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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.
1

Modelling short term probabilistic electricity demand in South Africa

Mokhele, Molete January 2016 (has links)
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
2

A study of various public lighting maintenance practices and the development of a locally applicable maintenance model in line with international trends.

Parfitt, Colin. January 2004 (has links)
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.
3

Formulation of a capacity mechanism for the Southern african power pool(SAPP) for sustaines long-term system adequacy

Wright, Jarrad G January 2019 (has links)
A thesis submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. University of the Witwatersrand, Johannesburg / Power system adequacy has been historically insufficient in the Southern African Power Pool (SAPP) region with resulting negative effects on economic growth and electrification efforts. Existing domestic regulatory frameworks and opaque longterm bilateral contracting for procuring capacity in the region have been shown to be insufficient in ensuring system adequacy. The concept of an adequacy product in the form of a Capacity Mechanism (CM) introduced into the SAPP region has not yet appeared in the literature. A Capacity Mechanism (CM) for the SAPP region has been proposed and designed as part of this research to address this. A framework has been developed to consider CMs via the combination of a screening assessment, quantitative (model-based) analysis of more favourable CM options and an identification and quantification of key design elements. The developed framework can also be generalised and applied to other jurisdictions where CMs are under consideration. A regional CM which transparently and explicitly values capacity is proposed in the form of a forward-looking annual Capacity Auction that is locationally disaggregated, supplied by all possible supply-side resources with all feasible SAPP market participants included. The CM should be technology agnostic and account for the dual requirement for firm capacity to meet peak demand and firm-energy to meet annual energy requirements considering the dominance of hydrobased capacity in the region when excluding South Africa. There should be a leadtime of 3-4 years with the possibility of long-term auctions for large hydro-based capacity. Strict market monitoring and adherence to performance incentives and penalties will need to be ensured to avoid exercising of market power considering the dominant size of the South African power system. Appropriately mandated institutions to run Capacity Auctions would include the SAPP Co-Ordination Centre as well as a sufficiently mandated regional regulatory body. A further contribution is made in the form of a public domain power system dataset of the SAPP region with sufficient detail to be used in power system operations and planning efforts by future researchers and practitioners. / E.K. 2020
4

Research and development of a linear programming function with specific reference to the generation expansion planning environment of Eskom

Botha, Lance Robert 17 August 2016 (has links)
A project submitted to the faculty of Engineering, University of the Witwatersrand, Johannesburg, in partial fulfilments of the requirements for the degree of Master of science in Engineering Johannesburg, 1994 / The purpose of this document is to report on the development of Linear Programming function for the Generation Expansion Planning environment of Eskom. This was achieved by researching the modeling methods employed in this and related fields of work. After establishing the scope of the work to be performed all the options were carefully assessed and it was decided to develop the Production Scheduling function first, as this would serve as the foundation for future work. The requirements were specified after extensive discussion with the customer. These requirements were utilize to establish the formulae, including their bounds and constraints. These were in turn converted into the Linear programming function. To faci1itate the data input process a simple input facility was developed. To maximize the value of the results the report writer was developed to enable sensitivity studies to be performed. This work was later used as the foundation of the NewGex programme.
5

Towards universal access : status of the KZN electrification programme 2013/14

Mthiyane, Zibuyisile 12 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2014. / Census 2011 put the rate of electrification in South Africa at 84 percent. Even though this is a positive outcome to the previously recorded 34 percent, it has served as a clear indication that the target for Universal Access to Electricity by 2014 as set by President Jacob Zuma is unlikely to be achieved. In June 2013, cabinet approved the implementation of the new household electrification strategy and in support of this decision the Department of Energy was tasked to develop a new electrification roadmap or implementation plan. The intention of this research study has been to contribute to the development of this strategic plan by analysing the status of electrification in KwaZulu-Natal, as extracted from the provincial Geographical Information System, in order to identify the optimal electrification roll out plan and to develop guiding principles for the electrification of the province. The research outcomes provide a view of the current state of electrification within the province, identify the major technical constraints which hinder the progress, and provide recommendations for implementation roll out for KwaZulu-Natal province. The finding of this research is that of the 497 799 thousand un-electrified houses, 169 506 HH are not electrifiable as there is not sufficient capacity on the existing networks to cater for these households. Of those, 132 007 households are dependent on the establishment and construction of new bulk infrastructure such as substations and lines, while 37 499 are dependent on the upgrade or refurbishment of the existing infrastructure. The research has identified and categorised the ‘critical’ bulk infrastructure that will benefit 5 000 households or more as well as the high impact infrastructure projects that cater for 3 000 households or more. The research has also identified municipalities that are above the average of 84 percent electrification and categorised these as quick win areas to help in the progression toward universal access. As the research has also identified the dark havens, named as such due to being less than 50 percent electrified and plagued by technical constraints which makes any electrification of these areas not possible in the next five to ten years. Recommendations for responding to all four categories of findings are put forward.
6

Opportunity for electricity generation from discard coal at the Witbank Coalfields

Le Roux, Armand 04 1900 (has links)
Thesis (MDF)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Coal export mines in the Mpumalanga Highveld region of South Africa generate growing volumes of discard coal estimated to be in excess of a billion tonnes. It presents a significant pollution hazard. Discard coal has a usable carbon content that can be used in the generation of power through the application of fluidized bed combustion technology. The objective of this study was to evaluate its potential as an economically viable fuel source for generation of electricity at the Witbank coalfields. This study was motivated by advances in fluidized combustion technology and significant changes in the South African electricity market in recent years. A holistic approach was adopted considering regulatory policy, market, technical, environmental and economic factors in the use of discard coal as an alternative fuel source. The policy and regulatory environment was assessed from the perspective of the private sector as project developer and the most likely source of funding, given government’s funding constraints. An evaluation of the future pricing structure of electricity, energy resource mix, demand growth, future development of the coal market, production of discard coal and the cost of coal was conducted. Levelised cost of electricity methodology was used to conduct the economic feasibility for comparison with the cost of Eskom’s pulverised coal technology for its new power stations. The study found that generating electricity from discard coal presents a significant commercial opportunity as its levelised cost of electricity was found to be lower than Eskom’s levelised cost of electricity for its new power stations. Plant sizes of 125 MW to 1 000 MW were considered. For plant capacities of about 500 MW and larger, the cost of electricity was found to be competitive with the current average electricity price taking into account the cost of transmission/distribution and interest charges. This is on condition that the electricity is sold to Eskom or wheeled through Eskom’s grid and sold to third parties. Otherwise, plant capacity will be limited to the maximum demand from large local users, which is expected to be considerably less than 500 MW. Currently there is no regulatory certainty on wheeling mechanisms and charges and it is an area where major policy development is required. The development of a project could be hampered by policy uncertainty and because of Eskom’s monopoly position as single buyer. The favourable results and findings of the economic evaluation conducted during this study warrant further detailed feasibility studies.
7

Eskom nuclear generation : risk mitigation through quality management development of small suppliers

Van Renen, Olaf Pieter January 2009 (has links)
Thesis (MTech (Quality))--Cape Peninsula University of Technology, 2009. / There is a South African Government initiative to use State-owned Enterprises (SOE's) to roll out a programme for the development and stimulation of local small businesses in South Africa. The state has requested SOE's to set targets on a voluntary basis to increase trade with small businesses, with the purpose of developing small enterprises to eventually enhance skills transfer, training and employment. However, when large customers such as Eskom Nuclear Generation require ISO certification as a prerequisite for a supplier to provide goods and/or services to them, most small businesses are unable to comply. The requirement of IS09000 compliance inhibits the ability of most small businesses to compete with their larger counterparts. Small businesses constitute as much as 90% of most world economies. They have many advantages to offer customers, such as a high level of flexibility, innovation and responsiveness to customer needs. These attributes can introduce healthy competition to the supply chain. Small businesses, by their very nature experience more risks, such as a higher vulnerability to volatile market forces and skills loss. In addition, they are generally less specialised.
8

Eskom nuclear generation : risk mitigation through quality management development of small suppliers

Van Reenen, Olaf Pieter January 2009 (has links)
Thesis (MTech (Quality)--Cape Peninsula University of Technology, 2009 / There is a South African Government initiative to use State-owned Enterprises (SOE’s) to roll out a programme for the development and stimulation of local small businesses in South Africa. The state has requested SOE’s to set targets on a voluntary basis to increase trade with small businesses, with the purpose of developing small enterprises to eventually enhance skills transfer, training and employment. However, when large customers such as Eskom Nuclear Generation require ISO certification as a prerequisite for a supplier to provide goods and/or services to them, most small businesses are unable to comply. The requirement of ISO9000 compliance inhibits the ability of most small businesses to compete with their larger counterparts. Small businesses constitute as much as 90% of most world economies. They have many advantages to offer customers, such as a high level of flexibility, innovation and responsiveness to customer needs. These attributes can introduce healthy competition to the supply chain. Small businesses, by their very nature experience more risks, such as a higher vulnerability to volatile market forces and skills loss. In addition, they are generally less specialised. They are under continuous competitive pressure, and are generally not able to provide assurance of a sustainable product over a longer period. Although there is an imperative to develop and use small suppliers, they introduce higher risk to the supply chain. The primary research objective of this dissertation is to develop a robust model to identify risks inherent to small businesses, and to propose measures to mitigate such risks. A classification of problems with small suppliers that have occurred at Koeberg Nuclear Power Station over a period of 3 years (from June 2005 to May 2008), will form the basis of the research methodology. The anticipated findings of the research include the following. _ Several common critical issues of failure will be identified in the internal processes of small suppliers, with variations between types of suppliers, which will indicate which elements within the context of ISO9000 can be applied to address shortcoming in the suppliers’ processes. _ A matrix will be compiled from this by which the customer can identify the type of supplier, the types of risks inherent to that supplier, and which elements of ISO9000 the customer should insist upon to be adopted into an elementary quality management system of that small supplier. This should be executed as part of a larger supplier development programme.
9

Electricity generation, transmission and distribution policy: a comparative study of Nigeria (1960-2011) and South Africa (1960-2011)

Okafor, Chukwuemeka January 2013 (has links)
The electric power policies in Nigeria and South Africa are considered the governments’ intention to provide quality and affordable electricity to the people. A comparative study on the electric power policies focuses on the similarities and differences in the policy approaches, the policy issues that affect electrification, and the impact of the policy issues in achieving the goal of universal access to quality and affordable electricity power in both countries. The methodological approach allows for an in depth textual study on the electric power policy documents in both countries. In Nigeria, the government intends to address the massive demand-supply imbalance and achieve the goal of electrification through reforms that focus on private sector-led growth in the sub-sector. In South Africa, the identification of electrification as a public problem by the post apartheid government leads to an integrated policy framework that focuses on balancing economic concerns with social and environmental considerations. The study identifies electricity provision as a social welfare responsibility of the governments in both countries and examines the policy issues in the context of public welfare. In Nigeria, the policy issues are found to be self serving and not in line with sustainable public interest, given the socio-economic challenges. As a result they, exert less impact on achieving the goal of universal access to quality and affordable electricity in the country. In South Africa, good governance in the sub-sector has enabled the identification of policy issues in line with sustainable public interests of social equity, poverty alleviation and environmental sustainability; and government using public administration agencies to play a key role in service delivery. Recommendations of the study mainly derive from the South African experience on electrification, and are intended to offer some policy-lessons to Nigeria in the sub-sector. The study contributes to new knowledge in the discipline of public administration by opening up new vistas for a comparative analysis of electric power policy issues in both countries in the context of public welfare. Besides, a comparative study on electrification in Nigeria and South Africa from a policy angle contributes to the existing knowledge base in the discipline.

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