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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
291

Modelling and simulation of the impacts of distributed generation integration into the smart grid

Onwunta, Onwunta Emea Kalu January 2014 (has links)
Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology 2014 / Distributed generation (DG) has been reincarnated after its demise by centralised generation. While economy of scale and efficiency are the advantages of the latter, deregulation of the electricity market, environmental concerns and the need to arrest dwindling reserve margins have necessitated the rebirth of the former. Indeed, a full circle has therefore evolved with generation being ‘embedded’ in distribution systems and ‘dispersed’ around the system rather than being located and dispatched centrally or globally. This development is in tandem with the history of industrial revolutions that started from energy and moved through services and communication and back to energy. South Africa is not immune to the global energy, especially tertiary energy, challenge phenomenon. At the peak of the 2007-2008 energy crisis, her generation net reserve margin fell below 10% – well below conventional industry benchmark of at least 15%. Also South Africa is Africa’s largest emitter of CO2 contributing over 40% of Africa’s total CO2 emissions. Therefore, DG’s relevance to South Africa is quite obvious. However, DG integration into distribution networks leads to a number of challenges. For instance, with significant penetration of DG power flow reversal may be experienced and the distribution network will no longer be a passive circuit. This underscores the crucial role of ICT in active distribution network occasioned by DG and especially the emergent of “prosumerism” (a hitherto consumer also becoming a producer). Therefore, a smart grid and similar phrases have all been used to describe a “digitised” and intelligent version of the present-day power grid. There are immense benefits derivable from modelling and simulation. Consequently, a typical radial distribution network model has been developed to evaluate the considerable impacts of DG integration. The modelling and simulation of the network are accomplished using the DIgSILENT PowerFactory simulation package. Impacts of DG on voltage profile, fault level, voltage stability and protection coordination have been investigated and their possible mitigation measures proferred. The results reveal that for a particular DG type its impacts depend mainly on its capacity and point of connection relative to a given load type. Smart grid technology addresses some of these impacts through its inherent capability which includes peer-to-peer relay communication for protective devices on the distribution feeder as well as communication to the DG facility.
292

Improving outage process maturity level using a process maturity model

Petersen, Mervyn January 2016 (has links)
Thesis (MTech (Quality (Engineering)))--Cape Peninsula University of Technology, 2016. / The research study establishes the maturity level of the outage process of the Outage Management Department at Eskom. The outage process started in 2012 to contribute to the effective planning and execution of outages. The successful completion of outages depends on effective planning and execution of an outage. At the time of the research study, poor outage performance at Eskom’s power stations contributed to load shedding of electricity in South Africa. The research problem statement reads as follows: The absence of an outage process maturity indicator diminishes the ability of the Outage Management Department (OMD) to comprehend the current process maturity level. The research question: Will the Outage Management Department be able to identify improvement opportunities if the maturity level of the outage process is established? iv The key research objectives are: • To consider how process maturity enables improvement. • To identify critical elements in an outage process. • To determine what is included in outage planning, control and improvement. • To identify a suitable process maturity model. • To identify a measurement instrument to determine the maturity level of Eskom’s outage process The research study uses a descriptive research design and applies the survey research method. Greener and Martelli’s (2015: Online) Business Research Process (Sources: Greener & Martelli, 2015: Online) is used together with Farooq’s Research Steps for Survey Research (2015, Online). The survey questionnaire adopted from Smith’s Maintenance Planning and Scheduling Maturity Matrix (2013: Online) was used to develop the survey questionnaire. The author developed the Outage Management Maturity Framework by combining Business Process Management Maturity model and a Maintenance Planning and Scheduling Maturity Matrix. The research finding is that a process maturity model can determine the maturity level of the outage process and is useful as a process improvement tool. The research findings rank the maturity level of the outage process at Level 2, Experimenting.
293

Improving outage process maturity level using a process maturity model

Petersen, Mervyn January 2016 (has links)
Thesis (MTech (Quality))--Cape Peninsula University of Technology, 2017. / The research study establishes the maturity level of the outage process of the Outage Management Department at Eskom. The outage process started in 2012 to contribute to the effective planning and execution of outages. The successful completion of outages depends on effective planning and execution of an outage. At the time of the research study, poor outage performance at Eskom’s power stations contributed to load shedding of electricity in South Africa. The research problem statement reads as follows: The absence of an outage process maturity indicator diminishes the ability of the Outage Management Department (OMD) to comprehend the current process maturity level. The research question: Will the Outage Management Department be able to identify improvement opportunities if the maturity level of the outage process is established? The key research objectives are: • To consider how process maturity enables improvement. • To identify critical elements in an outage process. • To determine what is included in outage planning, control and improvement. • To identify a suitable process maturity model. • To identify a measurement instrument to determine the maturity level of Eskom’s outage process The research study uses a descriptive research design and applies the survey research method. Greener and Martelli’s (2015: Online) Business Research Process (Sources: Greener & Martelli, 2015: Online) is used together with Farooq’s Research Steps for Survey Research (2015, Online). The survey questionnaire adopted from Smith’s Maintenance Planning and Scheduling Maturity Matrix (2013: Online) was used to develop the survey questionnaire. The author developed the Outage Management Maturity Framework by combining Business Process Management Maturity model and a Maintenance Planning and Scheduling Maturity Matrix. The research finding is that a process maturity model can determine the maturity level of the outage process and is useful as a process improvement tool. The research findings rank the maturity level of the outage process at Level 2, Experimenting.
294

Modeling Reductions in Greenhouse Gases in Arizona Resulting from California Demand Side Management Programs

January 2013 (has links)
abstract: The State of California has made great strides in reducing greenhouse gas (GHG) emissions through mandated, rate-payer funded Investor Owned Utility (IOU) electricity Demand Side Management (DSM) programs. This study quantifies the amount of reduced GHG emissions in Arizona that result from DSM in that state, as well as the DSM reductions within Southern California Edison (SCE), Pacific Gas and Electric (PG&E;), and San Diego Gas and Electric (SDG&E;) during the 2010 through 2012 California Public Utilities Commission (CPUC) DSM program cycle. To accomplish this quantification, it develops a model to allocated GHG emissions based on "operating margin" resources requirements specific to each utility in order to effectively track, monitor, and quantify avoided emissions from grid-based utility resources. The developed model estimates that during the 2010-2012 program cycle, 5,327.12 metric tons (MT) of carbon dioxide equivalents (CO2e) in GHG reductions (or 1.8 percent of total reductions) can be attributed to reduced demand from Arizona--based resources by California IOUs. By focusing on the spatial context of GHG emission reductions, this study models and quantifies the spill-over effect of California's regulatory environment into neighboring states. / Dissertation/Thesis / Ph.D. Geography 2013
295

A quantitative analysis of indices to assess voltage quality on an electricity transmission network

Venter, Erika 04 June 2012 (has links)
M.Phil. / Nearly every reference document, national and international standard, text book or web page discussing the topic of Power Quality has an introduction that refers to the demand from customers and regulators for better and more detailed reporting from electrical power utilities with regards power quality. Previously power quality was an internal utility measure with no external input. Today contracts are negotiated with customers and limits are set by regulators with regards Power Quality objectives. Current assessment methods defined in various international guidelines and standards recommend that for a “high percentage” of the assessment period, the measured performance must remain below specified levels (“compatibility levels” or contracted levels). In the case of NRS048-2:2008 the assessment criterion for voltage harmonics and voltage unbalance is based on 95% of the time and 95% of the space for an assessment period of 1 week, and that for voltage magnitude is based on 95% of the time and 95% of the space, with the additional requirement that no two consecutive values exceed the specified levels. A statistical research study was undertaken to analyse the performance of the Eskom transmission system in order to determine the impact of using different assessment methods (100% of the week, 99% of the week, 95% of the day etc). This thesis will present the results of the analysis done on the data in the Quality of Supply database. The analysis will mainly focus on the voltage waveform parameters: harmonic THD; unbalance; and regulation as measured in the Eskom Quality of Supply database. The objective of this thesis is to determine how the current performance of an electrical transmission network is characterised by different assessment methods. This thesis makes a contribution to the current international debate on appropriate assessment criteria and the conditions (“normal” vs. “abnormal”) under which these would apply.
296

Some cost implications of electric power factor correction and load management

Visser, Hercules 13 August 2012 (has links)
M. Phil. / Presently, ESKOM is rated as the fifth largest utility in the world that generates and distributes electricity power to their consumers at the lowest price per kilowatt-hour (kW.h). As a utility, ESKOM is the largest supplier of electrical energy in South Africa and is currently generating and distributing on demand to approximately 3000 consumers. This represents 92% of the South African market. ESKOM was selected as the utility supplying electrical energy for the purpose of this study. ESKOM's objective is to provide the means and systems by which the consumer can be satisfied with electricity at the most cost-effective manner. In order to integrate the consumers into these objectives, ESKOM took a decision in 1994 to change the supply tariff from active power (kW) to apparent power (kVA) for a number of reasons: To establish a structure whereby the utility and the consumer can control the utilisation of electrical power supply to the consumer. To utilise demand and control through power factor correction and implementation of load management systems. To identify some cost implications of electrical power factor correction and load management. Consumers with kW maximum demand tariff options had little or no financial incentives to improve their low power factor (PF) by reducing their reactive current supply. Switching to (kVA) maximum demand will involve steps to be taken to ensure that the reactive component is kept to a minimum with maximum power factor. ESKOM has structured various tariff rates and charges with unique features that would accommodate the consumers in their demand side management and load cost requirements, which, when applied, will result in an efficient and cost effective load profile. These tariffs are designed to guide consumers automatically into an efficient way of using electrical power, as it is designed to recover both the capital investment and the operating cost within two to three years after installation of power factor correction equipment. ESKOM's concept of Time-of-use (TOU) periods for peak, standard and off-peak times during week, Saturday and Sunday periods is discussed as load management. Interruptible loads can be scheduled or shed to suit lower tariff rates and to avoid maximum demand charge. The concept of load management will change the operation pattern of the consumer's electricity demand whereby the consumer will have immediate technical and financial benefits. In the last chapter of this dissertation, a hypothetical case study addresses and concludes on some of the technical and cost implications of electrical power factor correction and load management as a successful and profitable solution to optimize electrical power supply to the consumer. By implementing the above, ESKOM ensures that the consumer utilizes the electrical power supply to its optimum level at the lowest cost per kilowatthour (kW.h) generated.
297

Revision of the ESKOM harmonic apportioning standard by an international comparison with other standards

Van der Walt, Andre 22 October 2015 (has links)
M.Ing. (Electrical and Electronic Engineering) / The present Eskom procedure used for allocating harmonic current injection limits to large customers have been in use for the past three years. This thesis presents an international comparison of the Eskom procedure with other procedures. This comparison is used as a basis for development of recommendations that can lead to improvement of the present procedure ...
298

A cost-benefit analysis of electricity supply in a developing country, with reference to Venda

Themeli, Tshimangadzo Booi January 1992 (has links)
This study concentrates specificaUy on assessing those elements of private and external costs and benefits which need to be accounted for in analyzing the role of electricity supply in a developing region. To facilitate this aim, three interrelated questions are addressed. The first question examines the reasons why a critical need for electrification in developing areas exists. In this regard, a selective review of the literature on development economics is offered, illuminating the previous neglect of the rural dimension in development and the associated problems of poverty and inequality, a lack of infrastructure and the general inability to fulfill basic needs. The second question is devoted exclusively to an economic analysis of the supply of electricity in developing areas. A broad theoretical review on whether an unregulated or regulated (private or public) sector should be responsible for the provision of electrification is presented. This evaluation highlights the various welfare implications and efficiency considerations that appear to be relevant in the present context. The final question, which constitutes the central proposition of the thesis, establishes how electrification should be supplied in developing areas. To this end, the conditions specific to a region in Venda are discussed. An attempt is made to identify the private and external costs and benefits relating to electricity supply and the corresponding costs and benefits pertaining to alternative sources of energy. Since the incidence and nature of these costs and benefits could only be ascertained from individual households, it was deemed necessary to undertake a questionnaire study of residents in Makwarela township and its periurban settlement of Lufule-Tshisele. A number of basic trends were evident from the research results. As far as the various benefits are concerned, respondents tended to place a much higher value on both the private and external benefits associated with electricity than its alternatives. At the same time, the survey found that although the private (or monetary) cost of electricity far exceeded the corresponding cost of alternative energy sources, the external costs were significant in the case of alternative energy sources, but virtually non-existent in the case of electricity. On the whole, the Venda survey seems to suggest that an economic case can be made for involving the broader community in subsidising the supply of electricity in Makwarela, Lufule-Tshisele and other areas. While such a subsidy can perhaps be justified on distribution grounds alone, and more specifically in terms of the rapid and pronounced effect it is likely to have on the quality of life in the region, its real worth lies in the fact that it may confer certain external benefits on the community.
299

An evaluation of the relationship between payment of rates and service charges and the capacity of the municipality to deliver services with reference to Mnquma local municipality

Zondani, Nosiphiwo V January 2008 (has links)
Various allegations have been levelled against certain local authorities in South Africa. These allegations include poor governance, maladministration, corruption and poor service delivery. Some of the South African municipalities are unable to deliver sufficient services to the people due to financial instability. On the other side the fact that the municipalities have to generate their own revenue is no longer sufficient. However, government, both national and provincial has to support the municipalities in terms of their capacity to provide services. While government has to provide services to the people to ensure their welfare, people from local communities should also support the continuous provision of `these services by paying for municipal rates and services. These may include services such as water, refuse removal and electricity as well as property taxes. The main issue is that these services are not readily available, for instance water has to be purified. The situation at Mnquma Local Municipality as indicated in the financial and other reports is such that there is a very slow payment of rates and services, which leads to the municipality relying mostly on government grants, and this puts a heavy strain on service delivery by the municipality. Seemingly, it has been long that rates and services have not been paid in Butterworth-even before the restructuring of the municipality (i.e. before the Mnquma Municipality came into being). However, if alternatives could be found to enhance regular payment of rates and services the municipality might improve in terms of its capacity to deliver services.
300

Environmental planning and decision making for large-scale power projects

Le Marquand, David G. January 1972 (has links)
This study focuses on the institutional problems involved in planning for large-scale energy and resource projects in B.C. Fundamental to planning for these projects is the resolution of the tension between economic growth and environmental quality. Concern is expressed that, to date, planning has stressed economic values at the expense of environmental values held in society. A more equitable planning structure is needed whereby interested groups in society may present informed views to the planners and decision-makers to help them achieve solutions that more nearly represent the public interest. To reach a solution that reflects the public interest an advocacy approach to planning is suggested in Chapter Two. This approach stresses interest group participation in the "planning process" to conduct planning that meets public expectations. In order that environmental interests are incorporated into the planning and decision-making for major power and resource projects, an environmental review agency is proposed. This agency would have the power to conduct is own investigations into issues that might affect the environment and advocate its findings in the debate over the proposed Projects. To test the suitability in British Columbia of the advocacy approach a number of criteria are developed, The criteria reflect some basic democratic values held in our society and the problems associated with institutional design. The criteria include public participation and representation, information generation, efficiency, equality, professional humility, natural justice, liberty and political leadership. The characteristics of B.C.'s political milieu are examined in Chapter Three to see what problems the implementation of the advocacy approach for environmental and resource planning might face in the province. Three characteristics of the political milieu are seen as possible constraints on the effective implementation of a review agency - materialist values held in the province, lack of strong interest groups and the dependence on resource extraction for economic prosperity. A case study of the planning and decision-making for the Bennett Dam on the Peace River, presented in Chapter Four, outlines the inadequacy of the planning process. Even though there have been some changes in planning procedures since the initial planning for the Peace project, two principal deficiencies remain - there is virtually no scope for public involvement in the planning process and the information produced is too highly technical to make for effective public participation. As a consequence major energy and resource planning will likely produce results that favour energy and development interests. / Applied Science, Faculty of / Community and Regional Planning (SCARP), School of / Graduate

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