'n Ondersoek na begrensings by die kompensasie van vervorming in elektriese energieverspreidingsnetwerke
- Authors: Le Roux, Wiehan
- Date: 2012-08-16
- Subjects: Electric power distribution - South Africa , Electric networks
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/380435 , uj:9493 , http://hdl.handle.net/10210/5923
- Description: M.Ing. , This study investigates the limits to which distortion can be compensated in electrical distribution networks. Many factors hinder the "ideal" compensation of the line current to a perfect sinusoidal, in phase, scaled replica of the supply voltage. The different power theories that can be used to derive the reference compensation current, is one of the fundamental limits. The differences and correspondences between the FBD and Czarnecki theories are investigated in detail. Furthermore, it is shown by simulation and practical results, that the effectivity of compensation by the instantaneous power theory is load dependent. The compensation strategy and topology also impose limits on the effectivity of compensation. The position and strategy of a compensator determine whether the consumer is able to isolate his distortion from the rest of the network, or isolate himself from the distortion of other consumers. Distortion frequencies and system impedances are chosen specifically to visually show the effect of the different topologies and strategies, by means of simulation. One of the most important limits brought about by new technology, is the lagging of the reference compensation current, due to the use of signal processing in determining the reference signals. The effect of this lagging reference is clearly shown by means of simulation and practical compensation systems. An effectivity index for this phenomenon is defined for steady state systems. The dynamic limitations of this lagging reference compensation current is investigated thoroughly. A method is derived by which the maximum fault, due to the sampling time and signal processing time, can be calculated when a high f-region occurs in the line current. The dynamic response of the compensation system is also limited by the ' di-ability of the converter. Therefore, a method is developed to calculate the individual fault contribution of the lagging reference as well as the converter. This method enables designers to determine the parameters of the signal processing system and the converter in the planning phase. The use of a maximum sampling frequency is stressed. In the experimental work, a 10kVA, PWM-switched IGBT inverter is used as a parallel voltage fed compensator. It compensates for two non-linear loads : a three phase diode rectifier with an inductive load, and a three phase diode rectifier with a capacitive load. The practical compensation according to the instantaneous power theory of these two loads, confirms that the result of this compensation is load dependent. The effect of the lagging reference compensation current in a practical system is also shown.
- Full Text:
- Authors: Le Roux, Wiehan
- Date: 2012-08-16
- Subjects: Electric power distribution - South Africa , Electric networks
- Type: Thesis
- Identifier: http://ujcontent.uj.ac.za8080/10210/380435 , uj:9493 , http://hdl.handle.net/10210/5923
- Description: M.Ing. , This study investigates the limits to which distortion can be compensated in electrical distribution networks. Many factors hinder the "ideal" compensation of the line current to a perfect sinusoidal, in phase, scaled replica of the supply voltage. The different power theories that can be used to derive the reference compensation current, is one of the fundamental limits. The differences and correspondences between the FBD and Czarnecki theories are investigated in detail. Furthermore, it is shown by simulation and practical results, that the effectivity of compensation by the instantaneous power theory is load dependent. The compensation strategy and topology also impose limits on the effectivity of compensation. The position and strategy of a compensator determine whether the consumer is able to isolate his distortion from the rest of the network, or isolate himself from the distortion of other consumers. Distortion frequencies and system impedances are chosen specifically to visually show the effect of the different topologies and strategies, by means of simulation. One of the most important limits brought about by new technology, is the lagging of the reference compensation current, due to the use of signal processing in determining the reference signals. The effect of this lagging reference is clearly shown by means of simulation and practical compensation systems. An effectivity index for this phenomenon is defined for steady state systems. The dynamic limitations of this lagging reference compensation current is investigated thoroughly. A method is derived by which the maximum fault, due to the sampling time and signal processing time, can be calculated when a high f-region occurs in the line current. The dynamic response of the compensation system is also limited by the ' di-ability of the converter. Therefore, a method is developed to calculate the individual fault contribution of the lagging reference as well as the converter. This method enables designers to determine the parameters of the signal processing system and the converter in the planning phase. The use of a maximum sampling frequency is stressed. In the experimental work, a 10kVA, PWM-switched IGBT inverter is used as a parallel voltage fed compensator. It compensates for two non-linear loads : a three phase diode rectifier with an inductive load, and a three phase diode rectifier with a capacitive load. The practical compensation according to the instantaneous power theory of these two loads, confirms that the result of this compensation is load dependent. The effect of the lagging reference compensation current in a practical system is also shown.
- Full Text:
Energy capital, productive capital and economic growth : a crossmunicipality granger causality analysis
- Authors: Chiviya, Kudzai
- Date: 2017
- Subjects: Electric power distribution - South Africa , Electric power distribution - Economic aspects - South Africa , South Africa. Electricity Supply Commission , Electric power failures - South Africa , Municipal government - South Africa , Eskom (Firm) , Power resources - South Africa , Economic development - South Africa
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/271851 , uj:28921
- Description: M.Com. (Local Economic Development) , Abstract: In 2008 South Africa experienced a period of constrained electricity supply, which led to wide-spread blackouts. In order to deal with these electricity capacity constraints, there has since been a shift in focus in the country with significant investment in this sector. Most studies in the energy-economic growth nexus have focused on the economic effects of energy use. There is a body of literature that has looked at infrastructure investment and economic growth, but does not treat energy investment as a particular kind. We argue that it is not only energy consumption that matters for economic growth, but the investment it its production as well. Investors might carefully watch energy capacity development in order to make their investment decisions in other economic sectors, which make investment in energy a possible trigger of capital formation in other sectors and subsequent economic growth. With this hypothesis, our paper investigates the causal relationship between investments in energy and capital formation in other sectors of the economy on one hand, and the causal relations to economic growth on the other. We use annual data for 228 South African municipalities from 1993 to 2015. The paper uses the newly developed heterogeneous panel Granger causality methodology, which improves the traditional causality approaches in accounting for heterogeneity and cross-sectional dependence in the panel data. Traditional approaches were developed under the assumption of homogeneity in slope, intercept or both, and the independence of panel units. Our findings are therefore more robust to heterogeneity issues and account for individual differences between municipalities. Another difference between this paper and the majority of academic work is our shift in focus from a national level to a local/municipal level. Our findings suggest that there is an overall bidirectional causal relationship between investments in energy, capital formation in other sectors of the economy, and economic growth. This finding highlights the potential that investments in energy have to trigger capital formation in other sectors and promote economic growth. Such findings will have significant local economic development implications in terms of the role of energy capital in attracting capital in other sectors, with broader implications for economic growth in view of job creation and poverty reduction.
- Full Text:
- Authors: Chiviya, Kudzai
- Date: 2017
- Subjects: Electric power distribution - South Africa , Electric power distribution - Economic aspects - South Africa , South Africa. Electricity Supply Commission , Electric power failures - South Africa , Municipal government - South Africa , Eskom (Firm) , Power resources - South Africa , Economic development - South Africa
- Language: English
- Type: Masters (Thesis)
- Identifier: http://hdl.handle.net/10210/271851 , uj:28921
- Description: M.Com. (Local Economic Development) , Abstract: In 2008 South Africa experienced a period of constrained electricity supply, which led to wide-spread blackouts. In order to deal with these electricity capacity constraints, there has since been a shift in focus in the country with significant investment in this sector. Most studies in the energy-economic growth nexus have focused on the economic effects of energy use. There is a body of literature that has looked at infrastructure investment and economic growth, but does not treat energy investment as a particular kind. We argue that it is not only energy consumption that matters for economic growth, but the investment it its production as well. Investors might carefully watch energy capacity development in order to make their investment decisions in other economic sectors, which make investment in energy a possible trigger of capital formation in other sectors and subsequent economic growth. With this hypothesis, our paper investigates the causal relationship between investments in energy and capital formation in other sectors of the economy on one hand, and the causal relations to economic growth on the other. We use annual data for 228 South African municipalities from 1993 to 2015. The paper uses the newly developed heterogeneous panel Granger causality methodology, which improves the traditional causality approaches in accounting for heterogeneity and cross-sectional dependence in the panel data. Traditional approaches were developed under the assumption of homogeneity in slope, intercept or both, and the independence of panel units. Our findings are therefore more robust to heterogeneity issues and account for individual differences between municipalities. Another difference between this paper and the majority of academic work is our shift in focus from a national level to a local/municipal level. Our findings suggest that there is an overall bidirectional causal relationship between investments in energy, capital formation in other sectors of the economy, and economic growth. This finding highlights the potential that investments in energy have to trigger capital formation in other sectors and promote economic growth. Such findings will have significant local economic development implications in terms of the role of energy capital in attracting capital in other sectors, with broader implications for economic growth in view of job creation and poverty reduction.
- Full Text:
Serie injeksie as alternatief tot tapverstelbare transformators in EGAT kragverspreidingsnetwerke
- Van Niekerk, Hendrik Christoffel
- Authors: Van Niekerk, Hendrik Christoffel
- Date: 2015-10-14
- Subjects: Electric power distribution - South Africa , Electric transformers
- Type: Thesis
- Identifier: uj:14348 , http://hdl.handle.net/10210/14806
- Description: M.Ing. (Electrical and Electronic Engineering) , Please refer to full text to view abstract
- Full Text:
- Authors: Van Niekerk, Hendrik Christoffel
- Date: 2015-10-14
- Subjects: Electric power distribution - South Africa , Electric transformers
- Type: Thesis
- Identifier: uj:14348 , http://hdl.handle.net/10210/14806
- Description: M.Ing. (Electrical and Electronic Engineering) , Please refer to full text to view abstract
- Full Text:
Aspects of management of the electricity supply industry in a deregulated environment
- Authors: Pretorius, Zirk Bernardus
- Date: 2012-09-12
- Subjects: Electric power distribution - South Africa , Electric power distribution - Economic aspects , Deregulation - South Africa
- Type: Thesis
- Identifier: uj:10177 , http://hdl.handle.net/10210/7554
- Description: M.Ing. , Traditionally, the Electricity Supply Industry (ESI) organisational structure consisted of generating plant, transmission and distribution networks, a regulating authority and network control, all vertically integrated into single organisational structure. The result of the vertically integrated organisational structure, in other words an organisation where all the functions belong to a single organisation, and some of the organisation's functions are not the sole responsibility of one specific functional area, has been a captive market for the industry. No real market forces existed to control the industry. The responsibility for the industry was traditionally left in the hands of a single organisation, accountable only to the regulating authority. However, the industry has recently been subjected to incredible pressure to reform. The incentive to reform is based on various factors, ranging from sound business decisions, the need to reduce government debt, reduction of primary energy cost for key industries to political pressure. A common thread throughout the reform exercise is the requirement that competition must be introduced into the ESI to ensure market forces on the industry. To introduce competition into the industry, the authorities often start by unbundling the different functions in the industry. The second step is to identify the functions that can only operate effectively as a monopoly. The authorities then need to determine the optimum balance between regulatory rules and requirements and market forces on the. industry. By introducing the optimum balance between industry regulation, market forces and the specific needs of each country, the changes in the industry may result in long term gain for the industry's host country. The gains are often measured in reduced electricity cost and growth in industries dependant on the ESI as a primary energy source. The study incorporates a wide range of issues, starting with the drivers behind the deregulation effort through management tools to regulatory rules and requirements in the deregulated environment. The study evaluates the risks and benefits of the deregulated market, and examines the tools adopted from the financial markets and used in the new electricity markets. The requirement for regulatory rules will be evident throughout the dissertation, and will be discussed in detail in the final chapter. The study is concluded with the message that the common factors and resultant solutions are of such a nature that it would not be necessary to develop a new set of rules, regulations and management tools for a country starting down the road of deregulation. It would however be required to determine the needs of the industry's host country and to adapt the current tools and regulatory rules to the country it is implemented in. The final outcome of the dissertation is that the post-deregulated industry has only just started operating under the new regulatory regime and using the newly developed electricity markets. The industry is still subject to a severe learning curve, adapting and developing daily to satisfy the needs of a deregulated industry. There are sections of the industry that still need to be examined and optimised. However, the success of some of the deregulation efforts in the industry, and especially the deregulation in the UK confidently underwrite any equivalent exercise in the ESI.
- Full Text:
- Authors: Pretorius, Zirk Bernardus
- Date: 2012-09-12
- Subjects: Electric power distribution - South Africa , Electric power distribution - Economic aspects , Deregulation - South Africa
- Type: Thesis
- Identifier: uj:10177 , http://hdl.handle.net/10210/7554
- Description: M.Ing. , Traditionally, the Electricity Supply Industry (ESI) organisational structure consisted of generating plant, transmission and distribution networks, a regulating authority and network control, all vertically integrated into single organisational structure. The result of the vertically integrated organisational structure, in other words an organisation where all the functions belong to a single organisation, and some of the organisation's functions are not the sole responsibility of one specific functional area, has been a captive market for the industry. No real market forces existed to control the industry. The responsibility for the industry was traditionally left in the hands of a single organisation, accountable only to the regulating authority. However, the industry has recently been subjected to incredible pressure to reform. The incentive to reform is based on various factors, ranging from sound business decisions, the need to reduce government debt, reduction of primary energy cost for key industries to political pressure. A common thread throughout the reform exercise is the requirement that competition must be introduced into the ESI to ensure market forces on the industry. To introduce competition into the industry, the authorities often start by unbundling the different functions in the industry. The second step is to identify the functions that can only operate effectively as a monopoly. The authorities then need to determine the optimum balance between regulatory rules and requirements and market forces on the. industry. By introducing the optimum balance between industry regulation, market forces and the specific needs of each country, the changes in the industry may result in long term gain for the industry's host country. The gains are often measured in reduced electricity cost and growth in industries dependant on the ESI as a primary energy source. The study incorporates a wide range of issues, starting with the drivers behind the deregulation effort through management tools to regulatory rules and requirements in the deregulated environment. The study evaluates the risks and benefits of the deregulated market, and examines the tools adopted from the financial markets and used in the new electricity markets. The requirement for regulatory rules will be evident throughout the dissertation, and will be discussed in detail in the final chapter. The study is concluded with the message that the common factors and resultant solutions are of such a nature that it would not be necessary to develop a new set of rules, regulations and management tools for a country starting down the road of deregulation. It would however be required to determine the needs of the industry's host country and to adapt the current tools and regulatory rules to the country it is implemented in. The final outcome of the dissertation is that the post-deregulated industry has only just started operating under the new regulatory regime and using the newly developed electricity markets. The industry is still subject to a severe learning curve, adapting and developing daily to satisfy the needs of a deregulated industry. There are sections of the industry that still need to be examined and optimised. However, the success of some of the deregulation efforts in the industry, and especially the deregulation in the UK confidently underwrite any equivalent exercise in the ESI.
- Full Text:
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