Navegando por Assunto "Transient stability"

Agora exibindo 1 - 7 de 7

Acesso aberto (Open Access)
Análise de estabilidade transitória em geradores distribuídos: considerações sobre a proteção 78PS.
(Universidade Federal do Pará, 2024-09-09) HERINGER, Wesley Rodrigues; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
This dissertation aims to present the transient stability analysis in Distributed Generators, considering the performance of 78PS protection, against loss of synchronization. In this context, the studies developed in this work will be considered For two distinct real cases of two cogeneration plants with synchronous generators of different powers, being a sugar-alcohol plant, which will soon be connected to An extensive rural feeder of Equatorial Energia’s Paragominas 34.5 kV substation, being in the second case analyzed a fruit pulp industry that uses biomass Resulting from the processes as fuel for the steam boiler, which connects to the a turbine, to drive a generator. In turn, this system will be interconnected in a predominantly urban feeder, in a distribution substation of 13.8 kV at Castanhal in the interior of Pará. The analyses are carried out by means of complete simulation in the time domain through software Anatem© , considering two modes of voltage control of synchronous machines: 1) without voltage control; and 2) with voltage control. The studies provide the margins of transient stability of the machines and considerations on the protection against the loss of timing of synchronous generators. The results indicate that the use of the voltage control mode of the automatic voltage regulator and the coordination between the protection of the internal feeders of the industrial consumer and the protection of the plant are fundamental to ensure the maintenance of the timing of distributed generation.
Acesso aberto (Open Access)
Análise estática e dinâmica de parques eólicos mistos compostos por aerogeradores de velocidade fixa e variável
(Universidade Federal do Pará, 2014-11-21) SILVA, Helleson Jorthan Brito da; AFFONSO, Carolina de Mattos; http://lattes.cnpq.br/2228901515752720
The wind electric power generation systems are presented as an appropriate solution to meet the technical, economic, environmental, social and governmental requirements, therefore they have been largely used in several countries. Among the wind turbines technologies available, the speed-fixed with squirrel cage induction generator and variable-speed with doubly fed induction generator wind systems are the most popular. With increasing of the wind penetration levels in electrical grid and due the technologic drawbacks of the wind turbine with cage induction generator, a tend to replace this concept by wind turbine with doubly fed induction generator in the construction of new wind farms is seen. In the case of wind plant installed already, for economic reasons, the gradative modernization process is more convenient. Although both wind systems are well known, but about the combined operation of them is known a little. Thus, the present paper proposes a study to evaluate the impacts occurred by integration of a mixed wind farm in the electrical grid, with squirrel cage and doubly fed induction generators. Aspects related to transient stability under fault and short wind variations and voltage stability are analyzed. The interactions between the technologies are also object of study. Cases with different penetration levels of the wind systems are considered, representing the gradative replace of part of the old concept wind turbine by others of the concept more modern. The results obtained show that the characteristics of the doubly fed induction generator allied with the reduction of the power injection of the fixed-speed wind systems improve the wind farm behavior, suggesting that the combined operation of the wind turbines could be a more costeffective solution.
Acesso aberto (Open Access)
Avaliação dinâmica da interligação Tucuruí-Manaus-Macapá frente a pequenas e grandes perturbações
(Universidade Federal do Pará, 2013-07-11) VIEIRA, Dione José Abreu; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
This work presents small-signal and transient stability analysis in the Tucuruí- Manaus-Macapá regional system when connected to the Brazilian Interconnected Power System (BIPS). All data used were obtained in the database of the Brazilian National Electric System Operator. Power System Stabilizers (PSS) in Coaraci Nunes and Balbina hydroelectrics power plants, and Maua and Aparecida thermoelectrics power plants are designed utilizing the Nyquist method available in the PacDyn software. The design of the PSS focuses the damping enhancement of the electromechanicals modes, which appears when Tucuruí-Manaus-Macapá´s system is connected to the BIPS. The designs are evaluated on various operational scenarios through simulations in the time domain.
Acesso aberto (Open Access)
Comparação dos algoritmos C4.5 e MLP usados na avaliação da segurança dinâmica e no auxílio ao controle preventivo no contexto da estabilidade transitória de sistemas de potência
(Universidade Federal do Pará, 2013-03-06) OLIVEIRA, Werbeston Douglas de; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
This work compares the C4.5 and multilayer perceptron (MLP) algorithms applied for dynamic security assessment (DSA) and power system stability transient preventive control design. C4.5 is an algorithm of the decision tree (DT) technique and the MLP is a member of artificial neural network (ANNs) family. The advent of DTs and ANNs provides solution to real-time DSA issues in order to identify quickly when a power system is subjected to a critical disturbance (short-circuit) that may lead to transient instability. In addition, the knowledge obtained by both techniques can be utilized in the preventive control design to restore the power system security against critical disturbances. Based on the data base generation with exhaustive time-domain simulations, some specific critical disturbances are taken as examples to compare the C4.5 and MLP algorithms employed to DSA and guideline to preventive actions. The comparative study is tested on the New England power system. In the case studies, the knowledge database is generated by using PSTv3 (Power System Toolbox) software. The DTs and ANNs are trained and tested by the Rapidminer software. The obtained results have demonstrated a promising application of the C4.5 and MLP algorithms used in power system DSA and preventive control design.
Acesso aberto (Open Access)
Metodologia de controle preventivo baseado em árvore de decisão para a melhoria da segurança estática e dinâmica de sistemas elétricos de potência
(Universidade Federal do Pará, 2015-12-05) GAIA, Dieigo Sá; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
This work aims to present a set of computational tools to support the real time operation and preventive control to enhance the static and dynamic security of power systems. The data mining technique known as decision tree was utilized to determine power system operating state as well as to provide operating guidelines for the preventing control actions necessary to avoid continuous decline of bus voltages and transient instability problems. Preliminary tests were carried out using operation historical data collected by SCADA/SAGE host located at Eletrobrás Eletronorte's regional control center. The obtained results validated the set of computational tools and also demonstrated the prospective application in real time operating environment.
Acesso aberto (Open Access)
Modelos equivalentes de parques eólicos usando algoritmos genéticos
(Universidade Federal do Pará, 2013-09-11) MONTEIRO, Felipe; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
This work presents a genetic algorithm-based methodology that determines aggregated dynamic models of both squirrel cage induction generator (SCIG) and double fed induction generator (DFIG), presenting different electrical and mechanical parameters. The technique is based on a multi-objective optimal formulation solved by a genetic algorithm to minimize the quadratic error of the active power and reactive power between flue equivalent single-generator model and the investigated wind farm. The influence of flue wind farm equivalent model on flue dynamic behavior of synchronous generators in flue power system, are also investigated by using the proposed method. The approach is tested on a 10MW wind farm consisting of 4 wind turbines (2 x 2MW and 2 x 3MW) when both SCIG and DFIG are alternately integrated on the infinite bus and IEEE 14-bus power system. The results obtained using the detailed dynamic model for the wind farm representation are compared against those obtained with flue proposed aggregated model to evaluate the accuracy and the computational cost of the proposed model.
Acesso aberto (Open Access)
Otimização de controladores utilizando algoritmos genéticos para melhoria da capacidade de sobrevivência a afundamentos de tensão de aerogeradores de indução duplamente excitados
(Universidade Federal do Pará, 2009-12-01) VIEIRA, João Paulo Abreu; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
It is proposed in this thesis a methodology to obtain optimal controllers gains for the rotorside converter of doubly fed induction generators (DFIGs) using a genetic algorithm approach. The main objective is to enhance the operational security and robustness of the power system, by a more effective contribution of the DFIG controllers to the system controllability. To reach this goal, the crow-bar protection scheme is activated during the fault period when severe voltage sags occur in order to maintain the rotor-side converter connected to the DFIG. Immediately after the fault is cleared the crow-bar protection scheme is deactivated and simultaneously the rotor-side converter optimal controllers are turned on which permits the improvement of the converter ride-through capability and also contribute to enhance the overall power system stability margin. The effectiveness of this proposed methodology was assessed for the DFIG-based plants using a real electrical network, in three different operational conditions.