[pt] Quando ocorre algum tipo de falta em uma Linha de Transmissão (LT), sua localização exata é essencial para uma rápida recomposição do Sistema Elétrico. Métodos que utilizam tensão e corrente de apenas um terminal contêm simplificações que podem acarretar erros. Esta dissertação investiga a aplicação de Redes Neurais Artificiais (RNA) na obtenção de uma nova forma de identificar o tipo do curto- circuito e determinar a sua localização, utilizando dados obtidos em somente um terminal. O trabalho consiste de 4 partes principais: estudo bibliográfico da área de Redes Neurais; simulações de faltas para a obtenção de padrões; definição e implementação dos modelos de Redes Neurais para identificação e localização da falta; e estudos de casos. Na fase do estudo bibliográfico sobre RNA, foi verificado que as topologias de redes mais usuais são as Feed- Forward, que podem ter uma ou mais camadas de Elementos Processadores (EP), sendo as redes com múltiplas camadas (Multi-Layer) a configuração mais completa. Para treinamento da rede, o algoritmo de aprendizado mais utilizado é o Back Propagation. Como fruto deste estudo bibliográfico é apresentado neste trabalho um resumo sobre RNA. Nas simulações de faltas para obtenção dos padrões de treinamento e teste, foi utilizado um sistema automático que, através da combinação de vários parâmetros do sistema elétrico, gera situações diferentes de falta. Este sistema utiliza como base o programa Alternative Transient Program - ATP. Neste trabalho o sistema elétrico está representado por uma LT de 345 KV, com fontes equivalentes representando um sistema real de Furnas Centrais Elétricas. Todos o sinais de tensão e corrente utilizados são representados por fasores de 60 Hz, obtidos através da Transformada Discreta de Fourier (TDF). Os modelos de RNAs para identificação e localização de falta foram implementados com sub-rotinas de redes neurais do programa MATLAB ver. 6.0, representados por Redes Perceptron Multicamadas (Multi Layer Perceptron), treinadas com algoritmo Back Propagation com taxa de aprendizado adaptativa e o termo momentum fixo. Um modelo único de RNA identifica quais as fases (A, B, C e T) envolvidas, classificando o tipo de falta, que pode ser: Monofásica; Bifásica; Bifásica-Terra ou Trifásica. Para a localização da falta, foram definidas 4 arquiteturas de RNA, uma para cada tipo de falta. A ativação de cada topologia de RNA para localização é definida em função do tipo de falta classificada no modelo de identificação com RNA. Na etapa de estudo de casos testou-se o desempenho de cada modelo de RNA utilizando casos de testes em outras situações de falta, diferentes dos conjuntos de treinamento. A RNA de identificação de falta foi avaliada para situações de faltas envolvendo outras LTs, com diferentes níveis de tensão. Os resultados das 4 RNAs de localização da falta foram comparados com os resultados obtidos utilizando o método tradicional, tanto para os casos simulados quanto para algumas situações reais de falta. A utilização de RNAs para a identificação e a localização de falta mostrouse bastante eficiente para os casos analisados, comprovando a aplicabilidade das redes neurais nesse problema. / [en] When a kind of fault occurs in a Transmission Line, its exact location is essential for a fast reclosing of the Electric System. Methods that use voltages and currents from only one terminal contain simplifications that can to cause mistakes. This paper presents an investigation about application of Artificial Neural Network (ANN) obtaining a new way of identification for the type of the short circuit and its location, using data obtained only in one terminal. The work consists on the following 4 main parts: bibliographical study of Neural Network`s area; simulations of faults in order to obtain of patterns; definition and implementation of Neural Network`s models for identification and location of the fault; and studies of cases. In the bibliographical study step on ANN, it was verified that the topologies for the more usual nets are Feed- Forward,that can have one or more layers of Processor Elements (PE), being the nets with multiple layers the most complete configuration. For the net training, the more used learning algorithm is Back Propagation. Product of this bibliographical study presents in this work a summary about ANN. In the faults simulations in order to obtain the training patterns and test, it was used an automatic system that, through the combination of several parameters of the electric system, generates different fault situations. This system uses as base the program Alternative Transient Program - ATP. In this work the electric system is represented by a Transmission Line of 345 KV, with equivalent sources representing a real system of Furnas Centrais Elétricas. All the voltages and currents signs used are represented by fasors of 60 Hz, obtained from Discret Fourier Transformer (DFT). The ANN models for identification and fault location were implemented with subroutines of neural network of the program MATLAB version 6.0, represented by Multi Layer Perceptron, with algorithm Back Propagation with tax of adaptive learning and the term momentum fixed. Only one model of ANN identifies which phases (A, B, C and T) are involved, classifying the fault type, that can be: Singlephase; Phase-to-Phase; Double Phase-to-Ground or Three-phase. For the fault location, they were defined 4 architectures of ANN, one for each type of fault. The activation of each topology of ANN for location is defined depending on of the fault type classified in the identification model with ANN. In the stage of cases study the representation of each model of ANN was tested using cases of tests in other fault situations, different from the training groups. The ANN of fault identification was evaluated for situations of faults involving other Transmission Line, with different voltage levels. The results of 4 ANNs of fault location were compared with the obtained results using the traditional method, so much for the simulated cases as for some real situations of fault. The use of ANNs for the identification and the fault location has shown quite efficient for the analyzed cases, proving the applicability of the neural networks in that problem.

No description available.

Frequency response analysis (FRA) has emerged as the de-facto industry standard condition-monitoring tool to assess mechanical integrity of transformer windings during its service life. It the prerequisite detection sensitivity and customized portable commercial instruments are also available. Considering its importance and taking cognizance of its hidden potential, international bodies, viz., IEEE, IEC, and CIGRE have published standards/guides on its use and interpretation. In spite of all the progress witnessed over the past two decades, FRA has still not attained the status of a diagnostics tool. Probing the vast literature and research carried out in this points to the fact that lack of a rigorous mathematical basis to explain the underlying complex processes is, perhaps, one of the main reasons for the present predicament of FRA method. How-ever, it must be acknowledged that domain-knowledge is di cult to generalize in this. Having said that, the diagnostic part, which involves, the task of working back-wards starting from the FRA data to interpret a winding damage, locate it, and assess its severity, has so far remained teasingly elusive. As a consequence, FRA continues to remain as a sensitive condition-monitoring tool. Given its inherent potential, this situation seems to be a paradox, and so, calls for investigations. Once a mechanical damage has been detected by FRA, the next task is to locate its position and estimate its severity. An engineer expects FRA to provide these answers, so that corrective action, if needed, can be determined and initiated. In this context, even though FRA has attained global acceptance as a monitoring tool, it has failed as a diagnostic tool. Therefore, e orts that aim to address this issue are desirable. Driven by this motivation, the author's thesis proposes to explore a new school of thought in this direction, viz., to theoretically analyze the problem of localization of an incipient/minor mechanical damage (displacement in particular) and also assess its severity. Such an investigation seems to have not been undertaken previously. So, the goal is to establish a relationship to capture the complex interactions that exist between specific winding damages, winding parameters, and their overall in hence on the natural frequency deviations observable in the FRA data. Hence, exploring this possibility, subject to the constraint that the proposed method shall use inputs that are measurable at the terminals, becomes the primary objective of this research. In this thesis, a generalized analytical framework for handling winding displacements and FRA data has been successfully formulated. The formulation provides a general platform for localization and severity assessment of true radial and axial winding dis-placements occurring in an actual winding. An analytical solution becomes possible mainly due to manipulation of the system matrix, i.e., to consider the harmonic sum of squares of natural frequencies, instead of just the natural frequencies. This manipulation leads to an elegant closed-form expression that connects the displacement location and its severity, to changes in natural frequencies. For its implementation, short circuit natural frequencies and a few other terminal measurements are the only inputs that are necessary. This formulation is initially used in Chapter-3 to demonstrate localization of radial displacement in an isolated, actual, single, air-cored continuous-disk winding. Armed with this success, the supplicant proceeds further to show (in Chapter-4) how a minor manipulation of the formulation renders it suitable for localization of actual axial displacements as well. Extensive experimental verification was done and the results are encouraging. Accuracy of localization of radial/axial displacement is uniformly good for all positions, and so is the estimation of severity. Further details are presented in the thesis.

Dans le domaine du transport de l'électricité, les qualités intrinsèques des réseaux alternatifs s'estompent devant la difficulté imposée par le transport de la puissance réactive lorsque les lignes aériennes ou, plus particulièrement, les câbles souterrains ou sous-marins atteignent des longueurs critiques. Dans le cadre des réflexions visant à exploiter au mieux les énergies renouvelables d'origine éolienne off-shore ou hydrolienne, l'hypothèse de la création d'un réseau électrique à haute tension continue pour acheminer ces énergies jusqu'aux centres de consommation est considérée. Ce travail de thèse est en lien avec le projet européen TWENTIES (Transmission system operation with large penetration of Wind and other renewable Electricity sources in Networks by means of innovative Tools and Integrated Energy Solutions, ref 249812), financé dans le cadre du programme FP7 de la Commission Européenne. Ces travaux traitent de la protection des réseaux à courant continu contre les défauts d'isolement dans les câbles et au niveau des jeux de barre. L'étude se concentre sur des réseaux multi-terminaux bouclés et/ou maillés, et propose d'étudier la faisabilité d'un plan de protection comportant un algorithme principal et un secours en cas de défaillance d'un disjoncteur. / In the area of power transmission grids, the inherent qualities of alternative current networks fade behind the difficulty imposed by the transmission of the reactive power when overhead lines or, particularly, underground or undersea cables reach critical lengths. As part of thought aimed for operate at best renewable energy resources, namely wind or marine resources, the assumption of the creation of a high voltage direct current power grid to dispatch those energies to the consumption centers is considered. This Ph.D work is linked to the European project TWENTIES (Transmission system operation with large penetration of Wind and other renewable Electricity sources in Networks by means of innovative Tools and Integrated Energy Solutions, ref 249812), funded as a part of the 7th framework program of the European Commission. This work deal with the protection of DC grids against insulation faults occurring in the cables or at a busbar. The study focusses on meshed and/or looped multi-terminal grids, and proposes to study the feasibility of a protection plan including a main protection algorithm and a backup in case of breaker failure.

This work deals with design of battery management system. Requirements for battery management system and its conception is discussed in the first part of the work. System is able to disconnect load or charger from battery using MOS-FET transistors. It measures battery cell's voltages and is capable of passive balancing. Microcontroller is used for data processing and system control. Schematics, printed circuit board layout and control algorithm was designed. Prototype of the battery management system was then manufactured and tested.

This master thesis is focused on the design of earthing switch for the indoor three pole generator disconnector from IVEP, a.s. The main task of the theoretical part of the master thesis was mechanical and electrical calculations on the contact system and the design of two variants of earthing switch construction. It has been proposed two variants of earthing switch construction. The first variant included three earthing knives for each pole of earthing switch and the other variant included two earthing knives for each pole. The aim of the practical part of this diploma thesis was to create a model of the earthing switch for generator disconnector, to simulate the heating of the contact system by passing the short-circuit current and to prepare the production documentation. For modeling, calculations and simulations were used Autodesk Inventor 2018, Matlab and Ansys Workbench.

This master thesis is focused on the design of earthing switch for the indoor three pole generator disconnector from IVEP, a.s. The main task of the theoretical part of the master thesis was mechanical and electrical calculations on the contact system and the design of two variants of earthing switch construction. It has been proposed two variants of earthing switch construction. The first variant included three earthing knives for each pole of earthing switch and the other variant included two earthing knives for each pole. The aim of the practical part of this diploma thesis was to create a model of the earthing switch for generator disconnector, to simulate the heating of the contact system by passing the short-circuit current and to prepare the production documentation. For modeling, calculations and simulations were used Autodesk Inventor 2018, Matlab and Ansys Workbench.

This master's thesis deals with the comparison of the short-circuit current calculation for a model example according to the standard IEC 60909-0:2016 with simulation programs. The first part deals with short-circuit in general together with an example of calculation of short-circuit currents. The next part of the master’s thesis deals with creating models of network elements by different simulation programs. The last part deals with dynamic simulation of model example together with programs settings. Finally, the results of simulations are evaluated.

Knowlege of elektric power, power dissipation and voltage conditions in every single segments and elektric power system nodes is necessary for operations control and designing of another elektric power system expansion. In this Thesis, we will handle with steady state of system calculation using PAS-DAISY-OFF LINE software, solving various power network configurations and their verification.

This thesis dwells on program creating in program environment Excel, in accordance with submission from submitter. Program is going to be able solve all required values. This thesis has four parts. First part is oriented on problems of urban mass transportation a methods of specific energy consumption. Second part contains program flowchart and program description. Third part contains theoretical solution of specific energy consumption and theoretical comparison of computing methods. Last part contains numerical substitution in an equations and calculating of their values.