Navegando por Assunto "Grid-connected photovoltaic systems"

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Acesso aberto (Open Access)
Avaliação operacional dos efeitos do perfil de demanda de quatro sistemas de microgeração fotovoltaica conectados à rede
(Universidade Federal do Pará, 2018-06-29) PARIJÓS JÚNIOR, Ivan Ruy de; PEREIRA, Edinaldo José da Silva; http://lattes.cnpq.br/9596575345034065; MACÊDO, Wilson Negrão; http://lattes.cnpq.br/3386249951714088
Power quality has been widely researched. Several phenomena that affect power quality, and its consequences, have been investigated. When the power quality theme involves the operation of a grid-connected photovoltaic system, the main concern is about the operation of the inverter, which is responsible for the interface of the photovoltaic generator with the grid. The introduction of photovoltaic generation in the grid requires attention on certain factors such as changes in the load curve, voltage level, harmonic components in the inverter current and variation on the power factor (PF) of the costumer. This work aims to test and evaluate some aspects that may influence the power quality due to the insertion of photovoltaic generation in the grid, associated whit the load demand. Four grid-connected photovoltaic systems were used to develop this work, as well as a data acquisition bench that was set up to monitor the operation of these systems. In this work it is possible to conclude that the operation of photovoltaic systems causes changes in the voltage level at the point of common coupling. Also, the interaction between photovoltaic systems and loads causes changes in the load profile measured by the side of the grid, causing the total harmonic distortion in the current (THDi) and PF measured at this side to be different from those measured at the loads and photovoltaic sides. It is possible to observe that the grid-connected photovoltaic system can contribute to increase or reduce the THDi seen by the local grid, where the greatest contribution of harmonic distortion in the current delivered by the grid is associated to the demand profile of the load.
Acesso aberto (Open Access)
Influência da microgeração fotovoltaica no perfil de demanda e seus impactos na geração de harmônicos na rede
(Universidade Federal do Pará, 2024-02-29) PARIJÓS JÚNIOR, Ivan Ruy de; GALHARDO, Marcos André Barros; http://lattes.cnpq.br/6672470707462259; https://orcid.org/0000-0001-6248-5187; MACÊDO, Wilson Negrão; http://lattes.cnpq.br/3386249951714088; https://orcid.org/0000-0002-6097-8620
This study addresses the integration of photovoltaic generation into the electrical grid, emphasizing the necessity to consider changes in the load profile of consumer units and the presence of harmonic components in the grid current, originating from loads with nonlinear characteristics and photovoltaic inverters. Various percentages of inverter loading were considered in the study to evaluate their impact on grid operation due to varying levels of harmonic components. The research comprises an experimental phase, a phase dedicated to developing models of inverter output currents, and a simulation phase. In the experimental phase, data on the output currents of three photovoltaic inverters were collected. These data were then utilized in the development of models of inverter output currents for theoretical analyses, evaluating factors influencing the power quality of the grid. Subsequently, these models were applied in the simulation phase. The grids evaluated in the simulation phase include a standard IEEE system and a real isolated grid, located in the Northern region of Brazil. Comparative assessments of network hosting capacity were conducted using two different strategies. The first strategy employed conventional power flow analysis, while the second strategy applied the developed models. It is observed that the operation of different inverters within the same grid may contribute to harmonic attenuation. Furthermore, it is highlighted that the presence of grid-connected photovoltaic systems, operating in conjunction with loads, results in an apparent increase in harmonic current content in the grid, whereas, in reality, there is a reduction in the circulating fundamental component. The obtained results indicate that conventional power flow studies may underestimate the intensity of circulating currents in the grid by neglecting the presence of harmonic components. This study innovates by assessing the circulation of harmonic components in the grid due to the combined operation of photovoltaic generation and load, considering various inverter loading scenarios and the effects of consumer electrical current, including the phase of harmonic components.
Acesso aberto (Open Access)
Sistemas fotovoltaicos aplicados em redes móveis heterogêneas
(Universidade Federal do Pará, 2016-05-22) SOUZA, Marcela Alves de; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734
Mobile telecommunications operators are facing continuous challenges in increasing the capacity and coverage of the network in a way that can meet the growing demand from the users for better quality of service and experience in high-speed mobile applications. These frequent improvements have been followed by an unprecedented rise in the consmption of electric energy caused by the densification of heterogeneous mobile networks (HetNet – Heterogenous Network) through small cells. As a result, there has been an increase in the number of devices in backhaul mobile technologies which are needed to connect all the base stations by means of the access layer in the network core. Although they can be regarded as an efficient energy strategy, the small cells lead to a considerable increase in the energy consumption of HetNet, owing to the expansion of backhaul and this threatens to undermine its benefits and incurs extra energy costs for the mobile network operators. It is proposed that this problem can be overcome by exploiting renewable eneergy sources, in particular the photovoltaic system. This is expected to diversify the energy matrix and reduce the volume of CO2 emissions, as well as being more viable in technical and economic terms than conventional sources of energy supply. Thus the aim of this research study is to make a techno-economic assessment of the feasibility of acquiring, installing, and operating photovoltaic systems in the context of heterogeneous mobile networks while taking account of the energy consumption of both the fronthaul and backhaul radio networks. On the basis of the results, evidence was found of the financial viability of adopting photovoltaic frameworks, as well as the environmental sustainability that can be achieved through a considerable reduction of CO2 emissions in the atmosphere.