No contexto de Smart Grids, determinar a correta localização das fontes causadoras de Variação de Tensão de Curta Duração (VTCD) não é uma tarefa simples, devido à curta duração destes eventos e também, por sua rápida propagação nas redes de distribuição de energia elétrica. Neste sentido, esse trabalho apresentou um método híbrido recursivo baseado em ferramentas da área de aprendizado de máquinas (algoritmo de agrupamento e base de regras), o qual é capaz de localizar as fontes de VTCD, a partir da análise dos das características dos distúrbios disponibilizadas pelos smart meters instalados no sistema. Assim, o trabalho destinouse ao desenvolvimento de uma plataforma em hardware para aquisição, detecção e classificação dos distúrbios, através de um Sistema Operacional de Tempo Real. Em seguida o algoritmo de agrupamento (k-means) agrupou os dados dos medidores de forma a definir dois clusters, onde um deles correspondeu aos medidores que estão longe da região que ocorreu o distúrbio e o outro, correspondeu aos medidores que estavam localizados próximos da região de ocorrência do distúrbio. Na segunda etapa, um sistema baseado em regras determinou qual dos clusters abrangeu o nó de origem. No entanto, quando o algoritmo determinou uma região muito grande, essa região é introduzida recursivamente, como entrada da metodologia desenvolvida, para refinar a região de localização. O sistema resultante foi capaz de estimar a região de localização com uma taxa de acerto acima de 90%. Assim, o método teve sua concepção adequada ao empregado nos centros de controle e operações de concessionárias de energia elétrica, visando apoiar a decisão do corpo técnico para que ações corretivas fossem estabelecidas de forma assertiva. / In the Smart Grids context, the correct location of short-duration voltage variations sources is not a trivial task, because of the short duration of these events and for rapid propagation in the distribution feeder. In this sense, aiming to develop a recursive hybrid method based on machine learning area tools (clustering algorithm and rule base) that is able to locate the sources of short-duration voltage variations, it was used data from smart meters installed along the distribution feeder. The recursive hybrid method, as input, received the disturbance characteristics provided by the meters installed in the system. Thus, this thesis aimed to development of a measurement hardware for signal acquisition, detection, classification through a realtime operating system. Then, k-means clustering algorithm grouped the meters data in order to define two clusters, where one of them corresponded to the meters that were distant from the region that occurred the disturbance and the other one corresponded to the meters, which were located near to the disturbance occurrence region. In a second step, a rule-based system determined which of the clusters corresponded to the source node. When the algorithm determined a very large region, that region was recursively introduced as input of the developed methodology to decrease its size. The resulting system was able to estimate the location region with a accuracy above 90%. Therefore, this method showed a suitable design for employment by operation control centers of power sector concessionaires, aiming to support technical staff decision to stablish assertive corrective actions.

No contexto de Smart Grids, determinar a correta localização das fontes causadoras de Variação de Tensão de Curta Duração (VTCD) não é uma tarefa simples, devido à curta duração destes eventos e também, por sua rápida propagação nas redes de distribuição de energia elétrica. Neste sentido, esse trabalho apresentou um método híbrido recursivo baseado em ferramentas da área de aprendizado de máquinas (algoritmo de agrupamento e base de regras), o qual é capaz de localizar as fontes de VTCD, a partir da análise dos das características dos distúrbios disponibilizadas pelos smart meters instalados no sistema. Assim, o trabalho destinouse ao desenvolvimento de uma plataforma em hardware para aquisição, detecção e classificação dos distúrbios, através de um Sistema Operacional de Tempo Real. Em seguida o algoritmo de agrupamento (k-means) agrupou os dados dos medidores de forma a definir dois clusters, onde um deles correspondeu aos medidores que estão longe da região que ocorreu o distúrbio e o outro, correspondeu aos medidores que estavam localizados próximos da região de ocorrência do distúrbio. Na segunda etapa, um sistema baseado em regras determinou qual dos clusters abrangeu o nó de origem. No entanto, quando o algoritmo determinou uma região muito grande, essa região é introduzida recursivamente, como entrada da metodologia desenvolvida, para refinar a região de localização. O sistema resultante foi capaz de estimar a região de localização com uma taxa de acerto acima de 90%. Assim, o método teve sua concepção adequada ao empregado nos centros de controle e operações de concessionárias de energia elétrica, visando apoiar a decisão do corpo técnico para que ações corretivas fossem estabelecidas de forma assertiva. / In the Smart Grids context, the correct location of short-duration voltage variations sources is not a trivial task, because of the short duration of these events and for rapid propagation in the distribution feeder. In this sense, aiming to develop a recursive hybrid method based on machine learning area tools (clustering algorithm and rule base) that is able to locate the sources of short-duration voltage variations, it was used data from smart meters installed along the distribution feeder. The recursive hybrid method, as input, received the disturbance characteristics provided by the meters installed in the system. Thus, this thesis aimed to development of a measurement hardware for signal acquisition, detection, classification through a realtime operating system. Then, k-means clustering algorithm grouped the meters data in order to define two clusters, where one of them corresponded to the meters that were distant from the region that occurred the disturbance and the other one corresponded to the meters, which were located near to the disturbance occurrence region. In a second step, a rule-based system determined which of the clusters corresponded to the source node. When the algorithm determined a very large region, that region was recursively introduced as input of the developed methodology to decrease its size. The resulting system was able to estimate the location region with a accuracy above 90%. Therefore, this method showed a suitable design for employment by operation control centers of power sector concessionaires, aiming to support technical staff decision to stablish assertive corrective actions.

Eine angemessene Qualität der Elektroenergie ist Grundvoraussetzung für den störungsfreien Betrieb aller angeschlossenen Geräte und Anlagen und spielt in den Verteilungsnetzen moderner Industriegesellschaften wie Deutschland eine zentrale Rolle. Die Elektroenergiequalität (EEQ) wird in Strom- und Spannungsqualität unterteilt. Während die Stromqualität maßgeblich im Verantwortungsbereich der Hersteller von Geräten und Anlagen liegt, sind für die Sicherung einer angemessenen Spannungsqualität im Wesentlichen die Netzbetreiber verantwortlich. Durch die technische Weiterentwicklung bspw. neuer Gerätetechnologien und die zunehmende Integration dezentraler Erzeugungsanlagen wie Photovoltaikanlagen ist zu erwarten, dass die EEQ auch künftig weiter an Bedeutung gewinnt. Die EEQ im Niederspannungsverteilungsnetz ist abhängig von Ort und Zeit und wird durch verschiedene Qualitätskenngrößen beschrieben. Die örtliche und zeitliche Abhängigkeit resultieren aus einer Vielzahl verschiedener Einflussfaktoren, welche sich entweder der elektrischen oder der nicht-elektrischen Umgebung des betrachteten Verteilungsnetzes zuordnen lassen. Die elektrische Umgebung wird durch die Art und Anzahl angeschlossener Verbraucher bzw. Erzeuger (Abnehmer- bzw. Erzeugerstruktur) sowie Struktur und technische Parameter des Verteilungsnetzes (Netzstruktur) bestimmt. Die nicht-elektrische Umgebung umfasst u.a. Einflüsse der klimatischen Umgebung wie bspw. Temperatur oder Globalstrahlung. Ziel dieser Arbeit ist die systematische Identifikation korrelativer Zusammenhänge zwischen den genannten Umgebungseinflüssen und der EEQ sowie deren Quantifizierung auf Basis geeigneter Indizes und Kenngrößen. Die Ergebnisse der Arbeit helfen grundlegende Prinzipien der Ausprägung der Elektroenergiequalität im öffentlichen Verteilungsnetz besser zu verstehen sowie die Verteilungsnetze im Hinblick auf die Elektroenergiequalität zu charakterisieren und zu klassifizieren. Analog zu den Standard-Lastprofilen erfolgt die Definition von Standard-Qualitätsprofilen. / Power quality levels in public low voltage grids are influenced by many factors which can either be assigned to the electrical environment (connected consumers, connected genera-tion, network characteristics) or to the non-electrical environment (e.g. climatic conditions) at the measurement site. Type and amount of connected consumers (consumer topology) are expected to have a very high impact on power quality (PQ) levels. The generation topology is characterized by number and kind of equipment and generating installations like photovoltaic systems which are connected to the LV grid. The electrical parameters of the grid define the network topology. The parameters which are most suitable to describe each of the three topologies and the climatic environment will be identified. Voltage and current quality in public low voltage (LV) grids vary depending on location and time. They are quantified by a set of different parameters which either belong to events (e.g. dips) or to variations (e.g. harmonics). This thesis exclusively addresses continuous parameters describing variations. Continuous phenomena like harmonics are closely linked to an one-day-cycle which implies a more or less periodic behavior of the continuous power quality parameters. Consumer topologies such as office buildings or residential areas differ in their use of equipment. Time series analysis is used to distinguish between different consumer topologies and to identify characteristic weeks. The clustering of one-day time series is applied to identify characteristic days within the weeks of certain topologies. Based on the results, emission profiles for certain current quality parameters of different consumer topologies will be defined. Due to the characteristic harmonic current emission of certain consumer topologies which represents the typical user behaviour a classification system is developed. It is used to automatically classify the emission profiles of harmonic currents for unknown measurements and to estimate a likely consumer topology. A classification measure is introduced in order to identify unusual or false classified emission profiles. The usage behaviour of equipment by customers usually varies over the year. Subsequently, the levels of PQ parameters like harmonics may show seasonal variations which are identified by using newly defined parameters. The introduction of new device technologies on a large scale like the transition from incandescent to LED lamps might result in long-term changes to the levels of PQ parameters (e.g. harmonics). The analysis of the long-term behavior (trend) will be applied in order to quantify global trends (looking on the measurement duration as a whole) and local trends (looking on individual segments of the whole time series).

Regeringen har en vision att till 2050 ska Sverige uppnå en fordonsflotta som är fossilfri och för att uppnå den visionen ska el som drivmedel spela en avgörande roll på marknaden. HEM Nät AB är därmed intresserade av hur deras lokalnät i ett valt område kan påverkas när en större andel av hushållen införskaffar elbilar. Längs områdets högspänningsslinga finns nio nätstationer som matar ut effekt till 815 kunder. En känslighetsanalys genomfördes kring det valda lokalnätet med avseende till dess kapacitet idag till framtida belastningar från elbilar. Analysen baserades på fyra olika nätparametrar som möjligen kan riskeras med avseende till elbilars laddsystem: spänningsfall, transformatorbelastning, övertoner och osymmetri. Olika laddeffekter och kopplingssätt har även jämförts bland nätparametrarna för att visa vilken roll de kan ha i framtiden. Spänningsfallet samt transformatorbelastning för de båda effekterna 3,7 kW och 11 kW uppgick mot de satta nätkraven när 40 % respektive 20 % belastning sker i området. Två vetenskapliga metoder användes för att uppskatta övertonerna där ena tog hänsyn till en reduktion av sammanlagrade övertoner och den andra metoden använde en aritmetisk summering av strömövertonerna. Resultatet visade att med varken en inkluderad reduktion eller med den aritmetiska summeringen kommer övertonerna bli ett problem. Med simuleringen av osymmetri nåddes nätkravet när 7 % mer belastning skedde under en och samma fas. Slutligen kom studien fram till att lokalnätet är relativt starkt och kan klara av 322 elbilar vid 3,7 kW och 161 elbilar vid 11 kW. / The Swedish government have a vision that up untill 2050 Sweden’s transport system is going to be free of fossil fuels and to achieve this vision, electricity is going to be the main fuel and will play a decisive role in the future transportional market. As a result of this, HEM Nät AB is now interested in knowing how their local electrical grid will be affected by a larger amount of electric vehicles, EVs, charged through households. Along the local grid’s high voltage line there are nine substations, which provide power to 815 customers. A sensitivity analysis was conducted on the local grid to appreciate the available capacity for the future load of EVs. The analysis was based on four different gridparameters, which possibly can affect the set conditions of an electrical grid when an EV is being charged: voltage drop, transformer load, harmonics and dissymmetry. Different chargepowers and wirings have also been compared to see what roles they will have in the future. After the simulations and hand calculations all of the gridparameters exceeded the set conditions. This happened at different percentages of the households, which were charging their vehicles. The voltage drop and transformer load for both of the powers, 3,7 kW and 11 kW exceeded the limitations when 40 % respectively 20 % of the studied are was being loaded. Two scientific methods were used to appreciate the added current harmonics, where the first one regarded a reduction of the summarized value of the current harmonics, where the second did not. The results showed, that either of the methods would indicate a problem on the grid. The simulation of the dissymmetry, the limitation was met after 7 % more load was done under one and the same of the phases. Finally, the study concluded that the local grid is relatively strong and can hold 332 EVs with 3,7 kW and 161 EVs with 11 kW.

Arbetet Tillämpning av batterilager som energitjänsten lastutjämnare är en litteraturstudie och en kvantitativ studie. I studien har driftkarakteristiken år 2015 hos en matvarubutik legat till grunden. Arbetet har syftat i att besvara frågan kring ett batterilagers lämplighet som agerade för lastutjämning. För att ta reda på det har batterilagersegenskaper kartlagts och dimensionering gjorts utifrån två olika driftfall. En ekonomisk besparingspotential har även beräknats utifrån de bägge driftfallen. Driftfallen har valts att kallas teknisk dimensionering och ekonomisk dimensionering. De tekniska dimensionerade lagerna har en lager storlek om 617 kWh och 555kWh vilket motsvarar 7,1% respektive 5,8% av den dagliga energianvändningen. För de ekonomiskt dimensionerade lagerna har en lager storlek om 597 kWh och 233kWh vilket motsvarar 6,8% respektive 2,8% av den dagliga energianvändningen. Den ekonomiska besparingspotentialen blir som störst för en blandad körning av de bägge driftfallen. Trotts att besparingspotentialen är uppskattade under ideala förhållanden med varken förluster eller degraderad prestanda lönar det inte sig att investera i ett batterilager för att enbart utföra tjänsten effektutjämning idag. Investering i ett batterilager för effektutjämning har potential att bli lönsam först när den kan tillgodose fler energitjänster eller när alternativkostnaden är förhöjd. / This thesis, is a study of battery energy storage and its use as energy source and smoothening of power fluctuation. Studies have been made as a systematic review and a quantitative study. The study has consisted of analysing the power characteristic from a supermarket in the city of Varberg during year 2015. The object has been to evaluate the energy storage and the power smoothing qualities. Therefore the battery energy storages characteristics have been evaluated in this systematic review. For the quantitative study, calculations of the energy storage sizes were made for two separate operation modes. The two different operation modes were named technical dimensioning and economic dimensioning. The function of the technical dimensioning was to smooth the power outlet from the grid, while the function of the economic dimensioning was to enable the supermarket to buy more energy during low-price hours. Based on monthly power characteristics, each dimensioning gave as a result two energy storage possibilities, one in medium and one in small size. The technical dimensioning resulted in battery energy storage of the sizes 617 kWh and 555kWh which is comparable to 7,1% and 5,8% of the daily energy usage of the supermarket. The economic dimensioning resulted in battery energy storage of the sizes 597 kWh and 233kWh which is comparable to 6,8% and 2,8% of the daily energy usage of the supermarket. For optimizing the economic savings, a variation of technical and economic operation mode are needed, depending on calculated power usage through the day and elspot prices. The study shows that a battery storage is difficult to finance. The calculated economic savings were estimated during ideal conditions and without power loss or loss in performance. As a conclusion from this study a battery storage may have a good payback if there are several energy services to be filled.

Målet med detta arbete var att undersöka hur mikroproduktion med solceller och laddning av elbilar i våra hushåll kommer att se ut i framtiden och om elkvalitén, kapaciteten i distributionsnätet, utlösningsvillkoren och elnätsdimensioneringen i nya bostadsområden påverkas av detta. Två olika scenarier har tagits fram, där det som skiljer dem åt är hur många procent av hushållen som har elbilsladdare och solcellsproduktion. De två scenarierna jämförs sedan med hur det ser ut i dagsläget för att få en uppfattning om vad som krävs vid fram-tidens elnätsdimensioneringar. Två extremfall används där maximal produktion och minimal konsumtion sommartid jämförs med maximal konsumtion och ingen produktion vintertid. Arbetet visar att den totala effektförbrukningen ökar med procentökningen av elbilsladdare och solcellsanläggningar vilket leder till att nya bostadsområden måste dimensionernas för högre belastningsström-mar. Detta resulterar i att större transformatorer och att kablar med grövre ledarareor måste användas för att klara av den ökade belastningsströmmen. Spänningsvariationerna ökar vilket gör att acceptans-gränserna i vissa fall inte kan hållas. Vid simulering och beräkningar visade det sig att utlösningsvillkoren för alla sammankopplingspunkter och anslutningspunkter mot bostäder låg inom gränsvärdet fem sekunder samt att selektiviteten var god i de delsträckor som testades. / The goal with this work was to study how micro-production with solar cells and charging of electric cars in our households will look like in the future and whether the electricity quality, the capacity of the distribution network, the release conditions and the electricity grid dimensioning in new residential areas are affected by this. Two different scenarios have been developed, where what distinguishes them is how many percent of households have electric car chargers and solar cell production. The two scenarios are then compared with how it currently looks to get an idea of what is needed in future electricity grid dimensioning. Two extreme cases are used where maximum production and minimal consumption in summer are compared with maximum consumption and no production in winter. The work shows that the total power consumption increases with the percentage increase of electric car chargers and solar cell installations, which means that new residential areas must be dimensioned for higher load currents. This results in larger transformers and that cables with larger conductor areas must be used to cope with the increased power. The voltage variations increase, which means that the acceptance limits in some cases cannot be kept. During simulation and calculations, it was found that the triggering conditions for all inter-connection points and connection points against housing were within the limit value of five seconds and that the selectivity was good in the sub-sections that were tested.

A conexão de geradores distribuídos em sistemas de distribuição deve ser cuidadosamente avaliada para que os mesmos auxiliem efetivamente na melhoria do desempenho das redes elétricas, buscando reduzir ou eliminar eventuais situações que causem a degradação da qualidade da energia elétrica fornecida aos consumidores, entre outros aspectos. Neste contexto, existem vários trabalhos que analisam a influência da conexão de geradores distribuídos no perfil de tensão da rede elétrica, frequência, desequilíbrio de fases e distorção harmônica. No entanto, há poucos trabalhos analisando os efeitos da desconexão de geradores distribuídos na qualidade da energia fornecida aos consumidores. Uma vez operando em paralelo com a rede de distribuição, esses geradores influenciam o perfil de tensão e o comportamento dos dispositivos reguladores de tensão. Como consequência, sua desconexão pode provocar variações de tensão intensas causando danos ou mau funcionamento às cargas. A desconexão pode ser repentina ou devido à atuação da proteção anti-ilhamento, seguida dos procedimentos de religamento automático do alimentador, se houver. Visando estudar este problema, o qual tende a se tornar uma nova preocupação das concessionárias de energia elétrica, e no intuito de minimizar e/ou eliminar os possíveis efeitos negativos dessas variações de tensão, esta pesquisa propõe o desenvolvimento de um método de controle dos taps dos reguladores de tensão. Neste método, o controle dos taps foi modelado como um problema de otimização, minimizando as violações de tensão mencionadas anteriormente e também a quantidade de operações dos reguladores de tensão ao longo de um dia típico. A otimização foi solucionada com um Algoritmo Genético e os resultados obtidos indicaram que é possível minimizar as variações de tensão usando a curva de carga do sistema para planejar a operação dos reguladores de tensão. / The connection of distributed generators in an electric power system should be evaluated carefully to ensure that they effectively assist in improving the performance of electrical networks, reducing or eliminating any situations that cause degradation of the power quality of the consumers, and other issues. In this context, there are several studies that analyze the influence of generators connected to distribution systems and how they affect the frequency, cause variations in voltage magnitude, voltage unbalance and harmonic distortion. However, there are a few studies analyzing the effects that the disconnection of distributed generators induces to the power quality of consumers. Once operating in parallel with the distribution network, these generators have an effect on voltage variations and voltage regulator devices. As a result, disconnection can cause severe voltage variations causing damage or malfunction to the loads. The disconnection may be sudden or due to the action of anti-islanding protection, followed by the procedure to reconnect the substation, if it is possible. In order to study this problem, which tends to become a new power quality concern for electric utilities, and in order to minimize and / or eliminate the possible side effects of the voltage variations, this research proposes the development of a control method of voltage regulators\' taps. In this method, the control of taps was modeled as an optimization problem which aimed to minimize these voltage variations aforementioned and also the amount of voltage regulator operations over a typical day. The optimization was solved by a Genetic Algorithm and the results obtained demonstrate that it is possible to minimize the voltage variation by using the system load curve to plan the operation of voltage regulators.

Nesta pesquisa, é proposta uma metodologia para detectar e classificar os distúrbios observados em um Sistema Elétrico Industrial (SEI), além de estimar de forma não intrusiva, o torque eletromagnético e a velocidade associada ao Motor de Indução Trifásico (MIT) em análise. A metodologia proposta está baseada na utilização da Transformada Wavelet (TW) para a detecção e a localização no tempo dos afundamentos e interrupções de tensão, e na aplicação da Função Densidade de Probabilidade (FDP) e Correlação Cruzada (CC) para a classificação dos eventos. Após o processo de classificação dos eventos, a metodologia como implementada proporciona a estimação do torque eletromagnético e a velocidade do MIT por meio das tensões e correntes trifásicas via Redes Neurais Artificiais (RNAs). As simulações computacionais necessárias sobre um sistema industrial real, assim como a modelagem do MIT, foram realizadas utilizando-se do software DIgSILENT PowerFactory. Cabe adiantar que a lógica responsável pela detecção e a localização no tempo detectou corretamente 93,4% das situações avaliadas. Com relação a classificação dos distúrbios, o índice refletiu 100% de acerto das situações avaliadas. As RNAs associadas à estimação do torque eletromagnético e à velocidade no eixo do MIT apresentaram um desvio padrão máximo de 1,68 p.u. e 0,02 p.u., respectivamente. / This study proposes a methodology to detect and classify the disturbances observed in an Industrial Electric System (IES), in addition to, non-intrusively, estimate the electromagnetic torque and speed associated with the Three-Phase Induction Motor (TPIM) under analysis. The proposed methodology is based on the use of the Wavelet Transform WT) for the detection and location in time of voltage sags and interruptions, and on the application of the Probability Density Function (PDF) and Cross Correlation (CC) for the classification of events. After the process of events classification, the methodology, as implemented, provides the estimation of the electromagnetic torque and the TPIM speed through the three-phase voltages and currents via Artificial Neural Networks (ANN). The necessary computer simulations of a real industrial system, as well as the modeling of the TPIM, were performed by using the DIgSILENT PowerFactory software. The logic responsible for the detection and location in time correctly detected 93.4% of the assessed situations. Regarding the classification of disturbances, the index reflected 100% accuracy of the assessed situations. The ANN associated with the estimation of the electromagnetic torque and speed at the TPIM shaft showed a maximum standard deviation of 1.68 p.u. and 0.02 p.u., respectively.

As faltas de alta impedância (FAI) ocorrem quando um condutor entra em contato com objetos com uma alta resistência, o que não resulta em incrementos significativos de corrente. Este tipo de falta não pode ser detectada por dispositivos de proteção tradicionais que atuam por sobrecorrente. Neste trabalho uma pesquisa do estado da arte das FAI é apresentada e são implementados alguns algoritmos de detecção presentes na literatura. Nesta pesquisa também são propostas duas metodologias de identificação de FAI as quais são baseadas na identificação de buildup e incrementos de energias na faixa de frequências 1920Hz a 3840Hz. Os algoritmos implementados e as metodologias propostas foram testados com simulações de eventos de FAI e de eventos comuns numa rede simulada de uma concessionária do Estado de São Paulo utilizando o software ATP. Estudos do funcionamento de um medidor de qualidade de energia foram feitos com o propósito de determinar as limitações de uma eventual implementação real das metodologias de identificação propostas neste trabalho. Resultados do desempenho das metodologias propostas utilizando os sinais simulados em ATP apresentaram percentagens de identificação superiores aos 80%. Análise das ocorrências de cabo rompido do circuito em estudo foram feitas com o propósito de identificar possíveis eventos de FAI. O desempenho apresentado pelas metodologias propostas na identificação de FAI em sinais reais pode ser melhorado com a disponibilidade de uma maior quantidade de eventos reais de FAI. / High impedance faults (HIF) occur when a conductor makes contact with high resistance objects, generally not resulting in significant current increases. This type of fault cannot be detected by traditional overcurrent protection devices. In this work, a research of the HIF state-of-art is presented and some detection algorithms in the literature are implemented. This research also proposes two HIF identification methods based on respectively the identification of buildup current and energy increments in the frequency range from 1920Hz to 3840Hz. The implemented algorithms and the proposed methodology have been tested with ATP simulations of FAI events and other common events in a simulated network from an electric utility in the State of Sao Paulo. Studies are carried out in order to assess the operation of a power quality meter to determine the limitations of real implementations of the proposed methodologies. Performance results of the proposed methodologies using simulated ATP signals show identifications rates greater than 80%. Broken conductor occurrences in the studied feeder are analyzed to identify possible HIF events. The performance shown by the proposed methodologies in identifying HIF in real situations can be improved with the availability of a larger number of HIF events.

Este trabalho propõe um sistema fotovoltaico (PV) multifuncional conectado a um sistema elétrico trifásico a quatro fios e operando com estratégia dual de compensação ativa de potência. Além da injeção de potência ativa na rede elétrica, o sistema PV operara como um condicionador unificado de qualidade de energia (UPQC) suprimindo as correntes harmônicas da carga e compensando a potência reativa. Adicionalmente, tensões balanceadas, reguladas e livre de harmônicos são fornecidas para a carga. O sistema PV-UPQC é baseado em uma estratégia de compensação dual, na qual o conversor série opera como uma fonte de corrente senoidal, enquanto o conversor paralelo atua como uma fonte de tensão senoidal. Como resultado, nenhum comportamento transitório é observado na troca entre os modos de operação ilhado e interconectado do sistema PV-UPQC. Além disso, para contornar os problemas associados às mudanças bruscas de irradiação solar, uma malha de controle feed-forward atua na geração das referências de corrente do conversor série, de modo que se obtenha um rápido balanço de potência entre o sistema PV e a rede elétrica. Como resultado, as respostas dinâmicas tanto da corrente elétrica quanto da tensão do barramento CC são melhoradas. A análise detalhada envolvendo o fluxo de potência ativa dos inversores é realizada proporcionando um melhor entendimento sobre a operação do sistema PV-UPQC, bem como auxiliando no dimensionamento dos conversores de potência. Resultados de simulação e experimentais são apresentados para avaliar os desempenhos estáticos e dinâmicos do PV-UPQC conectado ao sistema elétrico de distribuição. / This work proposes a multifunctional single-stage three-phase four-wire grid-connected photovoltaic (PV) system operating with a dual active power-line compensating strategy. Besides injection of active power into the grid, the PV system operates as a unified power quality conditioner (UPQC), suppressing the load harmonic currents and compensating reactive power. Additionally, regulated, balanced and harmonic free output voltages are provided to the load. Since the PV-UPQC is based on a dual compensation strategy, the series converter operates as a sinusoidal current source, whereas the parallel converter operates as a sinusoidal voltage source. Thus, seamless transition can be achieved from the interconnected to the islanding operation modes, and vice-versa, without load voltage transients. Moreover, to overcome problems associated with sudden solar irradiation changes, fast power balance involving the PV array and the grid is obtained, since the feed-forward control loop acts on the generation of the series inverter current references. As a result, the dynamic responses of both inverter currents and dc-bus voltage are improved. Detailed analysis involving the active power flow through the inverters is performed allowing proper understanding of the PV-UPQC operation, as well as assisting to design of the power converters. Simulation and experimental results are presented to evaluate both dynamic and static performances of the PV-UPQC tied to the electrical distribution system.