published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Hong Kong, 1995. / Includes bibliographical references.

Thesis (Ph. D.)--University of Canterbury, 2008. / Typescript (photocopy). Includes bibliographical references (p. 131-136). Also available via the World Wide Web.

M. Tech. Electrical Engineering. / Discusses energy as the basic necessity for the economic development of a country. Many functions necessary to present-day living grind to halt when the supply of energy stops. Energy exists in different forms in nature but the most important form is the electrical energy. Therefore, enhancing power flow in transmission systems is important for efficient power supply because a modern-day society requires a large amount of electrical energy for domestic, commercial and industrial purposes. Among the various means of enhancing power flow in transmission systems with the help of FACTS devices, this research work focussed on the aspect of improving the power system stability. Therefore, efficient supply of electric power to various customer load demands can be achieved when the future power system engineers and researchers carry out nonlinear modelling, bifurcation analysis and control of their system with FACTS devices such as TCSC for power system stability enhancement.

Orientador: Helmo Kelis Morales Paredes / Banca: Flavio Alessandro Serrao Gonçalves / Banca: Wesley Angelino de Souza / Resumo: Este trabalho de mestrado descreve uma estratégia de operação multifuncional e flexível aplicado a conversores trifásicos CC-CA (inversores) conectados à rede de distribuição de energia elétrica. A estratégia proposta é capaz de injetar potência ativa na rede e compensar correntes de distúrbios (reativos, desbalanço e harmônicos) simultaneamente. O maior objetivo desta operação flexível é de melhorar a Qualidade de Energia Elétrica em um ponto de acoplamento comum (PAC) permitindo a compensação total ou parcial destes distúrbios ou fatores que degradam a Qualidade de Energia Elétrica. O fator de potência é o principal fator de qualidade a ser observado e ele é calculado através da Teoria da Potência Conservativa - CPT. Entretanto, com base no fator de potência medido pelo lado da rede de distribuição e o fator de potência desejado, um coeficiente de compensação - k é calculado para o ajuste das correntes de compensação dos distúrbios que geram a potência não ativa. / Abstract: This paper depicts a multifunctional and flexible control strategy applied in three-phase inverters, which are connected to the distribution network. The proposed strategy is able to inject active power into the electrical grid and compensate current disturbances (reactive, harmonics and unbalance) simultaneously. The main goal of this flexible strategy is to improve the Power Quality at the point of common coupling (PCC) allowing full or partial compensation of disturbances. Power factor is the main quality index observed and it is calculated according to Conservative Power Theory - CPT. Therefore, based on the power factor measured in the grid side and the desired value for the power factor, a compensation coefficient - k is calculated continuously adjusting the amplitude of the compensation current. / Mestre