Navegando por Assunto "Energia eólica"

Agora exibindo 1 - 5 de 5

Acesso aberto (Open Access)
An Investigation of a Mathematical Model for the Internal Velocity Profile of Conical Diffusers Applied to DAWTs
(Universidade Federal do Pará, 2015-06) BARBOSA, Disterfano Lima Martins; VAZ, Jerson Rogério Pinheiro; FIGUEIREDO, Sávio W.O. ; SILVA, Marcelo de Oliveira e; LINS, Erb Ferreira; MESQUITA, André Luiz Amarante
The Diffuser Augmented Wind Turbines (DAWTs) have been widely studied, since the diffusers improve the power coefficient of the wind turbine, particularly of small systems. The diffuser is a device which has the function of causing an increase on the flow velocity through the wind rotor plane due to pressure drop downstream, therefore resulting in an increase of the rotor power coefficient. This technology aids the turbine to exceed the Betz limit, which states that the maximum kinetic energy extracted from the flow is 59.26%. Thus, the present study proposes a mathematical model describing the behavior of the internal velocity for three conical diffusers, taking into account the characteristics of flow around them. The proposed model is based on the Biot-Savart's Law, in which the vortex filament induces a velocity field at an arbitrary point on the axis of symmetry of the diffusers. The results are compared with experimental data obtained for the three diffusers, and present good agreement.
Acesso aberto (Open Access)
Avaliação do impacto da produção eólica na reserva operativa de curto e longo prazo utilizando séries temporais
(Universidade Federal do Pará, 2019-05-30) SANTOS, Fernando Manuel Carvalho da Silva; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; BRANCO, Tadeu da Mata Medeiros; http://lattes.cnpq.br/8911039344594817
One of the main concerns of a system planner is to size generation equipment, mainly for meeting the load growth and to achieve certain spinning reserve requirements. In general, generation systems must be sized with sufficient capacity, flexibility and robustness to respond to several operational challenges. However, the volatility and variability that comes from renewable generation is a relatively recent concern for the system planners. This thesis evaluates the potential of diverse wind power patterns to balance the global power output of wind farms using the concept of operating reserve assessment. To achieve this, operating reserve assessment models are utilized to evaluate bulk generation systems under several conditions of wind power geographic distribution. Different wind behavior patterns and wind power penetration levels are tested using a modified configuration of the IEEE RTS-96 and a planning configuration of the Portuguese Generation System. The results highlight that on a large country scale system with different wind characteristics, the diversification of wind behavior might be conducive to a compensation of wind power fluctuations, which may significantly decrease the need for system operating reserves. This effect is verified using probability distribution functions of reserve needs estimated by sequential Monte Carlo simulations (SMCS), such that useful information regarding generation capacity flexibility is drawn from the evaluations.
Acesso aberto (Open Access)
Ferramenta computacional para análise do potencial de bombeamento de água utilizando aerogeradores de pequeno porte acoplados a motobombas por meio de inversores de frequência
(Universidade Federal do Pará, 2012-04-26) NASCIMENTO, Max Alexandre Seabra do; PINHO, João Tavares; http://lattes.cnpq.br/0847897516772421
The goal of this dissertation is to allow, through a computational tool, the analysis of the potential of a water pumping system based on the values of wind speeds in one location, using a small wind turbine coupled to a centrifugal pump through a variable speed drive. In the work two methods for the calculation of the flow are presented. Method 1 uses a theoretical model, while in method 2 the modeling is done from pumping data obtained in laboratory. The two methods describe the operation of a water pumping system involving the above equipment. Using the mathematical models described, a program was developed in Delphi® to obtain the values for the flow and volume of pumped water, and the number of people that can be supplied on the basis of the data of wind speed for the site, in order to analyze the feasibility of the system. The operation of the program is described through an example, in order to facilitate its understanding, which contains real values of wind speed, and the results are analyzed.
Acesso aberto (Open Access)
Modelagem e avaliação de estabilidade transitória de aerogeradores síncronos com magneto permanente em sistemas de energia elétrica
(Universidade Federal do Pará, 2005-04-29) SANTOS, Fernando Manuel Carvalho da Silva; NUNES, Marcus Vinicius Alves; http://lattes.cnpq.br/9533143193581447; BRANCO, Tadeu da Mata Medeiros; http://lattes.cnpq.br/8911039344594817
This work presents a study of the dynamic behaviour of permanent magnet variable speed wind generators, comparing it with doubly-fed and squirrel cage assynchronous generators. It also presents transient studies that have to be considered when evaluating the impacts of the grid-connection of wind turbines in the presence of the three technologies mentioned above, inserted in a standard electrical power system and supposing the operation of the wind farm together with conventional generation sources that use a diesel prime mover. The studies developed in this work are simulated through an algorithm of transient stability analysis, developed on MATLABTM computational programming language.
Acesso aberto (Open Access)
Modelo híbrido baseado em séries temporais e redes neurais para previsão da geração de energia eólica
(Universidade Federal do Pará, 2018-08-30) ALENCAR, David Barbosa de; OLIVEIRA, Roberto Célio Limão de; http://lattes.cnpq.br/4497607460894318; AFFONSO, Carolina de Mattos; http://lattes.cnpq.br/2228901515752720
The electric power generation through wind turbines is one of the practically inexhaustible alternatives sources of electric power. It is considered a source of clean energy, but still requires a lot of research to develop science and technologies that ensure uniformity in generation, providing a greater participation of this source in the energy matrix in Brazil as in the world, because the wind presents abrupt variations speed, density, and other important variables. In wind-based electrical systems, each forecast horizon is applied to a specific segment, forecast of minutes, hours, weeks, months, and future years of wind behavior, in order to evaluate the availability of energy for the next period, relevant information in the dispatch of the generating units and in the control of the electric system. This thesis aimed to develop ultra-short, short, medium and long-term prediction models of wind speed, based on computational intelligence techniques, using Artificial Neural Networks, SARIMA models and hybrid models and to predict the generation capacity of power for each horizon. For the application of the methodology, the meteorological variables of the database of the national environmental data system SONDA, Petrolina station, were used for the period from January 1st, 2004 to March 31st, 2017. The performance of the models was compared with 5, 10 and 20 steps forward, considering minutes, hours, days, weeks, months and years as the forecast horizon. The hybrid model obtained better response in the forecasts, among which the hour horizon was highlighted.