The forecasting of Eskom transmission electrical network demands is a complex task. The lack of historical data on some of the network components complicates this task even further. In this dissertation a model is suggested which will address all the requirements of the transmission system expansion engineers in terms of future loads and market trends. Suggestions are made with respect to ways of overcoming the lack of historical data, especially on the point loads, which is a key factor in modelling the electrical networks. A brief overview of the transmission electrical network layout is included to provide a better understanding of what is required from such a forecast. Lastly, some theory on multiple regression, neural networks and qualitative forecasting techniques is included, which will be of value for further model developments. / Computing / M. Sc. (Operations Research)

Le secteur industriel de l'énergie, et les réseaux électriques en particulier, rendent à nos sociétés modernes d'immenses services dont nous ne pouvons plus nous passer. Ils présentent aussi, hélas, un certain nombre de graves inconvénients, notamment en matière d'impact environnemental. Ces inconvénients apparaissent aujourd'hui comme inacceptables; le secteur de l'énergie s'efforce donc actuellement de les amoindrir autant que possible, dans le cadre de ce qu'on appelle la transition énergétique.Outre d'indispensables efforts en matière de sobriété et d'efficacité énergétique, deux grands axes d'amélioration se dessinent: d'une part, le remplacement progressif de certains moyens de production d'électricité conventionnels par des moyens de production renouvelables; et d'autre part, le transfert de certains usages aujourd'hui non-électriques vers l'électricité --- en particulier en matière de mobilité.L'intégration au réseau électrique de ces nouveaux types de dispositifs pose cependant des difficultés techniques considérables, qui motivent depuis le début des années 2000 de nombreux travaux sur le thème de ce que l'on appelle aujourd'hui les "smart grids": des réseaux électriques compatibles avec les exigences de la transition énergétique, c'est-à-dire capables d'accueillir massivement les nouveaux types d'usages comme la production photovoltaïque et les bornes de recharge des véhicules électriques, ceci notamment grâce à l'utilisation accrue des nouvelles technologies de l'information et de la communication. Parmi les difficultés susmentionnées, qui limitent la capacité d'accueil du réseau, figurent les congestions, c'est-à-dire les limites physiques à la puissance que l'on peut faire transiter d'un point à un autre sur une infrastructure donnée. C'est à la gestion des congestions que nos travaux sont consacrés. À ce sujet, la question fondamentale est de déterminer par quel enchaînement de mesures, de calcul, de communications et in fine d'actions, on peut passer d'une situation de contrainte sur un réseau de distribution d'électricité, à une situation où cette contrainte a été éliminée par l'action des flexibilités environnantes; autrement dit, en augmentant ou en réduisant judicieusement la production et/ou la consommation locales, et éventuellement en jouant sur d'autres types de leviers.L'objet de cette thèse est de participer à l'élaboration des outils conceptuels et informatiques qui nous permettront de répondre à la question fondamentale ci-dessus. Nos travaux portent ainsi sur la question de la modélisation des réseaux de distribution d'électricité "flexibles", et sur l'implémentation concrète des modèles retenus sous forme d'un logiciel de simulation ad hoc, parfaitement adapté à l'étude de ce type de réseaux. / The energy sector and the electrical networks in particular, provide great and indispensable services to our modern societies. Unfortunately, they also bring some serious drawbacks, especially with regard to the environment. These drawbacks are becoming more and more unacceptable; that is why the energy sector is trying to reduce them as much as possible, in the framework of the so-called energy transition.In addition to mandatory efforts in terms of energy efficiency and sobriety, two major directions of improvement have been identified: on the one hand, the progressive replacement of some conventional power plants with renewable production units; and on the other hand, the transfer of several non-electrical usages towards electricity --- in particular in the area of mobility.The integration of these new devices into electrical networks raise new technical challenges which, since the early 2000s, have been driving a lot of work about so-called "smart grids": electrical networks compatible with the requirements of the energy transition, ie. able to host new devices like photovoltaic solar panels and charging stations for electric vehicles, notably through the increasing usage of new information and communications technologies.Among the difficulties mentioned above, which limit the hosting capacity of the network, there are congestions ie. physical constraints limiting the amount of power that may be transmitted through a given infrastructure. Our work is devoted to the management of congestions. The fundamental issue thereon is to define a sequence of decisions, computations, communications and in fine actionsthat allows to move from a constrained situation on the electrical distribution network, to a situation in which the action of local flexibilities has lifted the constraint; in other words, to a situation where increasing or decreasing local generation and/or consumption, or taking some other control action, relieved the network.The aim of this thesis is to contribute to the development of conceptual and computing tools that will allow us to answer the fundamental aforementioned issue. Our work thus deals with the modelling of flexible electrical distribution networks, and with the tangible implementation of selected models in the form of ad hoc simulation software, specifically designed for the study of such networks.

Distúrbios em redes elétricas podem causar danos materiais e/ou operacionais em equipamentos eletrônicos sensíveis, em particular, sistemas em microcomputadores. Com o objetivo de registrar esses distúrbios, um monitor para redes elétricas foi desenvolvido. O equipamento desenvolvido é controlado por um microprocessador 80C86-2. Os seguintes distúrbios podem ser monitorados: desvios da freqüência nominal da rede, interferências de rádio freqüência, subtensão, sobretensão e surtos de tensão. Para minimizar o gargalo de Von Neumann, os circuitos foram projetados de forma que a maior parte das leituras é solicitada via interrupção. O equipamento foi testado a nível de laboratório e os resultados são apresentados. / Power line disturbances can adversely affect electronic sensitive equipment, particularly microcomputer based systems. In order to register these disturbances a power line monitor has been developed. The developed instrument is microprocessor based using a 80C86-2 as the main CPU. The following electrical disturbances can be monitored: nominal frequency deviations, radio-frequency interference, under and overvoltages, transient over voltages. Attempting to minimize Von Neumann´s bottle neck, the hardware was designed in such a way that most of the readings were requested through interrupts. The equipment was tested through a series of disturbance simulations, and the results are presented.

Elektros inžinerijos bakalauro baigiamojo darbo tema yra aktuali, nes elektros tinklai sumontuoti prieš 30–40 metų jau yra pasenę ir nebeatitinka šiuolaikinių poreikių. Vis daugiau elektros vartotojų keičia dujines virykles į elektrines, įsigija naujų elektros prietaisų, elektros suvartojimas auga, todėl būtina atnaujinti elektros tinklus, siekiant užtikrinti patikimą kokybiškos elektros energijos tiekimą. Šiuo projektu Skomantų kaime numatoma esamos oro linijos L-300 iš transformatorinės KT-V-305 rekonstravimas, ją pakeičiant apskaičiuoto skerspjūvio 0,4 kV elektros kabelių linijomis su reikiamu skaičiumi 0,4 kV skirstomųjų spintų (SS), įvadinių apskaitų skirstomųjų spintų (ĮASS) ir įvadinių apskaitų spintų (ĮAS). Numatoma trumpinti esamą oro liniją L-100 iš transformatorinės KT-V-305, pastatant dvi stulpines transformatorines su 25 kVA ir 40 kVA galios transformatoriais. Planuojamas oro linijos L-100 iš transformatorinės KT-V-305 ruožų nuo atramos Nr. 100/9 iki atramos Nr. 100/25 ir nuo atramos Nr. 101/18 iki atramos Nr. 101/25 demontavimas. / His Bachelors’ degree electrical engineering thesis is relevant, because the electricity network built 30-40 years ago in Skomantai village is already old and no longer meets todays’ needs. More and more electricity consumers change gas stoves into electrical stoves, purchase new electrical devices. The usage of electricity is increasing. That’s why the renewal of electrical network is needed in order to maintain reliable supply of high quality electric power. The plan of this project in Skomantai village is the reconstruction of existing transmission line L-300 from the transformer KT-V-305 reconstructing it by changing with calculated cross-section 0,4 kV electricity cables’ lines with needed number 0,4 kV 0,4kV distribution boards (SS), electrical distribution and metering equipment boards (ĮASS) and lead-in metering boards (ĮAS). Shortening of the existing transmission lines L-100 from transformer KT-V-305 and building two pole transformers with 25 kVA and 40 kVA power transformers. Dismantling of transmission line L-100 from transformer KT-V-305 parts from pole No. 100/9 up to pole No. 100/25, and from pole No. 101/18 up to No. 101/25.

The forecasting of Eskom transmission electrical network demands is a complex task. The lack of historical data on some of the network components complicates this task even further. In this dissertation a model is suggested which will address all the requirements of the transmission system expansion engineers in terms of future loads and market trends. Suggestions are made with respect to ways of overcoming the lack of historical data, especially on the point loads, which is a key factor in modelling the electrical networks. A brief overview of the transmission electrical network layout is included to provide a better understanding of what is required from such a forecast. Lastly, some theory on multiple regression, neural networks and qualitative forecasting techniques is included, which will be of value for further model developments. / Computing / M. Sc. (Operations Research)

Distúrbios em redes elétricas podem causar danos materiais e/ou operacionais em equipamentos eletrônicos sensíveis, em particular, sistemas em microcomputadores. Com o objetivo de registrar esses distúrbios, um monitor para redes elétricas foi desenvolvido. O equipamento desenvolvido é controlado por um microprocessador 80C86-2. Os seguintes distúrbios podem ser monitorados: desvios da freqüência nominal da rede, interferências de rádio freqüência, subtensão, sobretensão e surtos de tensão. Para minimizar o gargalo de Von Neumann, os circuitos foram projetados de forma que a maior parte das leituras é solicitada via interrupção. O equipamento foi testado a nível de laboratório e os resultados são apresentados. / Power line disturbances can adversely affect electronic sensitive equipment, particularly microcomputer based systems. In order to register these disturbances a power line monitor has been developed. The developed instrument is microprocessor based using a 80C86-2 as the main CPU. The following electrical disturbances can be monitored: nominal frequency deviations, radio-frequency interference, under and overvoltages, transient over voltages. Attempting to minimize Von Neumann´s bottle neck, the hardware was designed in such a way that most of the readings were requested through interrupts. The equipment was tested through a series of disturbance simulations, and the results are presented.

Este trabalho apresenta um estudo da aplicação da Transformada de Fourier Janelada à Qualidade da Energia Elétrica. Esta abordagem procura, pela implementação de um algoritmo computacional, detectar, localizar e classificar eventuais distúrbios que ocorrem em um determinado Sistema Elétrico. Da situação atual, tem-se que variações nas formas de ondas dos sinais de tensão como elevação, afundamento e interrupção de tensão, oscilações transitórias e ruídos, são freqüentes, chamando a atenção para a qualidade da energia elétrica fornecida pelas concessionárias. A análise de tais fenômenos, que normalmente é descrita no domínio do tempo (resolução de equação diferencial) ou no domínio da freqüência (através da Transformada de Fourier), pode agora ser analisada simultaneamente em ambos os domínios do tempo e da freqüência, dispondo-se da Transformada de Fourier Janelada. As janelas utilizadas para esta finalidade foram as de Hanning, retangular e a de Kaiser. Para esta análise em específico, a simulação dos diversos distúrbios ocorridos no sistema de distribuição foi realizada através do software ATP - Alternative Transients Program - cujas características seguem corretamente um sistema real da concessionária CPFL - Companhia Paulista de Força. Os testes efetuados mostraram que a Transformada de Fourier Janelada possui uma grande potencialidade quanto à sua aplicação na avaliação da qualidade da energia elétrica. / This dissertation presents a study of Windowed Fourier Transform applied to Power Quality. By the implementation of a computational algorithm, this approach aims to detect, locate and classify disturbances that may occur in Power Systems. Variations in voltage waveforms, such as sag, swell, interruption, oscillatory transient and noise have became frequent in electric systems, attracting the attention to the power quality supplied. The analysis of such phenomena, which is usually described either in the time domain (differential equation resolution) or in the frequency domain (Fourier Transform), can now be analyzed simultaneously in both domains: time and frequency, by the windowed Fourier Transform. The windows used to provide this information are the Hanning, rectangular and Kaiser. The simulation of the diverse disturbances occurred in the distribution system was accomplished by means of ATP software - Alternative Transients Program - whose characteristics correctly follow a real distribution system of CPFL electric utility. The tests show the windowed Fourier Transform has a great potentiality when applied to evaluate the power quality.

Parengtas bakalauro baigiamasis darbas yra skirtas suprojektuoti ir pagaminti automatinio rezervo įjungimo skydo prototipą, kurį būtų galima naudoti laboratoriniams darbams universitete.Šio darbo paskirtis yra papildyti elektros aparatų discipliną dar vienu, dažnai sutinkamu ir naudojamu visame pasaulyje stendu, paaiškinant jo veikimo principą, galimybes. Darbe aiškiai yra išdėstomos visos stendo dalys, stendui keliami reikalavimai, parodomos principinė ir valdymo schemos, paaiškinamas detalus veikimas, stendo valdiklio programos algoritmas. Taip pat supažindinama su Lucas-neulle mokomuoju dviejų atskirų tiekimo linijų stendu, parodant visas jo sudedamąsias dalis ir jas trumpai paaiškinant. / ATS helps to avoid serious problems in healthcare facilities for example by the same time when surgery is being held to save human lives and power supply interference occurs, it safely automatically switches power supply mains with no effect to the user. In industry it helps to avoid any power supply problems which every single of them could lead to destruction of expensive machinery or even harm people. Considering problems occurring in power supply lines, this was a great inspiration to produce automatic transfer switch prototype as my Bachelors degree thesis. Since Electrical Engineering Department had no real ATS system prototype before, it will surely supply existing basis and will help students to gain useful experience. Furthermore, all the details about ATS are expounded and will lead to full understanding of the system.

Este trabalho apresenta a proposta de um instrumento para utilização nos ensaios previstos nas Normas Brasileiras para certificação das instalações elétricas de baixa tensão. Descreve-se o projeto e a implementação do instrumento desenvolvido, bem como a metodologia para a execução dos testes de conformidade, de acordo com as Normas Brasileiras aplicáveis, utilizando os recursos disponíveis na instrumentação proposta. Um conjunto de testes para exemplificação de uso e validação dos testes é também apresentado. / This work presents an instrumentation system to perform tests and certification of low voltage electrical networks on residential and industrial buildings in accordance to Brazilian Norms. It intends to propose a methodology for tests executions using available resources on the developed instrumentation system. To show how the proposed system works several tests were done regarding to attend Brazilian technical standards.

Este trabalho apresenta a proposta de um instrumento para utilização nos ensaios previstos nas Normas Brasileiras para certificação das instalações elétricas de baixa tensão. Descreve-se o projeto e a implementação do instrumento desenvolvido, bem como a metodologia para a execução dos testes de conformidade, de acordo com as Normas Brasileiras aplicáveis, utilizando os recursos disponíveis na instrumentação proposta. Um conjunto de testes para exemplificação de uso e validação dos testes é também apresentado. / This work presents an instrumentation system to perform tests and certification of low voltage electrical networks on residential and industrial buildings in accordance to Brazilian Norms. It intends to propose a methodology for tests executions using available resources on the developed instrumentation system. To show how the proposed system works several tests were done regarding to attend Brazilian technical standards.