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The financing of power transmission interconnector projects : a case study of viable financial packaging utilising project finance principles for the Southern African Power Pool (SAPP)Hekandjo, O'Brien Alexander 12 1900 (has links)
Thesis (MBA)--Stellenbosch University, 2012. / Over the past few years the Southern African Development Community (SADC) has been facing regional power shortages. These regional power shortages currently being experienced within the SADC region have been partly due to a lack of generation capacity and transmission capacity constraints. This situation has been further aggravated by the unanticipated economic growth within the SADC region. In order for the SADC region to meet its electricity demand, the region needs to invest in new generation and transmission projects. However, due to the inability of regional utilities to raise funds to finance these projects, the projects tend to not reach financial close resulting in the increase of the regional power deficits.
Although these regional power shortages have been attributed to the lack of adequate investment in power generation projects and power transmission interconnector projects, this research report was limited to the development and financing of power transmission interconnector projects. The objective of this research report was to identify the dynamics that prohibit regional power transmission interconnectors from reaching financial close and to recommend possible solutions on how best to develop and package these projects. The research used the proposed developmental approach of the ZIZABONA transmission interconnector project as a case study to develop a generic model that could be utilised on other regional transmission interconnector projects.
Based on the research presented in this research report, the study has highlighted project finance as a viable funding strategy. Regional utilities can utilise this funding strategy to package and finance joint transmission regional interconnectors to alleviate the current regional power shortages by facilitating regional electricity trade.
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A comparison of the performance of high-voltage insulator materials in a severely polluted coastal environmentVosloo, Wallace L. (Wallace Lockwood) 04 1900 (has links)
Thesis (PhD)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The main aim of this research programme was to compare the relative
performance of different insulator materials used in South Africa when subjected
to a severe marine pollution environment. A test programme and procedure, test
facility and instrumentation were established. Some novel instrumentation and
monitoring equipment were developed and built specifically for this research
programme, supported by data analysing software programs. In order to
compare material performance only, all non-material design variables between
the test insulators had to be removed (e.g. creepage distance, connecting length,
inter-shed spacing, profile, etc.). To achieve this some of the test insulators had
to be specially manufactured. Leakage current, electrical discharge activity,
climatic and environmental data was collected successfully over a one-year test
period, starting with new test insulators.
The peak and energy values of the leakage current were identified as the two
main parameters needed to describe the leakage current activity on the test
insulators. A correlation was found between the climatic and environmental data
and the leakage current data, and it was found that the leakage current can be
determined successfully from some of the climatic and environmental parameters
monitored by using multiple regression techniques. Surface conductivity and
energy were found to be the best parameters to show the maximum and
continuous interaction of the insulator material surface with the electrolytic
pollution layer. A natural ageing and pollution test procedure was developed,
which has become a South African standard and is gaining international
acceptance.
A model and hypothesis are proposed to describe the electrical discharge activity
that takes place on the test insulators and explain the difference in leakage
current performance of the various materials.
Keywords: Insulator, Pollution, High Voltage, Leakage current, Material
performance. / AFRIKAANSE OPSOMMING: Die hoofdoel van hierdie navorsingsprogram was om die relatiewe prestasie van
verskillende isolatormateriale wat in Suid-Afrika gebruik word te vergelyk in 'n
swaar besoedelde marine omgewing. 'n Toetsprogram en prosedure, toets
fasiliteit en instrumentasie is gevestig. 'n Paar nuwe instrumente en moniteer
toerusting is ontwikkel en gebou spesifiek vir hierdie navorsingsprogram, gesteun
deur data analise sagteware programme. Ten einde slegs materiaalprestasie te
vergelyk, moes alle nie-materiaal ontwerpsveranderlikes tussen die toetsisolators
verwyder word (bv. kruipafstand, konnekteer lengte, tussen-skerm spasiëring,
profiel, ens.). Om dit reg te kry moes sommige van die toetsisolators spesiaal
vervaardig word. Lekstroom, elektriese ontladingsaktiwiteit, klimaat en
omgewingsdata is suksesvol versameloor 'n een-jaar toetsperiode, beginnende
met nuwe toets isolators.
Die piek en energie waardes van die lekstroom is identifiseer as die twee hoof
parameters wat nodig is om die lekstroomaktiwiteit op die toetsisolators te
beskryf. 'n Korrelasie is gevind tussen die klimaat- en omgewingsdata en die
lekstroom data, en dit is gevind dat die lekstroom data suksesvol bepaal kan
word van sekere van die klimaat- en omgewingsparameters wat gemoniteer is
deur veelvoudige regressie tegnieke te gebruik. Oppervlakskonduktiwiteit en
energie is gevind die beste parameters te wees om die maksimum en kontinue
interaksie van die isolatormateriaaloppervlak met die elektrolitiese
besoedelingslaag aan te toon. 'n Natuurlike veroudering en besoedeling
toetsprosedure is ontwikkel, wat 'n Suid-Afrikaanse standaard geword het en
besig is om internastionale aanvaarding te wen.
'n Model en hipotese word voorgestelom die elektriese ontladingsaktiwiteit wat
op die toetsisolators plaasvind te beskryf en om die verskil in lekstroomprestasie
van die verskeie materiale te verduidelik.
S/eufelwoorde: Isolator, Besoedeling, Hoog Spanning, Leek stroom, Materiaal
prestasie.
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Fault Location for Power Transmission Systems Using Magnetic Field Sensing CoilsFerreira, Kurt Josef 07 May 2007 (has links)
The detection and location of faults on power transmission lines is essential to the protection and maintenance of a power system. Most methods of fault detection and location rely on measurements of electrical quantities provided by current and voltage transformers. These transformers can be expensive and require physical contact with the monitored high voltage equipment. In this work, current transformers were replaced by magnetic field sensing coils. Such coils can be located remotely from substations and switching stations and do not require physical contact with the conductors. Rather than observing each individual conductor, the use of the magnetic field sensors allows the monitoring of the transmission line condition using a collective quantity. This study explores the use of the magnetic field sensors as an alternative measurement device for fault detection and location.
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Metodologia para a coordenação e seletividade da proteção direcional de sobrecorrente em sistemas de transmissão de energia elétrica / Methodology for the coordination and selectivity of directional overcurrent protection in electrical power transmission systemsNegrão, Danilo Luiz Alves 31 March 2015 (has links)
Este trabalho propõe uma nova metodologia para a solução do problema de coordenação de relés direcionais de sobrecorrente em sistemas de transmissão em malha. São utilizadas informações sobre a atuação do relé como dispositivo de proteção principal (ou retaguarda local no caso de se considerar o relé de distância) e também de sua atuação como proteção de retaguarda remota, fornecendo uma base mais sólida para definição dos ajustes. A partir de uma série de critérios determinados de acordo com a instalação, define-se uma área de ajuste do relé, diretamente sobre sua curva de atuação. Sobre esta área, aplica-se um método de otimização capaz de encontrar o melhor ajuste possível para o dispositivo em análise. A metodologia é aplicada sem a necessidade de uma análise topológica do sistema, sendo que as informações da localização do relé e sua integração com os outros dispositivos de proteção são resumidas durante o estudo de curto-circuito, que fornece os dados de entrada para a metodologia. O algoritmo resume os critérios de coordenação em pontos de referência, de modo que a análise é feita relé a relé, eliminando assim problemas comuns como o de tratamento de banco de dados e ganhando em agilidade e simplicidade no tratamento do problema. A resposta fornecida é bastante intuitiva, sendo fácil entender os resultados obtidos e quais seriam as implicações caso na prática sejam necessárias adequações à instalação. / This work proposes a new methodology to solve the problem of coordination of directional overcurrent relays in meshed transmission systems. Using information about the operation of the directional relay as primary protection (or local backup, in the case of considering the distance relay) and also its role as remote backup protection, the methodology provides a more solid basis for defining settings. Based on a series of criteria determined in accordance with the installation, an area of relay feasible settings is defined directly over their time-overcurrent curve. On this area, an optimization method is applied to find the best possible setting for the device under analysis. The method is applied without the need for topological analysis of the system, and the information of the relay location and its integration with other protective devices are summarized during the short circuit study, which provides the input data for the methodology. The algorithm summarizes the criteria of coordination in landmarks and the analysis is performed relay by relay, thus common problems are eliminated, such as database treatment, gaining agility and simplicity in treating the problem. The answer provided is extremely intuitive, making it easy to understand the results and what would be the implications in case of, in practice, be necessary to perform adjustments to fit with the installation.
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Metodologia para a coordenação e seletividade da proteção direcional de sobrecorrente em sistemas de transmissão de energia elétrica / Methodology for the coordination and selectivity of directional overcurrent protection in electrical power transmission systemsDanilo Luiz Alves Negrão 31 March 2015 (has links)
Este trabalho propõe uma nova metodologia para a solução do problema de coordenação de relés direcionais de sobrecorrente em sistemas de transmissão em malha. São utilizadas informações sobre a atuação do relé como dispositivo de proteção principal (ou retaguarda local no caso de se considerar o relé de distância) e também de sua atuação como proteção de retaguarda remota, fornecendo uma base mais sólida para definição dos ajustes. A partir de uma série de critérios determinados de acordo com a instalação, define-se uma área de ajuste do relé, diretamente sobre sua curva de atuação. Sobre esta área, aplica-se um método de otimização capaz de encontrar o melhor ajuste possível para o dispositivo em análise. A metodologia é aplicada sem a necessidade de uma análise topológica do sistema, sendo que as informações da localização do relé e sua integração com os outros dispositivos de proteção são resumidas durante o estudo de curto-circuito, que fornece os dados de entrada para a metodologia. O algoritmo resume os critérios de coordenação em pontos de referência, de modo que a análise é feita relé a relé, eliminando assim problemas comuns como o de tratamento de banco de dados e ganhando em agilidade e simplicidade no tratamento do problema. A resposta fornecida é bastante intuitiva, sendo fácil entender os resultados obtidos e quais seriam as implicações caso na prática sejam necessárias adequações à instalação. / This work proposes a new methodology to solve the problem of coordination of directional overcurrent relays in meshed transmission systems. Using information about the operation of the directional relay as primary protection (or local backup, in the case of considering the distance relay) and also its role as remote backup protection, the methodology provides a more solid basis for defining settings. Based on a series of criteria determined in accordance with the installation, an area of relay feasible settings is defined directly over their time-overcurrent curve. On this area, an optimization method is applied to find the best possible setting for the device under analysis. The method is applied without the need for topological analysis of the system, and the information of the relay location and its integration with other protective devices are summarized during the short circuit study, which provides the input data for the methodology. The algorithm summarizes the criteria of coordination in landmarks and the analysis is performed relay by relay, thus common problems are eliminated, such as database treatment, gaining agility and simplicity in treating the problem. The answer provided is extremely intuitive, making it easy to understand the results and what would be the implications in case of, in practice, be necessary to perform adjustments to fit with the installation.
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An evaluation of transfer capability limitations and solutions for South Mississippi Electric Power AssociationBrown, Nathan L. January 2002 (has links)
Thesis (M.S.)--Mississippi State University. Department of Electrical and Computer Engineering. / Title from title screen. Includes bibliographical references.
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Bird streamer initiated breakdowns under HVDC conditions.Naidoo, Kribashen. January 2007 (has links)
This dissertation describes the role played by bird streamers in transmission line faults under HVDC conditions. The research was initiated due to the lack of knowledge of these faults under HVDC conditions. An explanation as to what bird streamers faults are, the role they play in the breakdown of air-gaps and a means of preventing bird streamer caused faults from occurring is made Experimental work has been carried out in order to gain an understanding of these faults under HVDC conditions. The overall aim of the experiments was to find a horizontal distance (protected zone) on an HVDC tower top, in order to prevent birds from perching around the centre of the tower. This will lead to a reduction of bird streamer caused faults. A brass rod was used as the artificial streamer in the experiments, under both negative and positive polarity (voltages in the range 0 to 220 kV DC were applied). Later in the experimental phase, a string soaked in a saline solution was used as a more realistic simulation of a bird streamer. QuickField™, an FEM package, was used to simulate the electric field in the region of the live conductor fitting and the tip of the bird streamer, to assess the degree of distortion of the electric field caused by the introduction of the bird streamer. These simulations served as means of verifying the laboratory experiments. This dissertation has proposed a relationship between the breakdown voltage and the protected zone length, based on the air-gap breakdown voltages for both I-String and V-String insulator configurations in the air-gap range 0 to 350 mm. These curves can be used in the design of transmission lines, as a means of reducing bird streamer faults. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, 2007.
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Maximum power point tracking algorithm for photovoltaic home power supply.Nkashama, Cedrick Lupangu. January 2011 (has links)
Solar photovoltaic (PV) systems are distributed energy sources that are an environmentally friendly
and renewable source of energy. However, solar PV power fluctuates due to variations in radiation
and temperature levels. Furthermore, when the solar panel is directly connected to the load, the power
that is delivered is not optimal. A maximum peak power point tracker is therefore necessary for
maximum efficiency.
A complete PV system equipped maximum power point tracking (MPPT) system includes a solar
panel, MPPT algorithm, and a DC-DC converter topology. Each subsystem is modeled and simulated
in a Matlab/Simulink environment; then the whole PV system is combined with the battery load to
assess the overall performance when subjected to varying weather conditions.
A PV panel model of moderate complexity based on the Shockley diode equation is used to predict
the electrical characteristics of the cell with regard to changes in the atmospheric parameter of
irradiance and temperature.
In this dissertation, five MPPT algorithms are written in Matlab m-files and investigated via
simulations. The standard Perturb and Observe (PO) algorithm along with its two improved versions
and the conventional Incremental Conductance (IC) algorithm, also with its two-stage improved
version, are assessed under different atmospheric operating conditions. An efficient two-mode MPPT
algorithm combining the incremental conductance and the modified constant voltage methods is
selected from the five ones as the best model, because it provides the highest tracking efficiencies in
both sunny and cloudy weather conditions when compared to other MPPT algorithms.
A DC-DC converter topology and interface study between the panel and the battery load is performed.
This includes the steady state and dynamic analysis of buck and boost converters and allows the
researcher to choose the appropriate chopper for the current PV system. Frequency responses using
the state space averaged model are obtained for both converters. They are displayed with the help of
Bode and root locus methods based on their respective transfer functions. Following the simulated
results displayed in Matlab environment for both choppers, an appropriate converter is selected and
implemented in the present PV system. The chosen chopper is then modeled using the Simulink
Power Systems toolbox and validates the design specifications.
The simulated results of the complete PV system show that the performances of the PV panel using
the improved two-stage MPPT algorithm provides better steady state and fast transient characteristics
when compared with the conventional incremental conductance method. It yields not only a reduction
in convergence time to track the maximum power point MPP, but also a significant reduction in
power fluctuations around the MPP when subjected to slow and rapid solar irradiance changes. / Thesis (M.Sc.Eng)-University of KwaZulu-Natal, Durban, 2011.
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Improvement of steady state and voltage stability of a strong network overlayed with higher voltage transmission lines using phase shifting transformers.Molapo, Reentseng Majara. January 2011 (has links)
This research work deals with the application of the phase shifting transformer in improving the steady state performance and voltage stability of transmission network that has transmission lines at different voltage levels running in parallel to each other. Transmission power system networks are usually developed using lines built at a certain voltage level initially. As power demand requirements increase, building of the new lines at the same voltage level becomes necessary. However, lesser and lesser improvements in transfer capacity are realised when the additional lines are built. This prompts utilities to consider higher voltages for future lines as these have a higher transfer capacity. Utilities usually lay, i.e., they build in parallel, newer, higher voltage transmission lines along side the existing lower voltage ones. Power flow in power system is mainly influenced by impedances of equipment. If the combined impedance of the existing, lower voltage transmission system is relatively less than the impedance of the newer, higher voltage ones, power may primarily flow through it rather than via the newer, parallel higher voltage transmission network. This may lead to a serious underutilisation of the newer infrastructure with a higher transmission capacity. Transmission networks similar to the one described above are common throughout the world. This study was undertaken towards finding solutions to the problem of under utilisation of such transmission lines. The study was performed by first reviewing the literature on the use of phase shifting transformers to redirect power flow in transmission networks throughout the world. This was followed by analysis of the theory on how and what determines the power flow in power networks. Several simulations of varying the phase of the phase shifting transformer were performed on the Cape network, as a case study, to investigate the impact on the power flow distribution and voltage stability performance of the 765 kV and 400 kV transmission lines carrying power to the Western Cape. In this dissertation, it has been demonstrated that a phase shifting transformer can be used to alter the power flow patterns so that power flows are restructured or redistributed, such that power which originally flowed via the low impedance, lower voltage system is transferred to the parallel higher voltage transmission system of lines. It is shown that once the power flows are redistributed, steady state and voltage stability performance of the total system can be enhanced and an increase in its power transfer capacity can be realised. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.
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A comparison of the performance of high-voltage insulator materials in a severely polluted coastal environmentVosloo, Wallace L. (Wallace Lockwood) 04 1900 (has links)
Thesis (PhD)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The main aim of this research programme was to compare the relative
performance of different insulator materials used in South Africa when subjected
to a severe marine pollution environment. A test programme and procedure, test
facility and instrumentation were established. Some novel instrumentation and
monitoring equipment were developed and built specifically for this research
programme, supported by data analysing software programs. In order to
compare material performance only, all non-material design variables between
the test insulators had to be removed (e.g. creepage distance, connecting length,
inter-shed spacing, profile, etc.). To achieve this some of the test insulators had
to be specially manufactured. Leakage current, electrical discharge activity,
climatic and environmental data was collected successfully over a one-year test
period, starting with new test insulators.
The peak and energy values of the leakage current were identified as the two
main parameters needed to describe the leakage current activity on the test
insulators. A correlation was found between the climatic and environmental data
and the leakage current data, and it was found that the leakage current can be
determined successfully from some of the climatic and environmental parameters
monitored by using multiple regression techniques. Surface conductivity and
energy were found to be the best parameters to show the maximum and
continuous interaction of the insulator material surface with the electrolytic
pollution layer. A natural ageing and pollution test procedure was developed,
which has become a South African standard and is gaining international
acceptance.
A model and hypothesis are proposed to describe the electrical discharge activity
that takes place on the test insulators and explain the difference in leakage
current performance of the various materials.
Keywords: Insulator, Pollution, High Voltage, Leakage current, Material
performance. / AFRIKAANSE OPSOMMING: Die hoofdoel van hierdie navorsingsprogram was om die relatiewe prestasie van
verskillende isolatormateriale wat in Suid-Afrika gebruik word te vergelyk in 'n
swaar besoedelde marine omgewing. 'n Toetsprogram en prosedure, toets
fasiliteit en instrumentasie is gevestig. 'n Paar nuwe instrumente en moniteer
toerusting is ontwikkel en gebou spesifiek vir hierdie navorsingsprogram, gesteun
deur data analise sagteware programme. Ten einde slegs materiaalprestasie te
vergelyk, moes alle nie-materiaal ontwerpsveranderlikes tussen die toetsisolators
verwyder word (bv. kruipafstand, konnekteer lengte, tussen-skerm spasiëring,
profiel, ens.). Om dit reg te kry moes sommige van die toetsisolators spesiaal
vervaardig word. Lekstroom, elektriese ontladingsaktiwiteit, klimaat en
omgewingsdata is suksesvol versameloor 'n een-jaar toetsperiode, beginnende
met nuwe toets isolators.
Die piek en energie waardes van die lekstroom is identifiseer as die twee hoof
parameters wat nodig is om die lekstroomaktiwiteit op die toetsisolators te
beskryf. 'n Korrelasie is gevind tussen die klimaat- en omgewingsdata en die
lekstroom data, en dit is gevind dat die lekstroom data suksesvol bepaal kan
word van sekere van die klimaat- en omgewingsparameters wat gemoniteer is
deur veelvoudige regressie tegnieke te gebruik. Oppervlakskonduktiwiteit en
energie is gevind die beste parameters te wees om die maksimum en kontinue
interaksie van die isolatormateriaaloppervlak met die elektrolitiese
besoedelingslaag aan te toon. 'n Natuurlike veroudering en besoedeling
toetsprosedure is ontwikkel, wat 'n Suid-Afrikaanse standaard geword het en
besig is om internastionale aanvaarding te wen.
'n Model en hipotese word voorgestelom die elektriese ontladingsaktiwiteit wat
op die toetsisolators plaasvind te beskryf en om die verskil in lekstroomprestasie
van die verskeie materiale te verduidelik.
S/eufelwoorde: Isolator, Besoedeling, Hoog Spanning, Leek stroom, Materiaal
prestasie.
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