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Percorrer ISEP – CIETI – Artigos por Domínios Científicos e Tecnológicos (FOS) "Engenharia e Tecnologia::Engenharia Eletrotécnica, Eletrónica e Informática"
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- Adaptação de Laboratórios Remotos a Cenários de Ensino: Casos de Estudo com VISIR e RemotElectLabPublication . Fidalgo, André V.; Alves, Gustavo R.; Marques, Maria A.; Viegas, Maria C.; Costa-Lobo, Maria C.; Hernández-Jayo, Unai; García-Zubía, Javier; Gustavsson, Ingvar; Alves, Gustavo; Fidalgo, André; Marques, Maria Arcelina; Viegas, Clara; Costa Lobo, Cristina; Garcia-Zubia, JavierOs laboratórios remotos são uma ferramenta tecnológica e pedagógica com uso crescente em todos os níveis de educação, e sua utilização generalizada é uma parte importante do seu próprio aperfeiçoamento e evolução. Este artigo descreve vários problemas encontrados em aulas laboratoriais, em cursos de ensino superior, na utilização de laboratórios remotos baseados em sistemas PXI, utilizando o sistema VISIR ou uma solução alternativa. São identificados e explicados três problemas que foram relatados por professores que deram apoio aos estudantes na utilização dos laboratórios remotos. O primeiro problema prende-se com a necessidade de permitir aos alunos selecionar a localização específica onde um amperímetro deve ser inserido nos circuitos elétricos, mesmo que incorreta, replicando as dificuldades do mundo real. O segundo é causado por falhas de sincronismo quando são necessárias várias medições em intervalos curtos, como no ciclo de descarga de um condensador. E o último problema é provocado pelo uso de um multímetro em modo DC na leitura de grandezas em CA, um procedimento que colide com as definições do equipamento. Todos os cenários são apresentados e discutidos, incluindo a solução encontrada para cada caso. A conclusão que se retira do trabalho descrito é que a área de laboratórios remotos é um campo em expansão, onde a sua utilização prática permite o aperfeiçoamento e a evolução das soluções disponíveis, exigindo uma cooperação e partilha de informação entre todos os intervenientes, i.e. investigadores, professores e alunos.
- Graciosa Island’s Hybrid Energy System Expansion Scenarios: A Technical and Economic AnalysisPublication . Jesus, José; Nogueira, Teresa; Magano, JoséThe island of Graciosa in the Azores faces unique energy challenges due to its remote location and reliance on imported diesel fuel. As a result, a hybrid energy system has been implemented that combines wind and solar energy with energy storage and diesel generators. This article examines the expansion of the island’s hybrid energy system, by simulating four alternative scalable scenarios that take into account expected technological advances over the next 20 years, including technologies such as biomass and hydrogen. Homer Pro and PVSyst software were used for optimizing the design of the stand-alone hybrid renewable energy system, with the aim of achieving cost-effective configurations and optimizing production, storage, and power grid management. Four simulations were performed to evaluate the expansion scenarios, namely in terms of configurations, component sizing, and economic feasibility. The results show that the most balanced, cost-effective scenario is the one that combines all the energy sources considered: photovoltaic, wind, biomass, battery storage, and hydrogen. The originality of this study lies in the scenario comparison methodology used to evaluate the viability and expansion of a hybrid energy system using modern renewable energy production technologies adapted to the specific insular conditions of Graciosa Island, assessing the economic impact and taking into account the imperative of energy security. This paper provides valuable insights into the potential and challenges of hybrid energy systems on the island of Graciosa and is instrumental for projects alike in similar remote regions.
- Physiopathological effects of electric current on the human body and the protection against electric shocksPublication . Carvalho, José António Beleza; Beleza Carvalho, José António; Almeida, Maria; Silva, Catarina; Costa, CarolinaIn electrical installations and equipment, electric current preferentially flows through metallic circuits that offer it less opposition, that is, less electrical resistance. In the human body, electric current also seeks to flow through paths with less electrical resistance, and may be diverted inside the body, damaging surrounding organs and tissues. Its path and the magnitude of the current influence the type of injuries associated with electrical accidents, usually burns, which can be internal and external. In all electrical installations, there is a need and obligation to implement effective protection systems, with the aim of operating them under safe conditions. In Low Voltage Electrical Installations (LVEI), the protection measures that must be considered are overcurrent protection, overvoltage protection, but fundamentally the protection of people from the risk of electrocution, avoiding pathophysiological effects that can be irreversible.
- Safety in the operation of electrical networks: Inertia compensation as a measure of frequency and voltage stabilityPublication . Carvalho, José; Beleza Carvalho, José AntónioThe main purpose of electrical transmission and distribution networks is to carry electrical energy from the places where it is produced to the places of consumption, where the energy is used. Electrical energy is produced in power plants by generating units, which convert a form of primary energy into electrical energy. Primary energy comes from a number of sources, such as fossil fuels, nuclear energy, hydropower, wind, and solar. The carbon neutrality targets set by the European Union and several countries around the world have driven a transformation characterized by the gradual replacement of synchronous thermal generation based on fossil fuels with Renewable Energy Sources (RES), such as wind and solar. The energy transition, while necessary to achieve the established targets, introduces significant challenges to the stability of Electrical Power Systems (EPS) and electrical grids, since RES do not yet contribute to stability at levels comparable to the generating units of large thermal power plants, whether in terms of inertia, which has seen a notable reduction in recent years, or in voltage control or short-circuit power. This article presents and discusses solutions to mitigate the effect of this reduction in inertia in power plants using synchronous compensators and synthetic inertia emulation using battery storage.