6 results on '"Passos Filho, João Alberto"'
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2. Optimal offshore wind farms connection considering the wind capacity maximisation – a Benders decomposition approach.
- Author
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Vasconcelos, Leandro Almeida, Passos Filho, João Alberto, and de Oliveira, Leonardo Willer
- Subjects
OFFSHORE wind power plants ,WIND power ,WIND power plants ,ELECTRIC lines ,WIND forecasting ,OFFSHORE structures - Abstract
This study presents a new methodology to determine the optimal Offshore Wind Farms connection point in a power system, with the purpose of maximising the wind power penetration, considering a Benders decomposition approach to represent the security constraints related to the ' $N-1$N−1 ' contingency criterion. The proposed algorithm uses a mixed-integer non-linear programming approach associated with a non-linear programming, and it is evaluated in a tutorial system (IEEE 14-Bus) and two networks from the literature: a small case (IEEE RTS-79), and a medium and real case (Brazilian Birds System). In each case, three points geographically close to each other are selected as candidates in the onshore grid for the wind power injection. The experiments conducted clearly show that the connection decision from the proposed approach led to the maximum safe wind power penetration among the candidate options, which proves its applicability and effectiveness, even for more complex networks, and considering all single transmission line contingencies for safe operation. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
3. Tools for handling steady‐state under‐frequency regulation in isolated microgrids.
- Author
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La Gatta, Paula Oliveira, Passos Filho, João Alberto, and Pereira, José Luiz Rezende
- Abstract
This study presents two approaches to handling under‐frequency regulation in isolated microgrids. The first one is a governor power flow (PF) model in which the generators steady‐state governor equations are modeled into a full Newton PF formulation resulting in an augmented sparse linearised system of equations to be solved at each iteration. As a result, it is possible to evaluate the under frequency problem in the case of microgrid islanding as well as to set the reference bus angle to evaluate the possibility of reconnection to the main grid. The second approach presents an optimal PF (OPF) formulation in which the generators governor equations are considered as additional equality constraints to determine the minimum amount of load shedding to keep the system frequency between specified limits. In both methods, it is also used an equation that provides voltage regulation in a droop‐based control. The reactive power generation limits in the OPF approach are bounded by a proposed complementarity constraint‐based method adapted for the generators' droop‐controlled terminal voltage. The proposed approaches are evaluated and validated through the study of the EHV1 Network, a 61‐bus 33/11‐kV radial distribution system, and the New England test system. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
4. A Full-Newton AC-DC Power Flow Methodology for HVDC Multi-Terminal Systems and Generic DC Network Representation.
- Author
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Vasconcelos, Leandro Almeida, Passos Filho, João Alberto, Marcato, André Luis Marques, Junqueira, Giovani Santiago, and Senjyu, Tomonobu
- Subjects
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ELECTRIC power system planning , *NEWTON-Raphson method , *JACOBIAN matrices , *POWER transmission , *HIGH voltages - Abstract
The use of Direct Current (DC) transmission links in power systems is increasing continuously. Thus, it is important to develop new techniques to model the inclusion of these devices in network analysis, in order to allow studies of the operation and expansion planning of large-scale electric power systems. In this context, the main objective of this paper is to present a new methodology for a simultaneous AC-DC power flow for a multi-terminal High Voltage Direct Current (HVDC) system with a generic representation of the DC network. The proposed methodology is based on a full Newton formulation for solving the AC-DC power flow problem. Equations representing the converters and steady-state control strategies are included in a power flow problem formulation, resulting in an expanded Jacobian matrix of the Newton method. Some results are presented based on HVDC test systems to confirm the effectiveness of the proposed approach. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. New methodologies for constructing steady-state security regions of electric power systems
- Author
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Tiroco, Rafael Alberto Garcia, Passos Filho, João Alberto, Pereira, José Luiz Rezende, and Parreira, Thiago Masseran Antunes
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Voltage stability ,Steady-state security region ,Thévenin impedance ,Steady- state analysis ,Região de segurança estática ,Impedância de Thévenin ,Particle swarm optimization ,Segurança de sistemas de potência ,Análise em regime permanente ,ENGENHARIAS::ENGENHARIA ELETRICA [CNPQ] ,Estabilidade de tensão ,Power system security - Abstract
Este trabalho apresenta duas metodologias alternativas do processo de construção das Regiões de Segurança Estática (RSE). Esta ferramenta é amplamente utilizada para a avaliação da segurança de sistemas elétricos de potência, principalmente no ambiente de tempo real. Neste contexto, o principal objetivo deste trabalho é aprimorar a metodologia de obtenção das RSE, que são utilizadas em diversos programas comerciais como, por exemplo, o programa de análise de redes ANAREDE, desenvolvido pelo Centro de Pesquisas de Energia Elétrica (CEPEL), no Brasil. A primeira metodologia apresentada neste trabalho consiste em adicionar um indicador de estabilidade de tensão as RSE convencionais, com base nos cálculos das impedâncias de Thévenin e de carga. As RSE avaliam simultaneamente uma quantidade significativa de limites físicos e operacionais da rede, como: nível de tensão, limites térmicos nas linhas de transmissão e transformadores, entre outros. Contudo, atualmente as metodologias de obtenção das RSE não utilizem especificamente um indicador da condição de estabilidade de tensão do sistema analisado. Por outro lado, atualmente os sistemas elétricos operam perto de seus limites operacionais. Isto ocorre devido ao aumento continuo da carga e às restrições (econômicas, ambientais etc.) que limitam expansões adequadas, aproximando os sistemas das condições de instabilidade de tensão. Portanto, adicionar um indicador de instabilidade de tensão nas RSE torna-se um recurso útil e necessário para a ferramenta. A segunda técnica proposta neste trabalho visa reduzir significativamente o esforço computacional da metodologia convencional, criando um novo procedimento baseado no algoritmo “Particle Swarm Optimization” (PSO). Uma série de modificações e ajustes dos parâmetros usados no algoritmo PSO é necessária para adaptá-lo à construção das RSE. Os resultados mostram que a metodologia proposta é confiável, uma vez que o impacto da aleatoriedade usada no algoritmo PSO não tem um impacto significativo na qualidade das RSE, e também demonstra que a metodologia proposta apresenta um ganho computacional significativo quando comparado com a metodologia convencional de obtenção das RSE. This paper presents two alternative methodologies of the Steady-State Security Region (SSSR) construction process. This tool is widely used for security assessment of electric power systems, especially in the real-time environment. In this context, the main objective of this work is to improve the methodology for obtaining SSSRs, which is used in several commercial programs, such as the network analysis software ANAREDE, developed by the Electric Energy Research Center (CEPEL), in Brazil. The first methodology presented in this paper consists on adding a voltage stability indicator to the conventional SSSR, based on the Thévenin and load impedance computations. The SSSR simultaneously evaluate a significant amount of physical and operational limits of the network, such as voltage level, thermal limits on transmission lines and transformers, among others. However, the current methodologies for obtaining the SSSR do not specifically possess an indicator of the voltage stability condition of the analyzed system. On the other hand, electric power systems currently operate near their operating limits. This is due to the continuous increase in load and the restrictions (economic, environmental etc.) that limit proper expansions, bringing systems closer to voltage instability conditions. Therefore, adding a voltage instability indicator in the SSSR becomes a useful and necessary feature for the tool. The second technique proposed in this work aims to significantly reduce the computational effort of the conventional methodology, creating a new procedure based on the Particle Swarm Optimization (PSO) algorithm. A series of modifications and adjustments to the parameters used in the PSO algorithm are required to adapt it to the construction of SSSRs. The results show that the proposed methodology is reliable, since the impact of the randomness used in the PSO algorithm does not have a significant impact on the quality of SSSRs, and also demonstrate that the proposed methodology presents a significant computational gain when compared to the conventional methodology used for obtaining the SSSRs.
- Published
- 2019
6. Avaliação de segurança a pequenos sinais considerando redespacho mínimo
- Author
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Parreiras, Thiago José Masseran Antunes, Gomes Junior, Sergio, Assis, Tatiana Mariano Lessa de, Passos Filho, João Alberto, Uhlen, Kjetil, Martins, Nelson, and Taranto, Glauco Nery
- Subjects
Estabilidade do sistema de potência ,Controle de amortecimento de oscilação ,ENGENHARIAS::ENGENHARIA ELETRICA::SISTEMAS ELETRICOS DE POTENCIA::MEDICAO, CONTROLE, CORRECAO E PROTECAO DE SISTEMAS ELETRICOS DE POTENCIA [CNPQ] ,Engenharia elétrica - Abstract
Submitted by Aglair Aguiar (aglair@ct.ufrj.br) on 2019-01-31T15:50:22Z No. of bitstreams: 1 866009.pdf: 2225738 bytes, checksum: 62b42860d4d8881b362b96e14ba5b8e4 (MD5) Made available in DSpace on 2019-01-31T15:50:22Z (GMT). No. of bitstreams: 1 866009.pdf: 2225738 bytes, checksum: 62b42860d4d8881b362b96e14ba5b8e4 (MD5) Previous issue date: 2017-08 Este trabalho apresenta uma revisão dos principais conceitos relacionados à estabilidade eletromecânica de sistemas de potência e das características associadas às avaliações de segurança de tensão, transitória e a pequenos sinais (VSA, TSA e SSA). A última é o foco desta pesquisa. O desenvolvimento de novas ferramentas de avaliação de segurança a pequenos sinais e suas implementações computacionais no programa PacDyn, do Centro de Pesquisas de Energia Elétrica (CEPEL), são descritos. Um método para determinação de redespacho mínimo em sistemas de potência usando sensibilidades de geração (CSBGRES) é proposto. Este é um método de otimização que considera um fator de amortecimento desejado para modos de oscilação como restrição. O método CSBGRES pode ser utilizado para a determinação de margens de segurança a pequenos sinais ou de medidas corretivas, visando a melhoria do comportamento dinâmico de sistemas de potência. This work presents a review of the main concepts related to electromechanical stability of power systems and of characteristics associated to the voltage, transient and small-signal security assessments (VSA, TSA and SSA). The last one is the focus of this research. The development of new tools for small-signal security assessment and their computational implementations in software PacDyn, from Electrical Energy Research Center (CEPEL), are described. A method for determining minimum redispatch for power systems using generation sensitivities (CSBGRES) is proposed. This is an optimization method that considers a desired damping factor for oscillation modes as constraint. The CSBGRES method can be utilized for the determination of small-signal security margins or of corrective measures, aiming at the dynamic behavior improvement of power systems.
- Published
- 2017
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