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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
81

Túneis rodoviários: proposta de avaliação de conformidade para liberação ao uso e operação comercial / Road tunnels: propose of a conformity evaluation for the liberation use and commercial operation

André Luiz Gonçalves Scabbia 01 October 2007 (has links)
O processo de liberação da operação comercial de um túnel rodoviário, sempre é realizada sobre a pressão típica do final de um cronograma, cujo prazo final, está em vias de se esgotar. Por outro lado considerando os relevantes riscos envolvidos com a operação de um túnel, o órgão público que libera o início da operação comercial (Artesp no caso do Estado de São Paulo), deve ter plena certeza que a nova estrutura está pronta a utilização e apresenta-se totalmente preparada a atender os requisitos mínimos de segurança. O presente trabalho propõe uma metodologia de avaliação de conformidade aderente a NBR ISO/IEC 17020:2006 - avaliação de conformidade com os critérios gerais para o funcionamento de diferentes tipos de organismos que executam inspeções. Para tanto foi realizado um extenso e minucioso trabalho de identificação dos requisitos aplicáveis, concatenando as referências internacionais de túneis, o modus operandi nacional e a ferramenta gerenciamento de riscos, que resultaram numa proposta de metodologia de avaliação de conformidade composta por onze atividades, que aplicadas permitem avaliar as condições de liberação ao uso e operação comercial de túneis rodoviários. / The process of releasing the commercial operation of a road tunnel is always done under the typical pressure of a chronogram deadline. On the other hand, considering the relevant risks involved with the tunnel operation, the public institution that releases the beginning of the commercial operation (ARTESP, in the case of São Paulo State), should be totally sure that the new structure is ready to be used and shows it is completely prepared to meet the needs of the minimum security requirements. The present work proposes an evaluation methodology of adherent conformity the NBR ISO/IEC 17020:2006 Conformity evaluation with the general criteria for the functioning of different types of organisms that perform inspections. In order to do so, a large and detailed work of identification of the applicable requirements, linking together the international references of tunnels, national way of working and the tool Management of Risks, that ended in a proposal of conformity evaluation methodology composed by eleven activities, that if applied, allow evaluation of the releasing conditions to the use and commercial operation of road tunnels.
82

Processos de apoio ao desenvolvimento de aplicações web / Supporting process for Web applications development

Osnete Ribeiro de Souza 06 May 2005 (has links)
Num curto período de tempo, a Web tornou-se o aspecto central de muitas aplicações em diferentes áreas. Rapidamente, cresceu e diversificou seu uso, e diversos setores de negócio realizam suas operações no ambiente da Web. Entretanto, à medida que cresce a extensão de uso de aplicações Web, que se tornam mais complexas, aumenta a preocupação com a maneira como as aplicações são desenvolvidas. Freqüentemente, a abordagem de desenvolvimento é ad hoc, desprovida de técnicas sistemáticas e de metodologias sólidas, resultando em aplicações de baixa qualidade. A fim de alcançar aplicações Web bem sucedidas, há a necessidade de melhores princípios de esenvolvimento que devem considerar as características especiais dessas aplicações. Dessa forma, o objetivo do trabalho é propor Processos de Apoio ao desenvolvimento das aplicações Web, baseando-se nas características dessas aplicações e nos Processos de Apoio da ISO/IEC 12207. Os processos de Apoio visam auxiliar outros processos do ciclo de vida da aplicação a alcançar produtos de qualidade e o sucesso do projeto / Within a short period, the Web has become the central aspect of many applications in different areas. Rapidly, it has grown and diversified in its scope and use. Diverse business sectors improve their operations in Web environment. The Web application has become more complex and it has increased the concern with the way the application is developed. Frequently, the development is ad hoc, unprovide of systematic methods and methodologies, resulting in poor quality applications. In order to have successful Web applications, it is necessary better principles of development that have to consider the characteristics of these applications. The objective of this work is to propose Supporting Process for development Web applications, based on the characteristics of these applications and the Supporting Process of ISO/IEC 12207. The Supporting processes aim to assist other processes of the cycle of life of the application to reach quality products and successful projects
83

Kybernetické prostředí pro systémy typu ICS/SCADA / Cyber-environment for systems of ICS/SCADA type

Váňa, Martin January 2019 (has links)
The thesis explores the problematics of cyber environment for the ICS/SCADA systems. First, shorter section is mainly focused on general introduction into the ICS/SCADA systems and their inner workings. Communication model of a general SCADA system and its foundational elements are explained. It is mainly theoretical passage and it serves as an introduction. It is necessary for understanding the second part which is mainly practical. The appropriate system is chosen as a first thing in the practical part of the thesis for the implementation of the whole project. There are defined criteria on which the system itself is implemented. Following that the system itself is implemented under a framework called openMUC and it is tested with help of the simulators according to the objective of the thesis.
84

HiFi DA převodník a sluchátkový zesilovač / HiFi DA Converter with Integrated Headphone Amplifier

Doležal, Pavel January 2014 (has links)
This thesis is dealing with a design and fabrication of D/A coverter and headphone amplifier for stereo reproduction in Hi-Fi class. In opening chapter, overall problematics of digital audio signal distribution is discussed. Following chapters are dedicated to converter design, communication protocols, component selection, converter production, circuitry design and firmware programming. The final chapter is dealing with expansion options such as HDMI inputs and surround sound.
85

Model-Integrated Engineering of Smart Energy Distribution Systems

Galkin, Nikolai January 2023 (has links)
Model-Based Systems Engineering (MBSE) is a formal method that is used to support analysis, design, independent verification, and validation inherent in the development of software and hardware systems. MBSE applications are present in many areas of our daily lives, including manufacturing, robotics, healthcare, automation, etc. However, despite their rapid and sustainable growth during the last few years, the MBSE methods themselves are quite far away from perfect. There are some current problems, which resist more rapid penetration of MBSE systems in their development. One of them is that currently the majority of MBSE systems are vendor dependent and, as a result, they have poor compatibility with each other. Furthermore, currently, there is a gap between the design of a digital model and a control model of an engineering system. Currently, this problem is usually solved by involving two or more groups of engineers, where each of these groups works on their own problems. All this costs companies additional engineering time and, as a result, development costs. Therefore new, and more sophisticated approaches for the generation of MBSEs are needed in order to overwhelm the challenges highlighted above. In order to narrow the field of study and better concentrate on specific problems, smart power distribution systems have been chosen as the main research object for this dissertation. Thus, in this work, the author introduces Model-Integrated Systems Engineering (MISE), as the MBSE sub-discipline. Here and later in this paper, the author will refer to MISE as the main area of interest. Also, the author uses the term DigitalTwin to refer to the multilayered structure of a complex distributed automation system consisting of three layers, namely:– the static machine-readable information about the infrastructure of the smart energy system,– the simulation model layer,– the distributed control layer for the investigated smart energy system. In general, two new transformation approaches for automatic MISE generation are discussed in the scope of this dissertation, namely:1. Transformation of the System Configuration Design (SCD) files of an electric system(presented in IEC 61850) into the corresponding SIMULINK model.2. Transformation of specification files of electronic components into corresponding OPC UA information model.All discussed approaches are implemented in the form of a program code that is publicly available on the Internet. The IEC 61850 and OPC UA standards are considered key components of the current dissertation. IEC 61850 is an international standard covering different sides of smart energy distribution systems including communication protocols for diverse equipment in a substation, including protection, control, and measurement equipment, as well as intelligent electronic devices (IEDs). Information Modeling OPC UA is a platform-independent service-oriented architecture that combines the concepts of semantic modeling. First, the structure of the IEC 61850 standard is discussed, as well as its potential benefits for the MISE of smart power distribution systems in terms of the automatic transformation of the information model. Next, the architecture of the electrical system (the SCD file) of the electrical vehicle (EV) charging station (CS) is proposed as an example. The aim is to design a mechanism for the automatic transformation of MISE in two domains, namely:- Physical model of the electrical system itself,- Automatically build a communication channel between the digital replica (the model) of the electrical system and the virtual energy management system (EMS). Thus, this work aims to contribute to the design and virtual commissioning of Digital Twin systems, as well as to improve the interoperability between IEC 61850 compliant systems and electric vehicle charging stations (paper C explains that in more detail). Finally, by narrowing down the scope of the investigation to one specific electrical device, a new approach for converting integrated circuit (IC) specification files of an electric system into an OPC UA information model is discussed. The designed transformation algorithm is based on the directed graphs theory (paper D explains that in more detail). The purpose of this work is to highlight and contribute to the problems of the MISE analysis solutions.  In summary, the work presented in this dissertation raises questions about interoperability between different standards, the problems of converting the IEC 61850 information model into MISE, verification of the generated MISE compared to the original IEC 61850 information model, and the problems of forming an information model OPC UA.
86

Effekterna av en ISO/IEC 27001-certifiering : Upplevda förändringar bland små svenska organisationer / The effects of ISO/IEC 27001 certification : Perceived changes among small Swedish organizations

Ljunggren, Viktor, Freid, Emil January 2020 (has links)
Samhället idag är mer uppkopplat och hanterar större mängder information än tidigare. Informationen hanteras i större omfattning av IT-system där kraven på säker hantering av information blir allt större. För att hantera informationssäkerhet kan organisationer implementera ett ledningssystem för informationssäkerhet (LIS). Det tar både tid och resurser att designa och implementera ett LIS. För att denna investering ska vara lönsam bör den också ge ett mervärde för organisationer. För att standardisera och specificera uppbyggnaden av LIS har ISO/IEC 27001 (standard för LIS) utvecklats och implementerats av organisationer världen över. Syftet med denna studie är att identifiera vilka förändringar som en ISO/IEC 27001-certifiering leder till hos små organisationer i Sverige. En intervjustudie har utförts med en semistrukturerad intervju som datainsamlingsmetod. Utifrån den insamlade empirin har sex kategorier identifierats och beskrivs tematiskt utifrån varje informant. Studien visar att organisationer får en bättre process och kontroll över informationssäkerhet och en stärkt informationssäkerhetskultur. Utöver detta uppges informationssäkerhet ha förbättrats bland organisationer genom olika säkerhetsåtgärder. Dessutom har kommunikationen med kunder förenklats, när informationssäkerhet diskuteras. Studien undersöker ISO/IEC 27001-certifierings påverkan hos flera organisationer, för att få en diversitet på den insamlade empirin. Detta genomfördes med en informant per organisation, med överblick över både organisationen och certifieringen. Studien undersöker organisationer som redan är certifierade, då organisationen ska ha implementerat ISO/IEC 27001-standarden. Varken certifieringsprocessen, säkerhetsåtgärder, implementationen av eller tillämpningen av ledningssystemet har undersökts i denna studie. / Society today is more connected and handles more information than ever before. The information is handled to a greater extent by IT systems, where the requirements for secure information management have increased. To manage this increase in information flow, organization can implement an information security management system (ISMS). It takes both time and resources to design and implement an ISMS. For this investment to be profitable, it should also provide additional value for companies. In order to standardize and specify the structure of ISMS, ISO/IEC 27001 (Standard for ISMS) has been developed and implemented by companies all over the world. The purpose of this study is to identify the changes that an ISO/IEC 27001-certification leads to for small organisations in Sweden. An interview study has been conducted and semi-structured interviews has been used for data collection. Based on the collected empirical evidence, six categories have been identified and described thematically for each informant. The study shows that organisations get a better process and control over information security and a strengthened information security culture. In addition, information security is said to have improved among organisations through various security measures. In addition communications with customers have been simplified, whenever information security is discussed. The study examines the impact of ISO/IEC 27001-certification on four organisations, in order to ensure diversity of the empirical evidence collected. This was done with one informant per organisation, with an overview of both the organisation and the certification. The study examines organisations that are already certified, since the organisation need to have implemented the ISO/IEC 27001 standard. Neither the certification process, the security measures, the implementation nor the application of the management system have been investigated in this study.
87

Specifying Safety-Critical Heterogeneous Systems Using Contracts Theory

Westman, Jonas January 2016 (has links)
Requirements engineering (RE) is a well-established practice that is also emphasized in safety standards such as IEC 61508 and ISO 26262. Safety standards advocate a particularly stringent RE where requirements must be structured in an hierarchical manner in accordance with the system architecture; at each level, requirements must be allocated to heterogeneous (SW, HW, mechanical, electrical, etc.) architecture elements and trace links must be established between requirements. In contrast to the stringent RE in safety standards, according to previous studies, RE in industry is in general of poor quality. Considering a typical RE tool, other than basic impact analysis, the tool neither gives feedback nor guides a user  when specifying, allocating, and structuring requirements. In practice, for industry to comply with the stringent RE in safety standards, better support for RE is needed, not only from tools, but also from principles and methods. Therefore, a foundation is presented consisting of an underlying theory for specifying heterogeneous systems and complementary principles and methods to specifically support the stringent RE in safety standards. This foundation is indeed suitable as a base for implementing guidance- and feedback-driven tool support for such stringent RE; however, the fact is that the proposed theory, principles, and methods provide essential support  regardless if tools are used or not. The underlying theory is a formal compositional contracts theory for heterogeneous systems. This contracts theory embodies the essential RE property of separating requirements on a system from assumptions on its environment. Moreover, the contracts theory formalizes the stringent RE effort of structuring requirements hierarchically with respect to the system architecture. Thus, the proposed principles and methods for supporting the stringent RE in safety standards are well-rooted in formal concepts and conditions, and are thus, theoretically sound. Not only that, but the foundation is indeed also tailored to be enforced by both existing and new tools considering that the support is based on precise mathematical expressions that can be interpreted unambiguously by machines. Enforcing the foundation in a tool entails support that guides and gives feedback when specifying heterogeneous systems in general, and safety-critical ones in particular. / Kravhantering är en väletablerad praxis som ocksåbetonas i säkerhetsstandarder såsom IEC 61508 och ISO 26262. Säkerhetsstandarder förespråkar en särskilt noggrann kravhantering där krav skall struktureras på ett hierarkiskt sätt i enlighet med systemarkitekturen; på varje nivå så skall krav allokeras till heterogena (SW, HW, mekaniska, elektriska, etc.) arkitekturelement och spårlänkar skall upprättas mellan kraven. I motsats till den noggranna kravhanteringen i säkerhetsstandarder så är kravhantering i industrin av allmänt dålig kvalitet enligt tidigare studier. Ett typisk kravverktyg ger inte mycket mer stöd än grundläggande konsekvensanalyser, d.v.s.\ verktyget ger varken återkoppling eller vägledning för att formulera, allokera, och strukturera krav. Bättre stöd behövs för att industrin i praktiken skall kunna förverkliga den noggranna kravhanteringen i säkerhetsstandarder -- inte bara stöd från verktyg, men också från kravhanteringsprinciper och metoder. Därför presenteras ett fundament bestående av en underliggande teori för specifiering av heterogena system, samt kompletterande principer och metoder för att stödja den noggranna kravhanteringen i säkerhetsstandarder. Detta fundament är lämplig som en bas för att kunna implementera verktyg som ger återkoppling och vägledning för kravhantering; likväl så ger den föreslagna teorin, principerna och metoderna essentiellt stöd oavsett om verktyg används eller inte. Den underliggande teorin är en kompositionell och formell kontraktsteori för heterogena system. Denna kontraktsteori ger konkret form åt den centrala kravhanteringsegenskapen att separera kraven på ett system från antaganden på dess omgivning. Dessutom så formaliserar kontraksteorin den noggranna uppgiften att hierarkiskt strukturera krav i enlighet med systemarkitekturen. Således så är de föreslagna principerna och metoderna för att stödja den noggranna kravhanteringen i säkerhetsstandarder välförankrade i formella begrepp och villkor och är därmed också teoretiskt sunda. Det erbjudna stödet är dessutom välanpassat för att kunna verkställas av såväl befintliga som nyaverktyg med tanke på att stödet är grundat på exakta matematiska uttryck som kan tolkas entydigt av maskiner. Verkställandet av fundamentet av ett verktyg medför stöd i form av vägledning och återkoppling vid specifiering av heterogena system i allmänhet, och säkerhetskritiska sådana i synnerhet. / <p>QC 20160909</p> / ESPRESSO
88

Controlador fuzzy de código aberto para uso em controladores programáveis. / Open source fuzzy controller for use in programmable logic controller.

Legaspe, Edinei Peres 12 December 2012 (has links)
Sistemas de controle fuzzy são amplamente empregados na indústria de controle de processos. Normalmente controlando variáveis analógicas, tais como pressão, temperatura, vazão, posição e velocidade. Hoje existem diversas soluções de mercado que permitem o uso da lógica fuzzy em CPs (Controladores programáveis). Porém essas soluções são proprietárias e de custo elevado. Adicionalmente existe a norma IEC 61131-7, introduzida no ano de 2000, que especifica sistemas fuzzy em CPs, onde a mesma define um conjunto de regras que permite a definição de algoritmos fuzzy independente do hardware de um fabricante de CPs. A adoção da norma IEC 61131-7 não vem acontecendo de uma maneira rápida, devido a diversos fatores, mas principalmente, por já existirem soluções proprietárias e personalizadas fornecidas pelos fabricantes de CPs. Portanto, a contribuição deste trabalho é um método de desenvolvimento de controladores fuzzy por retroalimentação usando como solução um sistema de código aberto ou livre. Este método propõe o uso de uma arquitetura de controle distribuído envolvendo PCs (Computadores pessoais) e CPs. A construção do controlador fuzzy foi feita em linguagem Java e liberada sobre licença de código aberto, assim permitindo o seu uso de forma gratuita em uma grande variedade de aplicações industriais. O método é baseado na norma IEC 61131-7 para a aplicação da lógica fuzzy em sistemas de automação industrial. Diversos testes foram realizados, tais como testes de mesa do software de controle, e até em uma planta real para validação de software de controle em operação real. Com os resultados dos testes foram obtidas diversas curvas de resposta no tempo, que permitem a avaliação do controlador e do software de controle. Após a execução dos testes e verificado o comportamento obtido pelas curvas, foi constatada a compatibilidade do software construído com a norma IEC 61131-7, assim permitindo o seu uso em outras aplicações. / Fuzzy control systems are largely applied at the processes control industry, usually controlling analogic variables, such as, pressure, temperature, outflow, position and speed. Nowadays, there are several market solutions which allow the Fuzzy Logic usage in PLCs (Programmable Logic Controllers), therefore, these solutions are proprietary and have a high cost. Additionally, there is the IEC 61131-7 standard, introduced in 2000, which specifies Fuzzy systems in PLCs. It defines a set of rules which allow the Fuzzy definition regardless of the hardware from the PLCs manufacturer. The adoption of the IEC 61131-7 standard is not happening effectively, due to many factors, but mainly because there are already proprietary and customized solutions provided by the PLCs manufacturers. The contribution provided by this report, is a method of Fuzzy control development by feedback using as solution, a free or open source code system. This method proposes the usage of a distributed control architecture involving both PCs (Personal Computers) and PLCs. The building of the Fuzzy controller was made in Java language and released under open source code license, allowing its use to be free in a great variety of industrial applications. The method is based on the IEC 61131-7 standard for the Fuzzy logic application in industrial automation. Several tests were performed, such as, software control table test, and even in a real plant for control software validation in a real operation. With the tests results were obtained quite a few response curves at time, which allow the evaluation of the controller and of the control software. After the tests executions and the verifying of the behavior obtained by the curves, it was stated the compatibility of the built software with the IEC 61131-7 standard, admitting it to be used in other applications.
89

Aplicação de cartas de controle como ferramenta de melhoria frente às dificuldades operacionais de laboratórios acreditados na ABNT NBR ISO/IEC 17025 / Application of Control charts as an improvement tool considering the operational difficulties of accredited laboratories according to ISO/IEC 17025

Turuta, Tatiana Barbosa 05 March 2015 (has links)
É crescente o número de laboratórios que têm implantado sistemas de gestão da qualidade conforme a norma ABNT NBR ISO/IEC 17025, entretanto, para continuidade no atendimento aos requisitos da norma e às necessidades dos clientes, os laboratórios podem apresentar dificuldades que precisam ser identificadas e analisadas para melhoria continua da qualidade dos resultados. Desta maneira, uma avaliação preliminar das dificuldades operacionais após implantação do sistema de gestão da qualidade ABNT NBR ISO/IEC 17025 aponta como um dos requisitos de maior dificuldade a garantia da qualidade de resultados (requisito 5.9). Este requisito abrange a importância do monitoramento contínuo para validade dos ensaios realizados e acompanhamento de possíveis tendências das análises realizadas pelos laboratórios. Para realização desse monitoramento são aplicadas as cartas de controle que requerem maior atenção na sua aplicabilidade e interpretação em função do método de análise, da amostra de controle e da periodicidade do acompanhamento. As cartas de controle são ferramentas que possibilitam o monitoramento contínuo dos processos analíticos e permitem a avaliação de possíveis otimizações das atividades técnicas como, por exemplo, com a redução de custo analítico decorrente das curvas de calibração em análises cromatográficas. Desta maneira, neste trabalho, após realizar uma pesquisa de mercado e confirmar que o requisito 5.9 está entre os requisitos de maior dificuldades para laboratórios de rotina, foi realizado um estudo prático e orientativo de aplicação dos diferentes tipos de cartas de controle que podem ser utilizados pelos laboratórios de ensaio na manutenção contínua da qualidade dos resultados. Este estudo demonstra que a escolha de uma carta de controle está relacionada com a criticidade do método analítico e que pode gerar controles adequados dentro de uma relação custo/benefício que seja satisfatória. A interpretação de todos estes resultados também gerou a proposta de um guia orientativo para aplicação de cartas de controle aos laboratórios analíticos. / A growing number of laboratories have implemented quality management systems according to ISO / IEC 17025 standard, however, for continuity in meeting the requirements of the standard and the needs of customers, laboratories may present difficulties that need to be identified and analyzed to continuously improvement of the quality results. In this way, a preliminary assessment of operational difficulties following the implementation of ISO / IEC 17025 points as one of the most difficult requirements to guarantee the quality of results (requirement 5.9). This requirement covers the importance of continuous monitoring for validity of testing and monitoring of possible trends of the analyzes performed by laboratories. To conduct this monitoring are applied control charts that need more attention in its applicability and interpretation depending on the method of analysis, the control sample and the monitoring frequency. Control charts are tools that enable continuous monitoring of analytical processes and make assessments of possible optimizations of the technical activities, for example, by reducing analytical costs arising from the calibration curves in chromatographic analysis. Thus, in this study, after conducting market research and confirm that the requirement 5.9 is among the most difficult requirements for routine labs, was developed a practical study of application of different types of control charts that can be used by testing laboratories in the ongoing maintenance of the quality of results. This study demonstrates that the choice of a control chart is related to the criticality of the analytical method and that can generate adequate controls within a cost / benefit that is satisfactory. The interpretation of all these results also led to the proposal of an reference guide to application of control charts to analytical laboratories.
90

Proposta de metodologia e de modelo para modernizações de sistemas de automação de unidades geradoras hidráulicas de grande porte. / Proposal of methodology and of model for modernizations of automation systems of large hydraulic generating units.

Mendes, Marcos Fonseca 25 April 2011 (has links)
A geração de energia elétrica é importante para todos os ramos de atividades econômicas e tem demanda crescente. Isso implica constantes melhorias dos sistemas secundários, entre eles os sistemas de automação, que evoluíram muito nos últimos anos. Em várias usinas hidrelétricas esses sistemas estão obsoletos e apresentam outros problemas, portanto, carecem de atualizações tecnológicas. O objetivo desta tese é responder às principais questões relacionadas às modernizações dos sistemas de automação de unidades geradoras hidráulicas de grande porte: por que, quando e como modernizá-los? Para isso, foram estudados a evolução desses sistemas, o estado da arte, as modernizações já realizadas e planejadas. Os dados foram obtidos da bibliografia e diretamente de especialistas, através de pesquisa de campo envolvendo as principais concessionárias brasileiras. Baseando-se nos estudos, foram elaborados critérios para tomar a decisão por modernizar, foram escolhidas a forma de modernização e de realização mais adequadas para grandes usinas e foi criado um modelo de sistema de automação usando o estado da arte. Esse modelo é totalmente digital, utiliza uma única rede de comunicação em todos os níveis (incluindo o controle central), é à prova de futuro e fundamenta-se na norma IEC 61850. Todos os componentes e características do sistema foram examinados. Por fim, foi proposto um método para especificação e projeto do novo sistema incluindo todas as etapas. Concluiu-se que, um conjunto de indicadores quantitativos pode decidir a necessidade de modernização dos sistemas de automação de grandes unidades geradoras e, tomada a decisão por modernizar, a melhor solução é a substituição total de uma só vez (uma parada) usando o modelo criado. Os métodos e o sistema propostos podem ser usados como referências no setor elétrico para facilitar as atualizações tecnológicas e garantir resultados efetivos uniformes, com longo tempo de vida e independência dos fornecedores. / The generation of electricity is important to all branches of economic activities and faces a growing demand. This implies constant improvements of the secondary systems, including the automation systems, which have evolved a great deal in recent years. At several hydroelectric power plants these systems are obsolete and present other problems, therefore, technological upgrades are required. The objective of this thesis is to answer the key questions related to the modernizations of automation systems of large hydraulic generating units: why, when and how to modernize them? To this effect, studies were undertaken about the evolution of these systems, the state of the art, the modernizations already introduced and those planned. The data were obtained from the bibliography and directly from experts, through a field survey involving the major Brazilian utilities. Based on these studies, criteria to support the modernization decision were developed, the most suitable manner of modernization and of its implementation in large power plants were chosen and an automation system model using state of the art was created. This model is fully digital, uses only one communication network at all levels (including the central control), is future proof and is based on the IEC 61850 standard. All components and features of the system were examined. Finally, a method including all stages for specification and design of the new system was proposed. It was concluded that, a set of quantitative indicators can decide the need for modernization of the automation systems of large generating units and, once the decision to modernize is taken, the best solution is the total replacement during a single unit shut-down using the model created. The methods and system proposed can be used as references in the electricity sector to facilitate the technological upgrades and to ensure effective uniform results, with the prospect of a long service life and independence from the suppliers.

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