Recent widespread blackouts have indicated the need for more efficient and accurate power system monitoring, control and protection tools. Power system state estimation, which is the major tool that is used nowadays for providing the real-time model of the system, has significant biases resulting mainly from the complexity and geographic spread and separation of an electric power system. Synchrophasor technology is a promising technology that has numerous advantages compared to conventional metering devices. PMUs provide synchronized measurements, where synchronization is achieved via a GPS clock which provides the synchronizing signal with accuracy of 1 μsec. As a result, the computed phasors have a common reference (UTC time) and can be used in local computations, thus distributing the state estimation process. The first part of the work presents a PMU enabled dynamic state estimator (DSE) that can capture with high fidelity the dynamics of the system and extract in real time the dynamic model of the system. The described DSE is performed in a decentralized way, on the substation level based on local measurements which are globally valid. The substation based DSE uses data from relays, PMUs, meters, FDRs etc in the substation only, thus avoiding all issues associated with transmission of data and associated time latencies. This approach enables very fast DSE update rate which can go up to more than 60 executions per second. The distributed state estimation architecture that synchrophasor technology enables, along with the fast sampling rate and the accuracy of the measurements that PMUs provide, enable the computation of the real-time dynamic model of the system and the development of numerous power system applications for more efficient control and protection of the system. In the second part of the work, a transient stability monitoring scheme is presented that utilizes the information given by the dynamic state estimation and enables real-time monitoring of the transient swings of the system and characterizes the stability of the system in real time. In particular, the real-time dynamic model of the system, as given by the DSE, is utilized to evaluate the system's energy function based on Lyapunov's direct method and extract stability properties from the energy function. The two major components of the scheme are a) the calculation of the center of oscillations of the system and b) the derivation of an equivalent, reduced sized model which is used for the calculation of the potential and kinetic energy of the system based on which the stability of the system is determined. Finally, as an application of the transient stability monitoring scheme, an energy based out-of-step protection scheme is proposed. The energy of the generator is continuously monitored and if it exceeds a predefined threshold then instability is asserted and a trip signal can be sent to the generator. The major advantage of the scheme is that the out-of-step condition is predicted before its occurrence and therefore relays can act much faster than today's technology. The scheme is compared to presently available state of the art out-of-step protection schemes in order to verify its superiority.

Practically all everyday life tasks from economic transactions to entertainment depend on the availability of electricity. Some customers have come to expect a higher level of power quality and availability from their electric utility. Federal and state standards are now mandated for power service quality and utilities may be penalized if the number of interruptions exceeds the mandated standards. In order to meet the requirement for safety, reliability and quality of supply in distribution system, adaptive relaying and optimal network reconfiguration are proposed. By optimizing the system to be better prepared to handle a fault, the end result will be that in the event of a fault, the minimum number of customers will be affected. Thus reliability will increase. The main function of power system protection is to detect and remove the faulted parts as fast and as selectively as possible. The problem of coordinating protective relays in electric power systems consists of selecting suitable settings such that their fundamental protective function is met under the requirements of sensitivity, selectivity, reliability, and speed. In the proposed adaptive relaying approach, weather data will be incorporated as follows. By using real-time weather information, the potential area that might be affected by the severe weather will be determined. An algorithm is proposed for adaptive optimal relay setting (relays will optimally react to a potential fault). Different types of relays (and relay functions) and fuses will be considered in this optimization problem as well as their coordination with others. The proposed optimization method is based on mixed integer programming that will provide the optimal relay settings including pickup current, time dial setting, and different relay functions and so on. The main function of optimal network reconfiguration is to maximize the power supply using existing breakers and switches in the system. The ability to quickly and flexibly reconfigure the power system of an interconnected network of feeders is a key component of Smart Grid. New technologies are being injected into the distribution systems such as advanced metering, distribution automation, distribution generation and distributed storage. With these new technologies, the optimal network reconfiguration becomes more complicated. The proposed algorithms will be implemented and demonstrated on a realistic test system. The end result will be improved reliability. The improvements will be quantified with reliability indexes such as SAIDI.

The Liquid-Salt-Cooled Very High-Temperature Reactor (LS-VHTR) was modeled using the neutronics analysis code SCALE6.0 and the thermal-hydraulics and kinetics modeling code RELAP5-3D with objective to devise, analyze, and evaluate the feasibility and stability of a start-up procedure for this reactor using natural circulation of the coolant and under the Loss Of Offsite Power (LOOP) conditions. This Generation IV reactor design has been studied by research facilities worldwide for almost a decade. While neutronics and thermal-hydraulics analyses have been previously performed to show the performance of the reactor during normal operation and for shutdown scenarios, no study has heretofore been published to examine the active or passive start-up of the reactor. The fuel temperature (Doppler) and coolant density coefficient of reactivity of the LS-VHTR were examined using the CSAS6 module of the SCALE6.0 code. Negative Doppler and coolant density feedback coefficients were calculated. Two initial RELAP5 simulations were run to obtain the steady-state conditions of the model and to predict the changes of the thermal-hydraulic parameters during the shutdown of the reactor. Next, a series of step reactivity additions to the core were simulated to determine how much reactivity can be inserted without jeopardizing safety and the stability of the core. Finally, a start-up procedure was developed, and the restart of the reactor with natural convection of the coolant was simulated. The results of the simulations demonstrated the potential of a passive start-up of the LS-VHTR.

Fires generate heat and propel burning material into the air above and around the core of the fire. Fires under power lines reduce the breakdown strength of the air insulation due to the influence the heat and particles have on the electric field surrounding the conductors. The result can be flashovers and undesirable power supply interruptions in the electrical transmission network with a considerable impact on Eskom's 275 kV and 400 kV MTS (main transmission system) networks. Eskom typically experiences a loss in sales, a reduction in the quality of the power supplied to consumers and disgruntled consumers who in turn experience financial losses due to a loss in production. In this thesis, the high frequency characteristics of corona and electrical discharges generated by the fire phenomena are studied. The influence of the operating voltages on the electric fields, the potential of different media to initiate ionisation and comparison of conductor construction (bundling and diameter) are all considered in the measurement of high frequency signals in the range of frequencies available in the tuned circuits connected to power lines. The propagation of these high frequency signals is studied both in isolation of other sources of high frequency signals (within controlled laboratory conditions) and in the real environment adjacent to all other interfering sources. Finally the fingerprinting of the varying high frequency signal patterns associated with fires is considered with a view to implementing an operational early detection device. Early detection of a fire allows the utility to understand the source of a system fault, manage it effectively and if possible pre-empt possible failure by means of appropriately applied standard operating guidelines (SOG) to minimise the impact. / Thesis (M.Sc.Eng.)-University of Natal, Durban, 2003.

Thesis (MBA (Business Management))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: This research report discusses the development of a decision-making matrix during power crises. South Africa comes from a situation of excess supply and is currently in a situation where electricity demand exceeds supply. This report will provide the background of how the current electricity crisis came to be and what the future of the industry will look like. As electricity shortages is a worldwide issue, the study will explore international countries' experience of supply shortages and extract lessons learnt and best practices that can be applied in the South African context. The study reviews available solutions that exist to address the electricity crisis in South Africa and explores alternative energy sources that could be applied in South Africa. To establish an effective decision making tool for electricity shortage response mechanisms, the key decision making criteria are discussed and explained. A decision making matrix brings together all the available solutions and decision-making criteria based on the decision maker's relative importance placed on the considerations and the resultant impact on these considerations. The results of the decision-making matrix directs the decision maker to the least negative impact solution and provides a basis on which to make sound decisions during a time when quick and effective decisions will determine the success and sustainability of the power system. / AFRIKAANSE OPSOMMING: Hierdie navorsingsverslag bespreek die ontwikkeling van 'n besluitnemingsmodel wat aangewend kan word tydens kritiese tekorte in elekrisiteitsvoorsiening op 'n nasionale basis. Die elektrisiteits- ontwikkelingsvermoë in Suid-Afrika het beweeg vanaf 'n oorskot na 'n posisie waar daar nie in die aanvraag voorsien kan word nie. Hierdie navorsingsverslag skets die agtergrond van wat aanleiding gegee het tot die huidige elektrisiteitskrisis en wat die toekoms inhou vir elektrisiteitsvoorsiening in die algemeen. Die gebrek aan elektrisiteitsontwikkelingsvermoë is 'n wêreldwye tendens en die lesse wat ander lande geleer het tesame met hul beste praktyke word oorweeg binne die Suid-Afrikaanse konteks. Beskikbare oplossings wat op die manier geidentifiseer word, word ontleed, tesame met moontlike alternatiewe energiebronne wat in Suid-Afrika aangewend kan word. Die kern besluitnemingskriteria word bespreek en ontleed om sodoende 'n proses daar te stel waarvolgens die besluitnemingsmodel wat die mees effektiewe oplossing in tye van kritiese elektirsiteitstekorte sal voortbring te ontwikkel. Al die beskikbare en werkbare opsies tydens die periode van elektristeitstekorte word saamgevoeg binne die besluitnemingsmodel om die toepaslikheid daarvan op te weeg teenoor die relatiewe gewig wat die besluitnemer toeken aan al die onderliggende faktore. Die besluitnemingsmodel ondersteun die besluitnemer om, tydens 'n krisis in elektrisiteitsvoersiening, 'n vinnige en doeltreffende besluit te neem wat die minste negatiewe impak het op ekonomiese aktiwiteite en die sukses en stabiliteit van die elektrisiteitsvoorsieningsnetwerk waarborg.

No description available.

Thesis (M.Eng.)--University of Wollongong, School of Electrical, Computer & Telecommunications Engineering. / Typescript. Includes bibliographical references: leaf 143-147.

Provisioning for power failure is an important element of data center design. It is important to assess both tangible and intangible costs of unplanned data center downtime. These costs must be compared with the capital cost of providing various levels of backup power infrastructure to compute and cooling equipment. Various levels of backup power infrastructure each lead to a most probable transient scenario after utility power failure. Because of differences between facilities, the level of risk that unacceptable compute equipment inlet temperature associated with each level of backup power infrastructure is not standardized; in particular, facilities with differing compute equipment power densities may require different levels of backup power infrastructure to maintain safe operation. Choosing one level of backup power infrastructure above another is not necessarily obvious for every facility, as there may be large gaps in costs and unknown levels of risk for lower levels of provisioning. A first order model is also used to compare inclusion of various thermal capacitance values with experimental results. Room level experiments also illustrate the relative level of risk associated with various levels of provisioning for the same control volume and compute equipment. Although provisioning to back up as much equipment as possible remains the "safest" solution, cost will continue to play a factor in facility design decisions. This work offers a step toward appropriate modeling of data center power failure events and suggests further steps to continue the process.

Thesis (MPhil)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Electrical energy has become an indispensable part of the modern world, supporting industries and economic systems. Any disruption of supply is felt immediately in all spheres of life. The operation of a power system is a complex process involving rotating machines that may fail from time even though they are maintained regularly. The overhead transmission system is likewise prone to faults caused by environmental factors such as pollution and lightning. Power authorities therefore operate their systems in such a way that they have sufficient reserve capacity available to allow for contingencies. In the last decade of the previous century a condition developed, for various reasons, that the reserve margin was too small in the South African electricity supply system. At the end of 2005, a spate of failures occurred at Koeberg power station and later in 2007 serious coal supply problems developed at the large power stations in Mpumalanga, aggravating the situation. This research project focuses on the complexity of the task of the reporter when reporting on occurrences such as these. It is required to convey the factual situation to the readers, avoiding alarmism and sensationalism. At the same time the reporter also has a role to play in educating the readers. It was a difficult task, seeing that the reporters were not necessary versed in the technical field. They therefore had to rely on Eskom’s spokespersons. In this project newspaper clippings of various Western Cape newspapers containing the word Eskom were analysed. The method of analysis was content analysis. Firstly the quantitative content analysis was used to obtain distribution of articles over the period and among newspapers. Thereafter the topics covered and the types of article were obtained for the various newspapers and years. Next articles for 2006 and 2008 were investigated using qualitative content analysis. Certain attributes in the articles were detected manually and a profile was obtained for each newspaper for each year period. Questionnaires were sent to reporters responsible for some of the articles and to a technical expert who was consulted regularly by the news reporters. It was found that the number of articles and style of presentation vary among the newspapers. There is evidence of framing of Eskom as incompetent. / AFRIKAANSE OPSOMMING: Elektriese energie het ¢n onontbeerlike deel van die moderne wêreld geword wat nywerhede en ekonomiese stelsels ondersteun. Enige onderbreking van toevoer word onmiddellik in alle lewensfere gevoel. Die werking van kragstelsel is komplekse proses met roterende masjiene en ander toerusting wat onderworpe aan faling is, selfs al word dit in stand gehou. Die oorhoofse transmissiestelsel is ook onderworpe aan foute wat deur omgewingsfaktore soos besoedeling en weerlig veroorsaak word. Kragvoorsieners bedryf daarom hul stelsels so dat hulle voldoende reserwekapasiteit het om toe te laat vir gebeurlikhede. In die laaste dekade van die vorige eeu het die toestand, om verskeie redes, ontwikkel dat die reserwemarge in die Suid-Afrikaanse stelsel te klein geword het. Teen die einde van 2005 het reeks falings by Koeberg kragstasie plaasgevind en later in 2007 het ernstige steenkoolvoorsieningsprobleme by die groot kragstasies in Mpumalanga ontstaan en dus die situasie vererger. Hierdie navorsingsprojek fokus op die kompleksiteit van die taak van die verslaggewer as oor sulke gebeure verslag gedoen word. Dit word vereis om die feitelike situasie oor te dra sonder alarmisme en sensasie. Terselfdertyd moet die verslaggewer ook rol speel om die lesers op te voed. Dit is moeilike taak daar die verslaggewers nie noodwendig belese in die tegniese vakgebied is nie. Hulle moes dus staatmaak op Eskom se spreekbuise. In hierdie projek is koerantuitknipsels van verskeie Wes-Kaapse koerante wat die woord Eskom bevat, ontleed. Die metode wat gebruik is, is inhoudsanalise. Eerstens is kwantitatiewe inhoudsanalise gebruik om die verspreiding van artikels oor die tydperk en tussen die koerante te verkry. Daarna is die onderwerpe wat gedek is verkry vir die onderskeie koerante en jare. Vervolgens is artikels van 2006 en 2008 ondersoek deur kwalitatiewe inhoudsanalise te doen. Sekere kenmerke is in die artikels opgespoor en profiel is verkry vir elke koerant en elke jaarperiode. Vraelyste is aan verslaggewers wat sommige artikels geskryf het en ook aan tegniese deskundige wat gereeld deur verslaggewers genader is, gestuur. Dit is bevind dat die getal artikels en die styl van aanbieding wissel tussen die koerante Daar is ook tekens van raming van Eskom as onbekwaam.

Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2009 / The purpose of this project is to develop methods for distribution network power quality' variations monitoring. Power quality (PO) has become a significant issue for both power suppliers and customers. There have been important changes in power system regarding to power quality requirements. "Power quality" is the combination at voltage quality and current quality. The main research problem of the project is to investigate the power quality of a distribution network by selection of proper measurement, applying and developing the existing classic and modern signal conditioning methods for power disturbance's parameters extracting and monitoring. The research objectives are: To study the standard lEC 61000-4-30 requirements. to investigate the common couplings in the distribution network. To identity the points for measurement, to develop MySQL database for the data from the measurement and to develop MATLAB software tor simulation of the network To develop methods based on Fourier transforms for estimation of the parameters of the disturbances. To develop software for the methods implementation, The influence of different loads on power quality disturbances are considered in the distribution network. Points on the network and meters according to the lEC power quality standards are investigated and applied for the CPUT Bellville campus distribution network. The implementation of the power quality monitoring for the CPUT Bellville campus helps the quality of power supply to be improved and the used power to be reduced. MATLAB programs to communicate with the database and calculate the disturbances and power quality parameters are developed.