Dissertations / Theses on the topic 'Transformer'
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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.
Full textLapthorn, Andrew Craig. "High Temperature Superconducting Partial Core Transformers." Thesis, University of Canterbury. Electrical and Computer Engineering, 2012. http://hdl.handle.net/10092/7130.
Full textLiew, 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 textReyes, Rosa Maria Barragan. "Heat transformer studies." Thesis, University of Salford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.386347.
Full textWhite, Cynthia Quinn. "The Transformer Station." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/64190.
Full textFontana, Christian. "Solid State Transformer." Doctoral thesis, Università degli studi di Padova, 2018. http://hdl.handle.net/11577/3424940.
Full textIl 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.
Mao, Peilin. "Power transformer fault diagnosis based on wavelet transform and artificial neural network." Thesis, University of Bath, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760740.
Full textZhong, Ming. "Partial core power transformer." Thesis, University of Canterbury. Electrical and Computer Engineering, 2012. http://hdl.handle.net/10092/7537.
Full textChew, En Phin. "Superconducting Transformer Design and Construction." Thesis, University of Canterbury. Electrical and Computer Engineering, 2010. http://hdl.handle.net/10092/4977.
Full textZhang, Xingxing. "STRANDED CORE TRANSFORMER LOSS ANALYSIS." UKnowledge, 2008. http://uknowledge.uky.edu/gradschool_theses/533.
Full textWilson, Gordon. "Characterisation of mineral transformer oil." Thesis, University of Surrey, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392140.
Full textZandberg, Hermanus Andries Jakobus. "Wireless transformer condition monitoring system." Thesis, Cape Peninsula University of Technology, 2013. http://hdl.handle.net/20.500.11838/1186.
Full textPole 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.
Cho, Sung Don. "Parameter estimation for transformer modeling /." Available online. Click here, 2002. http://sunshine.lib.mtu.edu/ETD/DISS/chosd/SungCho.pdf.
Full textEdwards, John. "Magnetic flux based transformer model /." [St. Lucia, Qld.], 2002. http://www.library.uq.edu.au/pdfserve.php?image=thesisabs/absthe16945.pdf.
Full textHardie, Stewart Ramon. "A Prototype Transformer Partial Discharge Detection System." Thesis, University of Canterbury. Electrical and Computer Engineering, 2006. http://hdl.handle.net/10092/1114.
Full textHogg, 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.
Full textBergsåker, 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.
Full textGeomagnetiskt 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.
Adabi, Firouzjaee Mohammad Ebrahim. "Advanced modeling of solid state transformer." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/461451.
Full textEl 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.
Hu, Zili. "Development of PHP to UMPL transformer." Thesis, Ball State University, 2013. http://pqdtopen.proquest.com/#viewpdf?dispub=3590414.
Full textThis 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.
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.
Full textEn 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.
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.
Full textCargol, Timothy L. (Timothy Lawrence) 1976. "A non-destructive transformer oil tester." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/81576.
Full textIncludes 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.
Schlicker, Darrell Eugene. "Flow electrification in aged transformer oils." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38844.
Full textIncludes bibliographical references (p. 317-348).
by Darrell Eugene Schlicker.
M.S.
Iyengar, Pravin. "Pulsed MOSFET based linear transformer driver." Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=24217.
Full textSharapov, V. M., and K. V. Bazilo. "Piezoelectric transformer with parallel oscillatiry circuit." Thesis, Sumy State University, 2014. http://essuir.sumdu.edu.ua/handle/123456789/39938.
Full textБорисенко, Олексій Андрійович, Алексей Андреевич Борисенко, Oleksii Andriiovych Borysenko, and K. O. Teletov. "Transformer binary codes into binominal ones." Thesis, Видавництво СумДУ, 2004. http://essuir.sumdu.edu.ua/handle/123456789/22972.
Full textAslaksen, Jonasson Alexander, and Alfred Wahlforss. "Diagnosis of Dementia using Transformer Models." Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279226.
Full textDemens är ett syndrom av sjukdomar som orsakar kognitiv nedsättning och påverkar både de drabbade och deras familjer. Den vanligaste typen av demens ar Alzheimers sjukdom, med cirka 10 miljoner nya fall per ar. I denna studie undersöker vi olika maskininlärningsmodeller och tillvägagångssätt i syfte att underlätta får sjukvårdspersonal att ställa en tidig diagnos, och möjligtvis att även kunna automatisera vissa delar av diagnosprocessen. Vi utvärderar vara modeller på Pittcorpuset i DementiaBank-datasetet och använder 10-delad korsvalidering. Vi jämför två transformer-modeller: BERT och RoBERTa, och finner att bada modeller åstadkommer goda resultat avseende noggrannhet, precision, specificitet och sensitivitet. Den högsta noggrannheten uppnås av RoBERTa, på 86.72%, en precision på 90.69%, och en specificitet på 90.53%. Vidare undersöker vi gångbarheten i att använda automatisk taligenkänning for automatiserad transkribering av ljudinspelningar från patientmoten. RoBERTa uppnår da en noggrannhet på 83.59% när den använder transkriberad text från Googles automatiska taligenkänningstjänst, vilket tyder på att sådana metoder kan vara gångbara for att automatisera vissa delar av den diagnostiska processen. Förutom undersökning av transformermodeller bidrar detta verk även med en marknadsanalys av marknadspotentialen får ett verktyg får automatiserad demensdiagnostik. Analysen baseras på en litteraturstudie och två intervjuer; en med en VD får en start-upp som erbjuder liknande tjänster, och en intervju med en forskare inom demens. Med litteraturstudien och de två intervjuerna som grund analyserar vi marknadspotentialen med tre ramverk: Porters fem krafter, PEST-analys och SWOTanalys. Vi fastslår att det trots flertal hinder och svårigheter får marknadsinträde finns det stor potential och en stor efterfrågan på en sådan produkt.
Al, lulu Sadi, Lezan Amen, Mohammad Aljichi, and Mats Isaksson Sandberg. "Wireless signal transmission for HV Transformer." Thesis, Uppsala universitet, Institutionen för elektroteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-448131.
Full textLu, Shu. "Power transformer magnetization under GIC/GMD." Diss., This resource online, 1994. http://scholar.lib.vt.edu/theses/available/etd-09232008-144706/.
Full textAlabdrbalreda, Mohammed. "Power transformer modelling for optimal performance." Thesis, Alabdrbalreda, Mohammed (2015) Power transformer modelling for optimal performance. Honours thesis, Murdoch University, 2015. https://researchrepository.murdoch.edu.au/id/eprint/29836/.
Full textJansson, Vincent, David Bergman, and Niklas Hermansson. "High Frequency Transformer : Implementation of prototype." Thesis, Uppsala universitet, Elektricitetslära, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-387307.
Full textNtwoku, Stephane Ntuomou. "Dynamic transformer protection a novel approach using state estimation." Thesis, Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45879.
Full textLi, Xiang. "Mathematical Model for Current Transformer Based On Jiles-Atherton Theory and Saturation Detection Method." UKnowledge, 2016. http://uknowledge.uky.edu/ece_etds/89.
Full textO'Sullivan, Francis M. (Francis Martin) 1980. "A model for the initiation and propagation of electrical streamers in transformer oil and transformer oil based nanofluids." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40504.
Full textIncludes bibliographical references (p. 305-309).
The widespread use of dielectric liquids for high voltage insulation and power apparatus cooling is due to their greater electrical breakdown strength and thermal conductivity than gaseous insulators, while their ability to conform to complex geometries and self-heal means that they are often of more practical use than solid insulators. Transformer oil is a particularly important dielectric liquid. The issues surrounding its electrical breakdown have been the subject of extensive research. Much of this work has focused on the formation of electrical streamers. These are low-density conductive structures that form in regions of oil that are over-stressed by electric fields on the order of 1 x 108 (V/m) or greater. Once a streamer forms it tends to elongate, growing from the point of initiation towards a grounding point. The extent of a streamer's development depends upon the nature of the electrical excitation which caused it. Sustained over-excitation can result in a streamer bridging the oil gap between its point of origin and ground. When this happens an arc will form and electrical breakdown will occur. Streamers can form due to both positive and negative excitations. Positive streamers are considered more dangerous as they form at lower electric field levels and propagate with higher velocities than negative streamers. Historically, the modeling of streamer development has proved to be a very difficult task. Much of this difficulty relates to the identification of the relevant electrodynamic processes involved. In the first section of this thesis a comprehensive analysis of the charge generation mechanisms that could play a role in streamer development is presented.
(cont.) The extent of the electrodynamics associated with Fowler-Nordheim charge injection, electric field dependent ionic dissociation (the Onsager Effect) and electric field dependent molecular ionization in electrically stressed transformer oil are assessed and it is shown that molecular ionization, which results in the development of an electric field wave, is the primary mechanism responsible for streamer development. A complete three carrier liquid-phase molecular ionization based streamer model is developed and solved for a positive needle electrode excitation using the COMSOL Multiphysics finite element simulation suite. The modification of the liquid-phase molecular ionization model to account for the two-phase nature of streamer development is described and the performance of both the liquid-phase and gas/liquid two-phase models are compared with experimental results reported in the literature. The second section of this thesis focuses on the insulating characteristics of transformer oil-based nanofluids. These nanofluids, which can be manufactured from a variety of materials, have been shown to possess some unique insulating characteristics. Earlier experimental work has shown that oil-based nanofluids manufactured using conductive nanoparticles have substantially higher positive voltage breakdown levels than that of pure oil. A comprehensive electrodynamic analysis of the processes which take place in electrically stressed transformer oil-based nanofluids is presented, which illustrates how conductive nanoparticles act as electron scavengers in electrically stressed transformer oil-based nanofluids. As part of this analysis, a completely general expression for the charging dynamics of a nanoparticle in transformer oil is developed.
(cont.) The solutions for the charging dynamics of a range of nanoparticle materials are presented and the implications these charging dynamics have on the development of streamers in oil-based nanofluid is explained. To confirm the validity of the electrodynamic analysis, the electric field dependent molecular ionization model for streamers in pure oil is modified for use with transformer oil-based nanofluids. This model is solved for nanofluids manufactured using conductive and insulating particles and the results that are presented confirm the paradoxical fact that nanofluids manufactured from conductive nanoparticles have superior positive electrical breakdown performance to that of pure oil. The thesis concludes by exploring the possibility of developing simplified streamer models for both transformer oil and transformer oil-based nanofluids, which are computationally efficient and can be solved quickly meaning that they can be used as practical design tools.
by Francis M. O'Sullivan.
Ph.D.
Ribbenfjärd, David. "Electromagnetic transformer modelling including the ferromagnetic core." Doctoral thesis, KTH, Elektroteknisk teori och konstruktion, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-13080.
Full textQC20100708
TANTEH, DERICK NJOMBOG, SHAFIQ YOUSEF AL-LIDDAWI, and DANIEL SSEKASIKO. "PROPERTIES OF TRANSFORMER OIL THAT AFFECT EFFICIENCY." Thesis, Blekinge Tekniska Högskola, Institutionen för tillämpad signalbehandling, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-2664.
Full textPhillips, Lyndal, University of Western Sydney, of Science Technology and Environment College, and of Science Food and Horticulture School. "Analysis of polychlorinated biphenyls in transformer oils." THESIS_CSTE_SFH_Phillips_L.xml, 2002. http://handle.uws.edu.au:8081/1959.7/766.
Full textMaster of Science (Hons)
Phillips, Lyndal. "Analysis of polychlorinated biphenyls in transformer oil /." View thesis, 2002. http://library.uws.edu.au/adt-NUWS/public/adt-NUWS20031222.095244/index.html.
Full textA thesis submitted to the University of Western Sydney in fulfillment of the requirements for admission to the [degree of] Masters of Science (Honours). Bibliography : leaves 156-163.
Lavery, Grant. "A prototype transformer insulation condition monitoring system." Thesis, University of Canterbury. Electrical and Electronic Engineering, 1999. http://hdl.handle.net/10092/6037.
Full textKendall, Haydn G. "Investigation of leakage flux in transformer tanks." Thesis, Cardiff University, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329641.
Full textHeywood, Richard John. "The degradation models of cellulosic transformer insulation." Thesis, University of Surrey, 1997. http://epubs.surrey.ac.uk/2129/.
Full textDEMENICIS, LUCIENE DA SILVA. "TRANSMISSION LINE TRANSFORMER FOR HIGHSPEED OPTOELECTRONIC DEVICES." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5576@1.
Full textA utilização de transformadores de impedância banda larga possibilita o acoplamento de forma eficiente das linhas convencionais de 50 (ômegas) dos sistemas de alta freqüência aos componentes optoeletrônicos de alta velocidade de baixa impedância, tais como lasers semicondutores (tipicamente com 3 a 5 (ômegas) de resistência de entrada). Uma das principais restrições para a realização de um transformador de impedância planar para uso em sistemas de comunicações ópticas é a sua dimensão física. A fim de se obter um transformador de impedância compacto, de dimensões compatíveis com às dos dispositivos optoeletrônicos, foram analisadas diferentes configurações. Inicialmente foi analisada a configuração coplanar (CPW) utilizando substrato de altíssima constante dielétrica. Devido às limitações encontradas nesta configuração, são propostas, aqui, duas outras soluções. As duas novas configurações propostas associam ao substrato bulk convencional de alumina, filmes de elevada constante dielétrica. Foi desenvolvida uma técnica para caracterizar a constante dielétrica e as perdas dos filmes especialmente fabricados para este trabalho. As análises teóricas mostraram que as configurações propostas apresentam desempenho muito superior ao desempenho das configurações convencionais CPW. Foi implementado o transformador de impedância utilizando uma das soluções propostas e seu desempenho foi avaliado experimentalmente.
Wide-band transmission line impedance transformer enables efficient coupling of 50 (ômegas) transmission line circuits to low impedance high-speed optoelectronic components such as semiconductor lasers (typically with input resistance of 3 to 5 [ômegas]). The physical dimensions of the planar transmission line transformer have to be properly chosen to allow its use in optical communication systems. In order to design a high performance impedance transformer with physical dimensions compatible with optoelectronic components, several possibilities were investigated. A CPW configuration with very high dielectric constant bulk substrate has been analyzed. Simulations have shown some limitations in the performance of this configuration. Then, two new configurations were introduced. Both configurations are obtained using high dielectric constant films and alumina bulk substrate. A new technique has been developed in order to characterize the dielectric constant and the losses of the films specially made for this thesis. Simulations have shown that the performance of both new configurations is much better than the conventional CPW configuration performance. The planar transmission line impedance transformer has been constructed using a new configuration and its performance has been experimentally evaluated.
Mouayad, Lama. "Monitoring of transformer oil using microdielectric sensors." Thesis, Massachusetts Institute of Technology, 1985. http://hdl.handle.net/1721.1/39497.
Full textMICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING.
Includes bibliographical references.
by Lama Mouayad.
M.S.
Archer, Dale S. "An adaptive thermal module for transformer monitoring." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/11992.
Full textIncludes bibliographical references (leaves 132-133).
by Dale S. Archer.
M.S.
Junaydin, Mohamed Murad. "Automatically measuring the losses of a transformer." Thesis, Blekinge Tekniska Högskola, Institutionen för signalbehandling, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-12870.
Full textChiang, Arvin, and 姜義峰. "Current Transformer Saturation Detection Using Wavelet Transform." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/38630066492618497025.
Full text長榮大學
經營管理研究所
94
Digital protection relay for transmission lines utilizes voltage and current samples to discriminate faults in power system. Traditionally, current transformer (CT) is used to scale down the primary current to small secondary current for sampling. When a fault occurs on transmission lines, fault current contains an exponential decaying DC offset. It may cause the core of CT to saturate and result in distorted secondary current. Moreover, it results in a mal-operation in the protection relay. A CT saturation detection method is proposed in this thesis by analyzing the secondary current through Discrete Wavelet Transform (DWT). The level 1 detail coefficients in DWT are used to identify the start and end point when CT saturation occurs. The simulation results by MATLAB/SIMULINK revealed that the proposed method can detect the start and end point of CT saturation accurately.
McAlpine, Andrew. "Transformer." 2015. https://scholarworks.umass.edu/englmfa_theses/29.
Full textHuang, Jhao-Bi, and 黃昭弼. "Design of Transformer Terminal Unit for Transformer Management System." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/19054355524002454089.
Full text國立中山大學
電機工程學系研究所
100
With the economic development, the high quality has become a critical issue for service continuous of power companies. To ensure the stable power supply, the asset management of power equipments is applied to prevent the system outage. With voluminous distribution transformers over very wide area, the real time monitoring of temperature has been included in the scope of smart grid. During recent years, the service outage due to transformer overloading has caused customer panic as well as deterioration of service quality. This thesis develops the Transformer Terminal Unit (TTU) by integration of computer chip for power consumption, DSP and sampling circuit of temperature measurement to achieve the functions of real time monitoring of transformer operation condition. When an abnormal operation condition such as overloading or high oil temperature occurs, the TTU can report the contingency back to the control station via the hybrid communication system so that the distribution system operators can take remedy action to prevent the contingency. The actual loading and temperature of transforms are also measured and collected in this study to develop the relationship of temperature and loading levels. By collecting transformer temperature, the power demand of a transformer can be estimated and the load shedding can then be activated to prevent the problem of overloading when the temperature exceeds the operation constraint.
Liu, Chien-Chih, and 劉建志. "The Effects of Harmonics on Current Transformer and Differential Relay for Transformers." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/30803845673790025693.
Full text中原大學
電機工程學系
87
The use of nonlinear devices such as rectifiers ,converters, power supplies and other devices utilizing solid state switching has increased in industry during recent years. The power quality has been deteriorated by these equipments. This deterioration causes the increasing of power loss, resonance problem, insulation deterioration ,and even safety problem of system apparatus. This thesis aims at analyzing and probing into the influences of harmonics to differential relay. First it probes the operation of CT in frequency domain. Then, it analyzes and compares the mathematic model, which is constructed by using EMTP, and the real test results. There are many factors to be considered in transformer differential protection designing and exercising. This thesis only analyzes the influential phenomenons of harmonics to differential relay. The results of this research can provide the valuable references and assist in applying and designing differential relay.
Yeh, Yu-Chung, and 葉俞均. "Piezoelectric Ceramics Transformer." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/21807343980157655421.
Full text國立中央大學
光電科學研究所
92
Along with the invention of piezoelectric ceramic, there were many other small-sized but highly efficiency- transformed devices being researched and developed since then. In order to reduce the volume of power supplies and raise its efficiency simultaneously, researchers use piezoelectric transformers made by piezoelectric ceramic to serve their purpose. This thesis focuses in the piezoelectricity of piezoelectric ceramic, how to motivate a piezoelectric transformer, and how to use piezoelectric transformers to drive the backlight source.