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Abstract(s)
As descargas atmosféricas são um fenómeno natural, cujos efeitos podem trazer consequências muito significativas, quer em termos de danificação e perdas de bens materiais, quer em termos de perda de vidas humanas. Os equipamentos elétricos e eletrónicos estão em constante exposição a perturbações elétricas, e se não estiverem devidamente protegidos estão sujeitos a danos que na maioria das vezes são irreparáveis, causados por sobretensões transitórias ou permanentes. Torna-se, assim, mandatário a adoção de medidas de proteção e mitigação dos efeitos das descargas atmosféricas diretas e sobretensões nas instalações de assegurar a proteção de bens e pessoas. No âmbito desta dissertação, será abordada a temática da proteção das instalações contra descargas atmosféricas e sobretensões induzidas, em termos de enquadramento regulamentar, normativo, técnico/científico e tecnológico. Primariamente é apresentada uma breve análise da origem, formação e caracterização das descargas atmosféricas, bem como a análise da metodologia e soluções técnicas de proteção externa e interna aos edifícios. São também abordados e sintetizados os regulamentos e normas existentes destinados a normalizar métodos e procedimentos, para a decisão de implementação de medidas de segurança no sentido de proteger uma estrutura. Seguidamente foram desenvolvidas duas aplicações informáticas, de apoio ao projeto de sistemas de proteção contra sobretensões. A primeira uma aplicação informática de apoio à análise de risco e definição no nível de proteção, de acordo com o definido na norma IEC 62305-2, e a segunda, uma aplicação de apoio à seleção do material e realização de mapa de quantidades. As aplicações desenvolvidas permitiram a redução do tempo de projeto de sistemas de proteção contra sobretensões. Foi, ainda, desenvolvido um projeto técnico de proteção contra sobretensões de um edifício recebendo público, envolvendo a proteção externa, com recurso a sistemas passivos e sistemas ativos, assim como a proteção interna, com o projeto de descarregadores de sobretensões. Foi também realizada uma análise económica aos dois sistemas de proteção. Na parte final do documento são apresentadas as conclusões obtidas no estudo, assim como algumas considerações que poderão ser objeto de estudo em trabalhos futuros.
Lightning discharges are a natural phenomenon, the effects of which can have very significant consequences, both in terms of damage and loss of material goods and of human lives. Electrical and electronic equipment are constantly exposed to electrical disturbances, and if they are not properly protected they are subject to damage, which in most cases is irreparable, caused by transient or permanent overvoltages. It is therefore mandatory to adopt measures to protect and mitigate the effects of direct lightning strikes and overvoltages on installations to ensure the protection of people and property. Within the scope of this dissertation, the subject of the protection of installations against lightning and induced overvoltages will be addressed, in terms of the regulatory, normative, technical/scientific and technological framework. Firstly, a brief analysis of the origin, formation and characterisation of lightning discharges is presented, as well as the analysis of the methodology and technical solutions for external and internal protection of buildings. The existing regulations and standards aimed at standardising methods and procedures for the decision of implementing safety measures to protect a structure are also addressed and summarised. Two software applications were then developed to support the design of surge protection systems. The first was an application to support the risk analysis and the definition of the protection level, according to the IEC 62305-2 standard, and the second was an application to support the selection of material and the preparation of a bill of quantities. The applications developed allowed a reduction in the design time of surge protection systems. It was also developed a technical project of protection against overvoltages of a building receiving public, involving external protection, using passive and active systems, as well as internal protection, with the design of surge arresters. An economic analysis of the two protection systems was also carried out. The final part of the document presents the conclusions obtained in the study, as well as some considerations that may be the subject of study in future work.
Lightning discharges are a natural phenomenon, the effects of which can have very significant consequences, both in terms of damage and loss of material goods and of human lives. Electrical and electronic equipment are constantly exposed to electrical disturbances, and if they are not properly protected they are subject to damage, which in most cases is irreparable, caused by transient or permanent overvoltages. It is therefore mandatory to adopt measures to protect and mitigate the effects of direct lightning strikes and overvoltages on installations to ensure the protection of people and property. Within the scope of this dissertation, the subject of the protection of installations against lightning and induced overvoltages will be addressed, in terms of the regulatory, normative, technical/scientific and technological framework. Firstly, a brief analysis of the origin, formation and characterisation of lightning discharges is presented, as well as the analysis of the methodology and technical solutions for external and internal protection of buildings. The existing regulations and standards aimed at standardising methods and procedures for the decision of implementing safety measures to protect a structure are also addressed and summarised. Two software applications were then developed to support the design of surge protection systems. The first was an application to support the risk analysis and the definition of the protection level, according to the IEC 62305-2 standard, and the second was an application to support the selection of material and the preparation of a bill of quantities. The applications developed allowed a reduction in the design time of surge protection systems. It was also developed a technical project of protection against overvoltages of a building receiving public, involving external protection, using passive and active systems, as well as internal protection, with the design of surge arresters. An economic analysis of the two protection systems was also carried out. The final part of the document presents the conclusions obtained in the study, as well as some considerations that may be the subject of study in future work.
Description
Keywords
Descargas Atmosféricas Sobretensões Sistemas de Proteção Segurança Danos Regulamentação Estruturas Lightning Surge Protection Systems Security Damage Regulations Structure