Resumo: Este projeto de pesquisa tem por objetivo apresentar propostas para aprimoramento das principais normas e resoluções envolvidas, dentre as quais o PRODIST, quanto à metodologia para apuração do indicador de distorçõ de tensão harmôica total, bem como trazer contribuições para o processo de análise de compatibilidade de cargas potencialmente perturbadoras na qualidade da energia elétrica em sistemas de distribuição, através de uma visão proativa, ou seja, atuando principalmente no momento que antecede a instalação destas cargas. Estas propostas foram elaboradas a partir da análise e discussão dos resultados obtidos através dos ensaios realizados em um estudo de caso compreendendo a análise de ligação de um novo forno de indução em uma Fundição atendida por uma concessionárias de distribuição do Estado de São Paulo. Um histórico geral situando a qualidade da energia elétrica no setor elétrico é apresentado, as principais normas, resoluções e estudos técnicos são discutidos, e as diretrizes metodológicas e procedimentos utilizados nos ensaios experimentais são detalhados. A análise e discussão dos resultados é elaborada procurando responder às principais perguntas surgidas durante a investigação técnico-científica e a realização dos procedimentos, bem como indicando outros questionamentos a serem estudados, através da apresentação das propostas e indicações para trabalhos futuros / Abstract: This research project aims to present proposals for improvement of key standards and resolutions involved, among which the PRODIST, on the methodology for calculating the indicator of voltage total harmonic distortion, and should contribute to the analysis process of the potentially disturbance impacts of loads on power quality in distribution system, through a proactive vision, ie, working mainly in the moment before the installation of these loads. Those proposals were developed from the analysis and discussion of results obtained through tests on a case study including analysis of the connection of a new induction furnace in a froundry fed by a distribution utility in the State of São Paulo. A general historical situating the quality of electric energy in the sector is presented, the main standards, technical studies and resolutions are discussed, and methodological guidelines and procedures used in experimental trials are detailed. The analysis and discussion of results is prepared to answer the main questions that arise during the technical-scientific research and implementation of procedures as well as indicating other questions to be studied through the submition of proposals and directions for future work / Orientador: André Nunes de Souza / Coorientador: André Christóvão Pio Martins / Banca: Benedito Donizeti Bonatto / Banca: Pedro da Costa Junior / Mestre

Este trabalho apresenta um estudo da literatura pertinente sobre qualidade da energia elétrica. O estudo apresentado está baseado na evolução do tema em nível nacional e internacional, buscando explicar o conceito dos principais fenômenos e selecionar as recentes resoluções e normas que regem os princípios de medição e os limites dos distúrbios eletromagnéticos que os caracterizam. As normas da IEC foram selecionadas para a aplicação na construção de um protótipo de um medidor de qualidade da energia elétrica, onde o princípio construtivo é o de instrumento virtual por sua flexibilidade de arquitetura. A implementação do protótipo dá-se em um microcomputador padrão de mercado pelo software LabVIEW, através de vários módulos independentes para cada distúrbio a ser medido. Os resultados numéricos das simulações executadas frente a cada distúrbio, gerando comparações entre valores aplicados e valores medidos são apresentados em forma de tabelas com seus respectivos erros percentuais para cada grandeza de cada módulo. / This dissertation presents a study of existing literature about power quality. The study presented is based on a theme evolution in national and international environment, trying to explain the main phenomenon conceptions and select the most recent standards that rule the measurement conceptions and the electromagnetic disturbances limits that characterize it. The IEC standard were selected to build a prototype of a power quality measure device where the construction conception is a virtual instrument because it has a flexible architecture. The prototype implementation was made from a common computer by the LabVIEW software through some independent modules for each disturbance to be measured. The numerical results of executed simulations of each disturbance generating comparisons between applied values and measured values are presented as tables within their percentage error for each phenomenon of each module.

Made available in DSpace on 2014-06-11T19:22:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-25Bitstream added on 2014-06-13T18:49:36Z : No. of bitstreams: 1 torrezan_r_me_bauru.pdf: 1668461 bytes, checksum: ae59290a98e522168089dfc069101ce7 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este projeto de pesquisa tem por objetivo apresentar propostas para aprimoramento das principais normas e resoluções envolvidas, dentre as quais o PRODIST, quanto à metodologia para apuração do indicador de distorçõ de tensão harmôica total, bem como trazer contribuições para o processo de análise de compatibilidade de cargas potencialmente perturbadoras na qualidade da energia elétrica em sistemas de distribuição, através de uma visão proativa, ou seja, atuando principalmente no momento que antecede a instalação destas cargas. Estas propostas foram elaboradas a partir da análise e discussão dos resultados obtidos através dos ensaios realizados em um estudo de caso compreendendo a análise de ligação de um novo forno de indução em uma Fundição atendida por uma concessionárias de distribuição do Estado de São Paulo. Um histórico geral situando a qualidade da energia elétrica no setor elétrico é apresentado, as principais normas, resoluções e estudos técnicos são discutidos, e as diretrizes metodológicas e procedimentos utilizados nos ensaios experimentais são detalhados. A análise e discussão dos resultados é elaborada procurando responder às principais perguntas surgidas durante a investigação técnico-científica e a realização dos procedimentos, bem como indicando outros questionamentos a serem estudados, através da apresentação das propostas e indicações para trabalhos futuros / This research project aims to present proposals for improvement of key standards and resolutions involved, among which the PRODIST, on the methodology for calculating the indicator of voltage total harmonic distortion, and should contribute to the analysis process of the potentially disturbance impacts of loads on power quality in distribution system, through a proactive vision, ie, working mainly in the moment before the installation of these loads. Those proposals were developed from the analysis and discussion of results obtained through tests on a case study including analysis of the connection of a new induction furnace in a froundry fed by a distribution utility in the State of São Paulo. A general historical situating the quality of electric energy in the sector is presented, the main standards, technical studies and resolutions are discussed, and methodological guidelines and procedures used in experimental trials are detailed. The analysis and discussion of results is prepared to answer the main questions that arise during the technical-scientific research and implementation of procedures as well as indicating other questions to be studied through the submition of proposals and directions for future work

Este trabalho apresenta um estudo da literatura pertinente sobre qualidade da energia elétrica. O estudo apresentado está baseado na evolução do tema em nível nacional e internacional, buscando explicar o conceito dos principais fenômenos e selecionar as recentes resoluções e normas que regem os princípios de medição e os limites dos distúrbios eletromagnéticos que os caracterizam. As normas da IEC foram selecionadas para a aplicação na construção de um protótipo de um medidor de qualidade da energia elétrica, onde o princípio construtivo é o de instrumento virtual por sua flexibilidade de arquitetura. A implementação do protótipo dá-se em um microcomputador padrão de mercado pelo software LabVIEW, através de vários módulos independentes para cada distúrbio a ser medido. Os resultados numéricos das simulações executadas frente a cada distúrbio, gerando comparações entre valores aplicados e valores medidos são apresentados em forma de tabelas com seus respectivos erros percentuais para cada grandeza de cada módulo. / This dissertation presents a study of existing literature about power quality. The study presented is based on a theme evolution in national and international environment, trying to explain the main phenomenon conceptions and select the most recent standards that rule the measurement conceptions and the electromagnetic disturbances limits that characterize it. The IEC standard were selected to build a prototype of a power quality measure device where the construction conception is a virtual instrument because it has a flexible architecture. The prototype implementation was made from a common computer by the LabVIEW software through some independent modules for each disturbance to be measured. The numerical results of executed simulations of each disturbance generating comparisons between applied values and measured values are presented as tables within their percentage error for each phenomenon of each module.

Demand for electrical power is increasing everyday. Along with the increase in power demand, the characteristics of the loads are also changing. From being high power consuming, simple, robust loads, today loads are more efficient, but at the same time more sensitive. The performance and life of these highly sensitive loads depend a lot on the quality of power supplied to them. <p>Power quality is any deviation of the voltage or current waveform from its normal sinusoidal waveshape. These disturbances include, but are not limited to, sag, undervoltage, interruption, swell, overvoltage, transients, harmonics, voltage flicker and any other distortions to the sinusoidal waveform. Occurrence of one or more of such disturbances is called a power quality event. Automatic classification of these disturbances is important for quick determination of the causes and to characterize possible impacts of the disturbances.<p>Modern microprocessor based protective relays have numerous integrated functions that allow them to provide information on power quality events. It is proposed to utilize the existing numerical relays to analyze the quality of power at any point in the power system. The numerical relays can be programmed to capture the oscillographic waveform or any disturbance on the analogue signal or change of state of the digital signals and store it in the form of Common Format For Transient Data Exchange (COMTRADE) format. These records are then transferred to a central monitoring workstation for off-line analysis. <p>This thesis describes a technique to automate the classification and analysis of the power quality events using relay recorded data. The technique uses voltage duration and magnitude (as specified in the IEEE Std. 1159 - 1995, IEEE Recommended Practice for Monitoring Electric Power Quality) of three phases to detect and classify the events. The classified results are then presented in a user-friendly graphical form. Fast Fourier Transform (FFT) is used to estimate the fundamental frequency and harmonic components in power systems. The graphical user interface of the power quality analysis tool is developed using Microsoft Visual C++ IDE and the algorithms are programmed in C++. <p>The proposed technique was tested using data obtained by simulating different power system disturbances as well as on the data recorded by relays. The algorithms were able to classify the power quality events accurately. In the future, this facility will: enhance the real time monitoring of power quality and provide statistical analysis of available power quality data. From the utility viewpoint, it would allow them to monitor power quality in a cost effective manner and assist in preventive and predictive maintenance besides helping them to fix differential tariff based on the quality of the delivered power. It may also turn out to be a smart tool for them to penalize the consumer polluting the power quality.

Demand for electrical power is increasing everyday. Along with the increase in power demand, the characteristics of the loads are also changing. From being high power consuming, simple, robust loads, today loads are more efficient, but at the same time more sensitive. The performance and life of these highly sensitive loads depend a lot on the quality of power supplied to them. <p>Power quality is any deviation of the voltage or current waveform from its normal sinusoidal waveshape. These disturbances include, but are not limited to, sag, undervoltage, interruption, swell, overvoltage, transients, harmonics, voltage flicker and any other distortions to the sinusoidal waveform. Occurrence of one or more of such disturbances is called a power quality event. Automatic classification of these disturbances is important for quick determination of the causes and to characterize possible impacts of the disturbances.<p>Modern microprocessor based protective relays have numerous integrated functions that allow them to provide information on power quality events. It is proposed to utilize the existing numerical relays to analyze the quality of power at any point in the power system. The numerical relays can be programmed to capture the oscillographic waveform or any disturbance on the analogue signal or change of state of the digital signals and store it in the form of Common Format For Transient Data Exchange (COMTRADE) format. These records are then transferred to a central monitoring workstation for off-line analysis. <p>This thesis describes a technique to automate the classification and analysis of the power quality events using relay recorded data. The technique uses voltage duration and magnitude (as specified in the IEEE Std. 1159 - 1995, IEEE Recommended Practice for Monitoring Electric Power Quality) of three phases to detect and classify the events. The classified results are then presented in a user-friendly graphical form. Fast Fourier Transform (FFT) is used to estimate the fundamental frequency and harmonic components in power systems. The graphical user interface of the power quality analysis tool is developed using Microsoft Visual C++ IDE and the algorithms are programmed in C++. <p>The proposed technique was tested using data obtained by simulating different power system disturbances as well as on the data recorded by relays. The algorithms were able to classify the power quality events accurately. In the future, this facility will: enhance the real time monitoring of power quality and provide statistical analysis of available power quality data. From the utility viewpoint, it would allow them to monitor power quality in a cost effective manner and assist in preventive and predictive maintenance besides helping them to fix differential tariff based on the quality of the delivered power. It may also turn out to be a smart tool for them to penalize the consumer polluting the power quality.

Krav på överföringen av el ställs i föreskrifter och standarder för att hålla störande elkvalitetsparametrar inom godtagbara nivåer i nätet. På senare år har användandet av elnätet förändrats med nya belastningar, distribuerad generering och en ökande mängd kraftelektronik. Detta bidrar till ett ökat behov att utföra kontinuerlig övervakning av parametrar som kan orsaka problem för kund och nätägare. I samband med installationen av de nya ”smarta elmätarna” hos kunder finns möjligheten att få utökad elkvalitetsövervakning i stora delar av nätet. Till följd av detta har Geab valt att se över sin elkvalitetsövervakning. I denna rapport ligger fokus på vilka parametrar som ska övervakas, var i nätet de ska övervakas och hur man kan bedriva detta effektivt med en bra täckning av nätet. Syftet med denna övervakning är primärt att verifiera att nätet uppfyller standard. Men andra fördelar finns, bland annat kan åtgärder vidtas i ett område innan gränsvärden överskrids. Det går även att använda utrustningen för störningsanalys. I denna rapport sammanställs vilka parametrar som ska övervakas och vilka krav som gäller för mätutrustning vid mätning av elkvalitet enligt standard och föreskrift. Förslag ges även på var och hur mätning kan utföras. Sju mätsystem har jämförts utifrån dessa parametrar. Baserat på resultatet rekommenderas att fasta mätare installeras i fördelningsstationer på nedsidan av mellanspänningstransformatorn, i kombination med smarta elmätare i nätstation och i anslutningspunkt mot kund i lågspänningsnät. Detta för att få en kostnadseffektiv täckning och hantering av elkvalitetsövervakning i nätet. På grund av det stora antalet mätinstrument bör övervakning av elkvaliteten ske med hjälp av gränsvärdesövervakning och automatiskt genererade rapporter. Detta minskar hanteringstid för personal då portabla mätare inte behöver monteras men även då systemet behandlar den insamlade informationen på egen hand. Eftersom gränsvärdesövervakning kan missa vissa avvikelser bör även stickprov utföras för att verifiera den automatiska övervakningen. / Requirements for the transmission of electricity are set in regulations and standards to keep disruptive power quality parameters in the grid within acceptable levels. In recent years, the use of the electrical grid has changed with new loads, distributed generation, and an increasing amount of power electronics. This contributes to an increased need to perform continuous monitoring of parameters that can cause problems for customers and network owners. With the installation of the new ”smart meters” at customers connection point, there is the possibility of having extended power quality monitoring in large parts of the network. As a result, Geab has chosen to review its power quality monitoring. This report focuses on which parameters are to be monitored, where to monitor and how this can be done effectively with good coverage of the network. The purpose of this monitoring is primarily to verify that the network meets the requirements. But there are other advantages, for example, steps can be taken before a limit value is exceeded in an area. It is also possible to use the equipment for analyzing disturbances. This report summarizes which parameters to monitor and which requirements apply to measuring equipment when measuring power quality in accordance with standards and regulations. Suggestions are also given on where and how measurement can be performed. Seven measurement systems have been compared based on these parameters. Based on the results, the recommendation is that fixed meters be installed in substations on the medium voltage side of the transformer, in combination with "smart meters" in distribution substations and at the connection point to the customer in the low voltage network. This will result in cost-effective coverage and management of power quality monitoring in the network. Due to a large number of measuring instruments, monitoring of power quality should take place with the help of automatic limit monitoring and automatically generated reports. This approach will give alarms/warnings if any parameter exceeds its limit. This reduces handling time for personnel as portable meters do not need to be installed but also when the system processes the collected information on its own. Since automatic detection of exceeded limit values may miss certain deviations, random sampling should be performed to verify the automatic monitoring.

Cellular networks in Africa have grown exponentially over the past 10 years and their data centres (DCs) on average consume 3 MW of electrical power. They require a reliable electrical power supply and can have a downtime loss of over a million dollars per hour. Power quality, reliability and availability have emerged as key issues for the successful operation of a data centre. Investigations are carried out into emerging technologies and their application in data centre power distribution systems for cellular networks in Africa. Best practices are applied to develop a power distribution system (PDS) with the objective of achieving optimal reliability and availability. Analytical techniques are applied to determine and compare the reliability and availability of various power systems. Minimal cut set simulations identify system weak points and confirm component selection. Components’ inherent characteristics (CIC) and system connectivity topology (SCT) are key factors in the improvement of data centre availability. The analysis practices can be used by engineers and managers as a basis for informed decision making in determining power system reliability and the availability of an existing or a new data centre design. Weak points in the PDS of a data centre causing downtime are identified through analysis, and accurate solutions can be determined to prevent or minimise downtime. System connectivity topology (SCT) techniques were identified that could increase the reliability and availability of data centres for cellular networks in Africa. These techniques include multiple incomers from the utility company, redundancy levels of critical equipment and parallel distribution paths. Two case studies were carried out on data centres for a cellular network, one in Nigeria and one in Cameroon. The reliability and availability of both data centres was improved, with substantial reduction in downtime per year. The outcome of the case studies shows the importance of designing and implementing the power distribution system with sufficient levels of redundancy for critical equipment, and parallel distribution paths. / MSc (Engineering Sciences in Nuclear Engineering), North-West University, Potchefstroom Campus, 2014

Cellular networks in Africa have grown exponentially over the past 10 years and their data centres (DCs) on average consume 3 MW of electrical power. They require a reliable electrical power supply and can have a downtime loss of over a million dollars per hour. Power quality, reliability and availability have emerged as key issues for the successful operation of a data centre. Investigations are carried out into emerging technologies and their application in data centre power distribution systems for cellular networks in Africa. Best practices are applied to develop a power distribution system (PDS) with the objective of achieving optimal reliability and availability. Analytical techniques are applied to determine and compare the reliability and availability of various power systems. Minimal cut set simulations identify system weak points and confirm component selection. Components’ inherent characteristics (CIC) and system connectivity topology (SCT) are key factors in the improvement of data centre availability. The analysis practices can be used by engineers and managers as a basis for informed decision making in determining power system reliability and the availability of an existing or a new data centre design. Weak points in the PDS of a data centre causing downtime are identified through analysis, and accurate solutions can be determined to prevent or minimise downtime. System connectivity topology (SCT) techniques were identified that could increase the reliability and availability of data centres for cellular networks in Africa. These techniques include multiple incomers from the utility company, redundancy levels of critical equipment and parallel distribution paths. Two case studies were carried out on data centres for a cellular network, one in Nigeria and one in Cameroon. The reliability and availability of both data centres was improved, with substantial reduction in downtime per year. The outcome of the case studies shows the importance of designing and implementing the power distribution system with sufficient levels of redundancy for critical equipment, and parallel distribution paths. / MSc (Engineering Sciences in Nuclear Engineering), North-West University, Potchefstroom Campus, 2014

The concentration of this work is in estimating fault locations in power systems. After describing the basic concepts of fault locating methods, this work describes improving the fault location estimates, applying the fault locating methods, and implementing the methods in a software. Every work described in the Chapter will be evaluated whether by actual field data or simulated data based on field parameters. / text