et radiation sont calculées à partir de modèles détaillés. En particulier, l’anisotropie des matériaux est prise en compte pour la conduction thermique, et les coefficients de convection sont évalués via des corrélations différentes pour chaque face du TMF. Les schémas thermiques sont ensuite résolus de façon itérative et analytique pour prendre en compte les non-linéarités des résistances thermiques tout en optimisant le temps de calcul nécessaire. Enfin, l’ensemble de la méthodologie de conception mise en place a été appliqué sur trois cas d’études correspondant à des applications cibles : haute tension, moyenne tension et ferroviaire. Les résultats obtenus montrent effectivement la performance et la nécessité de cette approcheMedium Frequency Transformers (MFT) are an innovative technology compared to low frequency transformers, with the promise of reduced volume and increased efficiency. This PhD thesis focuses in particular on their design for high voltage, high power applications, such as high voltage and medium voltage DC networks, as well as railway networks. In these applications, MFTs are used in converters that can generate specific constraints to be taken into account during their design: non-sinusoidal signals, polarization voltage, target inductance values. Moreover, the technological choices currently available for the realization of MFTs are numerous, and there is currently no consensus on any technology for any given application. Trends could be identified using a tool to classify MFT designs from the literature. Thus, the most promising technologies were selected and retained for the future. Based on these technologies, a design methodology was developed to quickly and semi-automatically design and compare MFTs with different technological choices. It consists of three steps: pre-design, analytical design, and validation. The complete analytical design of the MFT with different technological choices is carried out using an automated design tool developed during this thesis, named SUITED (SUpergrid Institute TransformEr Design). This methodology requires models and data for each of the components and phenomena of the MFT. Concerning the magnetic core, a review and selection of models from the literature were carried out for the evaluation of the magnetizing inductance and magnetic losses. In addition, magnetic characterizations have made it possible to highlight the impact of certain technological processes on the levels of loss of magnetic cores made of nanocrystalline material, which is an excellent candidate for MFTs. Concerning the windings, analytical models to calculate the magnetic field, leakage inductance and skin and proximity effects were developed and compared with those in the literature and simulations. These models are proving to be more accurate on the MFT geometries considered. On top of that, a new method for evaluating the parasitic capacitances of windings with rectangular turns has been successfully implemented and validated. Thermal networks have been identified for the different MFT geometries. The thermal resistances of conduction, convection and radiation are calculated from detailed models. In particular, the anisotropy of materials is taken into account for thermal conduction, and the convection coefficients are evaluated via different correlations for each face of the MFT. The thermal networks are then solved iteratively and analytically to take into account the non-linearity of the thermal resistances while optimizing the required computation time. Finally, this entire design methodology was applied to three case studies corresponding to the target applications: high voltage, medium voltage and rail. The results obtained do show the performance and necessity of this approach
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Karlsson, Svante. "Power Transformer Monitoring and Diagnosis using Transformer Explorer." Thesis, Uppsala universitet, Institutionen för teknikvetenskaper, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-280958.
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Power transformers are one of the most expensive and vital components in the power system. A sudden failure could be a very costly process for both the transformer owner and the society. Several monitoring and diagnostic techniques have been developed over the last decades to detect incipient transformer problems at an early stage, so that planned outages for maintenance and reparation can be carried out in time. However, the majority of these methods are only secondary indicators which do not address the transformers fundamental function: to transfer electric energy between different voltage levels with turn ratio, short-circuit impedance and power loss within acceptable limits. Transformer Explorer is a concept developed by ABB which utilizes ordinary current and voltage signals available in the substation to extract transformer fundamental parameters such as: turn ratio, magnetizing current, impedance and power loss, which has significant diagnostic value. By estimating these parameters the method should be able to detect a number of problems related to the windings and the magnetic circuit of the transformer. Transformer Explorer is expected to find it's application in two different versions, either as an permanent on-line monitoring and diagnostic tool or as a short-time version for temporary measurements. The thesis could be divided into three main parts. The first one focusing on a quantitative study trying to answer questions regarding the concepts feasibility when the temporary version is used. The second part is about optimizing and improving the procedure by which the fundamental parameters are estimated. In the last part, a new method for reducing the impact of errors introduced by the acquisition system on the estimated power loss is proposed. All the investigations related to the three topics covered in this thesis showed interesting and promising results.
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Douzon, Thibault. "Language models for document understanding." Electronic Thesis or Diss., Lyon, INSA, 2023. http://www.theses.fr/2023ISAL0075.
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Chaque jour, les entreprises du monde entier reçoivent et traitent d'énormes volumes de documents, entraînant des coûts considérables. Pour réduire ces coûts, de grandes entreprises automatisent le traitement documentaire, visant une automatisation complète. Cette thèse se concentre sur l'utilisation de modèles d'apprentissage machine pour extraire des informations de documents. Les progrès récents en matière d'architecture de modèle, en particulier les transformeurs, ont révolutionné le domaine grâce à leur utilisation généralisée de l'attention et à l'amélioration des pré-entraînements auto-supervisés. Nous montrons que les transformeurs, pré-entraînés sur des documents, effectuent des tâches de compréhension de documents avec précision et surpassent les modèles à base de réseaux récurrents pour l'extraction d'informations par classification de mots. Les transformeurs nécessitent également moins de données d'entraînement pour atteindre des performances élevées, soulignant l'importance du pré-entraînement auto-supervisé. Dans la suite, nous introduisons des tâches de pré-entraînement spécifiquement adaptées aux documents d'entreprise, améliorant les performances même avec des modèles plus petits. Cela permet d'atteindre des niveaux de performance similaires à ceux de modèles plus gros, ouvrant la voie à des modèles plus petits et plus économiques. Enfin, nous abordons le défi du coût d'évaluation des transformeurs sur de longues séquences. Nous montrons que des architectures plus efficaces dérivées des transformeurs nécessitent moins de ressources et donnent de meilleurs résultats sur de longues séquences. Cependant, elles peuvent perdre légèrement en performance sur de courtes séquences par rapport aux transformeurs classiques. Cela suggère l'avantage d'utiliser plusieurs modèles en fonction de la longueur des séquences à traiter, ouvrant la possibilité de concaténer des séquences de différentes modalitésEvery day, an uncountable amount of documents are received and processed by companies worldwide. In an effort to reduce the cost of processing each document, the largest companies have resorted to document automation technologies. In an ideal world, a document can be automatically processed without any human intervention: its content is read, and information is extracted and forwarded to the relevant service. The state-of-the-art techniques have quickly evolved in the last decades, from rule-based algorithms to statistical models. This thesis focuses on machine learning models for document information extraction. Recent advances in model architecture for natural language processing have shown the importance of the attention mechanism. Transformers have revolutionized the field by generalizing the use of attention and by pushing self-supervised pre-training to the next level. In the first part, we confirm that transformers with appropriate pre-training were able to perform document understanding tasks with high performance. We show that, when used as a token classifier for information extraction, transformers are able to exceptionally efficiently learn the task compared to recurrent networks. Transformers only need a small proportion of the training data to reach close to maximum performance. This highlights the importance of self-supervised pre-training for future fine-tuning. In the following part, we design specialized pre-training tasks, to better prepare the model for specific data distributions such as business documents. By acknowledging the specificities of business documents such as their table structure and their over-representation of numeric figures, we are able to target specific skills useful for the model in its future tasks. We show that those new tasks improve the model's downstream performances, even with small models. Using this pre-training approach, we are able to reach the performances of significantly bigger models without any additional cost during finetuning or inference. Finally, in the last part, we address one drawback of the transformer architecture which is its computational cost when used on long sequences. We show that efficient architectures derived from the classic transformer require fewer resources and perform better on long sequences. However, due to how they approximate the attention computation, efficient models suffer from a small but significant performance drop on short sequences compared to classical architectures. This incentivizes the use of different models depending on the input length and enables concatenating multimodal inputs into a single sequence
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Reyes, Rosa Maria Barragan. "Heat transformer studies." Thesis, University of Salford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386347.
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White, Cynthia Quinn. "The Transformer Station." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/64190.
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Fontana, Christian. "Solid State Transformer." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3424940.
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The Solid State Transformer (SST) is an emerging solution that can advantageously substitute the conventional transformer, thanks to its capabilities. Furthermore, it is a multi-functional equipment that offers:
- conditioning of the power flow, whether of DC or AC form;
- reduced size and weight thanks to the high frequency transformer;
- good voltage regulating capabilities;
- no diffusion of voltage swell or sag thanks to the DC link (if any);
- power factor correction;
- fast fault detection and protection;
- capability to maintain the output feed for a time (hold up time) thanks to the DC link capacitors;
Moreover, it offers the conventional transformer properties:
- galvanic isolation between input and output;
- step up/down of the input voltage;
The SST capabilities make this technology an important solution to solve the current and future issues of the grid. The reduced weight and size allow getting high performances in the traction systems. The bidirectional power flow capabilities allow the connection and management of renewable energy sources (RES) with the grid and different loads, connected to AC side or, if present, to DC link.Il trasformatore a stato solido (SST) è un emergente tecnologia che può sostituire i trasformatori convenzionali, apportando notevoli vantaggi grazie alle sue potenzialità e funzionalità. Tra le più importanti abbiamo: -condizionamento del flusso di potenza, sia DC che in AC; -ridotte dimensioni e peso, grazie all'uso di un trasformatore in alta frequenza; -ottima regolazione della tensione; -limita diffusione di buchi di tensione; -correzione del fattore di potenza; -hold up time funzionalità; -isolamento galvanico. Grazie a queste funzionalità questa tecnologia diventa molto importante per poter affrontare problemi, presenti e futuri, legati alla gestione della rete elettrica. La possibilità di gestire il flusso di energia e la bidirezionalità del flusso di potenza consentono di facilitare l'integrazione delle risorse rinnovabili con la rete elettrica. Inoltre, la riduzione dipeso e dimensioni consentono di ottenere alte performance in sistemi usati per la trazione.
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Mercier, Adrien. "Contribution à l'étude et à la réalisation de composants magnétiques monolithiques réalisés par PECS/SPS et à leurs applications en électronique de puissance." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLN057/document.
Full textAbstract:
L’augmentation des fréquences de commutation des alimentations induit de nouvelles problématiques pour les composants. Que ces composants soient actifs ou passifs, il est nécessaire de contrôler les pertes afin que les rendements restent acceptables. La thèse se propose d’étudier et de fabriquer une nouvelle structure de transformateur destiné à s’insérer dans une alimentation à découpage. Ces transformateurs sont produits à l’aide du procédé PECS/SPS, qui est une technologie de frittage. Cette technologie permet de fritter des ferrites tout autour des enroulements primaires et secondaires. Il en résulte que les composants sont monolithiques.Une première partie présente l’état de l’art, ainsi que le magnétisme dans la matière. Il s’ensuit un chapitre dédié à la fabrication des matériaux magnétiques utilisés durant la thèse : les ferrites.Une deuxième partie concerne les ferrites fabriqués par le procédé PECS/SPS. Il est question dans un premier temps d’étudier l’anisotropie magnétocristalline de ces matériaux, et il est possible de la diminuer en jouant sur la composition chimique. Dans un second temps, d’autres grandeurs telles que la perméabilité ou la polarisation sont mesurées, toujours en fonction de la composition chimique. Les principaux résultats montrent que le frittage par le procédé PECS/SPS est plus réducteur que le frittage classique, ce qui dégrade certaines propriétés comme la résistivité des ferrites. Un dernier chapitre est dédié à la réalisation des transformateurs monolithiques. Un protocole détaillé de la fabrication est alors présenté.Une troisième partie illustre le fonctionnement des transformateurs réalisés. Les mesures usuelles permettent d’identifier les inductances propres, mutuelles et de fuite. Les valeurs de ces inductances montrent qu’il est plus judicieux d’utiliser les composants fabriqués non pas en tant que transformateur, mais en tant que coupleur. Enfin un convertisseur basé sur une structure de type VRM est réalisé. La fréquence de découpage est de 2 MHz, le rendement est supérieur à 90 %, et la densité de puissance est de 15 kW/litreThe increase in switching frequency of power supply induces new problems for the components. These components are active or passive, it is necessary to control the losses so that efficiency remains acceptable. The thesis deals with the study and production of a new transformer structure intended to be part of a switching power supply. These transformers are produced using PECS/SPS method, which is a sintering technology. This technology can be sintered ferrite around the primary and secondary windings. It follows that the components are monolithic.A first part presents the state of the art, and magnetism in the matter. It follows a chapter dedicated to the manufacture of magnetic materials used in the thesis : the ferrites.A second part concerns the ferrites produced by the PECS / SPS process. Firstly, the magnetocrystalline anisotropy of these materials is studied, and it is possible to decrease it by varying the chemical composition. In a second stage, other variables such as the permeability or the polarization are measured, always depending on the chemical composition. The main results show that the sintering by PECS / SPS method is more reducing than conventional sintering, which degrades certain properties such as the resistivity of the ferrites. The last chapter is dedicated to the realization of monolithic processors. A detailed manufacturing protocol is presented.A third part shows the operation of the realized transformers. The usual measurements allow identifying self, mutual and leakage inductances. The values of these inductances show that it is better to use components made not as a transformer, but as a coupler. Finally a converter based on a VRM structure is realized. The switching frequency is 2 MHz, the efficiency is greater than 90%, and the power density is 15 kW / liter
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Sherwood, Hayden. "Practical fault simulation on an earthing transformer using SFRA: A unique analysis approach towards simplifying SFRA results to assist with deformation diagnosis in Earthing Transformers." Thesis, Sherwood, Hayden (2017) Practical fault simulation on an earthing transformer using SFRA: A unique analysis approach towards simplifying SFRA results to assist with deformation diagnosis in Earthing Transformers. Honours thesis, Murdoch University, 2017. https://researchrepository.murdoch.edu.au/id/eprint/38691/.
Full textAbstract:
Earthing Transformers are an integral part of power and distribution systems around the world, although, little consideration is given to their ongoing monitoring and maintenance. The failure of an earthing transformer can cause a multitude of issues including compromised stability and safety of the electrical network. The necessity to maintain both safety and stability of electrical networks highlights valuable real world applications for an SFRA earthing transformer testing toolkit.
As a starting point, the project adopted a review of existing research along with an analysis of earthing transformer design principles. Research found that because of an inherent design strategy, many ZN wound earthing transformers have a unique failure type in common; axial displacement of the inner and outer windings.
The second project stage involved physical simulation of an earthing transformer’s axial windings displacement using SFRA as a diagnosis tool. Simulation results provided evidence that (for the given test subject) defect detection is possible using SFRA benchmarked comparisons.
Analysis of benchmarked comparisons found deviation only at select resonances with general spectral shape retention for all other points along the SFRA trace. Spectral consistency of benchmarked comparisons allowed the implementation of a speech processing technique known as Mel-Frequency Cepstral Coefficients (MFCC). An adaption of the MFCC process introduced a way of encoding and distilling the SFRA trace data while exaggerating critical points of deviation.
The third major project stage involved the development of code using Mathworks MATLAB as a platform to the fulfil data management and computational requirements of the adapted MFCC. Select variables were isolated throughout the code to ensure that the process was tune-able on multiple levels for future optimisation.
By selecting and mapping the appropriate resultant cepstral coefficients against each other, it was found that a meaningful representation of the SFRA trace can be graphically presented as a single point on a two-dimensional plot. Simulated transformer defect scenarios had notable deviation on both the x and y axis when processed and plotted together.
Analysis, processing and comparison of 28 different earthing transformer SFRA traces found possible real world applications for a single point spectrum classifier. The spectrum classifier was proposed as a substitution for pre-existing subjective analysis techniques, potentially building on the communal engineering toolbox for SFRA analysis.
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Larsson, Björn. "Transformers Heartbeats." Thesis, Konstfack, Inredningsarkitektur & Möbeldesign, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-4705.
Full textAbstract:
Efter fem år på Konstfack lämnar jag snart denna studietillvaro för att gå ut i verkligheten som inredningsarkitekt och möbelformgivare. Det blir ett nytt sammanhang för mig att adaptera till. Mitt examensarbete handlar därför om hur jag kan transformera den typ av arbete jag gjort i skolan till verkligheten som kommer efter skolan. Jag ser en risk i verklighetens tillvaro där jag tror att många fantastiska idéer blir reducerade till slutresultat som är berövande på de kvaliteter som varit upphov till idéerna. Jag har därför arbetat med hur jag kan minska avståndet mellan min tankevärld och den nya verklighet jag vill översätta mina tankar till. Det är viktigt för mig att det jag tänkt och känt under en process ska leva vidare i det jag gör på ett eller annat sätt, och att det känns i slutresultatet. I den praktiska delen av examensarbetet har jag därför utgått från en träkloss och associerat mig vidare i en växande process. Jag har varvat mellan konkret och abstrakt förhållningssätt och låtit träklossen transformeras om och om igen på olika sätt i en slags roterande evolution. I slutändan har det genererat en liten familj av möbelliknande objekt. På liknande sätt har jag låtit den skrivande delen av examensarbetet växa roterande med metaforer, relaterade sidospår, erfarenheter och insikter som det praktiska görandet har genererat. Tillsammans har skrivandet och görandet varit en växelverkande kraft som tagit mig framåt i processen. Det har styrt evolutionen av min möbelliknande familj och utformningen av deras personliga ”dna”.
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Liu, Tian. "Manoeuvre contrôlée des transformateurs de puissance avec flux rémanent." Phd thesis, Supélec, 2011. http://tel.archives-ouvertes.fr/tel-00631516.
Full textAbstract:
Le transformateur de puissance est un équipement essentiel d'un réseau électrique et le plus coûteux dans les postes. Pour augmenter son degré de disponibilité et de fiabilité, il est nécessaire d'appliquer la manœuvre contrôlée afin de diminuer la saturation du noyau lors de l'enclenchement, et donc limiter les courants d'appel. Ces derniers sont asymétriques, d'amplitude élevée, et riches en harmoniques. Ils peuvent causer des effets indésirables comme le disfonctionnement des dispositifs de protections, l'endommagement mécanique des enroulements du transformateur et réduire en général la durée de vie et la qualité des systèmes. Une technique efficace pour réduire ces courants d'appel est de mettre sous tension le transformateur quand le flux dynamique généré par la source est égal à son flux rémanent. Un modèle simplifié du transformateur de puissance est adopté pour l'analyse des phénomènes physiques liés à l'application des manœuvres. Pour évaluer le degré de faisabilité de cette technique, des simulations sont effectuées en utilisant le simulateur de réseau EMTP. Les contraintes requises pour chacun des composants du système de manœuvre contrôlée comme les segments de ligne, les disjoncteurs sont étudiées en détail pour déterminer l'algorithme de calcul de l'instant optimal de manœuvres. Ensuite des tests de validation statistiques sont effectués afin d'évaluer les performances des différentes approches employées. Enfin une étude consacrée à la reconstitution du flux rémanent via un transformateur capacitif de tension (TCT) est menée pour appliquer l'algorithme de manœuvre contrôlée dans les postes en utilisant les équipements de mesure déjà existants.
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Zhong, Ming. "Partial core power transformer." Thesis, University of Canterbury. Electrical and Computer Engineering, 2012. http://hdl.handle.net/10092/7537.
Full textAbstract:
This thesis describes the design, construction, and testing of a 15kVA, 11kV/230V partial
core power transformer (PCPT) for continuous operation. While applications for the partial
core transformer have been developed for many years, the concept of constructing a partial
core transformer, from conventional copper windings, as a power transformer has not been
investigated, specifically to have a continuous operation. In this thesis, this concept has been
investigated and tested.
The first part of the research involved creating a computer program to model the physical
dimensions and the electrical performance of a partial core transformer, based on the existing
partial core transformer models.
Also, since the hot-spot temperature is the key factor for limiting the power rating of the
PCPT, the second part of the research investigates a thermal model to simulate the change of
the hot-spot temperature for the designed PCPT. The cooling fluid of the PCPT applied in
this project was BIOTEMP®. The original thermal model used was from the IEEE Guide for
Loading Mineral-Oil-Immersed transformer. However, some changes to the original thermal
model had to be made since the original model does not include BIOTEMP® as a type of
cooling fluid. The constructed partial core transformer was tested to determine its hot-spot
temperature when it is immersed by BIOTEMP®, and the results compared with the thermal
model.
The third part of the research involved using both the electrical model and the thermal model
to design a PCPT. The PCPT was tested to obtain the actual electrical and the thermal
performance for the PCPT.
The overall performance of the PCPT was very close to the model estimation. However,
cooling of the PCPT was not sufficient to allow the PCPT to operate at the design rated load
for continuous operation. Therefore, the PCPT was down rated from 15kVA to maintain the
hot-spot temperature at 100°C for continuous operation. The actual rating of the PCPT is 80%
of the original power rating, which is 12kVA.
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Mouhamad, Malick. "Réduction des pertes à vide des transformateurs de distribution par utilisation de rubans amorphes." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2012. http://tel.archives-ouvertes.fr/tel-00719097.
Full textAbstract:
La présente étude traite l'application des rubans amorphes dans les transformateurs de distribution dans l'objectif de réduire les pertes dans le réseau d'électricité. Les matériaux utilisés sont un alliage à base de fer, silicium et bore. Les premières études sur ce matériau amorphe révèlent une très bonne compatibilité chimique de ces derniers avec les huiles de transformateur. Ces rubans possèdent des durées de vie entièrement conforme aux exigences d'ERDF. Les pertes à vide représentent un élément non négligeable dans l'efficacité énergétique des matériels. Un transformateur amorphe génère 2 fois moins de pertes pendant toute sa vie qu'un transformateur conventionnel C0Ck. D'un point de vue général, la technologie amorphe appliquée aux transformateurs de distribution publique présente un intérêt majeur pour la réduction des pertes à vide. L'investissement réalisé dans un matériel certes plus onéreux à l'origine se trouve rentabilisé grâce aux économies réalisées sur les pertes à vide. Le retour sur investissement est possible en 10 à 12 années environ mais reste très variable en fonction du prix d'achat négocié. La qualification des transformateurs amorphes nécessite que les matériels répondent aux exigences de la spécification d'ERDF comme le critère "Tenue aux courants de court-circuit" qui constitue une composante essentielle dans l'acceptation des transformateurs amorphes. La tenue aux efforts de court-circuit a historiquement été problématique sur les transformateurs triphasés à noyaux amorphes. Le noyau se cisaille pendant le court-circuit, libérant des particules métalliques préjudiciables à la tenue diélectrique de l'appareil. Depuis, les constructeurs ont fait des progrès dans la conception mais les matériels ne sont pas encore pleinement satisfaisants. La tenue aux courts-circuits est l'enjeu et le défi que doit franchir cette technologie pour s'implanter et être crédible en Europe.
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Cezar, Vinicius Oiring de Castro. "Contribution au renvoi de tension et à la reconstitution du réseau. Estimation des flux rémanents dans un transformateur." Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAT046/document.
Full textAbstract:
Lors de la réalimentation des auxiliaires d'une tranche nucléaire ou hydraulique, l'étape la plus à risque est la remise sous tension brusque du transformateur à cause des surtensions et courants d'appels générés. Ces phénomènes transitoires engendrent des effets très indésirables autant pour le réseau comme pour le transformateur (efforts électrodynamiques sous les bobinages, vibration du circuit magnétique, bruit et vieillissement prématuré du transformateur.) Le but de ces travaux de thèse est de proposer de nouvelles méthodologies permettant d'évaluer les paramètres mal connus (les valeurs des flux rémanents présents dans le circuit magnétique du transformateur avant sa mise sous tension). Face aux problèmes actuelles pour l'estimer (méthode non directe, dérive, imprécision de la mesure de la tension, etc.), deux nouvelles méthodes basées sur la magnétisation préalable du circuit magnétique (méthode de prefluxing) et sur la mesure des flux de fuites du circuit magnétique (méthode de mesure directe de flux par mesure de l’induction magnétique) sont proposéesDuring the re-energization of the auxiliaries of a nuclear or hydraulic power plant, the most dangerous step is the re-energization of the power transformer, because of the temporary overvoltage and inrush currents. These transients phenomenon causes undesirable effects for both network and for the power transformer (electrodynamic forces over the windings, the magnetic circuit’s vibration, noise and the premature aging of the transformer). The goal of these thesis is to suggest new methodologies allowing us to evaluate unknown parameters (the residual flux’s values in the magnetic circuit before transformer’s energization). According to the latest problems in order to evaluate it (no direct method, derivation, voltage measurement error, etc) two new methods based on the previous magnetization of the magnetic circuit (prefluxing method) and on the leakage flux measurement of the magnetic circuit (direct measurement of the flux by measuring the magnetic induction method) are proposed
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Eymard, Stéphanie. "Contribution à la valorisation tribologique des huiles de transformateur usagées." Thesis, Ecully, Ecole centrale de Lyon, 2014. http://www.theses.fr/2014ECDL0017.
Full textAbstract:
Les prévisions alarmistes en ressources naturelles encouragent la recherche de solutions alternatives au niveau mondial. Le recyclage devient alors un défi majeur pour la société, en particulier pour les produits dérivés du pétrole comme les huiles de transformateur. Cette étude est basée sur la recherche de nouvelles voies de revalorisation de ces huiles, par l’analyse critique du contexte concurrentiel, des segments de marché potentiels, ainsi que des propriétés physico-chimiques de ces huiles. Nous nous sommes attachés à déterminer l’adéquation des performances et caractéristiques des huiles de transformateur régénérées aux exigences propres au marché de l’usinage et de la mise en forme des métaux. L’usure des matériaux dans le cadre de la lubrification limite et au-delà, est un domaine d’étude complexe combinant la mécanique, la physique du solide, la chimie ainsi que la thermodynamique des phénomènes irréversibles. Dans le cadre de cette étude les performances d’hydrocarbures neufs, usagés (pollué par les Polychlorobiphényls) et régénérés, ayant des propriétés physico-chimiques et rhéologiques proches, sont comparés dans le cadre d’essais sclérométriques et tribométriques sur une fonte à graphite sphéroïdal, matériau de frottement largement employé dans l’industrie du transport. Une séquence de techniques d’analyse de surface est développée afin de caractériser les morphologies des surfaces et quantifier les déformations de matières résultantes du frottement. La complémentarité des essais sclérométriques et tribométriques, qui permettent d’étudier les performances des hydrocarbures dans différents états de contraintes, respectivement de compression et de cisaillement, révèlent les bonnes performances des huiles de transformateurs régénérées. En quantifiant spécifiquement les performances des huiles revalorisée à travers la détermination de paramètres tribologiques classiques, comme les taux de déformations, les coefficients de frottements ou encore les temps d’initiation au grippage. La composition finale de l’huile régénérée, à savoir la longueur des chaines hydrocarbonées, les teneurs en eau et en PCB, conditionne son comportement tribologique. Suite à ce bilan positif portant sur les performances des huiles de transformateur régénérées en usure abrasive et catastrophique, la mise en forme des métaux peut être identifiée comme une nouvelle voie de valorisation matière de ces huilesThe alarming forecasts of natural resources encourage worldwide the search for alternative solutions. Hence recycling becomes a major challenge for society, especially for petroleum products such as transformer oils. This study is based on finding new ways of valorizing these oils, which is a complex problem that must meet the economic, political, regulatory, environmental and scientific constraints and challenges. A critical analysis of the competitive environment, of the potential market segments, as well as physic-chemical properties of these oils is the basis to determine new ways of revalorization. In this study, we attempted to determine the suitability and performance characteristics of transformer oil regenerated to the specific requirements of the machining and shaping of metals. The wear of materials under boundary lubrication and beyond this regime, is a complex area of study combining mechanics, solid state physics, chemistry and thermodynamics of irreversible processes. In this study the performance of new, used ( polluted by polychlorinated biphenyls ) and regenerated oils with close physic-chemical and rheological properties are compared in scratch test and tribometric with a ductile cast iron, which is friction material widely used in the transportation industry. A sequence of surface analysis techniques is developed to characterize the morphologies of the surfaces and quantify the resulting deformation of the friction material. The complementarity of scratch an tribometric tests for the study of the performance of hydrocarbons in different stress states, respectively compression and shear, reveals the good performances of regenerated transformer oils. This study has allowed discriminating the behavior of various origins oils under conditions of extreme friction, and specifically quantifying the performance of the regenerated oils through the determination of classical tribological parameters such as rate of deformation, friction coefficients or time to seizure. The final composition of the regenerated oils, ie the length and nature of the hydrocarbon chains, the water and PCBs content and the presence of polar molecules, determines its tribological behavior. Thus, the study showed that the performance of regenerated oils increases with the water and PCB content. Following this positive assessment on the regenerated oil performances in case of abrasive and catastrophic wear, machining and shaping of metals can be identified as a new way for regenerated transformers oils
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Ntwoku, Stephane Ntuomou. "Dynamic transformer protection a novel approach using state estimation." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45879.
Full textAbstract:
Transformers are very important parts of any electrical network, and their size increase so does their price. Protecting these important devices is a daunting task due to the wide variety of operating conditions. This thesis develops a new protection scheme based on state estimation.The foundation upon which our protection scheme is built is the modeling of the single phase transformer system of equations. The transformer equations are composed of polynomial and differential equations and this system of equations involving the transformer's electrical quantities are modeled into a system of equations such that highest degree of each of the system's equations is quadratic―in a process named Quadratization and then integrated using a technique called Quadratic integration to give a set of algebraic companion equations that can be solved numerically to determine the health of the transformer.
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Bechara, Ricardo. "Análise de falhas de transformadores de potência." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-16082010-163504/.
Full textAbstract:
Transformadores de potência são equipamentos essenciais no sistema elétrico de potência, alterando os níveis de tensão para interligar os sistemas de geração, transmissão e distribuição de energia elétrica. Neste trabalho são relacionados e descritos os principais modos de falha normalmente verificados em transformadores, associados ao levantamento estatístico que compõe um banco de dados elaborado a partir de perícias realizadas entre os anos de 2.000 e 2.008 para companhias seguradoras. É apresentada e desenvolvida uma análise de falhas verificadas em cerca de uma centena de transformadores com diferentes tipos de aplicação, classes de tensão e níveis de potência. O objetivo do estudo é contribuir com um melhor entendimento de causas de falhas e os tipos de transformadores mais suscetíveis a cada uma delas.Power transformers are essential equipment in the electric system by changing the voltage levels in order to connect generation, transmission and distribution systems of electric energy. In this study are related and described the most common failure modes in transformers, associated with the statistical statement that makes up a database developed from expertise held between the years 2000 and 2008 for insurance companies. It is presented and developed an analysis of failures found in around a hundred transformers with different types of application, classes of voltage and power levels. The objective of the study is to contribute to a better understanding of the causes of failures and the transformers types most susceptible to each one.
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Alegria, Inês Mendes. "Transformar Alcântara." Master's thesis, Universidade de Lisboa, Faculdade de Arquitetura, 2020. http://hdl.handle.net/10400.5/20378.
Full textAbstract:
Dissertação de Mestrado Integrado em Arquitetura, com a especialização em Arquitetura apresentada na Faculdade de Arquitetura da Universidade de Lisboa para obtenção do grau de Mestre.A cidade de Lisboa expõe inúmeros espaços que esperam uma reestruturação, sendo um destes, Alcântara. Este lugar recebeu grande parte da população após o terramoto de 1755, por não ter sofrido como o centro da cidade. Este acontecimento contribuiu para a transformação do cenário rural desta parte da cidade para um industrial. A nível urbano tentou-se resolver a conectividade interrompida entre a cidade e a água. A frente ribeirinha foi um dos lugares que mais sofreu com a revolução industrial, sendo que a introdução da linha do comboio e das novas infraestruturas a desligou do resto da cidade. A proposta para o vazio urbano, adjacente à LX Factory, tem como premissa principal o diálogo entre o presente e a sua memória. Procura ainda os ambientes e funções desempenhadas na LX Factory, como se fosse uma extensão da mesma. O elemento desenvolvido até à escala do detalhe é um complexo habitacional para Alcântara, que tem em conta todas as premissas lançadas inicialmente.
ABSTRACT:The city of Lisbon exhibits numerous spaces awaiting restructuring, and one of them is Alcântara. This place had received much of the population after the 1755 earthquake, for not suffering as much as the city center. This event contributed to the transformation of the rural scenery of this part of the city to an industrial one. On the urban level, there were made attempts to resolve the interrupted connectivity between the city and the water. The riverfront was one of the places that suffered the most from the industrial revolution, because the introduction of the train line and new infrastructure cut it off from the rest of the city. The proposal for the urban void, adjacent to LX Factory, has as its main premise the dialogue between the present and its memory. It also looks at the environments and functions presented at LX Factory, as if it were an extension of it. The element developed down to the detail scale is a housing complex for Alcântara, which takes into account all the premises initially cited.
N/A
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Semard, Maxime. "Conception et réalisation de transformateurs intégrés pour les alimentations de faible puissance." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSE1091/document.
Full textAbstract:
Le chapitre 1 introduit le sujet et son contexte. Les verrous sont identifiés.Le chapitre 2 fait l’état de l’art sur la topologie des enroulements constituants le transformateur.Les points forts et les points faibles des différentes topologies sont discutés. Les différents matériaux nécessaires à la réalisation de transformateurs (conducteur, magnétique et isolant) satisfaisant les exigences sur la haute température et la haute fréquence sont identifiés.Enfin, je présenterai la méthode de fabrication LTCC qui constitue une alternative à la technologie développée dans ce mémoire.Le chapitre 3 traite de la modélisation et de la conception des transformateurs en définissant la structure et ses degrés de libertés. L’utilisation des calculs analytiques et de simulations par la méthode des éléments finis permettent d’évaluer des transformateurs à enroulements entrelacés et à enroulements concentriques avec une bonne précision. Le chapitre 4 présente les procédés technologiques permettant la fabrication collective de transformateurs sur substrat magnétique. Il s’agit de l’isolation du substrat, de la croissance électrolytique des enroulements et de l’assemblage final du transformateur.Le chapitre 5 présente les méthodes de caractérisations de différentes propriétés du transformateur : résistance des enroulements en continu, inductances propres d’un enroulement et capacité d’isolement entre enroulements primaire et secondaire. Ces caractérisations permettent de confirmer les calculs analytiques et les hypothèses sur lesquelles ils reposent ainsi que les simulations magnétostatique et électrostatique par éléments finis.Le chapitre 6 permettra de conclure sur les travaux réalisés dans le cadre de cette thèse et d’ouvrir des perspectives pour des travaux futursChapter 1 introduces the topic and its associated context. Locks are identified.Chapter 2 is reviewing state of the art of winding topologies. Their strengths and weaknesses are discussed. Then, materials required for transformers microfabrication (conductors, magnetic material and insulation material) satisfying both high temperature and high frequency criteria are identified. Finally, LTCC fabrication process, an alternative to process used here, is presented.Chapter 3 discuss modelisation and design of transformers by defining the structures and its degrees of freedom. Analytical expressions and finite element analysis allows evaluation of interleaved transformer and tapped transformer within a good accuracy.Chapter 4 present technological process involved in batch-processed fabrication of transformers onto magnetic substrate. Processes are substrate insulation, conductors electrolytic growth of windings and final assembly of transformers.Chapter 5 present characterization methods of several properties of the transformers such as DC winding resistance, self-inductances of windings and isolation capacitance between primary and secondary winding. These characterizations confirm analytical expressions and their underlying hypothesis as well as magnetostatic and electrostatic finite element analysis.Chapter 6 concludes on work achieved during this PhD thesis and opens to further perspectives
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Murthy, Bellur Dakshina S. "Hard-Switching and Soft-Switching Two-Switch Flyback PWM DC-DC Converters and Winding Loss due to Harmonics in High-Frequency Transformers." Wright State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=wright1278704361.
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Pereira, Albert Manuel. "Conception de Transformateurs Moyennes Fréquences : application aux convertisseurs DC-DC haute tension et forte puissance." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSE1326.
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Le transport et la distribution de l'énergie électrique sont traditionnellement réalisés en alternatif (50 Hz ou 60 Hz), un des éléments-clés de ces infrastructures est le transformateur de puissance. Ce dernier est utilisé depuis plus d'un siècle et donc sa conception est maîtrisée (avec des rendements très élevés, supérieurs à 99 %). Depuis quelques années, la part des énergies renouvelables est en constante augmentation. Bien souvent, la production des énergies renouvelables est éloignée des centres de consommation. Or, le transport en courant continu sous haute tension (HVDC) sur de grandes distances est plus rentable. Dans ce cas, nous avons besoin de convertisseurs de puissance fonctionnant pour certains avec des Transformateurs Moyennes Fréquences (TMF) entre 1 kHz et quelques dizaines de kilohertz. Dans ces applications, la recherche du rendement maximal est primordiale. L'augmentation de la fréquence de fonctionnement a pour effet bénéfique de diminuer l'encombrement d'un transformateur. Cependant un certain nombre de problèmes vont apparaître avec cette augmentation. Nous pouvons citer : les pertes dans les conducteurs et dans le circuit magnétique sont liées à la fréquence ; le type de bobinages (fil de Litz et feuillard) et les matériaux magnétiques (ferrites et nanocristallins) en moyennes fréquences sont différents de ceux utilisés en 50 Hz ; le refroidissement est plus complexe car la densité de puissance volumique est plus élevée... Ainsi dans cette thèse, nous avons mis en place une méthodologie de conception afin de maîtriser au mieux le dimensionnement d'un TMF avec un compromis précision et coût de calculs. Nous avons identifié les modèles (analytiques et numériques) susceptibles d'être utilisés pour estimer les performances d'un TMF. Deux TMF d'une puissance de 180 kVA et de 1 kVA ont été dimensionnés, fabriqués et testés afin de mettre en évidence le domaine de validité et d'ajuster les différents modèles. Ce travail nous a permis de mettre en place une méthodologie de conception allant des spécifications du convertisseur jusqu'à la simulation de celui-ci avec le modèle du transformateur dimensionné. Nous avons mis en évidence : l'influence de paramètres technologiques sur l'élévation de la résistance pour des bobinages de type feuillard et l'influence de paramètres technologiques sur les propriétés magnétiques des matériaux nanocristallins. Ce travail de thèse a été réalisé avec le groupe « Matériaux du Génie Electrique » du laboratoire Ampère et financé par l'institut pour la transition énergétique SuperGrid InstituteThe transmission and distribution of electric power is normally made by ac networks (50 Hz or 60 Hz), where one of the key elements of this infrastructure is the power transformer; used for more than a century, its design is very well understood, with a level of operating efficiency normally greater than 99%. In recent years, the share of renewable energy has been increasing. Often times the energy generated from renewable sources is produced far from consumption centers, and so transportation in the form of high voltage direct current (HVDC) over long distances is more profitable, due to the lower losses seen than with HVAC after a certain length of transmission line. In this case, we need power converters operating with Medium Frequency Transformers (MFT) from 1 kHz to tens of kilohertz. For these applications, the research of their maximum efficiency in operation is paramount. Increasing the transformer operating frequency has the beneficial effect of reducing its size. However, a number of problems will appear with this frequency increase, such as: the increase in the losses in the conductors and the magnetic circuit that are related to the frequency; the less well understood winding type (Litz wire and foil) and magnetic materials (ferrites and nanocrystalline) in the MF that are different from those used at 50 Hz; the cooling is more complex because the power density is higher, etc. In this thesis, a design methodology was developed in order to optimise the design of MFTs with respect to the compromise between accuracy and the length of calculations. In addition, analytical and numerical models were identified that can be used to accurately estimate the performance of an MFT. Furthermore, two MFTs (apparent power: 180 kVA and 1 kVA, respectively) were sized, manufactured and tested in order to demonstrate the domain of validity of the models, and also for optimisation of the different models. This work has enabled the development of a design methodology using the converter specifications and build a simulation with complete model of the transformer, which can then be used to validate an MFT design. We have highlighted: the influence of the technological parameters on the rise of resistance in the foil coils and the influence of the technological parameters on the magnetic properties of nanocrystalline materials. This work was performed with the group "Materials for Electrical Engineering" Ampère laboratory and funded by the Institute for Energy Transition SuperGrid Institute
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Chew, En Phin. "Superconducting Transformer Design and Construction." Thesis, University of Canterbury. Electrical and Computer Engineering, 2010. http://hdl.handle.net/10092/4977.
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This thesis first outlines the testing undertaken on a partial core superconducting
transformer under open circuit, short circuit, full load and endurance test conditions.
During the endurance test, a failure occurred after 1 minute and 35 seconds. During the
failure, voltage dipping and rapid liquid nitrogen boil off was observed. This prompted
a failure investigation which concluded that the lack of cooling in the windings was the
most probable cause to the failure.
Full core transformer and superconductor theories are then introduced. A copper
winding transformer model, based on a Steinmetz equivalent circuit and a reverse
design method, is described. A superconductor loss model which outlines the different
types of losses experienced under AC conditions is used to determine the resistance
of the windings in the Steinmetz equivalent circuit. This resistance changes with the
magnitude of current and the strength of the magnetic field that is present in the gaps
between each layer of the windings. An alternative leakage flux model is then presented,
where the flux is modelled based on the combination of the reluctance of the core and
the air surrounding the windings. Based on these theories, an iterative algorithm to
calculate the resistance of the superconductor is developed.
A new design of a 15kVA single phase full core superconducting transformer, operating
in liquid nitrogen, is presented. The issues with building the superconducting
transformer are outlined. First, a copper mockup of the superconducting transformer
was designed where the mockup would have the same tape and winding dimensions
as the superconducting transformer, which means the same core can be used for two
different sets of windings. This led to designing a core that could be easily taken apart
as well as reassembled. Construction of the core, the copper windings and the superconductor
windings ensued. The process of cutting the core laminations, insulating the
copper and superconductor tapes, and making the steel fasteners and terminations are
described.
The copper mockup and superconducting transformers was then tested under open
circuit, short circuit, different load and endurance conditions at both liquid nitrogen
and room temperatures. These test results were then compared with the those from
two models. The comparison showed a significant inaccuracy in the reactances in
the models. This introduced a correction factor into the superconductor model which
ii
made it more accurate. However, further work is required to explain and quantify the
correction factors for the copper transformer model under different load conditions.
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Zhang, Xingxing. "STRANDED CORE TRANSFORMER LOSS ANALYSIS." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_theses/533.
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We will present the approaches used to investigating the power loss for the stranded core transformers. One advantage of using stranded core is to reduce power loss or enhance transformer efficiency. One difficulty in the modeling of this type of transformer is that the core is not solid (there are small gaps between core wires due to circular cross section). A two dimensional finite element method with nodal basis function for magnetostatic field was developed to study the effects of the small gaps between core wires. The magnetic flux densities are compared for the uniform (solid) cores and the stranded cores for various permeability values. The effects of different air gap dimensions in stranded core to the magnitude of magnetic flux density were also discussed. The results of the two dimensional study were applied to modify the B-H curves in a 3D simulation with an equivalent simplified uniformed core transformer model via Ansoft Maxwell 3D. This is achieved by output the magnitude of magnetic flux density at fixed points of mesh center. The total core loss of a transformer was predicted by integration of the losses of all elements.
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Wilson, Gordon. "Characterisation of mineral transformer oil." Thesis, University of Surrey, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392140.
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Zandberg, Hermanus Andries Jakobus. "Wireless transformer condition monitoring system." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/1186.
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The Department of Electrical Engineering in fulfilment of the
requirements for the Magister Technologiae in Electrical
Engineering at the
Cape Peninsula University of Technology
November 2013Pole mounted transformers (PMT) in rural areas present an opportunity for local utilities to do current monitoring on these systems. These transformers are exposed to abnormal amounts of stress due to the vast power demand in these areas. The aim of this study is to develop a more cost-effective condition monitoring system. Transformer current monitoring can be a dangerous practice if not done by suitably trained utility electricians. Hence this study is partly aimed at the elimination of hazardous working environments associated with manual electrical measurements. An investigation to determine a safe and cost-effective way to obtain the electrical measurements required from PMTs is undertaken. Although current measurements can be done with a current clamp-on meter, these measurements still take place at the phases of the transformer and are unsafe. The possibility of implementing wireless data gathering on current clamp-on meters is therefore investigated. This is made possible by a wireless sensor node (WSN) which gathers information and transmits it wirelessly to a WSN base station. This wireless solution is battery powered, necessitating battery replacements, therefore leading to the investigation of magnetic fields, magnetic materials and magnetic induction. A current clamp able to generate a high voltage (HV) output with minimal magnetic field strength is developed. The magnetic fields produced by the transformer’s phase cables are used to generate an alternating voltage. With the help of a microcontroller and an energy harvesting circuit, this voltage is converted and used to charge supercapacitors. The magnetic fields are also used to determine the current flow in the transformer phase cables when the device is not in energy harvesting mode. The device will then undergo comprehensive laboratory testing to determine its accuracy and durability, and is then used to do ‘real life’ current measurements, the results of which are compared against an off-the-shelf current monitoring device.
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Cho, Sung Don. "Parameter estimation for transformer modeling /." Available online. Click here, 2002. http://sunshine.lib.mtu.edu/ETD/DISS/chosd/SungCho.pdf.
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Edwards, John. "Magnetic flux based transformer model /." [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16945.pdf.
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Rossi, Jose Osvaldo. "Transmission line transformers." Thesis, University of Oxford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.284500.
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Rabjohn, Gordon G. (Gordon Glen) Carleton University Dissertation Engineering Electrical. "Monolithic microwave transformers." Ottawa, 1991.
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Suzuki, Rami Noriko. "Differentiation of transformed and non-transformed human mammary epithelial cells." Thesis, University College London (University of London), 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405212.
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Hogg, Robert Andrew. "An adaptive, microprocessor based transformer differential relay with harmonic restraint and transformer tap changer detection." Thesis, University of Newcastle Upon Tyne, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.315575.
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Forghani, Behrang. "Transformed Random Walks." Thesis, Université d'Ottawa / University of Ottawa, 2015. http://hdl.handle.net/10393/32538.
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We consider transformations of a given random walk on a countable group determined by Markov stopping times. We prove that these transformations preserve the Poisson boundary. Moreover, under some mild conditions, the asymptotic entropy (resp., rate of escape) of the transformed random walks is equal to the asymptotic entropy (resp., rate of escape) of the original random walk multiplied by the expectation of the corresponding stopping time. This is an analogue of the well-known Abramov's formula from ergodic theory.
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Abuhassan, Hassan. "Some transformed distributions /." Available to subscribers only, 2007. http://proquest.umi.com/pqdweb?did=1456289011&sid=9&Fmt=2&clientId=1509&RQT=309&VName=PQD.
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Nguyen, The Van. "Circuit générique de commandes rapprochées pour l'électronique de puissance." Phd thesis, Université de Grenoble, 2012. http://tel.archives-ouvertes.fr/tel-00743576.
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Ces travaux de thèse portent sur la conception et la réalisation d'un circuit générique de commandes rapprochées pour les transistors à grille isolée, notamment pour les MOSFETs et les IGBTs, compatible avec différentes structures de conversion d'énergie de l'électronique de puissance. L'objectif principal est de concevoir un système de commande simple à mettre en oeuvre, compact, intégrable et configurable pouvant servir un panel varié d'applications dites multi transistors. Le mémoire de thèse se structure en quatre chapitres : état de l'art de la commande rapprochée des transistors à grille isolée, présentation et validation d'une nouvelle topologie de commande rapprochée à base de transformateur d'impulsion, présentation et validation d'une version améliorée pour travailler à large spectre de fréquence et de rapport cyclique, conception et validation du circuit de commande générique contenant une puce intégrée en technologie CMOS et 6 transformateurs d'impulsions planars. Les champs d'application de ce concept du driver sont multiples, celui-ci favorise la simplicité de la conception et de la mise en oeuvre des systèmes de commande pour l'électronique de puissance.
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Woodhead, N. "The heparan sulphates of control : virus-transformed and chemically-transformed fibroblasts." Thesis, University of Aberdeen, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372444.
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Vichare, Nitin Shrikrishna. "Measurement and modelling of errors for relaying current transformers and voltage transformers." Thesis, Virginia Tech, 1990. http://hdl.handle.net/10919/42139.
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A measurement tool has been developed to estimate errors in relaying current transformers and voltage transformers. The tool has been developed to collect data in a substation and send it to a remote location over a telephone line. Different schemes were evaluated and tested in the laboratory. The final choice was made on the basis of the hardware and transmission cost constraints.
The measurement unit was developed using hardware similar to that used in a computer relay. The signals from the current and voltage transducers were sampled using a microprocessor and an analog to digital converter in real-time. The measurement device has been installed in the field. The data from the field was collected remotely and analyzed in the Virginia Tech Power Systems laboratory. The analysis of the data is presented at the end.Master of Science
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Adabi, Firouzjaee Mohammad Ebrahim. "Advanced modeling of solid state transformer." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/461451.
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The solid state transformer (SST) is seen as a proper replacement of the conventional iron-and-copper transformer in the future smart grid . The SST offers several benefits (e.g. enhanced power quality performance or reactive power control at both primary and secondary sides) that can be of paramount importance for the development of the smart grid .
This research focuses on the development and implementation of an advanced model of a three stage bidirectional SST in Matlab/Simulink. The goal is to obtain an realistic SST model (i.e. as close to the real SST as possible) that could duplicate the performance of a real MV/LV SST. This considered design consists of three main stages: medium voltage (MV) stage, isolation stage, and low voltage (LV) stage. When the power flows from the MV side to the LV side, the input power-frequency ac voltage is converted into a MV dc voltage by the three-phase ac/dc converter, which in such case works as rectifier. The isolation stage, which includes a high-frequency transformer (HFT) and the two corresponding MV- and LV-side converters, first converts the MV-side dc voltage into a high-frequency square-wave voltage applied to the primary of the HFT; the secondary side square-wave signal is then converted to a LV dc waveform by the LV-side converter, which also works as rectifier. Finally, the output LV-side three-phase dc/ac converter, which works as inverter, provides the output power-frequency ac waveform from the LV-side dc link.
Si-based semiconductor technologies can be used for MV applications using a multilelvel configuration. Recently, modular multilevel converter (MMC) topologies have attracted attention for high or medium voltage applications. These converters can provide an effective topology for the MV side of the SST; their main advantages are modularity and scalability: the desired voltage level can be easily achieved by a series connection of MMC sub-modules (SMs). In addition,a MMC topology can provide high power quality and efficiency with reduced size of passive filters. These features made the MMC option an attractive topology for the MV stage of the SST.
This thesis proposes a three-stage SST configuration based on MMC technology for MV converters.
* The input stage of the SST is connected to the distribution system via RL filters and its three-phase configuration uses a MMC technology. A half-bridge configuration is proposed for each SM.
* The isolation stage consists of three parts: a MV single-phase MMC, the high-frequency transformer (HFT), and a single-phase LV PWM converter.
* The LV side of the SST uses a three-phase four-leg PWM converter, with an RL impedance for filtering currents and a capacitor bank for filtering voltages.
The converters and their controller have been implemented adn tested considering models without and with semiconductor losses, while the SST model has been tested as a stand-alone device and a compnent of a distribution system.
The model has been tested under severe dynamic and unbalanced conditions. The simulation results support the choices made for any SST stage and proves that the proposed design could be a feasible choice for the future SST.El Transformador de Estado Sólido ("Solid State Transformer" por sus siglas en inglés) es visto como un reemplazo adecuado del transformador convencional en las futuras redes inteligentes (smart grids ). Este nuevo dispositivo presenta una amplia gama de prestaciones (p.e. mejora de la cualidad de suministro) que pueden ser de crucial importancia para el desarrollo de las redes inteligentes. El principal objetivo de esta tesis es que desarrollar e implantar el en Matlab/Simulink un modelo realista de estado sólido trifásico y bidireccional, que pueda duplicar el comportamiento de un transformador de estado sólido de Media-Baja tensión. El diseño considerado consiste en tres etapas: etapa en media tensión (MT), etapa intermedia, etapa en baja tensión (BT). Cuando la potencia fluye del terminal en media al terminal en baja tensión, la tensión alterna en el terminal de entrada a media tensión y frecuencia de operación 50 Hz se convierte en continua a media tensión mediante un convertidor trifásico rectificador. La etapa intermedia es un puente activo dual, que incluye un transformador de alta frecuencia y los correspondientes convertidores en media y baja tensión: primero, la media tensión continua es convertida en media tensión alterna a alta frecuencia; esta tensión es reducida a baja tensión preservando la alta frecuencia mediante el transformador, finalmente, la tensión en el terminal de salida del transformador es rectificada y convertida en baja tensión continua). La entrada en la etapa de salida en BT es, por tanto, una tensión continua que es convertida en tensión alterna a frecuencia de operación 50 Hz mediante un convertidor que funciona como inversor. Puesto que el diseño del dispositivo estudiado en esta tesis es bidireccional, en caso de que la potencia tenga que fluir desde el lado de BT al lado de MT, la función de los convertidores se invierte (es decir, los rectificadores pasan a operar como inversores, los inversores pasan a operar como rectificadores) en cualquiera de las etapas. Los actuales semiconductores solo pueden ser utilizados en aplicaciones de media y alta tensión empleando convertidores multi-nivel. Durante los últimos años ha ganado popularidad la tecnología MMC (modular multilevel converter), que permite diseñar configuraciones adecuadas para el lado de MT de un transformador de estado sólido; sus principales ventajas están en modularidad y escalabilidad: el nivel de tensión adecuado se puede conseguir mediante la conexión en serie de tantos sub-módulos como sea necesario. Además con la tecnología MMC se puede obtener una alta calidad en las ondas de tensión y corriente, así como un elevado rendimiento con tamaño reducido en los filtros de entrada. Esta tesis propone un diseño trifásico bidireccional con las siguientes características: - La etapa de entrada está conectada a una red de distribución en MT mediante filtros RL y su configuración trifásica usa convertidores de tecnología MMC. - La etapa intermedia contiene tres secciones: un convertidor monofásico en configuración MMC, un transformador de MT/BT y alta frecuencia, y un convertidor monofásico en BT. - La etapa de salida en BT usa un convertidor trifásico PWM (pulse wide modulation), con un filtro RL para las corrientes y un banco de condensadores para filtrar tensiones. Los convertidores han sido implantados en Matlab/Simulink y simulados considerando modelos con y sin pérdidas en los semiconductores, mientras que el modelo completo de transformador de estado sólido ha sido analizado considerando dos configuraciones distintas del sistema a estudiar: el transformador aislado y formando parte de una red de distribución en MT. Los modelos de transformador con y sin pérdidas han sido simulados bajo ciertas condiciones de operación. Los resultados confirman que la configuración seleccionada para cada etapa del nuevo dispositivo permite obtener un diseño fiable que puede mejorar el funcionamiento de las futuras redes inteligentes.
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Hu, Zili. "Development of PHP to UMPL transformer." Thesis, Ball State University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3590414.
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This thesis developed a new markup language based on eXtensible Markup Language (XML), named as the Unified Programming Markup Language (UPML), which represents an abstraction of programming techniques of popular programming languages, and is used to store the programming semantic information of various programming languages. UPML aims to provide a general software quality analysis platform and as a gateway to translate programs between high-level programming languages. This research created and analyzed the features of UPML and concluded that UPML may have advantages over the traditional and newly appeared methods in software quality analysis and programming language translation. As the proof of concept in building such a software analysis and translation system, this research developed a PHP to UPML transformer. Execution examples showed its correctness of working in the core programming area of popular programming techniques, structure programming (SP) and object-oriented programming (OOP). The PHP implementation can be easily applied to other programming languages that support the same programming techniques. Since UPML is extensible, languages of other programming paradigms beyond the SP and OOP can be easily added.
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Ayddan, Jonas, and Emin Özbek. "Transformer test bench -implementation and usability." Thesis, KTH, Elektroteknisk teori och konstruktion, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-170534.
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The task of this master's thesis was to design a transformer test bench while focusing on safety and usability. There are several safety risks when working with high voltages, therefore the high demand for safety precautions. A bench was worked upon, and attachments, such as module frames and banana connectors were integrated into the bench. Further, a list of components were modied and installed on the new bench. A new design, using a magnetic non-contact safety interlock switch and an easy-to-apply circuitry, was proposed and implemented. In addition to the implementation, a code in LabVIEW was written in order to handle the measured data from the tests that can be performed on a transformer. Several tests were performed on a single-phase transformer and a three-phase transformer in order to verify the function of the transformer test bench, with respect to the design. Complications emerged due to random additive noise. After some work, the noise was suppressed and the results showed that the equipment worked well with the new design. Finally, a user's manual was written in order to guide the user through the wire connections, tests and the developed software in LabVIEW.En transformatortestbänk avsedd för laborationer inom forskning och utbildning har utvecklats, där fokus har lagts på säkerhet och användbarhet, eftersom arbete med höga spänningar medför säkerhetsrisker. En bänk modierades för att möjliggöra fastsättning av moduler samt banankontakter. Vidare anskaades elektroniska komponenter, bearbetades och installerades. En design med en magnetisk switch samt lättanvända kretsar föreslogs. Dessutom skrevs en kod i LabVIEW med ett brett användningsområde. Ett flertal tester utfördes på en enfastransformator och en trefastransformator med syfte att säkerställa att komponenter- na fungerar väl ihop med den framtagna transformatortestbänken. En del komplikationer uppstod på grund av slumpmässigt, additivt brus. Detta gick dock att undertrycka. Det slutliga resultatet visade att kom- ponenterna fungerade väl ihop med den framtagna transformatortestbänken. Slutligen skrevs en användarmanual med syfte att instruera använda- re av transformatortestbänken beträande kopplingarna, testerna samt mjukvaran som är skriven i LabVIEW.
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Rivera, Gomez Franco Wilfrido. "Heat transformer technology and steam generation." Thesis, University of Salford, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360445.
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Cargol, Timothy L. (Timothy Lawrence) 1976. "A non-destructive transformer oil tester." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/81576.
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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (leaves 62-63).
A new non-destructive test of transformer oil dielectric strength is a promising technique to automate and make more reliable a diagnostic that presently involves intensive manual efforts. This thesis focuses some of the issues that must be understood to bring the test from the laboratory to the field. Emphasis is placed on reliability and safety by exploring any effect the test has on the transformer oil, the mechanical parameters necessary to give optimal reliability, and failsafe electronics.
by Timothy L. Cargol.
M.Eng.
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Schlicker, Darrell Eugene. "Flow electrification in aged transformer oils." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38844.
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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.Includes bibliographical references (p. 317-348).
by Darrell Eugene Schlicker.
M.S.