Este trabalho apresenta uma metodologia para alocação eficiente de dispositivos indicadores de faltas em sistemas de distribuição de energia elétrica. São avaliadas como as principais variáveis que influenciam na quantificação da potencialidade para instalação de dispositivos indicadores de faltas se comportam ao longo do tronco principal dos alimentadores de distribuição de energia elétrica. Como metodologia, empregou-se sistemas de inferência fuzzy para quantificar a referida potencialidade a partir das variáveis avaliadas. Resultados com dados reais destacam também a eficiência da metodologia proposta para quantificar e avaliar a rede de dispositivos indicadores já existentes em alimentadores. / This work presents a methodology for efficient allocation of fault indicator devices in electric power distribution systems. The behavior of the main variables that influence in the quantification of the potentiality for installation of fault indicator devices were analyzed taking into account the feeder length. In methodology terms, fuzzy inference systems were used to quantify this potentiality from the analyzed variables. Results with real data have also highlighted the efficiency of the proposed methodology to quantify and to evaluate the fault indicator device network already existent in power distribution feeders.

Os dispositivos indicadores de faltas são utilizados para sinalizar a passagem de uma corrente de curto-circuito nos alimentadores de distribuição de energia elétrica. Tais dispositivos permitem uma redução significativa no tempo de inspeção das equipes de manutenção durante a busca pela região faltosa. Entretanto, associada a estes dispositivos, encontra-se uma elevada taxa de falhas de suas operações, que comprometem a confiabilidade do equipamento e, conseqüentemente, o tempo de localização de faltas. Neste trabalho é apresentada uma metodologia de ensaios laboratoriais a fim de complementar os testes padrões dos fabricantes de indicadores de faltas, buscando-se então identificar os fatores que colaboram para as falhas de tais equipamentos. Os resultados obtidos mostraram a eficiência da metodologia desenvolvida em detectar falhas de operação dos indicadores de faltas, as quais também não puderam ser detectadas por testes fornecidos por fabricantes. / Fault Indicators are devices used to signal the passage of a short-circuit current in electricity distribution feeders. Such devices allow a significant reduction in patrol time by maintenance linemen during the search for the faulty region. However, associated with these devices, it is a high failure rate of operations that compromise the equipment reliability and, consequently, the time of fault location. This work presents a new methodology for single-phase laboratory tests in order to complement the standard tests accomplished by the manufacturers of fault indicators, aiming to then identify the factors that contribute to failures of such equipment. The results showed the efficiency of the methodology developed to detect operation failures of faults indicators that could not be detected by tests provided by manufacturers.

Os geradores distribuídos em sistemas de distribuição de energia elétrica devem ser desconectados em eventos de ilhamento, que ocorrem quando parte da rede elétrica torna-se eletricamente isolada da concessionária e o subsistema isolado continua a ser energizado pela geração distribuída. A proteção anti-ilhamento deve detectar tal condição operativa, porém pode não atuar em condições de pequenos desbalanços entre carga e geração, ou atuar incorretamente para eventos de outra natureza. Assim, um ajuste adequado dessa proteção deve desconectar o gerador rapidamente quando detecta o ilhamento e, simultaneamente, deve ser imune a eventos como curtos-circuitos e chaveamentos de carga, por exemplo. Esta pode ser uma tarefa muito difícil face às variações de carga e diferentes eventos de não ilhamento que podem ocorrer no sistema de distribuição. Portanto, nesta tese são propostas metodologias de ajuste das funções de proteção anti-ilhamento de sub/sobrefrequência, taxa de variação de frequência, salto de vetor e sub/sobretensão, que são técnicas convencionalmente utilizadas para a detecção de ilhamento de geração distribuída. O objetivo das metodologias é maximizar a detecção de ilhamento e minimizar a atuação incorreta, e são considerados cenários com múltiplos geradores distribuídos de diferentes tecnologias. Inicialmente, são explorados os principais fatores que afetam as proteções, tais como distribuição das cargas, fator de potência e desequilíbrio das cargas. Esta análise permite identificar os casos mais difíceis de detecção de ilhamento. Como segunda contribuição, foi proposta a metodologia de análise gráfica denominada Mapa de Ajustes, cuja eficácia foi comprovada por meio de casos de teste, mostrando ser capaz de melhorar a sensibilidade da proteção anti-ilhamento e minimizar atuação incorreta. Na sequência, é apresentado um método automático para ajuste e bloqueio de tensão e outro baseado em proteção adaptativa para ajuste das funções de proteção. Ambos são baseados na metodologia de mapa de ajustes. Os resultados indicam que é possível melhorar a detecção de ilhamento e diminuir a atuação incorreta quando utilizadas as metodologias propostas. / Distributed generators in power distribution systems must be disconnected after an islanding event, which occurs when part of the power grid becomes electrically isolated from the utility and the isolated subsystem continues to be energized by the distributed generation. The antiislanding protection has to detect such operating condition, which may fail for critical loading conditions, or operate incorrectly for events of other nature than islanding. Therefore, an appropriate protection setting should quickly disconnect the generator when an islanding event is detected, and simultaneously, must be immune to events such as short circuits and load switches. This can be a very difficult task due to load variations and different nonislanding events that may occur in the distribution system. Therefore, in this thesis is proposed methodologies to adjust the anti-islanding protection functions of under/overfrequency, rate of change of frequency, vector surge and under/overvoltage, which are techniques conventionally used for islanding detection of distributed generation. The methodologies goals are to maximize the performance of the anti-islanding protection and minimize the incorrect operation to events of other nature, and scenarios with multiple distributed generators of different technologies are considered. At first, the main factors that affect the frequency and voltage-based protection will be explored, such as load distribution, power factor and unbalanced loads. This analysis aims to identify the most critical cases of islanding detection. The second contribution of this thesis is the Setting Map methodology, which is a graphical analysis whose effectiveness has been proved by case studies, showing to be able to improve the sensitivity of anti-islanding protection, minimizing the chances of incorrect operation. In sequence, is presented an automatic method to adjust the protection functions and voltage blocking and other based on adaptive protection. Both methods are based on the Setting Map methodology. The results indicate that it is possible to improve the islanding detection and reduce the incorrect actuation when it is used the proposed methodologies.

Com o crescimento constante da infraestrutura do sistema de distribuição de baixa tensão, tem-se a necessidade de um monitoramento mais preciso das grandezas elétricas no ponto de conexão com os clientes. O impacto da implantação de sistemas smart grids são positivos, visto que para o lado do consumidor o acompanhamento do consumo de forma online permite realizar um melhor planejamento, e para o lado da concessionária, o levantamento de perfil dos clientes e planejamento de demanda, visto que os medidores podem fornecer os dados em tempo real de horários de maior consumo e acompanhamento dos níveis, de forma a adequar conforme os níveis de qualidade de energia definidos pelo módulo 8 PRODIST. Além do acompanhamento, das variáveis e limites, este projeto poderá atuar de forma a auxiliar as companhias elétricas a comparar os pontos de cargas estimadas com o fornecimento para detectar possíveis fraudes no ponto de distribuição. Outro aspecto importante é tornar possível a integração com uma rede de clientes que além de consumidores podem tornar-se pequenas unidades geradoras, alimentando o sistema maior. / With the constant growth of the infrastructure of the low voltage distribution system, there is a need for a more refined monitoring of the electrical quantities in the distribution network. The impact of the implementation of smart grids systems are positive, since for the consumer side the monitoring of consumption in an online way allows to carry out consumption planning, and for the side of the concessionaire, customer profile survey and demand planning, Since the meters can provide the real time data of schedules of greater consumption and monitoring of the levels, in order to adapt according to the levels of quality of energy defined by the module 8 PRODIST. In addition to the monitoring of variables and limits, this project may act in a way that helps utilities compare the estimated load points with the supply to detect possible fraud at the distribution point. Another important aspect is to make it possible to integrate with a network of customers that in addition to consumers can become small generating units, feeding the larger system.

<p>This study deals with the perspective of vulnerability of the Swedish electricity distribution system to climate and weather related risks. How and to what extent the electricity sector is adapting to the risk and what possibilities are formed in this respect are investigated. This is a quantitative and qualitative analysis where statistical data has been used to apprehend the extent of disturbances of the electricity distribution system and their causes. Interviews have been used in order to investigate different views among actors working within the electricity distribution system sector.</p><p>The result shows that the dominating cause of disturbances in the electrical network in Sweden is the weather, giving most hours of breaks. The countryside has more often disturbances than urban areas. It also emerges that it is the lines overhead that are most affected by disturbances. The system is flexible. If one line is disturbed the electricity can be distributed using another line (redundancy). It seems like there is a diversion between the respondents on how and if a future climate change really is a risk for the electricity distribution system. It is clear that the vulnerability has increased in the society during the past 10-20 years, and so has the societal costs of the disturbances because of the increasing dependence on electricity. Reducing the consequences of a weather related impact on the electrical system will make society more resilient and less vulnerable. The respondents in this study are somewhat adapting to the weather related risks that they have identified with technical solutions. It is important to learn more about how the electrical system properties influence the sensitivity in society. There is a need to investigate the dependency of electricity in society. It is also important that all the actors have the same interpretation of the difference between a recurrent event and a nature disaster. More work should be done to clarify where the responsibility for adapting the electrical sector to the possible climate change lies. This complex responsibility issue with all affected actors influences the sensitivity of society and the electrical system.</p>

Environmental awareness and uncertainty about continued supply of fossil fuel has given rise to the renewable energy movement. Wind based power generation has been at the forefront of the motion to integrate distributed energy sources in the traditional power system. Due to various technical restrictions, wide scale penetration of wind generated power has been held back by most utilities. One such restriction is the variability of generation due to the technology’s dependence on Mother Nature. Energy storage devices can complement the wind generators by reducing this variability. These devices can store excess generation for supply during low generation periods. There are several promising technologies for both energy storage and power storage applications. Power storage devices provide short term fluctuation dampening capability while energy storage devices allow longer term storage. Pumped hydro, Vanadium Redox battery and Sodium-Sulphur battery are some of the viable energy storage technologies. This project provides a set of algorithms and guidelines to obtain the optimal configuration parameters of an energy storage device. To verify the efficiency of the algorithms, a model system has been obtained from a local utility. This system represents a typical radial distribution system in rural Ontario. The load demand, wind speed and energy prices for a period of one year have been obtained from utilities and Environment Canada. The main goal in determining the location of the storage device within a distribution system is to minimize the total cost of energy and the total energy loss during the period of analysis. Locating the storage device near the wind turbines or near the largest loads lead to the optimum results. Buses that are located near those elements can be considered as suitable locations for the storage device. The energy storage capacity and charge-discharge rate of the storage device are selected based on four criteria: maximize wind turbines’ load following capability, maximize capacity factors of the wind turbines, minimize system energy losses and minimize system energy costs. A weight based multi-objective optimization algorithm has been proposed to assign various priorities to these criteria and obtain a single solution. The larger the energy storage capacity of the storage device, the better the improvement in system performance. Lower charge-discharge ramp rates provide superior results. The parameters for storage device operating schedule, i.e. charge-discharge trigger levels, have been selected using similar criteria and weighted objective approach as for the capacity selection process. Higher charge trigger levels and moderate discharge trigger levels provide the optimum system performance. Once a set of parameters for the storage device has been selected, bus voltages over the period of study are analyzed. Voltage variations outside certain limits have been identified. Finally, a Monte Carlo based simulation approach is presented to obtain output parameter (system performance) variation ranges for pseudo random changes in input parameters.

Environmental awareness and uncertainty about continued supply of fossil fuel has given rise to the renewable energy movement. Wind based power generation has been at the forefront of the motion to integrate distributed energy sources in the traditional power system. Due to various technical restrictions, wide scale penetration of wind generated power has been held back by most utilities. One such restriction is the variability of generation due to the technology’s dependence on Mother Nature. Energy storage devices can complement the wind generators by reducing this variability. These devices can store excess generation for supply during low generation periods. There are several promising technologies for both energy storage and power storage applications. Power storage devices provide short term fluctuation dampening capability while energy storage devices allow longer term storage. Pumped hydro, Vanadium Redox battery and Sodium-Sulphur battery are some of the viable energy storage technologies. This project provides a set of algorithms and guidelines to obtain the optimal configuration parameters of an energy storage device. To verify the efficiency of the algorithms, a model system has been obtained from a local utility. This system represents a typical radial distribution system in rural Ontario. The load demand, wind speed and energy prices for a period of one year have been obtained from utilities and Environment Canada. The main goal in determining the location of the storage device within a distribution system is to minimize the total cost of energy and the total energy loss during the period of analysis. Locating the storage device near the wind turbines or near the largest loads lead to the optimum results. Buses that are located near those elements can be considered as suitable locations for the storage device. The energy storage capacity and charge-discharge rate of the storage device are selected based on four criteria: maximize wind turbines’ load following capability, maximize capacity factors of the wind turbines, minimize system energy losses and minimize system energy costs. A weight based multi-objective optimization algorithm has been proposed to assign various priorities to these criteria and obtain a single solution. The larger the energy storage capacity of the storage device, the better the improvement in system performance. Lower charge-discharge ramp rates provide superior results. The parameters for storage device operating schedule, i.e. charge-discharge trigger levels, have been selected using similar criteria and weighted objective approach as for the capacity selection process. Higher charge trigger levels and moderate discharge trigger levels provide the optimum system performance. Once a set of parameters for the storage device has been selected, bus voltages over the period of study are analyzed. Voltage variations outside certain limits have been identified. Finally, a Monte Carlo based simulation approach is presented to obtain output parameter (system performance) variation ranges for pseudo random changes in input parameters.

In this thesis, we focus on a forecasting tool, Martingale Model of Forecast Evolution (MMFE), to model the evolution of forecasts in a production-distribution system. Additive form is performed to represent the evolution process. Variance-Covariance (VCV) matrix is defined to express the forecast updates. The selected demand pattern is stationary and it is normally distributed. It follows an Autoregressive Order-1 (AR(1)) model. Two forecasting procedures are selected to compare the MMFE with. These are MA (Moving average) and ES (Exponential smoothing) methods. A production-distribution model is constructed to represent a two-stage supply chain environment. The performance measures considered in the analyses are the total costs, fill rates and forecast accuracy observed in the operation of the production-distribution system. The goal is to demonstrate the importance of good forecasting in supply chain environments.

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

<p>In reregulated and restructured electricity markets the production and retail of electricity is conducted on competitive markets, the transmission and distribution on the other hand can be considered as natural monopolies. The financial regulation of Distribution System Operators (DSOs) has in many countries, partly as a consequence of the restructuring in ownership, gone through a major switch in regulatory policy. From applying regulatory regimes were the DSOs were allowed to charge their customers according to their actual cost plus some profit, i.e. cost-based regulation, to regulatory models in which the DSOs performance are valued in order to set the allowable revenue, i.e. Performance-Based Regulation (PBR). In regulatory regimes that value performance, the direct link between cost and income is weakened or sometimes removed. This give the regulated DSOs strong cost cutting incentives and there is consequently a risk of system reliability deterioration due to postponed maintenance and investments in order to save costs. To balance this risk the PBR-framework is normally complemented with some kind of quality regulation (QR). How both the PBR and QR frameworks are constructed determines the incentive that the DSO will act on and will therefore influence the system reliability development.</p><p>This thesis links the areas of distribution system reliability and performancebased regulation. First, the key incentive features within PBR, that includes the quality of supply, are identified using qualitative measures that involve analyses of applied regulatory regimes, and general regulatory policies. This results in a qualitative comparison of applied PBR models. Further, the qualitative results are quantified and analysed further using time sequential Monte Carlo simulations (MCS). The MCS enables detailed analysis of regulatory features, parameter settings and financial risk assessments. In addition, the applied PBRframeworks can be quantitatively compared. Finally, some focus have been put on the Swedish regulation and the tool developed for DSO regulation, the Network Performance Assessment Model (NPAM), what obstacles there might be and what consequences it might bring when in affect.</p>