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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.
1

Dedu??o de Fun??es de Al?vio para Prioriza??o de Variantes de Chaveamento Adequadas ? Elimina??o de Sobrecargas

Oliveira, Arrhenius Vin?cius da Costa 03 March 2011 (has links)
Made available in DSpace on 2014-12-17T14:54:58Z (GMT). No. of bitstreams: 1 ArrheniusVCO_TESE.pdf: 1241211 bytes, checksum: 636a162e62ee1658f0ee78ed1516228d (MD5) Previous issue date: 2011-03-03 / Eventually, violations of voltage limits at buses or admissible loadings of transmission lines and/or power transformers may occur by the power system operation. If violations are detected in the supervision process, corrective measures may be carried out in order to eliminate them or to reduce their intensity. Loading restriction is an extreme solution and should only be adopted as the last control action. Previous researches have shown that it is possible to control constraints in electrical systems by changing the network topology, using the technique named Corrective Switching, which requires no additional costs. In previous works, the proposed calculations for verifying the ability of a switching variant in eliminating an overload in a specific branch were based on network reduction or heuristic analysis. The purpose of this work is to develop analytical derivation of linear equations to estimate current changes in a specific branch (due to switching measures) by means of few calculations. For bus-bar coupling, derivations will be based on short-circuit theory and Relief Function methodology. For bus-bar splitting, a Relief Function will be derived based on a technique of equivalent circuit. Although systems of linear equations are used to substantiate deductions, its formal solution for each variant, in real time does not become necessary. A priority list of promising variants is then assigned for final check by an exact load flow calculation and a transient analysis using ATP Alternative Transient Program. At last, results obtained by simulation in networks with different features will be presented / Na opera??o de sistemas el?tricos verificam-se, eventualmente, viola??es de restri??es operativas, como sobrecargas em linhas de transmiss?o e transformadores de pot?ncia de subesta??es ou viola??es de limites de tens?es em barramentos. Caso o monitoramento dessas grandezas indique poss?veis problemas, ? necess?rio adotar medidas corretivas para elimin?los ou atenuar sua intensidade, devendo a restri??o de carga ser utilizada como ?ltimo recurso. Uma medida de controle bastante eficaz ? a t?cnica intitulada Chaveamentos Corretivos, capaz de influenciar o fluxo de pot?ncia de redes malhadas a partir de altera??es em suas topologias, sem, entretanto, produzir qualquer custo operacional adicional. Em trabalhos anteriores, o c?lculo desenvolvido para verificar a capacidade de uma determinada variante de chaveamento em eliminar a sobrecarga em um ramo espec?fico era realizado atrav?s de redu??o de redes ou atrav?s de an?lises heur?sticas. O presente trabalho objetiva a dedu??o anal?tica de equa??es para estimar a altera??o de corrente em um ramo espec?fico, ap?s a realiza??o de chaveamentos em subesta??es, mediante o emprego de poucos c?lculos, decorrentes de aproxima??es lineares. Para o acoplamento de barras de subesta??es, as dedu??es ser?o baseadas na teoria de curto-circuito e na metodologia da Fun??o de Al?vio. J? para a abertura de barras de subesta??es, ser? deduzida uma nova Fun??o de Al?vio, fundamentada na t?cnica de circuito equivalente. Embora sistemas de equa??es lineares sejam utilizados para fundamentar as dedu??es, sua solu??o formal para cada variante, em tempo real n?o ? necess?ria. A partir das estimativas realizadas, elabora-se uma lista de variantes priorit?rias, para teste final atrav?s de um c?lculo exato de fluxo de carga e de uma an?lise de transit?rios atrav?s do software ATP Alternative Transient Program. Por fim, apresentamse resultados obtidos atrav?s de simula??es em redes el?tricas de caracter?sticas distintas

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