Submitted by Gustavo Nascimento (gustavo.diniz@ufcg.edu.br) on 2018-02-06T14:28:39Z No. of bitstreams: 1 EDUARDO JORGE CALHEIROS JUNIOR - DISSERTACAO PPGEE 2014.pdf: 3431884 bytes, checksum: 5d6e954510b9e7405666b81ef4f13f30 (MD5) / Made available in DSpace on 2018-02-06T14:28:39Z (GMT). No. of bitstreams: 1 EDUARDO JORGE CALHEIROS JUNIOR - DISSERTACAO PPGEE 2014.pdf: 3431884 bytes, checksum: 5d6e954510b9e7405666b81ef4f13f30 (MD5) Previous issue date: 2014-06 / As análises de adequabilidade de equipamentos são indispensáveis para permitir que as empresas do setor elétrico conheçam as condições em que os mesmos operam, garantindo assim o desempenho dos ativos da empresa e sua disponibilidade no Sistema Interligado Nacional. Dentre os equipamentos analisados, destacam-se os transformadores de potência pelo seu alto custo e a sua importância para o sistema elétrico. Grande parte das falhas em transformadores de potência é de origem dielétrica, relacionadas com a danificação da isolação dos condutores devido às deformações mecânicas ocasionadas pelas altas correntes de curto-circuito passantes nos enrolamentos, reduzindo a vida útil do equipamento. A partir destas considerações, propôs-se avaliar os esforços eletromecânicos internos a alguns transformadores de potência presentes no sistema CHESF, por intermédio de simulações computacionais, quando da ocorrência de curto-circuito trifásico. A metodologia para as simulações consistiu em selecionar os transformadores a serem analisados e coletar as informações técnicas necessárias fornecidas pelos fabricantes. Posteriormente foram determinadas as condições sistêmicas às quais os transformadores estariam submetidos e obtidos os níveis de curto-circuito resultantes, para então efetuar as simulações propriamente ditas. Os resultados das simulações computacionais mostraram os esforços eletromecânicos estimados em quatro transformadores de potência em operação no sistema elétrico da CHESF, resultantes do efeito dinâmico da corrente de curto-circuito trifásico que percorrem os enrolamentos do transformador, considerando diferentes configurações sistêmicas. As conclusões das análises dos resultados indicaram possíveis casos de superações de limites admissíveis e revelou a importância dos aspectos construtivos dos transformadores na sua capacidade de suportar os esforços mecânicos causados por curtos-circuitos. / Analysis of suitability of equipment are indispensable for the electric sector companies meet the conditions in which they operate, thus ensuring the performance of the company's assets and its availability in the National Interconnected System (Sistema Interligado Nacional). The power transformers are included among the analyzed equipment due to its high cost and importance for the electrical system. Most faults in power transformers is of dielectric origin, related to insulation damage due to mechanical deformations, caused by the high short-circuit currents in the windings, reducing the life of the equipment. Then, it was proposed to evaluate the internal electromechanical efforts to some power transformers present in the CHESF system, through computer simulations, in the event of a three-phase short circuit. The methodology for the simulations consisted to select the transformers to parse and collect the necessary technical information provided by the manufacturers. Later, certain systemic conditions in which the transformers would be subjected were defined, it was obtained the resulting short circuit levels and then was performed the simulations themselves. The results of the computer simulations showed the electromechanical efforts estimated at four power transformers in operation in the CHESF electrical system, resulting from the dynamic effect of three-phase short-circuit current that run through the windings of the transformer, considering different systemic configurations. The conclusions of the analysis results indicated possible cases of overruns of permissible limits and reveal the importance of the transformers constructive aspects in their ability to withstand the mechanical stress caused by short circuits.

This thesis is engaged in a theoretical calculation of short-circuit currents in electric power system in compliance with the norm ČSN 60909-0 and first of all with calculation of dynamical and thermal effects of short-circuit currents in HV switching stations in accordance with the norm ČSN 60865-1. Next the thesis is engaged in a production of programs for simulation of mechanical effects of short-circuit currents with respect to a dimensioning of constructional elements of switching station and afterwards in a practical simulation of selected parts of the real switching station type „H“ in Slavkov u Brna.

Die Physikalisch-Technische Bundesanstalt (PTB) unterstützt vielfältig die Gesellschaft, Wirtschaft und Wissenschaft. Eine ihrer Kernkompetenzen als das nationale Metrologie-Institut der Bundesrepublik Deutschland ist die Messtechnik. In diesem Sinne kalibriert die Arbeitsgruppe „Solarzellen“ der PTB i. d. R. den Kurzschlussstrom unter Standardtestbedingungen (I_STC) von Referenzsolarzellen. Der I_STC von Referenzsolarzellen ist in Photovoltaik-Kalibrierketten bei der Bestimmung der Bestrahlungsstärke von zentraler Bedeutung und fließt signifikant in die Berechnung der Wirkungsgrad von Solarzellen und Solarmodulen ein. Um den I_STC einer Solarzelle mit geringster Messunsicherheit zu bestimmen, wurde die Differential Spectral Responsivity (DSR)-Methode verwendet. Sie basiert auf der Messung der differentiellen spektralen Empfindlichkeit bei unterschiedlichen Bestrahlungsstärken. Anhand dieser kann die absolute spektrale Empfindlichkeit s(λ) unter Standardtestbedingungen sowie der I_STC berechnet werden. Da jedoch die Umgebungsbedingungen meistens von den STC abweichen, reichen letztere nicht zum umfassenden Vergleich der Wirkungsgrade in der Praxis aus. Um Einflussfaktoren (Temperatur, Bestrahlungsstärke, Winkelabhängigkeit,...) genauer untersuchen zu können, wurde im Rahmen dieser Arbeit an der PTB ein neuer Laser-basierter DSR-Messplatz aufgebaut und charakterisiert. Mit dem neuen Messplatz wurden c-Si Referenzsolarzellen, organische Solarzellen auf Basis kleiner Moleküle sowie Farbstoffsolarzellen umfassend untersucht. Unter anderem wurden die elektrischen Leistungsparameter einer organischen Solarzelle (aktive Schicht: DCV5T-Me:C60) mit denen einer c-Si Solarzelle verglichen. Es zeigt sich, dass der Wirkungsgrad der organischen Solarzelle mit zunehmender Bestrahlungsstärke sinkt und mit zunehmender Temperatur steigt, während die c-Si Solarzelle ein gegensätzliches Verhalten aufweist. Darüber hinaus wurde u.a. die Winkelabhängigkeit der zweiten organischen Solarzelle (aktive Schicht: C60:DCV5T-Me(3,3)) untersucht und mit den Resultaten einer c-Si Solarzelle verglichen. Diese Untersuchungen haben ergeben, dass die Winkelabhängigkeit des Kurzschlussstroms der organischen Solarzelle im Vergleich zu einer c-Si Solarzelle insbesondere zwischen 20° < ϑ < 60° eine „Super-Kosinus-Anpassung“ aufweist. Ergänzend wurde an der PTB im Rahmen dieser Arbeit ein mobiler Messplatz für Outdoormessungen aufgebaut. Mit diesem konnten die mittels Indoor-Untersuchungen erhaltenen spektralen Empfindlichkeiten mit Outdoor-Messungen verglichen werden. Des Weiteren wurden spektrale Charakterisierungen der Himmelshalbkugel durchgeführt und Methoden für Korrekturen von Sekundärkalibrierungen untersucht.

Ce travail est relatif à l’augmentation du courant de court-circuit du réseau électriqueportuaire alimentant le navire. Ceci passe par une modélisation des réseaux des charges, dutransformateur et enfin convertisseurs concernés. Munis de cette compréhension du système,diverses solutions à base d’électronique de puissance ou d’éléments passifs ont étéinvestiguées, simulées et évaluées à l’aune des performances exigées. Pour l’augmentation ducourant de court-circuit, un transformateur spécialement créé pour cette application à deuxenroulements primaires est proposé. L’esprit de la solution est de modifier la configuration dutransformateur au moment de la détection du court-circuit en modifiant son rapport detransformation. Un banc de test temps réel hybride a été architecturé afin de tester cettesolution. Les essais sur le banc de test ont permis d’obtenir des résultats satisfaisants etencourageants qui corroborent la théorie. Pour finir des études complémentaires, sousdifférents scenarii, ont été menées en simulation hors ligne. / This work is about the short-circuit current increase, inside the harbor’s electrical networkthat supplies the electrical grid of each vessel docked in port. We analyze the system’srequirements, the load demands, the transformer and finally the modeling of the convertersinvolved. Armed with this understanding of the system, various solutions like powerelectronics devices or passive equipments were investigated, simulated and evaluated in termsof performance requirements. To increase the short-circuit current, we provide a noveltransformer with two primary windings. The purpose of this solution is to change theconfiguration of the transformer when the short circuit is detected by changing thetransformation ratio. A real-time hybrid test bench has been build in order to test the solution.The real-time tests have yielded good and encouraging results, supporting the theory. Finally,further studies under various scenarios were conducted in offline simulations.

Darbe tiriami mažaanglio plieno S235J2 (LST EN 10025:2004) suvirintų siūlių pasikeitimai, plieną apvirinant skirtingais glaistytaisiais elektrodais ir suvirinimo režimais. Tyrimų metu buvo naudojami AV-23 ir AV-66 glaistytieji elektrodai bei keičiamas trumpojo jungimo srovės stipris. Nustatytas ryšys tarp metalo įvirinimo gylio, rumbelės aukščio, išlydytų lašų dydžio, išlydytų lašų kiekio, trumpojo jungimo trukmės ir trumpojo jungimo srovės dydžio. Gauti tyrimų rezultatai, nubraižyti priklausomybių grafikai ir pateiktos išvados. Darbą sudaro: įvadas, literatūros apžvalga, eksperimentuose naudojama įranga ir medžiagos, tyrimo metodika, tyrimų metu gauti rezultatai, grafikai, išvados, literatūra. Darbo apimtis: 83 p. teksto, 73 iliustr., 18 lent., 23 bibliografiniai šaltiniai. / In final work was analyzed the changes of seams properties of steel S235J2 (LST EN 10025:2004), produced by welding with different technology are discussed. Samples were welded by hand arc welding, using AV-23 and AV-66 welding electrodes. The welded seams were made by changing short-circuit current. The duration of weld depth, ridge height, metal drop size, metal drop frequency, short-circuit time and short-circuit current value are determinated. The results of the research are given in graphs, final conclusions are also written. Structure: the introduction, survey of the related literature, equipment and materials, description of the methodology, results of research, graphs of the results, conclutions, references. Thesis consist of: 83 p. text, 73 pictures, 18 tables, 23 bibliographical entries.

Ce travail est relatif à l’augmentation du courant de court-circuit du réseau électriqueportuaire alimentant le navire. Ceci passe par une modélisation des réseaux des charges, dutransformateur et enfin convertisseurs concernés. Munis de cette compréhension du système,diverses solutions à base d’électronique de puissance ou d’éléments passifs ont étéinvestiguées, simulées et évaluées à l’aune des performances exigées. Pour l’augmentation ducourant de court-circuit, un transformateur spécialement créé pour cette application à deuxenroulements primaires est proposé. L’esprit de la solution est de modifier la configuration dutransformateur au moment de la détection du court-circuit en modifiant son rapport detransformation. Un banc de test temps réel hybride a été architecturé afin de tester cettesolution. Les essais sur le banc de test ont permis d’obtenir des résultats satisfaisants etencourageants qui corroborent la théorie. Pour finir des études complémentaires, sousdifférents scenarii, ont été menées en simulation hors ligne. / This work is about the short-circuit current increase, inside the harbor’s electrical networkthat supplies the electrical grid of each vessel docked in port. We analyze the system’srequirements, the load demands, the transformer and finally the modeling of the convertersinvolved. Armed with this understanding of the system, various solutions like powerelectronics devices or passive equipments were investigated, simulated and evaluated in termsof performance requirements. To increase the short-circuit current, we provide a noveltransformer with two primary windings. The purpose of this solution is to change theconfiguration of the transformer when the short circuit is detected by changing thetransformation ratio. A real-time hybrid test bench has been build in order to test the solution.The real-time tests have yielded good and encouraging results, supporting the theory. Finally,further studies under various scenarios were conducted in offline simulations.

I denna rapport utfördes en selektivplan på uppdrag av Kraftkällan Konsult för ett elnätsbolag i södra Sverige. Det visades att elnätet hade selektiva problem i samtliga stationer mellan reläskydden. Problemen har uppstått då karakteristiken i elnätet ändrats i samband med ombyggnationer. För att lösa problemen simulerades en modell av elnätet i PowerTools för att ta reda på kortslutningsströmmarna och nya selektivkurvor ritades efter dessa. Rekommendationer för högspänningssäkringar i nätstationer har också gjorts baserat på de nya kortslutningsströmmarna.

No description available.

Foram desenvolvidos sistemas de medidas visando a caracterização de células solares de sílico monocristalino. Para isso, foram determinadas as características I x V no escuro para diferentes níveis de iluminação. Curvas de resposta espectral e capacitância em função da tensão inversa aplicada foram também obtidas. Foi feita uma avaliação do comportamento dessas células em função da temperatura e realizadas medidas de profundidade de junção utilizando-se três métodos distintos. Os principais parâmetros, que determinam o desempenho dessas células, foram obtidos boa concordância com a teoria e com os resultados apresentados na literatura. / Systems of measurements were developed for the characterization of single crystal silicon solar cells. For that, the curves I x V were measured in the dark and for different intensity of illumination. Curves of spectral response and of capacitance as a function of the reciprocal of the voltage were also measured. The behavior of the cells as a function of temperature was analysed and also measurements of junction depth were made by three different methods. Values for the parameters that characterize the cells were obtained, showing a good agreement with theoretical values and also with already reported values.

Le principal objectif de nos travaux était l’établissement de modèles suffisamment précis pour étudier le comportement des machines électriques en présence d’un défaut de court-circuit entre spires et d’en déduire les signatures pertinentes pour la détection de ce type de défaut. L’autre objectif était de dimensionner des machines électriques à courant de court-circuit d’amplitude limitée pour réduire le risque de propagation du défaut. La première approche de modélisation consiste à effectuer une étude complète en utilisant la méthode d’éléments finis pas à pas dans le temps. Les résultats obtenus par ce modèle "éléments finis" concernant une MSAP et une MAS, saines et aussi en présence de plusieurs défauts "entre spires" de niveaux de sévérité différents, concordent avec ceux obtenus expérimentalement sur deux bancs d’essai. La seconde approche a consisté à mettre au point un modèle "circuits électriques" dont la complexité dépend du type de structure magnétique et du type de bobinage de la machine étudiée. Nous avons proposé deux méthodes de détermination des paramètres : 1- des méthodes numériques (éléments finis) ; 2- l’établissement des nouvelles expressions analytiques. Dans le dernier chapitre, une méthode basée sur la segmentation des aimants sous un pôle qui n’est en fait qu’une démultiplication du nombre de pôles au rotor sans modification du bobinage statorique est proposée est utilisé pour réduire le courant de défaut / The main objective of this research is to establish the sufficiently precise models to study the behavior of electrical machines in the presence of inter-turn short circuit fault and then find the relevant signatures to detect this type of fault. The other objective is to design a limited short-circuit current electrical machines to reduce the risk of fault development. The first modeling approach is a comprehensive study using the time stepping finite element method. The results obtained by this model "finite element" on a MSAP and MAS, healthy and faulty, for different levels of fault severity, are close with those obtained experimentally by two test benches. The second approach is to develop a model circuit electric, whose complexity depends on the type of magnetic structure and the type of machine winding. We have proposed two methods for determining the model parameters: 1 - numerical methods (FEM) which require long time bur very precise; 2 – establish new analytical expressions which is fast but less precise. In the last part, a method based on segmentation of the magnet is presented in order to reduce the short circuit current. The segmented PM motor contains the reduced fault current and can be used in the application which requires high degree of reliability