Um dos mais importantes elementos que compõem uma rede de telecomunicações é o roteador. Os roteadores modernos empregam sofisticados comutadores para a transmissão de pacotes. A arquitetura de comutadores com filas de entrada exige um processo de escalonamento que estabelece a transferência de pacotes das portas de entrada às portas de saída. O desempenho do sistema depende diretamente do algoritmo de escalonamento, considerando sua vazão e complexidade. Esta dissertação realiza o levantamento teórico dos algoritmos de escalonamento mais relevantes e propõe uma abordagem de escalonamento usando algoritmos genéticos. Um simulador baseado em eventos discretos foi desenvolvido para a realização de testes de desempenho dos escalonadores estudados. O algoritmo proposto, denominado GENIUS, apresentou desempenho relevante e baixa complexidade. / One of the most important components of network telecommunications is the router. Modern routers employ input-queued crossbar switches that require sophisticated scheduling techniques for packet transmission. The architecture of switches with input queues requires an scheduling process that establishes the transfer of packets from input to output ports. The performance of router depends of the scheduling algorithm, considering its throughput and complexity. In this work we survey the most relevant theoretical scheduling algorithms and propose a scheduling approach using genetic algorithms. We developed a simulator of discrete events for testing of schedulers performance. The proposed algorithm, called GENIUS, presents relevant performance and low complexity.

Orientador: Maria Cristina Dias Tavares / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação / Made available in DSpace on 2018-08-25T04:21:56Z (GMT). No. of bitstreams: 1 Magrin_FabianoGustavoSilveira_M.pdf: 5471875 bytes, checksum: 204630879d78c9f5167f324d6d0f5fe9 (MD5) Previous issue date: 2014 / Resumo: Devido à dificuldade de execução de testes em sistemas reais os engenheiros procuram ferramentas e modelos para simular ou emular os sistemas reais em laboratório. Nesse sentido, o objetivo deste projeto de pesquisa foi desenvolver um modelo do relé de proteção diferencial de transformador no simulador digital em tempo real RTDS, baseando-se no relé SEL-787 da Schweitzer Engineering Laboratories Inc. O objetivo de criar um relé específico e já existente no mercado, saindo dos modelos genéricos, é devido à necessidade dos estudos em laboratório apresentarem resultados concretos e que representem o sistema real, desta forma apresentará grande valia para as futuras expansões do Sistema Elétrico Nacional ou Internacional. Após o desenvolvimento do modelo matemático do relé, foram criadas rotinas de teste exclusivas para análise do modelo e este foi testado em conjunto com um relé SEL-787 de forma a permitir uma comparação dos resultados. Para a realização deste trabalho foram estudadas e analisadas as situações em que um relé de proteção diferencial de transformador enfrenta no campo, como energização de transformador, saturação, faltas externas, faltas externas com saturação de TC, faltas internas a seção diferencial e externa ao transformador e faltas internas ao transformador como falta espira-terra e entre espiras. Os mesmos testes foram aplicados ao modelo de relé diferencial já existente na biblioteca do RTDS com o intuito de verificar se realmente modelos genéricos apresentam resultados diferentes de modelos específicos. A contribuição da pesquisa foi o desenvolvimento pioneiro do modelo do relé de proteção diferencial no ambiente RTDS / Abstract: Due to the difficulties involving tests in real systems engineers continuously look for tools and models to simulate or emulate real systems inside laboratories. With this focus, this job had the objective of developing a transformer differential protection relay in Real Time Digital Simulator, RTDS, based on SEL-787 relay, manufactured by Schweitzer Engineering Laboratories Inc. The objective of creating a specific relay already in the market, and not a generic model relay, is due to the necessity of the laboratories studies give real results and also represent the real system. This actual representation gives the engineers a more concrete data to support future expansions of the national and international electric systems. After the development of the relay model itself, it was tested in conjunction with a real SEL-787 allowing comparison of the results. For the accomplishment of this job many different situations which interfere in the daily operation of the relay in the field such as inrush, saturation, external faults, external faults with current transformer saturation, internal fault to the differential section but external to the transformer and internal faults like turn-to-turn faults and ground faults were studied and analyzed. The same tests were applied to a differential relay model already in the RTDS library with the purpose to verify whether generic models have different results compared to specific models. This research formerly presents a transformer differential relay model of a commercial relay for RTDS library / Mestrado / Energia Eletrica / Mestre em Engenharia Elétrica

This work deals with addressing the issues related to design of double toggle switch mechanisms with emphasis on structural, dimensional and dynamic aspects. Currently, almost all the issues related to electrical switches are dealt from electromagnetic point of view; the operating mechanism is hardly touched. It is observed that kinematic parameters influence electrical performance of switch significantly. Therefore, there is a need to develop methodologies for supporting exploration of diverse kinematic chains (KCs) for this purpose. Visual inspection is tedious and error prone even when a complete list of design criteria is available, hence, the work presented in the thesis contributes towards automated design of toggle switch mechanisms. In this context, in house modular kinematics data structure is found useful for using it as a tool in the design of toggle switch. Modular kinematics, typically used for kinematic analysis, works on the principle of finding the configuration of a mechanism using a given set of modules by a procedure called module sequence. This module sequence is used and interpreted in a number of ways for its effective use in various design stages. Structurally, a set of seven conditions must be satisfied by a KC to exhibit double toggle. These conditions are broadly classified into three categories: criteria for KC, function assignment criteria and criteria for stoppers. These three criteria are to be checked automatically by use of module sequence in the same order as mentioned. In the criteria for KC, one of the conditions is that, the KC should not have fractionated degrees of freedom (d.o.f.). Hence, detection of fractionation in a KC is inevitable. In literature, is was found that the algorithms for detection operate at their worst case complexity, O(n4), and some of them do not report joint fractionation. Thus, the algorithms are not only robust but also computationally expensive. Therefore, a frugal and comprehensive method O(n2) is implemented to detect fractionation using modular kinematics. Also, inherent structural pattern embedded in fractionated KCs is hardly studied in literature. It is found that the way body and joint fractionation is defined in fractionated KCs is inconsistent. So, fractionation is interpreted as symbolic partitioning of joints and links in the traditional body and joint fractionation types respectively. Based on the number of ways of partitioning, simple and multiple types of fractionation are recognized. Valid partitions are identified using the notion of fractionating and non-fractionating subchains. Relative locations of these subchains influence distribution of d.o.f. across the fractionated KC. Conventional representation of KCs as links and joints or graphs is difficult to comprehend this distribution. For this, a novel concept of fractionation graph is introduced that gives d.o.f. distribution information and the relative locations of the constituent subchains across the KC. Modular kinematics gives a constructive description of fractionated KCs. Characterization of fractionated KCs, based on presence of multiple separation links, is introduced as order of fractionation. Uniqueness for a given order of fractionation is also justified. After the criteria for KC, a KC is tested for feasibility for function assignment criteria. This requires recognition of active and passive subchains of the KC with respect to input and output pairs. For this, module sequence is characterized for recognition of the subchains. Based on these subchains, locations of stoppers are derived. Using this information, an algorithmic approach to assign functions (functions like spring, ground link, input link, etc.) to derive distinct driving mechanisms provided isomorphic elements (links and joints) of the KC are known beforehand, is introduced. The design parameters influencing dimensional synthesis have been identified as dimensions of links, spring anchor points and stopper locations. Sub-problems associated with each parameter are analyzed. It is found out that optimum location of stoppers for selecting operational range of motion is necessary by taking into account the considerations of timing of switch and impact velocity. Based on the analysis, an algorithmic way to design single toggle switch mechanisms is introduced. Timing for closing or opening of a switch is one of the critical measure that determines its performance. Timing should be as low as possible without exceeding the impact velocity at the instant contacts meet each other. Timing of a switch depends on the dimensions of the links, inertial parameters, spring stiffness etc. For a given timing for a mechanism, dynamic synthesis, in this thesis, deals with finding the inertial parameters of the links using Quinn's energy distribution method, modular kinematics, and Nelder and Mead's downhill simplex method for optimization. This thesis helps the designer to use modular kinematics as a potential automated tool to select a valid design to make the solution space more meaningful in the design of toggle switch mechanisms.

The theses is focused on efficient use of numerical methods in development of low-voltage switching devices, namely to create a physically correct and reliable numerical model of the temperature field to find an application in the design of the current path of a device for various operating conditions. The creation of this numerical model requires not only correct inclusion of all modes of heat transfer - conduction, convection and radiation, but also correct solution of problematic transient resistance - both electrical and thermal in electrical contacts at different stages of usage. Therefore an essential part of the theses forms a thorough experimental analysis of the necessary material properties and dependencies which forms input data for the numerical model that is based on the finite volume method. The last part of the theses deals with debugging and verification of numerical model to correspond with experimentally obtained data. The result of the theses is the numerical model which is able to solve correctly both steady and various transient states of swiching devices.

The Master’s Thesis comprises a summary of the differences existing design of MNS switchgear series against AGOMIN project innovative proposal. The introduction deals with the introduction to the CAD program SolidWorks and its extension for enterprise data management SolidWorks Enterprise PDM. The body of the paper deals with a new range of air circuit breakers ABB SACE Emax 2 and their implementation into the product line of low voltage switchgears. Included are other improvements that together with implementation of circuit breakers AGOMIN project brings.

Cílem této práce je analýza teplotního pole vysokonapěťového rozvaděče. Tato analýza je založena na kombinaci experimentálního měření a CFD simulace proudění vzduchu v prostoru rozvaděče. Na základě výsledků pro referenční geometrii jsou předloženy návrhy na úpravu topologie rozvaděče, které mají za cíl snížení teploty kritických komponent rozvaděče během jeho provozu. Druhá část práce je spojena s problematikou oteplení plošných spojů, jakožto hlavních zdrojů tepla v prostoru rozvaděče. Pro popis závislosti oteplení plošného spoje na jeho charakteru byla použita statistická metoda design experimentu. Výsledky z experimentálního měření jsou podpořeny konečně prvkovým modelem kontaktu spoje.

This master's thesis deals with the temperature-rise of selected parts of the low-voltage switchgear. The theoretical part describes the physical principles and the basic mechanisms of heat transfer. The next part describes the possible effect of elevated temperature on the device inside the switchgear. The master's thesis is awarded by ABB Ltd., so another part is dedicated to MNS switchgear. The following part describes the permitted limit of temperature-rise of switchgear in accordance with IEC 61439-1. In the practical part is a calculation temperature-rise of selected part of switchgear based on IEC 60890. Model in SOLIDWORKS Flow Simulation was created for the same part of the switchgear and thermal analysis was performed. The values of allowable temperature rise of individual parts are compared with the results obtained by calculations and simulations. In the last part is verified the possibility of calculating the temperature-rise in the EPLAN software.

This term project’s aim is to theoreticaly analyze thermal phenomena and losses in electrical power devices, describe the design and application of UniGear ZS1 type switchgear, put together a computer simulation model for thermal calculations of current and optimized solution and finally to discuss obtained results and compare them with experimentally acquired values. The main objective of this project is to determine, whether simulation is a viable and reliable enough method, that it could replace the costly real life physical testing. Modelling of the progress of thermal processes in different parts of the examined busbar will be done in computer aided design program Solidworks and its simulation plugin Flow Simulation.

This work is focused on the measurement of partial discharges in gas insulated conductors manufactured by ABB. The theoretical part contains the definition of partial discharges, their analysis and detection methods. It also deals with the general description of gas-insulated substations and then with the concrete components manufactured at ABB in the Brno-Slatina production plant. The practical part describes the course of measurement, definition of the main problems and their explanation. The output from the practical part is a measurement library with given characteristics, which show the location and character of the problem in detecting partial discharge in a given encapsulated assembly.

Indiana University-Purdue University Indianapolis (IUPUI) / This research introduces a new design of a converter modified from SEPIC converter (Single end primary inductive converter), capable of generating desired voltage levels and polarities. The new switching converter topology allows for boost and buck of the input voltage theoretically achieving infinite positive and negative voltage levels. The proposed topology utilizes single high frequency switch to perform the power conversion which simplifies the design of the gate driver, but meanwhile, it still retains the ability to provide a wide range of output voltage. Mathematical modeling of the converter and computer simulations are validated by experimental data. To verify its performance a prototype was designed and built. It is experimentally proven that the circuit can generate a desired voltage in the range of voltages up to ±170 V, delivering 480 Watts of power to a resistive load.