Thesis (M.Eng.)--Memorial University of Newfoundland, 2003. / Bibliography: leaves 148-151.

Thesis (Ph. D.)--University of Canterbury, 2005. / Typescript (photocopy). Includes bibliographical references (p. 135-138). Also available via the World Wide Web.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 157-163). Available also in a digital version from Dissertation Abstracts.

Orientador: Percival Bueno de Araujo / Co-orientador: Marcos Amorielle Furini / Banca: Anna Diva Plasencia Lotufo / Banca: André Luiz Silva Pereira / Resumo: O advento da energia elétrica e seu uso, ainda no final do século XIX, foram sem dúvida os grandes responsáveis pelo avanço tecnológico conquistado desde então. A oferta de energia para a população permitiu agregar maior conforto às pessoas e maior eficiência aos processos produtivos. Nos primórdios, os sistemas de energia eram compostos por unidades geradoras conectadas próximas aos consumidores. Essa proximidade era consequência direta do uso de transmissão em corrente contínua, o que naquela época inviabilizava a transmissão de energia elétrica através de longas distâncias. Com a invenção e utilização de máquinas de corrente alternada e transformadores, as características dos sistemas de energia passaram a ser de unidades geradoras cada vez mais distantes dos centros de consumo, sendo conectadas por longas linhas de transmissão de alta tensão. Pela metade do século XX, vislumbrou-se que a interligação de unidades geradoras, antes operando de maneira isolada, permitiria um melhor aproveitamento do potencial elétrico dos sistemas. Da mesma forma, a interligação dos consumidores permitiria maior confiabilidade no fornecimento de energia elétrica. Tais vantagens motivaram a interligação do sistema elétrico de potência. O que os visionários não poderiam imaginar era que a interconexão dos sistemas também traria novos problemas atrelados às oscilações de baixa frequência dos sistemas elétricos. Tais oscilações, em especial as relacionadas com os modos interárea, foram responsáveis por grandes blecautes ocorridos nos anos 1950 nos Estados Unidos e Canadá. Tornava-se evidente a necessidade de estudar e analisar tais oscilações, tal como o comportamento do sistema elétrico interligado como um todo quando submetido às contingências de grande e pequeno porte. Com as interligações os sistemas elétricos de potência se tornaram um dos mais complexos sistemas já desenvolvidos pelo homem. Tal ... / Abstract: The arising of electrical energy and its use in the end of 19th century are, for sure, one of the major responsible for the technology improvements conquered since then. The available of electrical energy for population also improved people's welfare and the production process efficiency. In the early days, electrical systems were composed by generator units connected close to consumers. This proximity was a straight consequence of DC (direct current) transmission, which one did not allow the transmission of power over large distances due to physical and economic constraints. With the development and use of AC (alternate current) machines and transformers, the electrical systems became composed of generator units far even more from consumer's centers, being connected to them by high voltage transmission lines. By the 1950's, it was noted that the interconnection of generators units, which was operating isolated from each other, would allow a better use of electric power system. From the same way, the interconnection of consumers allow more reliability in the electrical energy supply. Those advantages led to the interconnection of Electric Power Systems. What the visionaries could not imagine was that the interconnection would also bring to surface some new problems linked to the system's low frequency oscillations. Those oscillations, in special those related to the interarea mode, were responsible for big blackouts occurred in the 1950's in the USA and Canada. It was evident the necessity of study and analysis of those oscillations, also as the interconnected Power System behavior when under big and small contingencies. With the system's interconnection, Power Systems became one of the most complex systems already built by the man. Such complexity is extended for its analysis and study. Due to this, it was necessary create models to simplify the analysis without a loss in the results reliability. As regards to the study of small ... / Mestre

Made available in DSpace on 2014-06-11T19:22:33Z (GMT). No. of bitstreams: 0 Previous issue date: 2013-11-29Bitstream added on 2014-06-13T20:09:47Z : No. of bitstreams: 1 000739791.pdf: 1468115 bytes, checksum: ad923e4b63aea183e8523102990d35de (MD5) / O advento da energia elétrica e seu uso, ainda no final do século XIX, foram sem dúvida os grandes responsáveis pelo avanço tecnológico conquistado desde então. A oferta de energia para a população permitiu agregar maior conforto às pessoas e maior eficiência aos processos produtivos. Nos primórdios, os sistemas de energia eram compostos por unidades geradoras conectadas próximas aos consumidores. Essa proximidade era consequência direta do uso de transmissão em corrente contínua, o que naquela época inviabilizava a transmissão de energia elétrica através de longas distâncias. Com a invenção e utilização de máquinas de corrente alternada e transformadores, as características dos sistemas de energia passaram a ser de unidades geradoras cada vez mais distantes dos centros de consumo, sendo conectadas por longas linhas de transmissão de alta tensão. Pela metade do século XX, vislumbrou-se que a interligação de unidades geradoras, antes operando de maneira isolada, permitiria um melhor aproveitamento do potencial elétrico dos sistemas. Da mesma forma, a interligação dos consumidores permitiria maior confiabilidade no fornecimento de energia elétrica. Tais vantagens motivaram a interligação do sistema elétrico de potência. O que os visionários não poderiam imaginar era que a interconexão dos sistemas também traria novos problemas atrelados às oscilações de baixa frequência dos sistemas elétricos. Tais oscilações, em especial as relacionadas com os modos interárea, foram responsáveis por grandes blecautes ocorridos nos anos 1950 nos Estados Unidos e Canadá. Tornava-se evidente a necessidade de estudar e analisar tais oscilações, tal como o comportamento do sistema elétrico interligado como um todo quando submetido às contingências de grande e pequeno porte. Com as interligações os sistemas elétricos de potência se tornaram um dos mais complexos sistemas já desenvolvidos pelo homem. Tal... / The arising of electrical energy and its use in the end of 19th century are, for sure, one of the major responsible for the technology improvements conquered since then. The available of electrical energy for population also improved people's welfare and the production process efficiency. In the early days, electrical systems were composed by generator units connected close to consumers. This proximity was a straight consequence of DC (direct current) transmission, which one did not allow the transmission of power over large distances due to physical and economic constraints. With the development and use of AC (alternate current) machines and transformers, the electrical systems became composed of generator units far even more from consumer’s centers, being connected to them by high voltage transmission lines. By the 1950’s, it was noted that the interconnection of generators units, which was operating isolated from each other, would allow a better use of electric power system. From the same way, the interconnection of consumers allow more reliability in the electrical energy supply. Those advantages led to the interconnection of Electric Power Systems. What the visionaries could not imagine was that the interconnection would also bring to surface some new problems linked to the system´s low frequency oscillations. Those oscillations, in special those related to the interarea mode, were responsible for big blackouts occurred in the 1950´s in the USA and Canada. It was evident the necessity of study and analysis of those oscillations, also as the interconnected Power System behavior when under big and small contingencies. With the system´s interconnection, Power Systems became one of the most complex systems already built by the man. Such complexity is extended for its analysis and study. Due to this, it was necessary create models to simplify the analysis without a loss in the results reliability. As regards to the study of small ...

Transient stability analysis is an important part of power planning and operation. For large power systems, such analysis is very time consuming and expensive. Therefore, an online transient stability assessment will be required as these large power systems are operated close to their maximum limits. In this thesis swallowtail catastrophe is used to determine the transient stability regions. The bifurcation set represents the transient stability region in terms of power system transient parameters bounded by the transient stability limits. The system modelling is generalized in such, that the analysis could handle either one or any number of critical machines. This generalized model is then tested on a three-machine as well as a seven-machine system. The results of the stability analysis done with the generalized method is compared with the time solution and the results were satisfactory. The transient stability regions determined are valid for any changes in loading conditions and fault location. This method is a good candidate for on-line assessment of transient stability of power systems. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

No description available.

This thesis investigates the impacts of superconducting magnetic energy storage (SMES) unit on the power system first-swing stability by the impedance model of the SMES unit and EMTP simulations. The impedance model of the SMES unit is established in this thesis for study purpose. It has been concluded that SMES unit can greatly improve the power system first-swing stability. Based on the theoretical analysis and simulation results, the concept of the "Stability Protection Zone" of the SMES unit is proposed. Future work directions are discussed in the conclusion part. / Master of Science

A new methodology is proposed to investigate the large-signal stability of interconnected power electronics systems. The approach consists of decoupling the system into a source subsystem and a load subsystem, and stability of the entire system can be analyzed based on investigating the feedback loop formed by the interconnected source/load system. The proposed methodology requires two stages: (1) since the source and the load are unknown nonlinear subsystems, system identification, which consists of isolating each subsystem into a series combination of a linear part and a nonlinear part, must be performed, and (2) stability analysis of the interconnected system is conducted thereafter based on a developed stability criterion suitable for the nonlinear interconnected-block-structure model. Applicability of the methodology is verified through stability analysis of PWM converters and a typical power electronics system. / Ph. D.

This work presents a centralized control scheme applied to a power system. The scheme has adaptive characteristics which allow the controller to keep track of the changing power system operating point and to control nonlinear functions of state variables. Feedback to the controller is obtained from phasor measurements at chosen power system buses, generator field voltage measurements, and state estimators. Control effort is aimed at minimizing the oscillations and influencing the power system state trajectory through the control of linear and nonlinear functions of state variables during a power system disturbance. The main contributions of this dissertation are the simultaneous introduction and utilization of measurement based terms in the state and output equations in the derivation and implementation of the control law, the study of limits on controller performance as the state residual vector becomes very large, and the simulation of the performance of local state estimators to prove the need for faster phasor measurement systems. The test system is a hypothetical 39-Bus AC power system consisting of typical components which have been sufficiently modelled for the simulation of power system performance in a dynamic stability study. / Ph. D.