Non-transposed three-phase line analyses with a single real transformation matrix

In transmission line transient analyses, a single real transformation matrix can obtain exact modes when the analyzed line is transposed. For non-transposed lines, the results are not exact. In this paper, non-symmetrical and non transposed three-phase line samples are analyzed with a single real transformation matrix application (Clarke's matrix). Some interesting characteristics of this matrix application are: single, real, frequency independent, line parameter independent, identical for voltage and current determination. With Clarke's matrix use, mathematical simplifications are obtained and the developed model can be applied directly in programs based on time domain. This model works without convolution procedures to deal with phase-mode transformation. In EMTP programs, Clarke's matrix can be represented by ideal transformers and the frequency dependent line parameters can be represented by modified-circuits. With these representations, the electrical values at any line point can be accessed for phase domain or mode domain using the Clarke matrix or its inverse matrix. For symmetrical and non-transposed lines, the model originates quite small errors. In addition, the application of the proposed model to the non-symmetrical and non-transposed three phase transmission lines is investigated. ©2005 IEEE.

Modal transformation obtained from Clarke's matrix - Asymmetrical three-phase case

Some constant matrices can be used as phase-mode transformation matrices for transposed three-phase transmission lines. Clarke's matrix is one of these options. Its application as a phase-mode transformation matrix for untransposed three-phase transmission lines has been analyzed through error and frequency scan comparisons. Based on an actual untransposed asymmetrical three-phase transmission line example, a correction procedure is applied searching for better results from the Clarke's matrix applicaton as a phase-mode transformation matrix. The error analyses are carried out using Clarke's matrix and the new transformation matrices obtained from the correction procedure. Applying Clarke's matrix, the relative errors of the eigenvalue matrix elements can be considered negligible and the relative values of the off-diagonal elements are significant. If the the corrected transformation matrices are used, the relative values of the off-diagonal elements are decreased. Based on the results of these analyses, the homopolar mode is more sensitive to the frequency influence than the two other modes related to three-phase lines. © 2007 IEEE.

Modelo AC para el despacho combinado de contratos bilaterales y bolsa de energía considerando restricciones de seguridad

Reliability is a key aspect in power system design and planning. Maintaining a reliable power system is a very important issue for their design and operation. Under the new competitive framework of the electricity sector, power systems find ever more and more strained to operate near their limits. Under this new scenario, it is crucial for the system operator to use tools that facilitate an energy dispatch that minimizes possible power cuts. This paper presents a mathematical model to calculate an energy dispatch that considers security constraints (single contingencies in transmission lines and transformers). The model involves pool markets and fixed bilateral contracts. Traditional methodologies that include security constraints are usually based in multistage dispatch processes. In this case, we propose a single-stage model that avoids the economic inefficiencies which result when conventional multi-stage dispatch approaches are applied. The proposed model includes an AC representation of the transport system and allows calculating the cost overruns incurred in due to reliability restrictions. We found that complying with fixed bilateral contracts, when they go above certain levels, might lead to congestion problems in transmission lines.

Mapeamento geoambiental como subsídio na determinação de áreas de instabilidades da faixa de dutos Osvat/Osplan - São Sebastião, SP

Works of linear engineering such as roads, pipelines and transmission lines have specific mapping due to their large scale impact on the environment, thus requiring mapping methods that are both efficient and of low cost. This paper presents a proposal of Geoenvironmental mapping for works linear. The work chosen for the implementation of the method was the Osvat/Osplan pipeline located in the cities of São Sebastião and Caraguatatuba. The geoenvironment mapping was elaborate trough photo-interpretation of images of the ETM+/Landsat-7 sensor and analysis of the drainage network, thus resulting in the partitioning of the geoenvironmental units and the fracture area (structural lineaments and lines of strikes), these maps were subsequently integrated into a product called Map of environmental susceptibility to gravitational and erosive processes, which helped define the areas with potential geotechnical problems that could damage both the pipeline and the environment.

Interface Gráfica para o planejamento da expansão da transmissão de energia elétrica

Pós-graduação em Engenharia Elétrica - FEIS

Um procedimento de estimação de parâmetros de linhas de transmissão baseado na teoria de decomposição modal

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Um modelo para condutores múltiplos considerando a distribuição da corrente nos subcondutores

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Inclusão do efeito corona em modelos de linhas de transmissão bifásica utilizando a técnica de variáveis de estado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Análise de transitórios eletromagnéticos utilizando matrizes de transformação reais-sistemas trifásicos com a presença de cabos pára-raios

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Metodologia para o planejamento da operação de sistemas hidrotérmicos em mercado elétrico competitivo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Representação de linhas de transmissão, utilizando elementos discretos de circuitos, no domínio das fases

Pós-graduação em Engenharia Elétrica - FEIS

Sistema de aterramento com cabo contrapeso representado por linhas de transmissão implementado em Matlab com circuitos em cascatas de PÍ

Pós-graduação em Engenharia Elétrica - FEIS

Análise da estabilidade a pequenas perturbações do sistema elétrico de potência considerando a atuação do TCSC e controladores suplementares de amortecimento: representação pelo modelo de sensibilidade de corrente

Pós-graduação em Engenharia Elétrica - FEIS

Utilização de sinais adicionais estabilizantes para o amortecimento de oscilações de baixa frequência do sistema elétrico de potência multimáquinas

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Estudo de campo elétrico em linha de transmissão utilizando o método dos elementos de contorno

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)