Thesis (Ph.D.) - Carleton University, 2007. / Includes bibliographical references (p. 180-182). Also available in electronic format on the Internet.

M.Phil. / The Motraco transmission system is a classical case illustrating the increase in power transfer of a network considering the possibility of a voltage collapse. This case study was used in the dissertation to find a techno-economical solution for the Motraco system to increase the power transfer to satisfy an additional load. The Motraco power system is operating close to a voltage collapse at present. A voltage collapse will be experienced if additional load is added at the Maputo substation. The possibility of a voltage collapse can be reduced if the power transfer capability of the Motraco power system is increased. Various technologies can be used to increase the power transfer of the Motraco power system. The technologies used in this study to increase the power transfer were limited to the following: • Adding shunt capacitor banks at critical locations in the network • Adding a series capacitor bank on an existing 400 kV transmission line • Adding an additional 400 kV transmission line • Adding a series capacitor bank on the new 400 kV transmission line The correct use of the combination of the shunt capacitor banks, series capacitor bank and the new transmission line contributes to: • support voltages in the network; • reduce the transmission losses; and • increase the fault levels at the receiving end. The principles used in this dissertation can be used to increase the power transfer limit of any power system with the same characteristics.

Oceans cover two thirds of the Earth’s surface and the energy potential of ocean waves as a renewable energy source is huge. It would therefore be a tremendous achievement if the vast mechanical energy in waves was converted into a form of energy that could be used successfully by society. For years, scientists and engineers have endeavored to exploit this renewable energy by inventing various generators designed to transform wave energy into electrical energy. Generally, this sort of generator is called a Wave Energy Converter (WEC). In this thesis, the research is based on the WEC developed in the Lysekil Project. The Lysekil Project is led by a research group at Uppsala University and has a test site located on the west coast of Sweden. The project started in 2002. So far, more than ten prototypes of the WEC have been deployed and relevant experiments have been carried out at the test site. The WEC developed at Uppsala University can be categorized as a point absorber. It consists of a direct-drive linear generator connected to a floating buoy. The linear generator is deployed on the seabed and driven by a floating buoy to extract wave energy. The absorbed energy is converted to electricity and transmitted to a measuring station on land. The work presented in this thesis focuses on building a linear generator model which is able to predict the performance of the Lysekil WEC. Studies are also carried out on the damping behavior of the WEC under the impact of different sea climates. The purpose is to optimize the energy absorption with a specific optimal damping coefficient. The obtained results indicate an optimal damping for the Lysekil WEC which can be used for optimizing the damping control. Additionally, the impact two central engineering design features (the translator weight and the stroke length) are investigated. The aim is to find a reasonable structural design for the generator which balances the cost and the energy production.

Thesis (PhD (Electrical Engineering))--Cape Peninsula University of Technology, 2018. / The generation of electricity through the conventional conversion system such as thermal and hydroelectric plants may no longer be sufficient to meet the increasing demands and usage. One of the major reasons for shortage supply of electric power is due to the lack of fossil fuel and other conventional resources that are currently being used in Africa. In addition, the conversion process of the conventional system often causes pollution which contributes to global warming. Therefore, there is a need for this research to develop novel and alternative methods of generating electric power. Among these methods is the Magnetohydrodynamics (MHD) conversion system, which is a direct energy conversion system. In this system, plasma or ionised gas is directly converted into electric power with generating efficiency of about 62 %. The conversion process of the MHD system is based on the principle of Faraday’s Law of electromagnetism and fluid dynamics. The focus of the present study is to investigate alternative methods through which an MHD power generator can be coupled to the existing thermal plants in South Africa. In doing so, the thermal cycle efficiency of these conventional plants can be improved. Another goal of this study is to investigate the behaviour of an MHD generator prototype under exposure to plasma through simulation and experimentation in a laboratory setting.

The concept of using Magnetohydrodynamics to provide thrust has been around for decades. However little work has been carried out in one of the fundamental aspects that allows for these systems to operate in seawater. Therefore a series of tests were carried out to determine how the electrochemical reactions occurring at the electrodes affect the seawater system. These tests were used to determine the effects magnetic fields have on seawater conductivity, the pH changes around the electrodes, and consider the double layer capacitance model as a means to decrease the amount of gas bubbles created at the electrodes. As a result significant increases in resistivity in seawater were observed when the magnetic field was introduced, pH changes were seen on both the cathode and anode, and pulsing of the applied potential may stimulate further work to be considered. / by Juan E. Moreno. / Thesis (M.S.C.S.)--Florida Atlantic University, 2011. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2011. Mode of access: World Wide Web.

Dissertation submitted for Masters of Science degree in Mathematical Statistics in the Faculty of Science, School of Statistics and Actuarial Science, University of the Witwatersrand Johannesburg May 2016 / Electricity demand in South Africa exhibit some randomness and has some important implications on scheduling of generating capacity and maintenance plans. This work focuses on the development of a short term probabilistic forecasting model for the 19:00 hours daily demand. The model incorporates deterministic influences such as; temperature effects, maximum electricity demand, dummy variables which include the holiday effects, weekly and monthly seasonal effects. A benchmark model is developed and an out-of-sample comparison between the two models is undertaken. The study further assesses the residual demand analysis for risk uncertainty. This information is important to system operators and utility companies to determine the number of critical peak days as well as scheduling load flow analysis and dispatching of electricity in South Africa. Keywords: Semi-parametric additive model, generalized Pareto distribution, extreme value mixture modelling, non stationary time series, electricity demand

Orientador: Antonio Roberto Balbo / Coorientadora: Célia Aparecida dos Reis / Banca: Hassan Costa Arbex / Banca: Tatiana Miguel Rodrigues de Souza / Resumo: Atualmente a produção e o consumo de energia têm suma importância para a realização de diversas atividades humanas, o que implica em uma grande quantidade a ser produzida para atender a demanda, que, com o passar do tempo, aumenta cada vez mais. Esse aumento do consumo faz com que pesquisas sejam desenvolvidas com relação a sistemas de captação ou colheita de energia, que são chamados de "energy harvesting". Estas possibilitam sua conversão em energia elétrica, que pode ser diretamente utilizada ou armazenada para uso posterior. Um sistema de colheita de energia captada através de material piezoelétrico é aquele que colhe a energia gerada por vibração mecânica. Neste trabalho fez-se um estudo, em termos do plano de fase e estabilidade assintótica, de um modelo de vibração massa-mola-amortecedor associada a sistemas de colheita de energia, o qual é baseado em uma equação de Duffing. O modelo é formulado através de um sistema de equações diferenciais ordinárias não lineares e, para análise de suas soluções de equilíbrio, foi utilizado o método de Cardano - Tartaglia. Testes com um problema real são realizados apresentando as soluções obtidas pelo método, bem como uma simulação numérica do retrato de fase de dois pontos críticos destes, utilizando o software MatLab. / Abstract: Currently the production and consumption of energy is very important for the performance of various human activities, which entails a great demand to be met and, with the passage of time, increases more and more. This increase in energy consumption makes researches are developed in relation to energy harvesting systems called energy harvesting. These enable their conversion into electrical energy, which can be directly used or stored for later use. A system of energy harvesting captured by piezoelectric material is one that harvests the energy generated by mechanical vibration. In this work is investigated a mass-spring-damper vibration model associated with an energy harvesting system, which is based in a Duffing's equation. This model is formulated through a system of ordinary nonlinear differential equations and, to analyze of their equilibrium solutions, the Cardano - Tartaglia's method was used. Tests with an actual problem are done, presenting the solutions obtained by the method, as well as a numerical simulation a phase portrait analysis of two critical points of this, using the MatLab software. / Mestre

PhD / This study investigates how actions – especially narratives and claims – of civil society advocates influenced electricity generation planning and hydropower project implementation, in the context of a democratising authoritarian state. To pursue this research agenda, I use a critical realist philosophy of science to ground a conceptual framework whose fundamental components consist of institutions, interests, and discourses. The research presents three case studies from Thailand, a nation-state with distinct authoritarian legacies, as well as significant economic and political dynamism in the late 20th century. The cases step from macro to micro levels of analysis: (1) Electricity generation planning: an overview and critique of the social construction of peak power demand and supply options in Thailand, 1960s–2004. I focus on the rise of energy conservation advocacy in the early 1990s, and the rise of more confrontational energy activism in the late 1990s; (2) Pak Mun Dam: contention between EGAT, anti-dam villagers, and other state and civil society actors, 1989–2003; (3) Pak Mun Dam: analysis of how knowledge discourses shaped debates over fisheries and local livelihoods in the lower Mun river basin, 1999–2004. I pursue these cases in the larger context of Thai state–society relations, 1932–early 2000s: from the Khana Ratsadorn (People’s Party) and its founders’ increasingly authoritarian struggles to shape the state; through to the rise of civil society in the Indochina-war era; through the emergence of parliamentary politics and NGO evolution in the 1980s and early 1990s; to the Thai Rak Thai “money politics” party that emerged in 1998. Specific research questions focus on patterns and outcomes of state–society interaction, the role of lay and expert knowledge discourses in structuring conflict, and plausible causal connections between outcomes and concepts used in the conceptual framework. The study is based on fieldwork conducted between 2001 and 2005, with 18 months of intensive work concentrated in 2002 and 2004. Recurrent procedures consisted of collecting policy narratives and arguments and re-constructing actors’ interests (including those of leaders in organizations) via participant observation, interviews, and textual analysis. The thesis argues that anti-dam advocates influenced project implementation practices at Pak Mun Dam by forming social change networks, gaining contingent recognition as new political actors. Through innovative and disruptive action, through claims for transparency and justice, through mass performances of worthiness, unity, and commitment, and through the production of local knowledge, they helped set agendas. They triggered elite intervention, as well as reactive counter-mobilization and occasional violence. The escalation of uncertainty from unintended outcomes challenged elites – aided by deliberative exchanges – to reconsider unfavourable decisions, to reconsider their preferences, and to make concessions. At the same time, a number of events made the Assembly of the Poor, the main anti-dam movement organization, vulnerable to destabilizing action at the local and national levels. These include: the formation of competitive organizations in the lower Mun basin; complex and intractable issues (such as multiple rounds of compensation); and inability to take credit for championing the interests of vulnerable small farmers. Destabilizing interactions occurred particularly in the restricted media space of the post-financial and economic crisis years. Populist platforms put forward by Thai Rak Thai and Prime Minister Thaksin Shinawatra pre-empted the AOP’s influence. Sustainable energy advocates influenced practices of power system planning by teaching new techniques of energy conservation, and diffusing new norms. In the recent period, however, as some of them engaged in more contentious interaction, such as intervening in conflicts over new coal and hydroelectric power plants (in southern Thailand and Laos respectively) they disrupted dominant rationalities, and found themselves confronting some of the same core practices of a power-wielding bureaucracy and an authoritarian state, namely rhetorical strategies that police the boundaries of policy-relevant knowledge. The thesis, intended to contribute to social science methodology and theory, concludes with a critical appraisal of the conceptual framework. I suggest new research agendas for analysts interested in mechanisms of civil society advocacy in the context of democratising states.

If the observations of unregulated and recently deregulated essential services were to hold for electricity reform, we could expect to see market segmentation of household customers. This is a corporate strategy aimed at the acquisition of attractive customers and the avoidance of unattractive customers. It is a function of market relations and commodification. Some markets already segment and assign unattractive customers to 'residual' markets, 'sub-prime' markets or 'markets of last resort'. Residual markets tend to involve market abuse by suppliers because these customers lack market power. It is possible therefore to suggest that segmented markets are characterised by simultaneous competition and monopoly. The implications for the supply of essential services, such as electricity, are profound. This research sought to identify whether there is evidence of emerging segmentation of the domestic electricity market in Victoria. In practice, few essential services areas are completely deregulated. The history of segmentation in the US insurance and lending industries provides valuable insights into markets, market failure and social protections. Taking this history and the more recent experiences of reforms in the US, the UK and Australia, it has been possible to identify three models of social protection: 'universal service', a 'civil rights' model, and a 'market' model. The Victorian reforms reflect some elements of each of these. The social protections included in the reform package both encourage and present barriers to market segmentation. At the time of the research, some elements of the safety net arrangements and customer inertia (born out of negative attitudes to competition) have acted to inhibit segmentation. Customer inertia in its own right poses questions for the efficacy of competition policy. The key understanding that is gained from this research is that both civil rights and socioeconomic entitlements (social rights) are required to prevent markets in essential services acting upon and exacerbating inequality. This suggests that universal service, as a model of social protection, is most likely to ameliorate the impacts of inequality.

Thesis (M.E.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (leaves 106-109). Also available via the World Wide Web.