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Advisor(s)
Abstract(s)
Neste trabalho é efectuado, não só o diagnóstico em regime permanente, mas também o estudo, simulação e análise do comportamento dinâmico da rede eléctrica da ilha de São Vicente em Cabo Verde. Os estudos de estabilidade transitória desempenham um importante papel, tanto no planeamento como na operação dos sistemas de potência. Tais estudos são realizados, em grande parte, através de simulação digital no domínio do tempo, utilizando integração numérica para resolver as equações não-lineares que modelam a dinâmica do sistema e dependem da existência de registos reais de perturbação (ex: osciloperturbografia).
O objectivo do trabalho será também verificar a aplicabilidade dos requisitos técnicos que as unidades geradoras devem ter, no que concerne ao controlo de tensão, estabelecidos na futura regulamentação europeia desenvolvida pela ENTSO-E (European Network Transmission System Operator for Electricity). De entre os requisitos analisou-se a capacidade das máquinas existentes suportarem cavas de tensão decorrentes de curto-circuitos trifásicos simétricos, Fault Ride Through, no ponto de ligação à rede. Identificaram-se para o efeito os factores que influenciam a estabilidade desta rede, em regime perturbado nomeadamente: (i) duração do defeito, (ii) caracterização da carga, com e sem a presença do sistema de controlo de tensão (AVR) em unidades de geração síncronas.
Na ausência de registos reais sobre o comportamento do sistema, conclui-se que este é sensível à elasticidade das cargas em particular do tipo potência constante, existindo risco de perda de estabilidade, neste caso, para defeitos superiores a 5ms sem AVR. A existência de AVR nesta rede afigura-se como indispensável para garantir estabilidade de tensão sendo contudo necessário proceder a uma correcta parametrização.
In this work it was done, not only the diagnosis in steady state, but also the study, simulation and analysis of the dynamic behavior of the electricity network on the island of São Vicente in Cape Verde. The transient stability studies play an important role, both in the planning and operation of power systems. Such studies are conducted, largely, through computer simulation in time domain, using numerical integration to solve the nonlinear equations that model the dynamics of the system and depend of the existence of real distress records (ex. osciloperturbography). The objective of this work will also verify the applicability of the technical requirements that generating units must have, regarding the control voltage, established by the future European regulations ENTSO-E (European Network Transmission System Operator for Electricity). Among the requirements it was analyzed the capacity of existing machines withstand voltage sag due to short-circuit three-phase symmetrical, Fault Ride Through, at the point of connection to the supply network. It was also identified the factors that influence the stability of the network, under disturbed, as follow: (i) duration of the fault, (ii) load characteristics, with and without the presence of the automatic voltage regulator (AVR) in synchronous generating units. In absence of real records of the system behavior, it is concluded that this is sensitive to the power load elasticity, particularity with constant power type , existing the risk oflosing stability, in this case, for faults greater than 5ms without AVR. The existence of AVR in this network it’s absolutely necessary to assure de voltage stability, doing for that a correct parameterization.
In this work it was done, not only the diagnosis in steady state, but also the study, simulation and analysis of the dynamic behavior of the electricity network on the island of São Vicente in Cape Verde. The transient stability studies play an important role, both in the planning and operation of power systems. Such studies are conducted, largely, through computer simulation in time domain, using numerical integration to solve the nonlinear equations that model the dynamics of the system and depend of the existence of real distress records (ex. osciloperturbography). The objective of this work will also verify the applicability of the technical requirements that generating units must have, regarding the control voltage, established by the future European regulations ENTSO-E (European Network Transmission System Operator for Electricity). Among the requirements it was analyzed the capacity of existing machines withstand voltage sag due to short-circuit three-phase symmetrical, Fault Ride Through, at the point of connection to the supply network. It was also identified the factors that influence the stability of the network, under disturbed, as follow: (i) duration of the fault, (ii) load characteristics, with and without the presence of the automatic voltage regulator (AVR) in synchronous generating units. In absence of real records of the system behavior, it is concluded that this is sensitive to the power load elasticity, particularity with constant power type , existing the risk oflosing stability, in this case, for faults greater than 5ms without AVR. The existence of AVR in this network it’s absolutely necessary to assure de voltage stability, doing for that a correct parameterization.
Description
Keywords
Análise de sistemas de energia Estabilidade Modelos dinâmicos Sistema de excitação Power system analysis Stability Dynamic models Exciter system
Citation
Rocha, Humberto Alexandre Milício da - Comportamento dinâmico da rede eléctrica da ilha de São Vicente em Cabo Verde: estabilidade de tensão. Lisboa: Instituto Superior de Engenharia de Lisboa, 2011. Dissertação de mestrado.