Orientador: Maria Cristina Dias Tavares / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-13T12:17:57Z (GMT). No. of bitstreams: 1 Montanari_AllanAlves_M.pdf: 7585929 bytes, checksum: 4c00ba94f40e488cc4da50c4089e8630 (MD5) Previous issue date: 2009 / Resumo: Este trabalho apresenta um esquema de religamento monopolar adaptativo rápido para otimizar o tempo compreendido entre a abertura e o religamento da fase sob falta. A proteção adaptativa recompõe rapidamente o sistema de transmissão de energia elétrica, minimizando a probabilidade de propagação de perturbações severas no sistema. O método é fundamentado na análise de dados de ensaios de arco secundário gerados e monitorados numa estrutura de testes construída em campo, composta por um trecho real de linha de transmissão (três torres e dois vãos). Analisou-se o conteúdo harmônico da tensão e da corrente de arco secundário através da aplicação da Transformada de Fourier Janelada. Tais análises viabilizaram a realização de um tratamento estatístico para a caracterização da assinatura harmônica de arco secundário. Simulações de faltas monofásicas foram realizadas utilizando dados provenientes dos Ensaios de arco secundário. Desenvolveu-se um algoritmo baseado nas características Harmônicas da tensão da fase sob falta, calculadas através do deslocamento de uma janela de tempo sobre os sinais analisados (Transformada de Fourier Janelada). O algoritmo determina a existência do arco secundário e fornece informações a respeito do instante no qual o religamento pode ser realizado com sucesso. O método apresenta também um mecanismo para a detecção da característica permanente ou transitória da falta. / Abstract: This work presents a fast adaptive single-phase autorec1osingseheme to optimize the period between the tripping operation and the rec10sure of the faulted phase breakers. The adaptive proteetion quiekly reeomposes the eleetric power transmission, minimizing the probability of severe damages propagation in the system. The method is based on the analysis of secondary are field tests data that were generated and monitored in an infra-structure which consists of a real transmission line section (three towers and two spans). The harmonic content of the secondary are voltage and eurrent was analyzed by the application of Short Time Discrete Fourier Transform. Such analysis made it possible to implement a statistical approach in order to obtain the secondary are harmonic signature. Single-phase faults computer simulations were performed using the data obtained from the secondary are tests. It was developed an algorithm based on the voltage harmonic content of the faulted phase, which was ea1culated by shifting a window on the analyzed signals (Short Time Discrete Fourier Transform). The algorithm determines the secondary are existence and provides information in order to suceessfully rec10se the circuit breaker. The method also presents a control mechanism responsible for identifying whether the fault is a permanent one or a transient fault. / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

M.Ing. (Electrical And Electronic Engineering) / In-vehicle Power Line Communication (PLC) is an emerging technology that can easily bene t the automotive industry by reducing the amount of wires (and hence cost, weight and complexity) for vehicle wire harnesses. The reduction in weight would also lead to less fuel consumption. This dissertation aims at taking the research of this technology a step towards fully understanding the vehicle's power line as a communication medium. We investigate the bit error characteristics of a readily available transceiver on the vehicle's power bus. To do so, we develop and perform bit error recording over the medium to get experimental results with the battery line under di ferent operating conditions. Using the rst set of these results, we parametrise di erent kinds of Markov models to see which one simulates the channel best. Using the preferred model, we then model the rest of the sets of results so that we can simulate the channel's bit error characteristics under these di erent conditions. Using these models, we demonstrate how these simulations can be used to evaluate the performance of di erent error detection and correction techniques. In particular, we evaluate the error detection mechanisms used in the popular in-vehicle Local Intercon- nect Network (LIN) protocol, in addition to some simple error correction techniques.

D.Ing. / In this study we consider the application of Reed-Solomon codes on two distinct channels. The first channel is the packet erasure channel, where packets are either received errorfree,or packets are lost. The second channel is the power line channel where additive Gaussian noise,, impulsive noise and narrowband noise are encountered In this thesis we focus on M-FSK modulation for the power line channel. For the packet erasure channel,we develop two new erasures-only decoders .The distinction between the two decoders is that the one is optimized for burst erasure correction, while the second decoder is optimized for random erasure correction.It is found that for single burst erasures, or bursterasures contained within n - k elements (where n is the code length and k is the number of information elements to be encoded), the best performance is obtained with the burst erasure decoder. When used in conjunction with a modified interleaver found in the literature, the developed random erasure decoder yields the best all-round performance. The main contribution to the power line channel is the development of a combined demodulation and decoding strategy to detect narrowband interference When standard Reed-Solomon codes operate in a channel where narrowband interference is present, undetected errors result. With the proposed decoding strategy it is found that wideband noise (a generalization of impulsive noise) affects the performance more negatively than narrowband noise for M-FSK modulation. .

The central problem which overhead electric transmission lines pose for suburban areas is that right of way location decisions made in earlier years have influenced, and sometimes determined, the present overall pattern of suburban development and especially its residential aspects. The study is therefore limited to considerations of the impact on residential areas. The result has been that past decisions made by one agency on the basis of technical determinants and economic criteria applicable to a utility project have often been responsible for the present form and pattern of urban areas. Another problem is that in the suburban areas near those lines which have ugly structures and unmaintained rights of way, there is an adverse effect upon the quality of adjacent residential development. This effect is most marked in those areas which are striving for urban standards of residential density and neighbourhood amenity. Almost equally important with the effects which power lines may have on the areas they pass through is the simple fact of the tremendous amount of land which they use and alienate for most other urban uses. The study is concerned with the impact of overhead electric transmission lines on suburban areas, and not with electric lines at distribution voltages. Extra high voltage lines are of special interest to planning, for they present technical and economic problems which either preclude or make impractical converting them to underground forms. Accordingly, as overhead transmission lines are likely to have continuing effect, the following hypothesis is advanced. Because the location of overhead electric transmission lines has had considerable influence (sometimes adverse) on the spatial pattern of residential development, there is need for coordinating the requirements of the utility agency and the appropriate planning agencies. The study describes in some detail those locational requirements and standards of electric transmission lines which have a bearing upon the use of land. The optimum locational requirements for overhead electric transmission line rights of way and suburban density and types of residential development are shown to be nearly identical. The two are therefore in competition for the use of land, and this competition is most marked in suburban areas where land values are lower than in the central city. A specific examination is carried out of transmission line effects on the suburban residential area of Surrey, British Columbia, which is an urbanizing municipality on the fringes of the Vancouver metropolitan area. The case study shows that there is a significant correlation between the present pattern of residential development, as measured by assessment values and population distribution, and the presence of transmission line rights of way. The study concludes that the presence of the lines is the most likely causal factor. That the influence has been sometimes adverse is not as definitely established, but the conclusion may be inferred from subjective evaluation of the aesthetic evidence presented. Further study of objective evidence is called for. The statement in the hypothesis that it is necessary to coordinate the requirements of the utility agency and the appropriate planning agencies is basically valid, but is felt to be inadequate. It is concluded that the activity must, wherever possible, be an integrative one, and involve many other departments of government, including the federal. It is suggested that an integrative Provincial Development Department could well be the most effective method of controlling the more unfavourable aspects of electric transmission line right of way location and appearance. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

Several methods for calculating the electrical phase and modal parameters of overhead transmission lines are described in this thesis; then, a graphical method for evaluating communication frequency response of delta transmission lines -based on the guidelines given by W. H. Senn [12,13,14]- is developed. The graphical method, combined with the parameters calculation methods, obviates the need of large mainframe computers for the analysis of power line carrier (PLC) systems. A new technique for assessing coupling alternatives, based on Senn's method, is developed. The technique is applied to generate coupling recommendations; it is found that many of the current recommendations given elsewhere [21] are not reliable. Finally, future work to be done in this field is proposed. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

M.Phil. / The advantages offered by power line communications (hereon after called PLC) cannot be over-emphasized neither can the inherent problems affecting its commercial takeover be underestimated. This research work creates a background study for experimental measurement and eventual implementations on power lines. It explains those salient aspects of commercially available communication modules that are rather not straight forward to understand from reading the Comblocks user manual. Especially, addressing those shortcomings of Comblocks that were not indicated in the documentation, we o er solutions to those we could nd our way around. M-ary frequency shift keying was implemented. This implementation tested the ro- bustness of the scheme against noises, attenuation and other power line channel char- acteristics as encountered practically. Based on our results, we nally recommend an optimal set of frequencies; we believe to be good for use in most PLC application pur- poses. Pseudo random bits of information were generated, encoded and modulated; the signals were transmitted over power line channels. The impact of noise sources, impulse noise especially was observed at di erent distances along the channel. Coupling and decoupling circuits used for this research, with associated issues sur- rounding the use of coupling circuitry are also presented. The CENELEC norm for PLC communication was adhered to, hence only frequencies that fall within the CENELEC speci cation for low voltage power distribution network were considered for MFSK use. Signal-to-noise ratio and other factors that a ect signal transmission over PLC was also measured. A complete communication system comprises of the transmitter, the channel and the receiver. This work however did not cover the receiver part of the system. Future work can now be done on this aspect which amongst others can take care of synchronization issues, in which a coding system as well as bit error rates can be determined.

D.Ing. / The technique of using a live power cable to simultaneously transport a communication signal, has been practiced since the early 1900’s. In most cases, power-line communications has been implemented as a retrofit technology, with its main benefit being the utilization of a ‘free’ existing network. This driving force of power-line communications is typical for high-, medium-, and low-voltage distribution networks, as well as intra-building networks currently targeted for home automation and home networking. Researchers have thus focused on the optimum use of these existing power-line channels, often accepting the inherent drawbacks of this hostile communication channel. Apart from unpredictable noise sources, two main disadvantages of the low-voltage powerline network as a communication channel, are i) the unknown power cable characteristics and topology and ii) time-dependent fluctuation of the power-line impedance level as loads are unpredictable switched into, and out of the network. These two factors have obscured the requirements for proper coupling and impedance adaptation to the degree that most researchers and manufacturers have merely accepted this typical ≈ 20-dB coupling loss as one of the inherited disadvantages of the power-line channel. Most researchers and manufacturers have thus defaulted to a guessed power-line impedance level, and have used one fixed coupler winding ratio under all circumstances, regardless of power-line conditions. This study has shown that proper coupling and impedance adaptation can yield significant transmission gains even with limited (qualitative) knowledge of a power-line channel and its topology. After formulating design steps for an impedance-adapting coupler that facilitates bidirectional transmission, the impact of the fluctuating power-line impedance on coupler bandwidth was investigated. Next, impedance adaptation strategies were considered and the tradeoff between series cable requirements and parallel load requirements was explored. A model of sufficient simplicity was developed to facilitate qualitative description and classification of power outlets – functioning as communication nodes. Very interesting simulation results were obtained and these were verified using a laboratory setup of characterized power cables and calibrated loads. Next, these simulation results were employed to improve power-line transmission over a live, uncharacterized 220-V residential network by means of i) classifying typical residential rooms qualitatively in order to choose proper coupler winding ratios and ii) using an innovative dual coupler for dedicated on-off switching with harsh loads, thereby mitigating the fluctuating impact of said loads on low-voltage power-line communications.

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