Dissertations / Theses: 'Electric power systems – Quality control'

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Tai, Sio Un. "Power quality study in Macau and virtual power analyzer." Thesis, University of Macau, 2012. http://umaclib3.umac.mo/record=b2586277.

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Newman, Michael John 1976. "Design and control of a Universal Custom Power Conditioner (UCPC)." Monash University, Dept. of Electrical and Computer Systems Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/5651.

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Nduku, Nyaniso Prudent. "Development of methods for distribution network power quality variation monitoring." Thesis, Cape Peninsula University of Technology, 2009. http://hdl.handle.net/20.500.11838/1144.

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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.

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Manmek, Thip Electrical Engineering &amp Telecommunications Faculty of Engineering UNSW. "Real-time power system disturbance identification and its mitigation using an enhanced least squares algorithm." Awarded by:University of New South Wales. Electrical Engineering and Telecommunications, 2006. http://handle.unsw.edu.au/1959.4/26233.

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This thesis proposes, analyses and implements a fast and accurate real-time power system disturbances identification method based on an enhanced linear least squares algorithm for mitigation and monitoring of various power quality problems such as current harmonics, grid unbalances and voltage dips. The enhanced algorithm imposes less real-time computational burden on processing the system and is thus called ???efficient least squares algorithm???. The proposed efficient least squares algorithm does not require matrix inversion operation and contains only real numbers. The number of required real-time matrix multiplications is also reduced in the proposed method by pre-performing some of the matrix multiplications to form a constant matrix. The proposed efficient least squares algorithm extracts instantaneous sine and cosine terms of the fundamental and harmonic components by simply multiplying a set of sampled input data by the pre-calculated constant matrix. A power signal processing system based on the proposed efficient least squares algorithm is presented in this thesis. This power signal processing system derives various power system quantities that are used for real-time monitoring and disturbance mitigation. These power system quantities include constituent components, symmetrical components and various power measurements. The properties of the proposed power signal processing system was studied using modelling and practical implementation in a digital signal processor. These studies demonstrated that the proposed method is capable of extracting time varying power system quantities quickly and accurately. The dynamic response time of the proposed method was less than half that of a fundamental cycle. Moreover, the proposed method showed less sensitivity to noise pollution and small variations in fundamental frequency. The performance of the proposed power signal processing system was compared to that of the popular DFT/FFT methods using computer simulations. The simulation results confirmed the superior performance of the proposed method under both transient and steady-state conditions. In order to investigate the practicability of the method, the proposed power signal processing system was applied to two real-life disturbance mitigation applications namely, an active power filter (APF) and a distribution synchronous static compensator (D-STATCOM). The validity and performance of the proposed signal processing system in both disturbance mitigations applications were investigated by simulation and experimental studies. The extensive modelling and experimental studies confirmed that the proposed signal processing system can be used for practical real-time applications which require fast disturbance identification such as mitigation control and power quality monitoring of power systems

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Fleshman, Muller Eunamia. "Development of a supplier quality assessment system in Eskom." Thesis, Stellenbosch : Stellenbosch University, 2015. http://hdl.handle.net/10019.1/97323.

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Thesis (MBA)--Stellenbosch University, 2015.
ENGLISH ABSTRACT: Eskom, the South Africa and trans-Africa electrical power utility, has a capacity expansion project that is estimated to cost roughly R340 billion. The programme is anticipated to continue through 2018. Eskom will be contracting with a multitude of suppliers and it is imperative that the projects delivered under the capacity expansion programme meet Eskom’s required quality standards. The question then arises whether the set quality standards are sufficiently comprehensive to provide confidence that suppliers will achieve high quality standards. This aim of this research was to examine supplier assessment programmes to determine the criteria that will best provide supplier assurance. The researcher consulted a vast range of literature available on supplier quality assessment programmes. From the literature consulted, there appeared to be some recurring themes from the range of assessment tools. It also becomes apparent that the assessment tool cannot only focus on a quality system, but a balance of strategic and operational focus was needed to fully understand suppliers’ ability to deliver. One of the key considerations was establishing longer-term collaborative relationships with key suppliers. Long-term relations encourage trust, transparency and innovation. It was equally important to ensure that operational assessments provided insight on suppliers’ capability. Based on the literature reviewed, a proposed framework was tested against the current methodology for supplier evaluation. From these comparisons, some gaps were identified and recommendations were suggested to improve the supplier evaluation programme.

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Lam, Chi Seng. "An adaptive low dc-voltage controlled LC coupling hybrid active power filter in three-phase four-wire power systems." Thesis, University of Macau, 2012. http://umaclib3.umac.mo/record=b2580608.

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Grobler, Frederik Antonie. "The development of harmonic content and quality of electricity supply measuring system incorporating scada processing." Thesis, Bloemfontein : Central University of Technology, Free State, 2005. http://hdl.handle.net/11462/61.

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Thesis (D.Tech (Engineering Electrical)) - Central University of Technology, Free State, 2005
When Thomas Edison invented his carbon filament lamp in 1879, gas shares fell overnight. A committee of inquiry was set up to examine the future possibilities of the new method of lighting, and had reached the conclusion that electric light in the home was fanciful and absurd. Today electric light burns in practically every house in the civilised world, with many great advances in the production and use of electricity and electric power supplied by various utilities. The objective of the electric utility to deliver pure sinusoidal voltage at fairly constant magnitude throughout their system is complicated by the fact that there are currently loads on the system that produce harmonic voltages, which result in distorted voltages and currents that can adversely impact on the system performance in different ways. Because the numbers of harmonic producing loads have increased over the years, it has become necessary to address their influence, when making any additions or changes to an installation. Quality of supply measurements have long been used to characterise non-linearity on the power system, and have traditionally been measured with expensive portable analysers. A potentially faster, more integrated, and more flexible solution to measure the harmonics with a Supervisory System is accomplished by this research. Any script which aspired to cover in full detail the whole field of a subject so enormous as techniques to measure the quality of electricity supply on a SCADA system, would hardly be practical in less than a few volumes. The pretensions of this research are both modest and of a more immediate value to the reader.

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Looja, Tuladhar R. "Control of Custom Power System using Active Disturbance Rejection Control." Cleveland State University / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=csu1438913443.

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Zhang, Li. "Study of FACTS/ESS Applications in Bulk Power System." Diss., Virginia Tech, 2006. http://hdl.handle.net/10919/28465.

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The electric power supply industry has evolved into one of the largest industries. Even though secure and reliable operation of the electric power system is fundamental to economy, social security and quality of modern life, the complicated power grid is now facing severe challenges to meet the high-level secure and reliable operation requirements. New technologies will play a major role in helping today's electric power industry to meet the above challenges. This dissertation has focused on some key technologies among them, including the emerging technologies of energy storage, controlled power electronics and wide area measurement technologies. Those technologies offer an opportunity to develop the appropriate objectives for power system control. The use of power electronics based devices with energy storage system integrated into them, such as FACTS/ESS, can provide valuable added benefits to improve stability, power quality, and reliability of power systems. The study in this dissertation has provided several guidelines for the implementation of FACTS/ESS in bulk power systems. The interest of this study lies in a wide range of FACTS/ESS technology applications in bulk power system to solve some special problems that were not solved well without the application of FACTS/ESS. The special problems we select to solve by using FACTS/ESS technology in this study include power quality problem solution by active power compensation, electrical arc furnace (EAF) induced problems solution, inter-area mode low frequency oscillation suppression, coordination of under frequency load shedding (UFLS) and under frequency governor control (UFGC), wide area voltage control. From this study, the author of this dissertation reveals the unique role that FACTS/ESS technology can play in the bulk power system stability control and power quality enhancement in power system. In this dissertation, almost all the studies are based on the real system problems, which means that the study results are special valuable to certain utilities that have those problems. The study in this dissertation can assist power industry choose the right FACTS/ESS technology for their intended functions, which will improve the survivability, minimize blackouts, and reduce interruption costs through the use of energy storage systems.
Ph. D.

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Silva, Newton da. "Contribuições ao estudo, projeto e aplicação de filtros ativos híbridos de potência." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260365.

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Orientadores: José Antenor Pomilio, Edson Adriano Vendrusculo
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Os filtros híbridos combinam o filtro passivo com o filtro ativo para a obtenção de um filtro que aproveita as qualidades de ambos. O filtro híbrido possui uma redução de potência na sua parte ativa e apresenta um melhor desempenho que o filtro passivo. Existem diferentes topologias de combinações entre o filtro passivo e o filtro ativo, cada uma com suas características. A topologia mais usual é aquela em que o filtro ativo fica em série com o filtro passivo. Neste trabalho será analisada a topologia com o filtro ativo em paralelo com o indutor do filtro passivo. A vantagem desta topologia é a divisão das correntes harmônicas entre ambos os filtros, o que não ocorre na topologia série. O funcionamento do filtro híbrido na compensação das harmônicas de corrente da carga é aprofundado, ampliando as discussões anteriormente publicadas, identificando novas características de operação, contribuindo no estabelecimento de procedimentos de projeto tanto do circuito de potência quanto de controle. Um estudo teórico da atuação do filtro híbrido em um alimentador industrial de média tensão descrito na norma IEEE 519-1992 (workbench) é também apresentado. Resultados experimentais de implementação em um protótipo são apresentados de modo a comprovar a técnica de controle usada e também avaliar a compensação de correntes harmônicas em situações distintas de carga e harmônico de tensão na rede
Abstract: Hybrid Filters combine the passive filter with the active filter to obtain a filter that takes advantage of the qualities of both. The hybrid filter has a power reduction in its active part and presents better performance than the passive filter. There are different topologies of the combinations between the passive filter and the active filter, each with its own characteristics. The most common topology is the active filter in series with the passive filter. In this work the topology that will be analyzed is one where the active filter is parallel to the inductor of the passive filter. The advantage of this topology is the division of the harmonic current between the two filters, this does not occur in the series topology. The operation of the hybrid filter in the compensation of the load harmonic current is improved, expanding the discussions previously published, identifying new characteristics of operation, contributing to the establishment of design procedures in the power circuit as in the control. A theoretical study of the hybrid filter performance in an industrial medium voltage power supply described in IEEE standard 519-1992 (workbench) is presented too. Experimental results from a prototype implementation are presented in order to check the control technique used and also to evaluate the current harmonic compensation in different situations of the load and harmonic voltage in the source
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica

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11

Lamour, Bernhardt Gustave. "An analysis of the reliability of the 22kV distribution network of the Nelson Mandela Bay Municipality." Thesis, Nelson Mandela Metropolitan University, 2011. http://hdl.handle.net/10948/1537.

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This dissertation is a systematic study of the 22kV Nelson Mandela Bay Municipality (NMBM) electricity power distribution network reliability evaluation and improvements to be applied. Reliability evaluation of electric power systems has traditionally been an integral part of planning and operation. Changes in the electricity utility, coupled with aging electrical apparatus, create a need for more realistic techniques for power system reliability modelling. This work presents a reliability evaluation technique that combines set literature and evaluation criteria. In analysing system reliability, this research takes into account the reasons for many outages and voltage dips and seeks to find mitigating approaches that are financially justified. The study analyses the power system in terms of the methodology developed, using power system reliability techniques, power quality evaluation, protection analyses and evaluating the network against maintenance interventions and programs, manpower availability and weather conditions contributing to the outages. In evaluating the power system various techniques are used to determine if the power network operates within the NRS standards, namely, reliability calculations, testing of protection equipment, interrogation of power quality instruments and modeling the network on Digsilent. This study will look at all the important factors influencing power system reliability, analysing the network in terms of the methodology and recommend improvements.

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Cetin, Alper. "Design And Implementation Of A Voltage Source Converter Based Statcom For Reactive Power Compensation And Harmonic Filtering." Phd thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/12608307/index.pdf.

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In this thesis, design and implementation of a distribution-type, voltage source converter (VSC) based static synchronous compensator (D-STATCOM) having the simplest converter and coupling transformer topologies have been carried out. The VSC STATCOM is composed of a +/- 750 kVAr full-bridge VSC employing selective harmonic elimination technique, a low-pass input filter, and a &
#8710
/Y connected coupling transformer for connection to medium voltage bus. The power stage of VSC based STATCOM is composed of water-cooled high voltage IGBT modules switched at 850 Hz for the elimination of 5th, 7th, 11th, 13th, 17th, 19th, 23rd,and 25th voltage harmonics. Special care has been taken in the laminated busbar design to minimize stray inductances between power semiconductors and dc link capacitor. Reactive power control is achieved by applying the phase angle control technique. The effect of input filter on total demand distortion has been investigated theoretically by mathematical derivations. The proposed VSC STATCOM has been implemented for reactive power compensation of Coal Preparation System in Kemerkö
y Thermal Power Plant. The field test results have shown the success of the implemented system in view of fast response in reactive power compensation, and minimum input current harmonic content, and compliance with the IEEE Std. 519-1992 even for the weakest power systems. The application of selective harmonic elimination technique and phase angle control to VSC STATCOM has led to optimum switching frequency and device utilization for high voltage IGBTs at the expense of slower response as compared to other PWM techniques.

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Pimentel, Sergio Pires. "Aplicação de inversor multinivel como filtro ativo de potencia." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259300.

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Orientador: Jose Antenor Pomilio
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e Computação
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Resumo: Este trabalho aborda a implementação de um filtro ativo de potência utilizando um inversor multinível com topologia em cascata assimétrica. Justificativas para utilização de estruturas multiníveis são discutidas. O sistema de controle utilizado garante um fornecimento nulo de potência ativa pelo filtro ativo e que a corrente fornecida pela fonte de alimentação tenha a mesma forma de onda da tensão de alimentação. Com isso, o fator de potência visto pela fonte é próximo de seu valor unitário e a fonte fornece apenas potência ativa à carga. Resultados de simulações e experimentais validam o esquema adotado. Também é descreva uma proposta para se realizar o controle das tensões CC da topologia em cascata assimétrica. Palavras-chave: Eletrônica de Potência, Inversor Multinível, Qualidade da Energia Elétrica, Filtro Ativo de Potência, Controle Digital
Abstract: This work regards a shunt active power filter implementation using an asymmetrical cascaded multilevel convel1er. Reasons for using multilevel structures are discussed. The system control guarantees that the active power filter does not supply active power and the source current has the same waveform of the source voltage. Consequently, the power factor from the source side is almost one and the source only supplies active power to the load. Simulation and experimental results validate the applied scheme. A proposal for controlling the DC voltages from the asymmetrical cascaded topology is also described.
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica

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Meira, Paulo César Magalhães 1985. "Análise da filosofia de eliminação de defeitos em sistemas de distribuição considerando aspectos de confiabilidade e de qualidade de energia." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261202.

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Orientador: Walmir de Freitas Filho
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: A estratégia de eliminação de defeitos (faltas) empregada pela concessionária de distribuição de energia elétrica tem grande impacto na confiabilidade e na qualidade de energia do sistema. Por exemplo, a política de empregar religadores automáticos tipicamente tem um impacto benéfico nos índices de confiabilidade baseados na frequência e duração das interrupções sustentadas mas, por outro lado, tem um impacto negativo nos índices de qualidade de energia baseados na frequência de interrupções temporárias. Isto pode ser comprovado pelo número de concessionárias ao redor do mundo que estão revendo suas estratégias de empregar religadores automáticos de forma generalizada conforme cresce a preocupação do consumidor com a qualidade de energia. Somado a isso, tem-se o fato de o sistema estar sendo modernizado com o uso de mais equipamentos de monitoração e automação, como chaves seccionadoras automáticas, relés digitais, etc., dentro do contexto que se convencionou chamar redes inteligentes (smart grids). Portanto, atualmente, as estratégias de eliminação de faltas e de melhoria dos índices de confiabilidade e de qualidade de energia em sistemas de distribuição estão passando por modificações e têm atraído o interesse da comunidade científica e tecnológica. Este trabalho tem como objetivo desenvolver métodos para auxiliar na tomada de decisão sobre a estratégia de eliminação de defeitos em sistemas de distribuição via avaliação integrada dos índices de confiabilidade e qualidade de energia. Os métodos empregados são baseados no uso de registros históricos e de medições da concessionária, no cálculo de índices de confiabilidade e de qualidade de energia e em técnicas de otimização e de tratamentos estatísticos. Para permitir o emprego dos métodos a sistemas reais, algoritmos clássicos para análise de confiabilidade e qualidade de energia são revisitados e reformulados de forma a permitir sua aplicação a sistemas de grande porte em tempo de execução factível. São investigadas também formas de permitir a execução paralela e distribuída dos principais algoritmos empregados nos métodos propostos
Abstract: The fault elimination policy used by an electric energy distribution utility has great impact on the reliability and in the power quality of the system. For example, the policy of using automatic reclosers typically has a positive impact in the reliability indices based on frequency and duration of sustained interruptions but, on the other hand, has a negative impact on the power quality indices based on the frequency of temporary interruptions. This can be verified by the number of utilities around the world that are reevaluating their policies in using automatic reclosers in a generalized fashion as the customers demand better power quality. At the same time, the systems are being modernized, including the usage of more monitoring and automation equipment, such as automatic sectionalizing switches, digital relays, etc., in a context that is usually called smart grids. Therefore, currently, the policies regarding fault elimination and improvement of the reliability and power quality indices in distribution system are being reformulated and have attracted the interest of the academic and technology communities. The objective of this thesis is to develop methods to assist in the decision-making process on the fault elimination policies in distribution systems using the integrated evaluation of reliability and power quality indices. The methods are based on the use of historical records and utility measurements, in the computation of reliability and power quality indices, in optimization techniques and statistical analysis. To achieve the implementation of the methods in actual systems, the classic algorithms used to analyze the reliability and power quality are revisited and reformulated in order to allow their application to large-scale systems in feasible running time. Alternatives to allow the parallel and distributed execution of the main algorithms of the proposed methods are also explored
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica

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El-Sedawi, I. R. M. "Hierarchical control for electric power systems." Thesis, City University London, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.379642.

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Garcia, Enoque Dutra. "Previsão de tensão em sistemas de distribuição considerando as possibilidades das redes inteligentes." Universidade Federal de Santa Maria, 2012. http://repositorio.ufsm.br/handle/1/8515.

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With the deployment of Smart Grids, the voltage quality has a new focus, and the ANEEL (National Agency of Electric Energy), Brazilian regulator organ, is able to improve its supervision activity. The electric energy customer has access to the value of voltage in real time and the utility needs to identify alternatives to attend the rigor of the regulatory acts and the intense expectative of its customers. Nowadays, in the conventional networks, the voltage setting is performed from the reference voltage set point of itself or of center of load. In the scenario of Smart Grids, beyond these values, it is also possible to use the online measures at any point of the feeder. In this new scenario it is possible to indentify alternatives related to advances in distribution networks power quality, in this way, the present work shows a methodology to be used as tools of operational support in the control of voltage profile in primary networks. Through application of computational intelligent techniques it is suggested a system of steady state voltage prediction for the monitored points along the feeder. The loading system and meteorological informations are used for the method application. From the result obtained for the very-short time forecasting, it is introduced the concept of Smart Grids, which considers proactive actions to optimize the process of maintenance of voltage level.
Diante da implantação das redes inteligentes, a qualidade da tensão passa a ter um novo enfoque, e a Agência Nacional de Energia Elétrica (ANEEL), órgão regulador brasileiro, tem possibilidade de aprimorar sua atividade fiscalizatória. O usuário de energia elétrica tem acesso ao valor da tensão em tempo real e a distribuidora por sua vez, necessita identificar alternativas para atender ao rigor dos atos regulatórios e a expectativa intensa de seus clientes. Atualmente, nas redes convencionais o ajuste de tensão é realizado a partir da tensão de referência do próprio ponto ou do centro de carga. Já no cenário das redes inteligentes, além destes, também é possível utilizar os registros online das grandezas de outros trechos do alimentador, inclusive pontos a jusante. Neste novo cenário é oportuno identificar alternativas relacionadas ao avanço da qualidade da energia nas redes de distribuição, neste sentido, o presente trabalho apresenta uma metodologia a ser utilizada como ferramenta de apoio operacional no controle do perfil de tensão nas redes primárias. Através da aplicação de técnicas de inteligência computacional é proposto um sistema de previsão de tensão em regime permanente para pontos de monitoramento localizados ao longo do alimentador. Para tanto são utilizados dados do carregamento do sistema e informações meteorológicas. A partir dos resultados obtidos para a previsão no curtíssimo prazo é introduzido o conceito de controle de tensão inteligente, o qual considera a tomada de ações proativas para otimizar o processo de manutenção dos níveis de tensão.

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Moreno, Martinez Rodolfo Manuel. "Estudo de técnicas de controle de fluxo de potência e de gerenciamento de ilhamento em sistemas de geração distribuída com interfaces eletrônicas de potência para conexão com a rede elétrica." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/260867.

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Orientadores: José Antenor Pomilio, Luiz Carlos Pereira da Silva
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação
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Resumo: O presente trabalho estuda problemas do controle de fluxo de potência e de gestão de ilhamento em sistemas de geração distribuída de pequeno porte nos quais a interface com a rede elétrica sejam feitas por meio de conversores eletrônicos de potência. O sistema completo apresenta conversor "on-line", no qual a potência produzida localmente é totalmente processada pelo conversor, juntamente com uma estrutura "interativa com a rede", na qual o conversor opera para manter determinados padrões de desempenho sem, no entanto, processar potência ativa. É também focalizado o problema de qualidade da energia elétrica, analisando-se maneiras de operar os conversores de modo a mitigar problemas relacionados a harmônicos. Além de estudos de modelagem e simulação, avança-se na implementação experimental de algumas das técnicas analisadas
Abstract: This work studies problems of power flow control and islanding management in small power distributed generation systems in which the interface with the grid is made through electronic power converters. The complete system has "on-line" behavior, in which the power produced locally is fully processed by the converter, and also a structure "line-interactive," in which the converter operates to maintain certain performance standards without, however, process active power. It is also focused on the problem of power quality, analyzing ways to operate the converter in order to mitigate problems related to harmonics. In addition to modeling and simulation, some experimental implementation of the proposed techniques are realized
Doutorado
Energia Eletrica
Doutor em Engenharia Elétrica

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Restrepo, Juan Diego Echeverry. "Otimização em tempo real para o controle Volt/VAr em sistemas de distribuição de energia elétrica." Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/3/3143/tde-22092016-104547/.

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Atualmente, as concessionárias de energia enfrentam vários desafios na tentativa de fornecer energia com qualidade e confiabilidade, por exemplo, redes de distribuição com pouco monitoramento e controle, envelhecimento dos ativos, atender a crescente demanda dos consumidores e satisfazer padrões de qualidade, entre outros. No Brasil, para atingir os índices de qualidade no fornecimento de energia estabelecidos pela Agência Nacional de Energia Elétrica (ANEEL), tem-se como alternativa aumentar a inteligência da rede com sistemas de tecnologia de informação (TI), além de utilizar Dispositivos Eletrônicos Inteligentes (IEDs), medidores inteligentes e sensores. Adicionalmente é necessário o emprego de uma infraestrutura de comunicação que forneça uma visibilidade abrangente das condições de carga e do estado do sistema de distribuição, permitindo fazer uso de técnicas de otimização e tomada de decisão para aumento da inteligência. O controle da tensão e o gerenciamento da potência reativa (Volt/VAr) são práticas de automação que podem ser empregadas nos sistemas de distribuição. Estas práticas ajudam a aumentar o benefício, a confiabilidade e a eficiência no fornecimento da qualidade do produto, minimizando os custos de operação e manutenção nas concessionárias. Na presente dissertação foi desenvolvida uma metodologia de controle Volt/VAr descentralizado (subestação), por meio da coordenação e controle dos transformadores com mudança de tap sob carga - LTC, dos bancos de capacitores localizados na subestação e ao longo dos alimentadores, bem como dos reguladores de tensão instalados ao longo dos alimentadores. Destaca-se a utilização da técnica de Estimação de Estados, a qual possibilita o uso da metodologia de controle Volt/VAr em tempo real. O algoritmo de otimização desenvolvido neste trabalho foi implementado através de simulações numa rede teste e numa rede real que permitem mostrar o potencial da formulação matemática desenvolvida. Os resultados da metodologia proposta comprovam a melhoria do perfil de tensão dos alimentadores da rede testada ao longo do dia, assim como uma diminuição das perdas técnicas, as quais chegaram a diminuir 7% em energia. Estes resultados foram alcançados sem ultrapassar a quantidade de operações definidas por dia nos diferentes dispositivos de controle.
Currently, power utilities face challenges in order to provide energy considering minimum requirements of power quality and reliability due to the absence of control and monitoring infrastructure, aging assets, growing demand, amongst others. In Brazil, the Agência Nacional de Energia Elétrica (ANEEL) establishes specific power quality and reliability indices. Power utilities should attend the limits for those indices by improving intelligence of network using IT systems, installing Intelligent Electric Devices (IEDs), smart meters and sensors, amongst others. Additionally, communication infrastructure is needed to provide the monitoring of load conditions and distribution system state. Optimization and decision-making tools are important for developing smart grids. Voltage control and reactive power management (Volt/VAr) are automation techniques that can be used in distribution systems. These practices lead to benefits for the utilities such as improvement of reliability and efficiency of the system, minimization of operation and maintenance costs, amongst others. In the present dissertation a methodology for decentralized control (Volt/VAr) was developed, through the coordination and control of load tap changers (LTCs) in power transformers and capacitors banks located at the substation, as well as capacitor banks and voltage regulators scattered throughout the feeders. State Estimation was utilized, which allows the application of the Volt/VAr Control methodology in real time environment. The optimization algorithm developed in this work was implemented through simulations in a test network and in a real network which validated the proposed methodology showing the potentiality of the mathematical model. The results of the proposed method showed voltage profile improvement over the day for the network tested as well as a 7% decrease in power energy losses. These results were achieved without exceeding the number of operations per day defined for all control devices.

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19

Herbig, Arnim. "On load flow control in electric power systems." Doctoral thesis, KTH, Electric Power Systems, 2000. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-2919.

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Yamamoto, Kazusa. "Control of electromechanical systems, application on electric power steering systems." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT069/document.

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De nos jours, la plupart des véhicules sont équipés de Directions Assistées Electriques (DAE). Ce type de systèmes d'aide à la conduite permet de réduire les efforts que le conducteur doit fournir pour tourner les roues. Ainsi, grâce à un moteur électrique, la DAE applique un couple additionnel en accord avec le comportement du conducteur et la dynamique du véhicule. Il est donc nécessaire de développer une commande en couple basée en particulier sur le signal provenant d'un capteur mesurant le couple agissant au niveau de la barre de torsion (correspondant à une image du couple conducteur). Ce composant est donc essentiel au fonctionnement de la DAE. Or, une défaillance de ce capteur entraine le plus souvent une coupure de l'assistance, pouvant mener à un risque d'accidents. Au regard de la sécurité fonctionnelle, un développement d'un mode de sécurité est recommandé, par de plus en plus de constructeurs automobiles. D'autre part, le marché des équipementiers automobiles reste un secteur très concurrentiel où une baisse des coûts de production est un challenge constamment recherché afin de gagner de nouvelles parts de marchés. Cet aspect de réduction du nombre de capteurs et d'analyse de la dynamique du véhicule s'inscrit donc dans le prolongement de la stratégie de sécurité. Cette thèse, menée au sein de JTEKT Europe, aborde ces divers enjeux. Après une présentation des différents systèmes de directions assistés électriques, des modèles sont présentés pour être utilisés lors de la conception de lois de commande et d'estimateurs. Ensuite deux méthodes d'estimation du couple conducteur sujet aux perturbations de la route et aux bruits de mesures sont proposées : la première est un observateur proportionnel intégral (PI) à synthèse mixte $H_infty/H_2$, et la seconde une approche par filtrage $H_infty$. Puis plusieurs stratégies de commande sont proposées suivant deux cas de figures distincts, soit en utilisant un observateur PI qui estime les états du système et le couple conducteur (LQR, commande LPV par retour d'état), soit en faisant abstraction d'estimateur de couple conducteur (commande $H_infty$ par retour de sortie dynamique). Ce dernier aspect présente l'avantage de nécessiter moins de mesures que le précédent. Ces approches ont été validées en simulation et mises en œuvre sur un véhicule prototype où des résultats prometteurs ont été obtenus
Nowadays, modern vehicles are equipped with more and more driving assistance systems, among them Electric Power Steering (EPS) helps the driver to turn the wheels. Indeed, EPS provides through an electric motor, an additional torque according to the driver's behaviour and the vehicle's dynamics to reduce the amount of effort required to the driver. Therefore, a torque control is developed based on the torque sensor signal which measures in practice the torsion bar torque (corresponding to an image of the driver torque). Consequently, this component is essential to the functioning of EPS systems.Indeed, a torque sensor failure usually leads to shut-off the assistance which may increase the risk of accident. Regarding functional safety, a back-up mode is recommended and required by more and more car manufacturers. On the other hand, a major challenge for automotive suppliers is to reduce cost production in order to meet growing markets demands and manage in the competitive sector. This issue considering a reduction of sensors' numbers and analysis of vehicle's dynamics is therefore an extension of applying the safety strategy. This thesis, carried out within JTEKT Europe, addresses these various issues.After introducing an overview of the different EPS systems, some models used for the design of controllers and estimators are presented. Then, two methods to estimate the driver torque subject to road disturbances and noise measurements are proposed: the first is a proportional integral observer (PI) with mixed synthesis $H_infty / H_2 $, whereas the second is an $ H_infty $ filtering approach. Then, several control strategies are proposed according to two different cases, either by using a PI observer which estimates the system states and the driver torque (LQR, LPV feedback control) or by not taking into account the driver torque estimation ($ H_infty $dynamic output feedback control). This latter approach has the advantage to require less measurements than the previous one. These approaches have been validated in simulation and implemented on a prototype vehicle where promising results have been obtained

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21

Jiang, Haibo. "Robust control strategies for the transient control of interconnected power systems." Diss., Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/15728.

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22

Bachry, Andrzej. "Power quality studies in distribution systems involving spectral decomposition." Magdeburg : Univ, 2004. http://www.loc.gov/catdir/toc/fy0604/2005390390.html.

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Khare, Rahul. "An operator assistant for emergency control of large-scale power systems /." Thesis, Connect to this title online; UW restricted, 1997. http://hdl.handle.net/1773/6123.

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Watson, Robert V. "Mains power quality improvement using active filters." Thesis, University of South Wales, 2009. https://pure.southwales.ac.uk/en/studentthesis/mains-power-quality-improvement-using-active-filters(e798030f-aca0-49c1-b85f-c9cb856109bb).html.

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25

Torres, Neto Floriano. "Cálculo de fluxo de potência em alimentadores de distribuião baseado em tensões nodais e de ramos." [s.n.], 2010. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261969.

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Orientador: Anésio dos Santos Júnior
Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
Made available in DSpace on 2018-08-16T14:59:47Z (GMT). No. of bitstreams: 1 TorresNeto_Floriano_M.pdf: 6057035 bytes, checksum: 2cdfde24e040137be367f6b427f6a38e (MD5) Previous issue date: 2010
Resumo: Propõe-se nesta dissertação uma formulação e um método iterativo de cálculo para o fluxo de potência em alimentadores primários de Distribuição de Energia Elétrica. Este é formulado com base em equações lineares de circuitos elétricos, para alimentadores primários radiais e fracamente malhados. Para tanto, um modelo linear de circuito é inicialmente introduzido para alimentadores radiais e a partir desse modelo é proposto um método para o cálculo das magnitudes de tensão dos nós por meio das correntes de carga. As magnitudes das tensões nodais são iterativamente atualizadas até que as especificações de potência das cargas sejam atendidas. Essa formulação é estendida para os casos de redes fracamente malhadas, isto é, alimentadores que contém um moderado número de percursos fechados em sua configuração. Desta forma unifica-se o modelo de representação e o algoritmo de cálculo para redes radiais e fracamente malhadas. A metodologia proposta foi testada e o comportamento do método é comparado com o apresentado por método similar. Os resultados obtidos com vários sistemas são apresentados
Abstract: It is proposed in this work a formulation and an iterative method for calculating the power flow on feeders of a Primary Electric Power Distribution. This is formulated based on linear equations of electrical circuits, for radial and weakly meshed primary feeders. Thus, a linear model of the circuit is initially introduced for radial feeders and from that model it is proposed a method for calculating the voltage magnitudes of the nodes through the load currents. The magnitudes of nodal voltages are updated iteratively until the power specifications of the loads are met. This formulation is extended to the cases of weakly meshed networks, that is, networks that contain a moderate number of closed paths in your configuration. Thus the model unifies the representation and algorithm for calculating radial networks and weakly meshed. The proposed methodology was tested and compared with a similar method. The results obtained with various systems are presented
Mestrado
Energia Eletrica
Mestre em Engenharia Elétrica

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26

Chan, Ting. "Analytical methods for power monitoring and control in an underwater observatory /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/6053.

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Cote, James W. "Voltage security assessment and control in electric power systems /." Thesis, Connect to this title online; UW restricted, 1992. http://hdl.handle.net/1773/5925.

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28

Cheung, Siu-pan. "Direct transient stability margin assessment of power system with excitation control and SVC control /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B1753706X.

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29

Parsons, Antony Cozart. "Automatic location of transient power quality disturbances /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.

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30

Tan, Pee-Chin 1975. "A VSI-based power quality conditioner for 25kV electrified railway systems." Monash University, Dept. of Electrical and Computer Systems Engineering, 2003. http://arrow.monash.edu.au/hdl/1959.1/5537.

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31

張小彬 and Siu-pan Cheung. "Direct transient stability margin assessment of power system with excitation control and SVC control." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31212979.

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32

Menezes, Ramon Maciel. "Desenvolvimento de um sistema distribuído de identificação em tempo real de parâmetros de qualidade de energia elétrica." Universidade Tecnológica Federal do Paraná, 2012. http://repositorio.utfpr.edu.br/jspui/handle/1/508.

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CNPq, CAPES
O presente trabalho inclui a revisão das normas de qualidade de energia elétrica, a fim de normatizar o desenvolvimento do projeto seguindo normas nacionais e internacionais; a simulação de algoritmos como CFA e FFT, a fim de verificar a viabilidade de seu uso, bem como as limitações associadas ao processamento de formas de onda fortemente distorcidas. Inclui também a proposição e a verificação de um algoritmo capaz de calcular os índices (selecionados durante a revisão das normas) que pudessem avaliar a qualidade de energia através de sinais de tensão e corrente. Para o desenvolvimento do protótipo, foram selecionados sensores de tensão e de corrente confiáveis para o sistema de aquisição; um DSP, que executa os algoritmos previamente simulados, processando em tempo real os sinais adquiridos pelos sensores, a fim de reportar o estado da rede elétrica e/ou eventos ocorridos na rede através de um módulo ZigBee, responsável pela transmissão desses dados de forma segura. A classe de eventos de variação de tensão de curta duração foi incluída no processamento em tempo real realizado pelo DSP. Devido à imprevisibilidade e à rapidez da ocorrência desses eventos, foi desenvolvida uma ferramenta capaz de gerar essa classe de eventos, o gerador de VTCD. A análise de QEE em tempo real se mostrou viável mesmo com a utilização de dispositivos de baixo custo, permitindo, ainda que com algumas limitações, o levantamento de informações de QEE às quais cargas conhecidas estavam submetidas.
The present document includes a comprehensive literature review on power quality issues, to keep the development of this project aligned with national and international standards related; simulation algorithms such as FFT and CFA in order to verify the feasibility of its use, as well as limitations associated with the processing of strongly distorted waveform. It also includes the proposal and verification of an algorithm able to calculate the indices (selected during the standards review) that could assess the power quality through voltage and current signals. For prototype development, voltage and current sensors were selected for reliable acquisition system; a DSP, which running the previously simulated algorithms in order to process in real time the acquired voltage and current signals provided by sensors in order to report the status of the mains grid and/or events occurrence on the network through a ZigBee module, responsible for safety transmission data. The short term voltage change events class was also included in the real time processing performed by the DSP. Due to the unpredictability and short duration of these events, it was developed a tool capable of generating this class of events, the STVC generator. The PQ analysis in real time was feasible even with the use of low cost devices, allowing, although with some limitations, the survey of PQ information which known loads was submitted.

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33

Lee, Seung Jae. "Configuration control of distribution feeders in normal and emergency states /." Thesis, Connect to this title online; UW restricted, 1988. http://hdl.handle.net/1773/5923.

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Alvarez, Rogelio E. "Interdicting electrical power grids." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Mar%5FAlvarez.pdf.

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Thesis (M.S. in Operations Research)--Naval Postgraduate School, March 2004.
Thesis advisor(s): Javier Salmeron, R. Kevin Wood. Includes bibliographical references (p. 69-70). Also available online.

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35

Choi, Byungcho. "Dynamics and control of switchmode power conversions in distributed power systems." Diss., This resource online, 1992. http://scholar.lib.vt.edu/theses/available/etd-06062008-171616/.

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36

Hu, Dongchen. "A wide-area control for mitigating angle instability in electric power systems." Online access for everyone, 2006. http://www.dissertations.wsu.edu/Thesis/Fall2006/d_hu_091406.pdf.

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37

Wang, Min. "Pattern recognition methodology for network-based diagnostics of power quality problems /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/6099.

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38

Gonçalves, de Oliveira Janaína. "Power Control Systems in a Flywheel based All-Electric Driveline." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-157074.

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Flywheel systems are attractive in hybrid and electric vehicles due to their ability to handle power during acceleration and braking. The combination of a flywheel device with a battery source has several advantages such as high peak power capacity, high energy density and reduction in the number of charge/discharge cycles of the battery. A flywheel based all-electric driveline is investigated in this thesis. The novelty of the system consists in the use of a double wound flywheel machine, which divides the system in two different power levels. Due to this configuration, the system becomes efficient and can handle the power developed during fast dynamical processes. The complete driveline consists of three main components: the battery, the flywheel machine and the wheel motor. The High-Power (HP) side of the driveline connects the flywheel machine to the wheel motor, whereas the Low-Power (LP) side connects the flywheel machine to the battery. The connections of different components of the system are made electrically through power converter devices. The present thesis focuses on the electrical converters and control strategies used in the flywheel based all-electric driveline. The control of power converters is responsible for the logic and functionality of the driveline, being a challenging step within this project. Different power converter topologies have been investigated: a DC/DC plus a DC/AC converter on the LP side, and an AC/DC/AC converter on the HP side. The design and assembly of the power electronics and their control scheme have been successfully implemented. Different control strategies have been suggested and a complete scaled driveline has been assembled and tested based on previous simulation results. Results have confirmed the functionality of the driveline, where smoothed output power has been obtained from the battery, whereas the flywheel handles power transients on the traction side. An average efficiency of about 87% (battery to wheels) has been obtained. The power converter systems have been shown to be efficient and robust, with control strategies able to handle the peak energy flow in the system. A regenerative braking strategy has been simulated and a wheel-to-wheel efficiency of about 80% has been estimated.

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Eidson, Donald Brian. "Estimation and hierarchical control of market-driven electric power systems." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/11068.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.
Includes bibliographical references (leaves 328-337).
by Donald Brian Eidson.
Ph.D.

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40

Yu, Chien-Ning 1970. "Real power and frequency control of large electric power systems under open access." Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/38154.

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41

Atić, Nedz̆ad. "Model predictive control design for load frequency control problem." Morgantown, W. Va. : [West Virginia University Libraries], 2003. http://etd.wvu.edu/templates/showETD.cfm?recnum=3192.

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Thesis (M.S.)--West Virginia University, 2003.
Title from document title page. Document formatted into pages; contains vii, 68 p. : ill. Includes abstract. Includes bibliographical references (p. 66-68).

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42

曾坤明 and Kwan-ming Tsang. "Decoupling and stabilizing control of multi-machine power systems withstatic VAr compensators." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1993. http://hub.hku.hk/bib/B31211008.

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43

Kirawanich, Phumin. "Fuzzy logic control for an active power line conditioner /." free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060114.

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44

Radan, Damir. "Integrated Control of Marine Electrical Power Systems." Doctoral thesis, Norwegian University of Science and Technology, Faculty of Engineering Science and Technology, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-1984.

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This doctoral thesis presents new ideas and research results on control of marine electric power system.

The main motivation for this work is the development of a control system, power management system (PMS) capable to improve the system robustness to blackout, handle major power system faults, minimize the operational cost and keep the power system machinery components under minimal stress in all operational conditions.

Today, the electric marine power system tends to have more system functionality implemented in integrated automation systems. The present state of the art type of tools and methods for analyzing marine power systems do only to a limited extent utilize the increased knowledge available within each of the mechanical and electrical engineering disciplines.

As the propulsion system is typically consisted of the largest consumers on the vessel, important interactions exists between the PMS and vessel propulsion system. These are interacted through the dynamic positioning (DP) controller, thrust allocation algorithm, local thruster controllers, generators' local frequency and voltage controllers. The PMS interacts with the propulsion system through the following main functions: available power static load control, load rate limiting control and blackout prevention control (i.e. fast load reduction). These functions serve to prevent the blackout and to ensure that the vessel will always have enough power.

The PMS interacts with other control systems in order to prevent a blackout and to minimize operational costs. The possibilities to maximize the performance of the vessel, increase the robustness to faults and decrease a component wear-out rate are mainly addressed locally for the individual control systems. The solutions are mainly implicative (for e.g. local thruster control, or DP thrust allocation), and attention has not been given on the interaction between these systems, the power system and PMS. Some of the questions that may arise regarding the system interactions, are as follows: how the PMS functionality may affect a local thruster control, how the local thruster control may affect the power system performance, how some consumers may affect the power system performance in normal operations and thus affect other consumers, how the power system operation may affect the susceptibility to faults and blackout, how various operating and weather conditions may affect the power system performance and thus propulsion performance though the PMS power limiting control, how propulsion performance may affect the overall vessel performance, which kind of faults can be avoided if the control system is re-structured, how to minimize the operational costs and to deal with the conflicting goals. This PhD thesis aims to provide answers to such questions.

The main contributions of this PhD thesis are:

− A new observer-based fast load reduction system for the blackout prevention control has been proposed. When compared to the existing fast load reduction systems, the proposed controller gives much faster blackout detection rate, high reliability in the detection and faster and more precise load reduction (within 150 miliseconds).

− New advanced energy management control strategies for reductions in the operational costs and improved fuel economy of the vessel.

− Load limiting controllers for the reduction of thruster wear-out rate. These controllers are based on the probability of torque loss, real-time torque loss and the thruster shaft

accelerations. The controllers provide means of redistributing thrust from load fluctuating thrusters to less load fluctuating ones, and may operate independently of the thrust allocation system. Another solution is also proposed where the load limiting controller based on thrust losses is an integrated part of DP thrust allocation algorithm.

− A new concept of totally integrated thrust allocation system, local thruster control and power system. These systems are integrated through PMS functionality which is contained within each thruster PLC, thereby distributed among individual controllers, and independent of the communications and dedicated controllers.

− Observer-based inertial controller and direct torque-loss controller (soft anti-spin controller) with particular attention to the control of machine wear-out rate. These controller contribute to general shaft speed control of electrical thrusters, generators and main propulsion prime movers.

The proposed controllers, estimators and concepts are demonstrated through time-domain simulations performed in MATLAB/SIMULINK. The selected data are typical for the required applications and may differ slightly for the presented cases.

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45

Eriksson, Robert. "Security-centered Coordinated Control in AC/DC Transmission Systems." Licentiate thesis, Stockholm : Royal Institute of Technology, 2008. http://kth.diva-portal.org/smash/record.jsf?searchId=4&pid=diva2:101.

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46

ABDULLA, ABDULLA I. M. "SOME NEW TECHNIQUES FOR THE LOAD FREQUENCY CONTROL OF MULTI-AREA POWER SYSTEMS." Diss., The University of Arizona, 1986. http://hdl.handle.net/10150/183902.

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In this dissertation, the problem of multi-area load frequency control in large power systems is investigated. The load frequency control problem is concerned with the minimization of the deviations in the frequencies of the different areas and in the tie line power exchange between these areas, and is a problem of major importance in the satisfactory operation of large power systems. Some new techniques for designing load frequency control systems are presented through the use of concepts from singular perturbation and hierarchical system theory. To provide appropriate vehicles for the design of the new control systems, state variable models for power systems are developed. These models progress from a two-area interconnected power system model to large scale models comprising of N areas. Two centralized state feedback schemes are proposed for the load frequency control by utilizing the separation of the system models into two time scales. In the first scheme, composite controls and reduced order controls are developed to meet the required performance specifications by. The second scheme is obtained by using the theory of variable structure systems where the existence of a sliding regime leads to the design of a single discontinuous state feedback controller that meets the performance requirements. In order to further improve the performance of the closed loop system, a two level hierarchical control scheme is developed. This consists of a set of local controllers that are designed using either the singular perturbation approach or the variable structure system approach as before and a set of global control functions provided by a higher level controller that attempts to coordinate the local controllers. The interaction prediction principle is used as a tool in the design of the global controller. The performance of the presently developed control schemes is examined in detail for the illustrative cases of a two-area and a three-area power system. From this analysis, it is shown that these controllers provide an improved performance compared to the existing control schemes in reducing the frequency and tie line power deviations.

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47

Jung, Ju-Hwan. "Intelligent systems for strategic power infrastructure defense /." Thesis, Connect to this title online; UW restricted, 2002. http://hdl.handle.net/1773/5971.

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48

Liu, Xiaojun Zhang. "Structural modeling and hierarchical control of large-scale electric power systems." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/12034.

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49

Begovic, Miroslav M. "Analysis, monitoring and control of voltage stability in electric power systems." Diss., Virginia Polytechnic Institute and State University, 1989. http://hdl.handle.net/10919/54490.

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The work presented in this text concentrates on three aspects of voltage stability studies: analysis and determination of suitable proximity indicators, design of an effective real-time monitoring system, and determination of appropriate emergency control techniques. A simulation model of voltage collapse was built as analytical tool on 39-bus, 10-generator power system model. Voltage collapse was modeled as a saddle-node bifurcation of the system dynamic model reached by increasing the system loading. Suitable indicators for real-time monitoring were found to be the minimum singular value of power flow Jacobian matrix and generated reactive powers. A study of possibilities for reducing the number of measurements of voltage phasors needed for voltage stability monitoring was also made. The idea of load bus coherency with respect to voltage dynamics was introduced. An algorithm was presented which determines the coherent clusters of load buses in a power system based on an arbitrary criterion function, and the analysis completed with two proposed coherency criteria. Very good agreement was obtained by simulation between the results based on accurate and approximate measurements of the state vector. An algorithm was presented for identification of critical sets of loads in a voltage unstable power system, defined as a subset of loads whose changes have the most pronounced effect on the changes of minimum singular value of load flow Jacobian or generated reactive powers. Effects of load shedding of critical loads were investigated by simulation and favorable results obtained. An investigation was also done by sensitivity analysis of proximity indicators of the effects that locations and amounts of static var compensation have on the stability margin of the system. Static compensation was found to be of limited help when voltage instabilities due to heavy system loading occur in power systems. The feasibility of implementation of the analyses and algorithms presented in this text relies on development of a feasible integrated monitoring and control hardware. The phasor measurement system which was designed at Virginia Polytechnic institute and State University represents an excellent candidate for implementation of real-time monitoring and control procedures.
Ph. D.

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Godart, Thierry F. "An expert system approach to voltage control design and operation in power systems." Diss., Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/15787.

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Dissertations / Theses on the topic 'Electric power systems – Quality control'

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