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Com o constante crescimento da frota mundial de veículos elétricos, é necessário ponderar as os impactos desse aumento. A Tecnologia V2G e o uso de carregamentos inteligentes e dinâmicos têm sido apontadas como potenciais tecnologias para o uso de VE para serviços auxiliares da rede elétrica, colmatando o próprio impacto que os VE criam na procura de energia, bem como as falhas existentes no uso de uma maior percentagem de recursos renováveis no mix energético. Esta tecnologia permite o fluxo bidirecional de energia elétrica entre o VE e a rede de distribuição, possibilitando o uso dos VE como consumidores, fornecedores e armazenadores de energia. No entanto, isto implica o funcionamento dos postos de carregamento com potências abaixo da nominal, instigando preocupações nos parâmetros da qualidade da energia. Neste trabalho foi feita a análise da qualidade de energia de um VE Nissan Leaf 2015 conectado a um posto V2G de 10 kW em ambos os modos, carga e descarga. As componentes avaliadas foram o fator de potência, distorções harmônicas totais e individuais da tensão e corrente bem como a possível relação entre as mesmas. Verificou-se na maioria dos casos as componentes estudadas se encontravam dentro dos limites das normas, no entanto, para potências inferiores de operação houve valores pontuais a não respeitar os limites. Foi também possível constatar que o processo de descarga (V2G) apresentou valores piores de qualidade de energia quando comparado com o modo de carga. Por último, verificou-se a compatibilidade do uso de modelos matemáticos apresentados na literatura para descrever o perfil do fator de potência e distorção harmônica total da corrente em sistemas fotovoltaicos. Uma vez que, é um tema já bastante investigado, e com características semelhantes no que toca ao funcionamento do posto de conversão, com potências irregulares e variáveis. Os modelos utilizados conseguiram descrever os dados experimentais com eficácia. Para compreender melhor o impacto dos VE serão necessários estudos posteriores por forma a serem inseridos de forma segura e eficiente no mix energético.
With the steady growth of the world's electric vehicle fleet, it is necessary to weigh its advantages and disadvantages. V2G technology and the use of intelligent and dynamic charging have been pointed out as potential technologies for the use of EV for auxiliary services of the electrical network. Mitigating the impact that EVs create on energy demand, as well as the existing failures of using a higher percentage of renewable resources in the energy mix. However, this implies charging stations to operat below their nominal power, instigating concerns about the parameters of energy quality. In this work the power quality of a Nissan Leaf 2015 EV connected to a 10 kW V2G station in both modes, charging and discharging, was analysed. The components evaluated were the power factor, total and individual harmonic distortions of voltage and current as well as the possible relation between them. In most cases the components studied were within the limits of the standards, however, for lower operating powers there were some values not respecting the limits. It was also possible to verify that the discharge process (V2G) presented worse power quality values when compared with the charging mode. Finally, it was verified the compatibility of the use of mathematical models presented in the literature to describe the profile of the power factor and total harmonic distortion of current in photovoltaic systems. The models used were able to describe the experimental data effectively. In order to better understand the impact of EV, further studies will be necessary in order to insert them safely and efficiently in the energy mix.
With the steady growth of the world's electric vehicle fleet, it is necessary to weigh its advantages and disadvantages. V2G technology and the use of intelligent and dynamic charging have been pointed out as potential technologies for the use of EV for auxiliary services of the electrical network. Mitigating the impact that EVs create on energy demand, as well as the existing failures of using a higher percentage of renewable resources in the energy mix. However, this implies charging stations to operat below their nominal power, instigating concerns about the parameters of energy quality. In this work the power quality of a Nissan Leaf 2015 EV connected to a 10 kW V2G station in both modes, charging and discharging, was analysed. The components evaluated were the power factor, total and individual harmonic distortions of voltage and current as well as the possible relation between them. In most cases the components studied were within the limits of the standards, however, for lower operating powers there were some values not respecting the limits. It was also possible to verify that the discharge process (V2G) presented worse power quality values when compared with the charging mode. Finally, it was verified the compatibility of the use of mathematical models presented in the literature to describe the profile of the power factor and total harmonic distortion of current in photovoltaic systems. The models used were able to describe the experimental data effectively. In order to better understand the impact of EV, further studies will be necessary in order to insert them safely and efficiently in the energy mix.
Descrição
Tese de mestrado integrado, Engenharia da Energia e do Ambiente, Universidade de Lisboa, Faculdade de Ciências, 2020
Palavras-chave
Veículos Elétricos Carregamento de VE Qualidade da Energia armónicas Fator de Potência Teses de mestrado - 2020
