Made available in DSpace on 2016-08-17T14:52:58Z (GMT). No. of bitstreams: 1 Raimundo Nonato Rosa Filho.pdf: 1125835 bytes, checksum: 91689e7b58443f6d0eb73d752860ce37 (MD5) Previous issue date: 2005-03-31 / In this work a methodology for reduction of maintenance cost in the on-load tap changers (OLTC) of extra high voltage is proposed. The methodology is based on the use of Artificial Neural Networks (ANN) for the intelligent processing of input signals of the commutator. The neural nets adequately trained allow to create an information system and dedicated diagnosis of the OLTC. This system can interpret and diagnosis the components through the real time input signals in order to delay the power transformer maintenance intervals, foreseeing when the OLTC is going to maintenance have intervention based on its condition. It has been adopted a multiperceptron ANN architecture in which the input vector has 22 components and the output considers only one component with the status of the OLTC condition in function of its operation time. This output information is used to determine the periods of maintenance of the commutators. It is reported an application of the proposed system considering the on load tap changer of an autotransformer bank of 500/230/13.8 kV, 600MVA of Centrais Elétricas do Norte do Brasil S/A (ELETRONORTE). The results indicate the advantages of the maintenance based on the condition using ANN. / Neste trabalho é proposta uma metodologia para redução de custo de manutenção nos comutadores de tap sob carga (OLTC) dos transformadores de potência de extra alta tensão. A metodologia está baseada na utilização de redes neurais artificiais (RNA) para o processamento inteligente dos sinais de entrada dos comutadores. As redes neurais adequadamente treinadas permitem criar um sistema de informação e diagnóstico dedicado a OLTC que podem interpretar e diagnosticar os componentes através das entradas em tempo real de forma a, postergar os intervalos de manutenção, prevendo quando o OLTC deverá sofrer intervenção de manutenção baseada na condição do OLTC. Foi adotada uma arquitetura de RNA de multiperceptron na qual a entrada considera um vetor com 22 entrada e apenas uma saída com o status da condição do OLTC em função do tempo de operação. Essa informação de saída é utilizada para determinar os períodos de manutenção dos comutadores de tap. É realizada uma aplicação do sistema proposto considerando o comutador de tap sob carga de um banco de autotransformador de 500/230/13.8kV, 600MVA da Centrais Elétricas do Norte do Brasil S/A( ELETRONORTE) e os resultados indicam as vantagens da manutenção baseada na condição usando RNA.

This master´s thesis with the peripheral and structural design of power converter that will be used for DC welding. The drive itself is based on the principle of two single-acting permeable converters operating in counter strokes to a mutual load. The inverter operates at a frequency of 60kHz, and its output current can be controlled from 0 - 100A. Welder is equipped with a variable constant current or power adjustment. The device is powered from a single-phase 230V.

Der Ausbau dezentraler Energieanlagen wie fotovoltaischen Anlagen beeinflusst die Netzzustände signifikant. Dabei ist unsicher, wo und in welchem Maße deren Ausbau zukünftig erfolgt. Es ist nun an den Netzbetreibern gleichzeitig die aktuellen Herausforderungen zu meistern und die Netzplanung und -regelung für die Zukunft zu aktualisieren. Eine statistische Methode wird entwickelt, die Verteilnetzplanung unter Einsatz von quasi-stationär modellierten ”Smart Grid”-Lösungen wie Blindleistungsreglern und regelbaren Ortsnetztransformatoren ermöglicht. Durch Stichprobenverfahren werden Unsicherheiten wie Ort, Größe und Leistungsprofile der Energieanlagen in das Netzmodell eingebunden. Diese als probabilistischer Lastfluss bekannte Methode wird durch Gütemaße im Bereich geringer Kombination evaluiert. Beispiele probabilistischer Netzplanung werden an Netztopologien präsentiert.:Abbildungsverzeichnis iv Tabellenverzeichnis viii Abkürzungsverzeichnis viii Formelzeichen x 1. Einleitung 1 1.1. Definition der Herausforderung 1 1.2. Netzplanung 2 1.3. Ziel der Arbeit3 1.4. Struktur der Arbeit 5 2. Normen und technische Rahmenbedingungen 6 2.1. DIN EN 50160 6 2.2. VDE-AR-N 41057 2.3. Technische Anschlussbedingungen 9 2.4. Erneuerbare-Energien-Gesetz 11 2.5. Zusammenfassung 12 3. Gliederung probabilistischer Lastflussverfahren 13 3.1. Punktschätzende und iterative Verfahren 14 3.2. Gliederung nach Stichprobenverfahren 15 3.3. Reduzierung des Grundraumes 16 3.3.1. Cluster-Analyse17 3.3.2. Ausreißerbehandlung 21 3.3.3. Wahrscheinlichkeits- und Verteilungsfunktion 21 3.4. Methode der Stichprobenziehung 22 3.4.1. Einfache Zufallsstichprobe 23 3.4.2. Systematische Stichprobe24 3.4.3. Geschichtete Zufallsstichprobe 25 3.5. Reduzierung des Stichprobenraumes 26 3.6. Invertierung von Stichproben 26 3.7. Zusammenfassung 27 4. Vergleich probabilistischer Verfahren 28 4.1. Nicht-Gaußsche Eingangsdaten 28 4.2. Bestimmung notwendiger Clusterzentren 29 4.3. Erstellung des Stichprobenraumes pro Kombination 31 4.4. Gütemaße und Effizienz von Stichprobenverfahren 33 4.4.1. Median 34 4.4.2. Median der absoluten Abweichung vom Median 37 4.4.3. Maximale normierte Perzentilsdifferenz 40 4.4.4. Zusammenfassung 43 4.5. Streuung der Stichprobenverfahren bei wiederholter Ausführung 44 4.5.1. Median 44 4.5.2. Median der absoluten Abweichung vom Median 45 4.5.3. Maximale normierte Perzentilsdifferenz 47 4.5.4. Zusammenfassung 49 4.6. Sensitivität bei unterschiedlicher Anzahl statistischer Netzknoten 52 4.6.1. Median 52 4.6.2. Median der absoluten Abweichung vom Median 54 4.6.3. Maximale normierte Perzentilsdifferenz 56 4.6.4. Zusammenfassung58 4.7. Notwendige Kombinationen für Ziel-Gütemaße 59 5. Software-basierte probabilistische Verteilnetzplanung 61 5.1. Struktur der entwickeltenSoftware 61 5.2. Last- und Erzeugungsprofile 63 5.2.1. Synthetische Haushaltslast 63 5.2.2. Elektrofahrzeug 64 5.2.3. Wärmepumpe 65 5.2.4. Photovoltaische Anlagen 66 5.2.5. Windenergieanlagen 66 5.3. Optimale Auswahl nach Regeleffizienz 67 5.4. DezentraleWirkleistungsregler 68 5.4.1. P(U)-Regler für Schnellladeinfrastruktur 68 5.4.2. P(U)-Regelung von Wärmepumpen gemäß thermischer Grenzen 69 5.5. Blindleistungsregler 72 5.5.1. Zentrale Steuerung 73 5.5.2. Dezentrale Regelung 75 5.5.3. Verteilte Regelung 79 5.6. Regelbarer Ortsnetztransformator 83 5.7. Automatisierte Netzausbauplanung 86 5.7.1. Transformatortausch 87 5.7.2. Vergrößerung des Leiterquerschnitts 89 5.7.3. Zusätzliche Stichleitung 89 5.7.4. Kostenberechnung 90 5.8. Zusammenfassung 91 6. Anwendungsfälle probabilistischer Planung 92 6.1. Verwendete Verteilnetzmodelle 94 6.2. Abschätzung der Auswirkung von PV-Anlagenausbau 95 6.2.1. Unterschiede der Planungsverfahren zur Schätzung der PVA-Nennleistung 95 6.2.2. Einfluss der Blindleistungsregelung auf mögliche Anlagenleistung 100 6.3. Abschätzung von Netzauslastungen in Wohngebieten 106 6.3.1. Annahmen und Szenarien 107 6.3.2. Auswertung der Knotenspannungen 110 6.3.3. Auswertung der Betriebsmittelauslastungen 116 6.4. Zusammenfassung 118 7. Zusammenfassung und Ausblick 119 Literaturverzeichnis 121 Anhang 135 A. Statistische Merkmale 135 A.1. Empirische Wahrscheinlichkeitsfunktion 135 A.2. Kumulative empirische Verteilungsfunktion 136 A.3. Quantile 136 A.4. Interquartilsabstand 137 B. PLF-Methoden 138 B.1. Veröffentlichte PLF-Methoden 138 B.2. Test Gaußsche Verteilung 138 C. Definitionen 140 C.1. Symbole für Flussdiagramme 140 C.2. Zählpfeilsystem 140 D. Ergänzende Ergebnisse 142 E. Danksagung 143 / Development of distributed energy units such as photovoltaic systems affects grid states significantly. It is uncertain, where and to what extent the development of these units is carried out in the future. It is now up to the distribution system operator to cope with todays grid challenges and to update grid planning and control for the future. A statistical method is developed, which incorporates quasi-stationary modeled ”smart grid” solutions such as reactive power controllers and on-load tap-changers. Uncertainties such as location, size and power profiles of energy systems are integrated into the grid model by sampling. This method is known as probabilistic load flow and is evaluated by quality measures at low combinations. Examples on probabilistic grid planning of different grid topologies are presented.:Abbildungsverzeichnis iv Tabellenverzeichnis viii Abkürzungsverzeichnis viii Formelzeichen x 1. Einleitung 1 1.1. Definition der Herausforderung 1 1.2. Netzplanung 2 1.3. Ziel der Arbeit3 1.4. Struktur der Arbeit 5 2. Normen und technische Rahmenbedingungen 6 2.1. DIN EN 50160 6 2.2. VDE-AR-N 41057 2.3. Technische Anschlussbedingungen 9 2.4. Erneuerbare-Energien-Gesetz 11 2.5. Zusammenfassung 12 3. Gliederung probabilistischer Lastflussverfahren 13 3.1. Punktschätzende und iterative Verfahren 14 3.2. Gliederung nach Stichprobenverfahren 15 3.3. Reduzierung des Grundraumes 16 3.3.1. Cluster-Analyse17 3.3.2. Ausreißerbehandlung 21 3.3.3. Wahrscheinlichkeits- und Verteilungsfunktion 21 3.4. Methode der Stichprobenziehung 22 3.4.1. Einfache Zufallsstichprobe 23 3.4.2. Systematische Stichprobe24 3.4.3. Geschichtete Zufallsstichprobe 25 3.5. Reduzierung des Stichprobenraumes 26 3.6. Invertierung von Stichproben 26 3.7. Zusammenfassung 27 4. Vergleich probabilistischer Verfahren 28 4.1. Nicht-Gaußsche Eingangsdaten 28 4.2. Bestimmung notwendiger Clusterzentren 29 4.3. Erstellung des Stichprobenraumes pro Kombination 31 4.4. Gütemaße und Effizienz von Stichprobenverfahren 33 4.4.1. Median 34 4.4.2. Median der absoluten Abweichung vom Median 37 4.4.3. Maximale normierte Perzentilsdifferenz 40 4.4.4. Zusammenfassung 43 4.5. Streuung der Stichprobenverfahren bei wiederholter Ausführung 44 4.5.1. Median 44 4.5.2. Median der absoluten Abweichung vom Median 45 4.5.3. Maximale normierte Perzentilsdifferenz 47 4.5.4. Zusammenfassung 49 4.6. Sensitivität bei unterschiedlicher Anzahl statistischer Netzknoten 52 4.6.1. Median 52 4.6.2. Median der absoluten Abweichung vom Median 54 4.6.3. Maximale normierte Perzentilsdifferenz 56 4.6.4. Zusammenfassung58 4.7. Notwendige Kombinationen für Ziel-Gütemaße 59 5. Software-basierte probabilistische Verteilnetzplanung 61 5.1. Struktur der entwickeltenSoftware 61 5.2. Last- und Erzeugungsprofile 63 5.2.1. Synthetische Haushaltslast 63 5.2.2. Elektrofahrzeug 64 5.2.3. Wärmepumpe 65 5.2.4. Photovoltaische Anlagen 66 5.2.5. Windenergieanlagen 66 5.3. Optimale Auswahl nach Regeleffizienz 67 5.4. DezentraleWirkleistungsregler 68 5.4.1. P(U)-Regler für Schnellladeinfrastruktur 68 5.4.2. P(U)-Regelung von Wärmepumpen gemäß thermischer Grenzen 69 5.5. Blindleistungsregler 72 5.5.1. Zentrale Steuerung 73 5.5.2. Dezentrale Regelung 75 5.5.3. Verteilte Regelung 79 5.6. Regelbarer Ortsnetztransformator 83 5.7. Automatisierte Netzausbauplanung 86 5.7.1. Transformatortausch 87 5.7.2. Vergrößerung des Leiterquerschnitts 89 5.7.3. Zusätzliche Stichleitung 89 5.7.4. Kostenberechnung 90 5.8. Zusammenfassung 91 6. Anwendungsfälle probabilistischer Planung 92 6.1. Verwendete Verteilnetzmodelle 94 6.2. Abschätzung der Auswirkung von PV-Anlagenausbau 95 6.2.1. Unterschiede der Planungsverfahren zur Schätzung der PVA-Nennleistung 95 6.2.2. Einfluss der Blindleistungsregelung auf mögliche Anlagenleistung 100 6.3. Abschätzung von Netzauslastungen in Wohngebieten 106 6.3.1. Annahmen und Szenarien 107 6.3.2. Auswertung der Knotenspannungen 110 6.3.3. Auswertung der Betriebsmittelauslastungen 116 6.4. Zusammenfassung 118 7. Zusammenfassung und Ausblick 119 Literaturverzeichnis 121 Anhang 135 A. Statistische Merkmale 135 A.1. Empirische Wahrscheinlichkeitsfunktion 135 A.2. Kumulative empirische Verteilungsfunktion 136 A.3. Quantile 136 A.4. Interquartilsabstand 137 B. PLF-Methoden 138 B.1. Veröffentlichte PLF-Methoden 138 B.2. Test Gaußsche Verteilung 138 C. Definitionen 140 C.1. Symbole für Flussdiagramme 140 C.2. Zählpfeilsystem 140 D. Ergänzende Ergebnisse 142 E. Danksagung 143

This master thesis investigates a redesign for a maintenance tube, used for both sampling and draining transformer oil from a tap changer compartment. With the current design, one can do one or the other of sampling and draining. The effect of this on a transformer site during maintenance means that personnel must bring extra equipment to do the maintenance routine. Along with the extra equipment, it also involves climbing the transformer an extra time to place the equipment for draining. The project aims to address several issues in the context of the product. Redesigning the product to reduce maintenance time, and therefore downtime and electrical outages. Reducing the number of times that the transformer housing needs to be climbed in order to perform maintenance work. This with the purpose of improving working environment for maintenance personnel. With the new design of the maintenance tube, draining and sampling can be done with the same pipe without the need for extra equipment. This is through a mechanism in the tube which allows the personnel to choose whether to drain oil from the bottom of the container or to take oil samples from an area in the tap-changer housing which gives more accurate results. The function of the mechanism can be described in the same way as a pen, where if you push the button, a tube will extract itself and close of the sampling inlets, enabling draining from the bottom. Push the button again and the same tube will retract, allowing you to take samples from the appropriate area again. The new design also adheres to the dimensional requirements needed for the design to fulfil the additional functions the tube has. The project results in a design which would not only fill requirements of functions but also preserves some of the previous parts along with their interfaces. This means that the new design could be installed on current versions of tap-changer models when the next service interval is due.

Vibrations are everywhere around us all the time and we often recognise them as sounds that we can hear and analyse with our brain. In this thesis, data that has been gathered from a diverter switch (DS) in a controlled environment, is analysed. This data consists of vibroacoustic measurements and information to indicate what is happening inside the DS as the vibroacoustic data is gathered. The frequency properties of vibroacoustic data from the DS gathered before this thesis are displayed using a wavelet transformation model. This means the frequency properties of the signal can be approximated for all times in the operation with a certain accuracy. As the DS is built from many different components, the frequency properties of these components are compared to the time-frequency picture of the full DS operation. This sort of comparison ends up not being feasible as the complexity of the DS frequency pattern is much more than that of a sum of its component’s frequency pattern. A second approach of analysing the gathered vibroacoustic data is by using a classification model. The information about what is happening inside of the DS is used to train a logistic regression model on different defined regions of the vibroacoustic data. Before the training is preformed though, the different defined regions are transformed into frequency space with help of the fast Fourier transform. With this, a classification model is produced, where vibroacoustic data of any time region can be fed into the model and the model will classify which defined region this vibroacoustic data belongs to. The results are promising, and the model can be used both for classification of the defined regions and potentially used to determine if the vibroacoustic properties of the DS has changed due to wear of the mechanical components or transformer oil.

This is a bachelor's thesis in Mechanical engineering. The main topic of the thesis is the electrical calculation of the tap changer's shield. Although there are many kinds of tap-changers, this study focuses on VUCL models. The theoretical background of the thesis is that the new shield is suitable and useable in all VUCL models. The primary topic of the thesis is to study that the new shield protects the resistance box in the middle of the tap changers. To do this study, Creo Parametric, Comsol, and SpaceClaim are the programs used. / Detta är en kandidatexamen i maskinteknik. Avhandlingens huvudämne är den elektriska beräkningen av kranbytarens sköld. Även om det finns många olika typer av lindnings fokuserar denna studie på VUCL modeller. Den teoretiska bakgrunden för avhandlingen är att den nya skölden är lämplig och användbar i alla VUCL-modeller. Det primära ämnet för avhandlingen är att studera det nya sköld skyddar motståndet rutan i mitten av lindningskopplare. För att göra denna studie är Creo Parametric, Comsol och SpaceClaim de program som används.

The modern day power system is witnessing a tremendous change. There has been a rapid rise in the distributed generation, along with this the deregulation has resulted in a more complex system. The power demand is on a rise, the generation and trans-mission infrastructure hasn't yet adapted to this growing demand. The economic and operational constraints have forced the system to be operated close to its design limits, making the system vulnerable to disturbances and possible grid failure. This makes the study of voltage stability of the system important more than ever. Generally, voltage stability studies are carried on a single phase equivalent system assuming that the system is perfectly balanced. However, the three phase power system is not always in balanced state. There are a number of untransposed lines, single phase and double phase lines. This thesis deals with three phase voltage stability analysis, in particular the voltage stability index known as L-Index. The equivalent single phase analysis for voltage stability fails to work in case of any unbalance in the system or in presence of asymmetrical contingency. Moreover, as the system operators are giving importance to synchrophasor measurements, PMUs are being installed throughout the system. Hence, the three phase voltages can be obtained, making three phase analysis easier. To study the effect of unbalanced system on voltage stability a three phase L-Index based on traditional L-Index has been proposed. The proposed index takes into consideration the unbalance resulting due to untransposed transmission lines and unbalanced loads in the system. This index can handle any unbalance in the system and is much more realistic. To obtain bus voltages during unbalanced operation of the system a three phase decoupled Newton Raphson load ow was used. Reactive power distribution in a system can be altered using generators voltage set-ting, transformers OLTC settings and SVC settings. All these settings are usually in balanced mode i.e. all the phases have the same setting. Based on this reactive power optimization using LP technique on an equivalent single phase system is proposed. This method takes into account generator voltage settings, OLTC settings of transformers and SVC settings. The optimal settings so obtained are applied to corresponding three phase system. The effectiveness of the optimal settings during unbalanced scenario is studied. This method ensures better voltage pro les and decrease in power loss. Case studies of the proposed methods are carried on 12 bus and 24 bus EHV systems of southern Indian grid and a modified IEEE 30 bus system. Both balanced and unbalanced systems are studied and the results are compared.

This thesis deals with a power flow control in the electric power system. An overview of FACTS devices is introduced; their basic characteristics as well as examples of their application are discussed. A significant part of this thesis investigates phase shifting transformers (PST´s), which seem to be suitable for implementation in the transmission system of the Czech Republic. The PST´s are useful devices that control active power flows on cross-border lines and regulate unwanted and unexpected power flows. Basic types and characteristics of the PST´s are discussed. In chapter 7 is designed laboratory task that should validate the regulatory capabilities of the transformer PST. Designs of models of individual parts of this laboratory task are presented. In the last part of this thesis the regulation effect of the PST is validated in the GLF/AES program.

This thesis is an engineering design of an intelligent fast-charger for lead-acid accumulators. It contains calculations of each component. The switching power supply is the mainstay of the charger that makes the charger portable, lightweight and small. The Intelligent fast-charger for lead-acid accumulators charges the accumulator by method of constant voltage with current limitation of 0,5A, 5A, 10A, 50A. 50A current is used in winter during starting of a car, when the battery can´t provide sufficient current. There are three LEDs placed on the front side of the charger reflecting status of the device. The device comprises safety protection for the charger, supply network and battery.

Pour le superviseur, une approche historique de la banque permet de mieux assimiler ses modes de fonctionnement. Elle sert aussi à mieux comprendre pourquoi ses acteurs, toujours dotés, à raison, de la confiance indispensable au développement des affaires, font preuve parfois d’un sur-optimisme conduisant à leur ruine. La mobilisation du droit : telle est ce qui guide l’action du contrôleur de banque. La dernière crise financière a provoqué une prise de conscience en Europe : l’impossibilité pour chaque pays membre de l’Union d’exercer individuellement une surveillance efficace sans une harmonisation totale. Ainsi est née l’idée puis la construction du MSU. Centralisée à Francfort, la supervision unique est en place depuis le 4 novembre 2014. Mais sa feuille de route porte sur un champ plus diversifiable encore. Par construction, le MSU possède les qualités d’efficacité et de pérennité requises. Mais aura-t-il la volonté de contribuer à la transformation de toute l’Union européenne en zone de supervision optimale ? / For the supervisor, an historical approach of banks allows to better assimilate its ways of functioning. She also serves to better understand why her actors, always endowed of the confidence to develop business, sometimes, show an over-optimism leading to their ruin. The mobilization of the law guides the action of the banking control. The 2007-2008 crisis has provoked awareness in Europe: the impossibility for every member state of the Union to exercise individually an effective supervision without a total harmonization. So was born the construction of the MSU. Located in Frankfurt, the “supervision unique” has been working since November 4th, 2014. But the road map assigned to the supervision a new and more diversifiable field. For sure, the MSU is skilled enough, but is there a will to change the European Union into a “zone de supervision optimale”?