Navegando por Assunto "Photovoltaic generation"

Agora exibindo 1 - 9 de 9

Acesso aberto (Open Access)
Análise dinâmica da condição de runaway em reguladores de tensão devido á presença de geração fotovoltaica nas redes de distribuição
(Universidade Federal do Pará, 2016-08-19) COSTA, Juliana Portugal da; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
Intelligent Transport Systems are several information and communication technologies applied to vehicular transportation. It is called intelligent due to its memory capacity, sensing, communication, information processing and adaptive behavior. Within this universe, the Vehicular Ad-hoc Networks (VANET) provide communication between vehicles, as well as the telecommunications infrastructure over the roads. In order to achieve connectivity continues with high data rate and low latency, the integration of vehicular networks with LTE system is pointed as a potential access technology solution. There are many challenges found to reach the QoS requirements characteristic of entertainment applications, road safety and traffic efficiency. Therefore, this dissertation proposes a methodology for the study of the impact of radio resource scheduling algorithms for vehicular networks using LTE as the access technology. This study uses a discrete simulation approach, carried out with NS-3 and SUMO tools, to evaluate five scheduling algorithms: RR, PF, TTA, CQA and PSS. The criteria used in the analysis are throughput, delay, packet loss, spectral efficiency, fairness and qualitative analysis of computational complexity. The results indicate for vehicular networks is more appropriate to apply strategies that guarantee high level of fairness between connected vehicles. The evaluation also confirm the need to use algorithms more specific, taking into account the data generation pattern of these kind of application, with the aim to ensure the best performance for the network.
Acesso aberto (Open Access)
Análise do impacto de geradores fotovoltaicos na estabilidade transitória de geradores síncronos distribuídos
(Universidade Federal do Pará, 2018-02-19) PINHEIRO, Wanessa Tâmiris de Souza; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
This dissertation aims to present a comparative analysis between two models of inverter control for the study of the transient stability analysis and voltage stability, with the insertion of the photovoltaic generation in the distribution electric grid. It is also proposed an analysis of the influence, both negative and positive, caused by the control modes of these inverters in the stability of synchronous machine connected to the grid. Another proposed solution to be investigated in this work will be the use of the reactive power control mode of photovoltaic generators via the inverter, which can contribute to the relief of the reactive demand of distributed synchronous generators interconnected in the same electric system, in order to reduce the possibility of generating a voltage instability condition, after a big disturbance, or in the occurrence of contingencies in the electric power system that may affect weak or overloaded electrical grids and with large insertion of photovoltaic generators. The analysis of the control models will be carried out through simulations in the time domain, through the ANATEM and ANAREDE computational tools.
Acesso aberto (Open Access)
Controle de frequência de geração fotovoltaica considerando inércia virtual
(Universidade Federal do Pará, 2018-01-30) RAMOS, Vanessa Menezes; NUNES, Marcus Vinícius Alves; http://lattes.cnpq.br/9533143193581447
The large-scale integration of intermittent sources of renewable energies, such as photovoltaic systems, into electrical power systems generates new technical issues, since such sources do not participate in frequency regulation because they do not exhibit inertia of rotation. The rapid frequency variation, normally found in networks with a high degree of integration of renewable generation, therefore causes greater difficulty in maintaining frequency stability, unlike conventional systems (for example Hydro and Thermal), where the inertia of the generators is sufficiently high , for most of these new systems this is not valid. In this context, the present dissertation will propose the use of the concept of "virtual inertia", which corresponds to a combination of control algorithms, electrical energy storage devices and power electronics applied to renewable sources, such as photovoltaics, connected to networks of power through inverters, which emulates the inertia of a conventional generation system. It will be presented a model based on a small linearized signal analysis, developed to evaluate the stability of a power control circuit when the photovoltaic generator provides frequency response and the inertial response emulated with photovoltaic systems by means of techniques based on the MPPT controller in the Displacement Method and the Droop control strategy in the time domain. This modeling is tested in an electric power system composed of synchronous machines and a large-scale photovoltaic power generation plant for the analysis of the effects of the control system in relation to frequency stability. The simulations performed with MATLAB/Simulink software consider different inertia constants for a condition of variation (decrease) in the electric frequency, caused by the insertion of loads in the electric system. Comparative results indicate that the impact of photovoltaic generation on the stability of the power system is greater when the power supplied by the conventional plant generator is lower. Results also prove that when the photovoltaic system is supplying power to the grid, its frequency decreases, affecting the stability and operation of the power system through the degradation of the frequency dynamics.
Acesso aberto (Open Access)
Desenvolvimento de monitoração na geração fotovoltaica em comunidades isoladas
(Universidade Federal do Pará, 2023-04-26) GONÇALVES, Francisco Reginaldo Conceição; VIEIRA JÚNIOR, Petronio; http://lattes.cnpq.br/1958791286192330
Nowadays, photovoltaic solar energy represents a significant portion of all electricity consumed in the world. It is crucial to develop tools for monitoring the solar system that aim to maintain generation productivity and mitigate security risks. This work presents a proposal for a development platform for monitoring photovoltaic generation for isolated communities, consisting of generation simulation, data transmission, database and supervisory system. The mathematical model used in the simulation is based on a system being implemented by the Automation Technology Group (GTA) at the Electrical Engineering Laboratory of the UFPA University Campus in Belém. Data are obtained by simulation and are transmitted to the cloud through a NodeMCU ESP8266 microcontroller. The computer, in addition to performing the simulation to obtain photovoltaic generation data, also accesses the clouds, acquiring data for the supervisory. The supervisory system is developed on the Internet of Things (IoT) platforms Thingspeak and Cloud Database, allowing the detection and diagnosis of failures. Measures such as solar radiation intensity, temperature, humidity, electric voltage and electric current are analyzed in order to diagnose faults. Through cloud computing, data is stored and made available in real time, with ample capacity and mobility, allowing remote monitoring of the system. Database tools with dedicated interfaces are used, as well as platforms focused on the internet of things. The photovoltaic generation is being implemented in an experimental bench, and the parameters of the simulated model have the same amplitudes as the real model, which has 1 solar panel with a maximum power of 130W, a maximum voltage of 17.6V and a maximum current of 7.39A. The perspective of this work is to improve the supply of electricity to isolated communities through remote monitoring of the generation system, with social and economic impact.
Acesso aberto (Open Access)
Desenvolvimento e modelagem de uma nanorrede de distribuição em corrente contínua em baixa tensão com sistemas de geração distribuída
(Universidade Federal do Pará, 2019-10-23) TORRES, Pedro Ferreira; MACÊDO, Wilson Negrão; http://lattes.cnpq.br/3386249951714088
The concept of direct current distribution minigrids has been gaining ground in academia and industry regarding the development of distribution grid applications with high penetration of distributed energy sources and storage systems. The adoption of a direct current distribution system facilitates the integration of sources such as photovoltaic and wind generation and storage systems such as batteries, as these technologies in general operate intrinsically in direct current. This work presents the development of a direct current distribution nanogrid (DCDN) installed in the laboratory of the Grupo de Estudos e Desenvolvimento de Alternativas Energéticas (GEDAE), of the Universidade Federal do Pará. The developed grid is composed of three photovoltaic generation and storage systems in battery banks and three load banks, distributed over the 200 m grid in a ring topology, with a 24 Vdc bus. Two simulation methodologies were developed and are capable of reproducing the nanogrid’s operational behavior under static and dynamic conditions, allowing the evaluation of the grid performance over a day of operation. Tests are also presented with measurements at strategic points of the grid to evaluate the system behavior under specific operating conditions, being normal or under contingency. The results attest the nanogrid's ability to reliably supply the loads, as long as it respects the limitations of the implemented power generation and storage capacities. In addition, it was found that the characteristics related to the topology of the commercial charge controller that is used to form the DC distribution nanogrid benefits the power quality for the developed grid size and topology.
Acesso aberto (Open Access)
Gerenciamento de energia residencial com geração fotovoltaica utilizando recozimento simulado
(Universidade Federal do Pará, 2016-09-16) VILAR, Diego Branches; AFFONSO, Carolina de Mattos; http://lattes.cnpq.br/2228901515752720
The evolution of turning traditional grid into smart grid has contributed the enhancement of penetration of distributed generation in electric systems. Furthermore, the greater integration of Information and Communication Technology (ICT) and Power Electric Systems (PES) has provided the commitment among costumers and demand side management (DSM), which has become increasingly more interested in the last years. Nevertheless, being such a debated topic since 1980, it only has been more defunded throughout the smart grid. Hence this point of view, the costumer must understand some strategies of demand side management in order to take some advantage of this program. Therefore, this master’s dissertation aims developing a Home Energy Management System (HEM), in order to assist the costumer in making up his decision of the load shifting, providing scheduling proposals for home energy consumption, in Demand Response (DR) in order to reduce consumer spending on the purchase of energy provided by the concessionaire and optimize the use of photovoltaic generation.
Acesso aberto (Open Access)
Impacto de redes de distribuição com massiva conexão de geradores fotovoltaicos na estabilidade de tensão de longo-prazo em sistemas de potência
(Universidade Federal do Pará, 2017-03-31) BARATA, Heitor Alves; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
This dissertation aims to show the impact of distributed photovoltaic generators connected to distribution networks on long term voltage stability using full time simulation. The effect of different penetration levels of photovoltaic generation is investigated. Different distribution network models considering distributed generation (DG) connections is also investigated: 1) Load and DG represented by ZIP model and negative active power loads, respectively, connected to the substation bus; 2) Load and DG represented by ZIP model and dynamic equivalent, respectively, connected to the substation bus; 3) Load and GD represented by ZIP model and dynamic model, respectively, distributed along a MV distribution network. Equipments such as On-Load Tap Changer (OLTC) transformers, Overexcitation Limiter (OEL), static loads and step voltage regulators are taken into account in the analyzes, since they significantly affect the long-term voltage stability. The investigations were conducted using both the power flow software ANAREDE and transient stability simulator ANATEM, developed by the Electrical Energy Research Center (CEPEL). For the purpose of power flow studies, photovoltaic generators are modeled as PQ buses with Q=0. The modelling of photovoltaic generators for dynamic studies is based on WECC (Western Electricity Coordinating Council) model, wich was inserted into file User Defined Controller (CDU) from ANATEM. The undervoltage protection of photovoltaic generator is also considered. The case studies were performed on a combined transmission and distribution model.
Acesso aberto (Open Access)
Metodologia de planejamento para inserção de geradores fotovoltaicos em redes elétricas isoladas e supridas por geradores a diesel
(Universidade Federal do Pará, 2013-09-05) GONÇALVES, Cláudio; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
Renewable energy sources based on photovoltaic generation (PVG) are promising energy alternatives to complement conventional, centralized power generation, as the diesel thermal plants supplying power to isolated grids in cities and remote locations in the Amazon Region. The allocation and sizing of generators for distributed generation application (DG) is a challenging problem, with technical and economic implications related to the planning, design and operation of these systems. Particularly, the PVG presents added difficulty as it is a function of environmental conditions, mainly temperature and solar radiation. This thesis presents an analytical methodology to allocate and size active power photovoltaic generation units with embedded DC/AC inverter (PVGI) to be integrated as concentrated or dispersed generation in isolated medium voltage electrical grids. The proposed methodology considers multiple objectives to be reached namely: improving the electrical grid voltage profile; reducing active power losses; and reducing the diesel generation participation, providing, this way, a reduction in diesel oil consumption and in the environmental pollution. The global obtained solution of the proposed method is a weighted commitment to these goals, presenting different weights according to priorities established in the electrical system under planning. To validate the proposed methodology, the IEEE 33 and 69 buses networks and an isolated real electrical system were modeled and simulated. The real electrical system is located in Aveiro City, in the Amazon region, Brazil. The simulation results obtained demonstrated that the proposed methodology is effective in providing a solution with significant improvement in voltage profile, active power losses reduction, and diesel generation participation reduction, according to viable technical and economic indicators to the PVGI integration in the isolated electrical grid.
Acesso aberto (Open Access)
Utilização de um sistema de armazenamento térmico para aplicação de gerenciamento pelo lado da demanda em uma rede de distribuição universitária
(Universidade Federal do Pará, 2018-08-16) SOUZA, Zaire de Assis Ferreira; AFFONSO, Carolina de Mattos; http://lattes.cnpq.br/2228901515752720
The present dissertation proposes the optimal management of the refrigeration demand of a university distribution network to promote greater economy and energy efficiency using the thermal inertia of air-conditioned classrooms as storage element of thermal energy and photovoltaic generation. The proposed method considers the hourly variation of the ambient temperature influencing the variation of the internal temperature of the classrooms and the consumption of energy throughout the day, knowing that the consumer unit is charged in the green model. The analysis of the loads of the consumer unit leads to the conclusion that most of the energy consumed is destined to some kind of refrigeration load, especially to ambient air conditioners, thus, to consider the management of this type of loads in the context of intelligent networks is a coherent way of positively impacting on increasing energy efficiency. Demand side management is based on Genetic Algorithm and the results prove the effectiveness of the proposed method in balancing the energy management and promoting a considerable increase in the economy with the energy expenses.