Thesis (Ph. D.)--University of Texas at Austin, 2001. / Vita. Includes bibliographical references. Available also from UMI/Dissertation Abstracts International.

This dissertation analyses the reliability of power transformers and its impact of failure on system performance. Eskom Distribution, Eastern Region is used as a practical case study, which has an installed transformer base of 6066MVA comprising of 428 transformers ranging from 1 MVA to 8OMVA with voltage levels of 6.6kV to I 32kV. The literature review illustrates the theory and principles of transformers, evolution and changes in design criteria, the function of cellulose and insulating oil, failure modes. operations and maintenance practices and factors affecting the distribution systems performance. This study included a conditional assessment and an oil analysis review of transformers at Eskom. A method to trend multiple oil samples was developed and illustrated. The research further investigates the reliability of series and parallel systems using actual component reliability values. A study was conducted to establish the degree of network firmness. Transformer failure data was analysed and were shown to be characteristic of a bathtub curve. Defects from on site inspections were analysed and identified oil leaks as a maintenance focus area. The Distribution Supply Loss Index was determined to be the major impact Key Performance Index due to transformer failures. Transformer failures using statistical methods, showed HV/LV winding to be the main component to fail. The cost of a transformer failure to Eskom and the customer was determined. International Benchmarking was investigated to establish the criteria for network reliability indices and to compare the network infrastructure and performance of international utilities and Eskom. The later part of the study involved the analysis of a risk ranking methodology to establish a risk ranking matrix. The transformers were ranked according to the matrix, identifying the high risk focus areas. Projects were raised within Eskom to replace the identified high risk transformers. This study has concluded that the reliability of transformers is impacted by the changes in transformer design, increased maintenance defects and inadequate transformer protection at substations. The reduced oil volume per kVA, increased hot spot and ambient temperature, and compact tank designs have resulted in the cellulose being overheated and fault gases being produced during normal operating conditions. The increase in load demand from the existing transformer fleet and a reduction in capital expenditure to maintain and build additional substations have also contributed to accelerated aging, since the transformers are forced to operate at 100 percent loading. There is an increase in transformer maintenance defects due to in sufficient operational staff, high staff turnover, reduced skills transfer. and insufficient network contingencies to allow for planned outages to clear the defects identified. The failure analysis showed that the main component to fail is HV/LV windings. The winding failures were traced to there being no or inadequate transformer protection at -20% of substations. / Thesis (M.Sc.)-University of KwaZulu-Natal, 2007.

Public lighting is seen as a non-core function by many municipalities and therefore does not always receive the necessary management attention. As a result the provision of public lighting maintenance differs substantially between Local Authorities; in some instances public lighting is in a state of disrepair and in other instances the service delivery is excellent. One of the major problems identified is the lack of information with regard to the number and types of fittings installed and also the number of failures that occur. As a consequence many municipalities cannot provide accurate costs to enable comparison with other Local Authorities. There is also a general lack of consensus as to what constitutes appropriate service delivery in terms of system availability and failure response times. This results in large differences in terms of costs, which range from R11.50 to R26.60 per fitting per month and system availability, which ranges from less than 70% to better than 99%. To establish appropriate service levels responses were obtained from the general public and two groups more directly involved with streetlight maintenance namely, public officials and street lighting experts. This data together with the evaluation of historical data collected over the last 16 months on the Benoni network allows the formulation of appropriate cycle times in order to achieve the expected service delivery in terms of system availability and response times. A holistic literature survey is presented covering the major aspects which impact on service delivery such as the restructuring of the electricity distribution industry and local authority transformation. The aspects of energy efficiency and equipment life expectancy are covered in detail and recommendations are made as to the appropriate replacement cycles. The different lamp replacement policies are also discussed and cost comparisons made. Recommendations made are that a system availability of 98% is both acceptable and achievable with a moderate budget. Response times of less than 24 hours would be ideal but this does not optimise the utilisation of resources, budget constraints may dictate a longer response time. Response times of more than 5 days would generally be unacceptable. Optimal fitting replacement age is between 19 and 23 years. Under normal circumstances the introduction of energy efficient luminaires is the most cost effective when inefficient fittings have reached their optimal replacement age. Changes in energy costs, tax concessions or cost subsidisation will however impact on the appropriate replacement strategy. / Thesis (MBA)-University of KwaZulu-Natal, 2004.

The successes or failures one experiences in life depend greatly on the decisions that one makes. This is not only true in one’s personal life but is also the case in the business environment. In this modern world, simple and complex decisions are the key elements for a business to be successful in the competitive global environment. Effective decision making is an intricate process. In Eskom it is important to integrate the technological and business aspects to support the decision making process. Research methodology provides one with the necessary tools to support this decision making. The main focus of the study is the development of an Optimisation Model for the Management of Transformers in the Eskom East Grid Transmission Sysytem. In the Eskom Transmission system, there are a large number of power transformers which are the most expensive and strategically important component of the Transmission system. There were three main objectives. The first objective included the forecasting of transformer failures using the forecasting techniques of moving average, weighted moving average, exponential smoothing and regression analysis. The second objective focused on the investigation of the re – location of the tap changer maintenance team to a new area using the mathematical and statistical methods of simulation and decision tree analysis. The third objective included the investigation of an inventory control and management model where the optimum number of spares pertaining to transformer units that should be made available was determined using the mathematical and statistical model called the economic order quantity. These objectives were then used to investigate the development of the optimisation model pertaining to transformers. The results of the study concluded that the operating research techniques which included the forecasting methods and the economic order quantity models were suitable for research in Eskom. However it is important to note that the Eskom system and the environment in which transformers operate in is dynamic and has some factors that cannot be controlled. These factors must be taken into consideration when the various models are used in the investigation of the optimisation model. The introduction of these external factors is beyond the scope of this study and is not included. It was concluded that the simulation and decision tree analysis could be used as an integral part of the optimisation model successfully. The limitations that were highlighted included the integrity of the secondary data (sample size, the source of the secondary data, data quality and data governance), the limitations associated with forecasting, the limitations of the operations research, mathematical and statistical models and the fact that the Eskom network is dynamic. . The recommendations included the application of the forecasting techniques and the inventory control model to a larger population size which was that of the transformers in the entire Transmission system. It was indicated that Eskom resources, time and money must be used to support the business’s strategy to train and develop employees to an acceptable competency level. Future studies should include the factors that affect forecasting and the implementation of the inventory control model to increase the accuracy of the results. The introduction of these external factors is beyond the scope of this study and was not included in the models. / Thesis (MBA)-University of KwaZulu-Natal, Westville, 2009.

No description available.

Thesis (DBusinessAdministration)--University of South Australia, 2004.

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.

Thesis (M.S. in electrical engineering)--Washington State University, May 2008. / Includes bibliographical references (p. 90-95).

Thesis (Ph. D.)--Auburn University. / Abstract. Vita. Includes bibliographical references (p. 118-124).

Thesis (M. Phil.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.