This dissertation contains a strategy to minimize the non-technical electrical energy losses in an electrical distribution network. In order to develop the strategy, a model was constructed that simulates an electrical distribution network and includes different parameters that calculate the estimated technical losses in the electricity distribution network. The model was then used as the base to develop the strategy to minimize the electrical energy losses in an electrical distribution network. Increasing energy costs and environmentalists actions to protect the natural resources, force energy supply companies to conserve and reduce energy usage. Therefore the research focused on the reduction of electrical energy losses in distribution networks. The loss occurrences are divided into two categories: technical and non-technical losses. Reducing these losses ensure that the cost of electricity to customers will be reduced and in turn improve the efficiency of the distribution network. The model developed to calculate the non-technical losses in an electrical distribution network was tested at two different networks. Firstly at the University of Pretoria, where the network segment consisted of different network busses delivering electrical energy. Secondly results were obtained in a residential network of the Tshwane Metropolitan Council. In this network there was only one bus but various different time intervals were used to determine the time interval most suitable for determining the electrical energy losses in the electrical distribution network. The model was used primarily to quantify the technical losses as a base point towards determining the non-technical losses. Using the model one is able to forecast the technical energy losses of a section in the electricity distribution network and this enabled one to develop a strategy to minimize the energy losses in the distribution network. The model will enable municipalities or electricity distribution companies to estimate electrical energy losses in their electrical supply networks and facilitate the development of strategies to reduce electrical energy losses. / Dissertation (MEng (Electrical Engineering))--University of Pretoria, 2006. / Electrical, Electronic and Computer Engineering / unrestricted

This thesis demonstrates the value of integrating electrical distribution engineering analysis with Geographic Information Systems (GIS). The 37-Node IEEE Feeder model was used as the base distribution system in this study. It was modeled separately, both in software capable of unbalanced load-flow and in an industry-standard GIS environment. Both tools utilized were commercially available, off-the shelf products indicative of those used in academia and in basic GIS installations. The foundational data necessary to build these models is representative of information required by a variety of utility departments for a multitude of applications. It is inherent to most systems within an enterprise-level, business-wide data model and therefore can be used to support a variety of applications. In this instance, infrastructure information is assumed to be managed and housed with the GIS. This data provides the required information as input for load-flow calculations. The engineering analysis is performed within DistributionSystem 4.01 and its output is passed back to the GIS in tabular format for incorporation. This thesis investigates the transfer of information between GIS and DistributionSystem 4.01 and demonstrates the extended display capabilities in the GIS environment. This research is implemented on a small scale, but is intended to highlight the need for standardization and automatic integration of these systems as well as others that are fundamental to the effective management of electrical distribution systems. / Master of Science

A troca de informações entre os vários sistemas de gerenciamento e outros sistemas de informação de uma empresa do setor elétrico não é apenas desejada, mas na maioria dos casos, necessária. Com a necessidade desenvolveu-se uma pesquisa com o objetivo de descrever as metodologias de integração entre Sistemas de Informações Geográficas e Sistemas de Projetos de Redes de Distribuição, incluindo referências a diversos trabalhos de integração no Brasil e no mundo. Como exemplo e caso prático, utilizou-se uma metodologia desenvolvida para a concessionária de distribuição de energia elétrica AES Eletropaulo. / The information interchanges between management systems and others information systems of an electrical distribution company is not only desirable, but in most cases necessary. Due this necessity it was developed one research aiming to describe the integration methodologies between geographic information systems and electrical grid expansion designer systems, including references for some integration works in Brazil and in World. As a practical example, it was used one methodology developed for the electrical distribution company AES Eletropaulo.

Este trabalho apresenta as principais causas de desligamento de cubículos classe 15kV, restringindo-se aos cubículos conhecidos como cabines primárias, que fazem a interface entre a rede das concessionárias de energia e os consumidores primários. Conhecidas as razões pelas quais as cabines desligam, verificou-se quais são as taxas de falha presumidas para os componentes individuais como: chaves seccionadoras e seus acessórios, disjuntores e suas bobinas, relés de proteção de sobrecorrente, transformadores de corrente e de potencial, componentes de serviços auxiliares, etc. Para avaliar a taxa de falhas das diversas configurações possíveis foram estabelecidos dezoito modelos específicos e estudadas matematicamente suas taxas de falha. Para tanto, foram utilizados os padrões estabelecidos pelas concessionárias Brasileiras como AES-ELETROPAULO, ESCELSA e CPFL, além da proposição de modelo que pode ser considerado como OTIMIZADO. Com base na experiência adquirida com os modelos estudados foi possível ainda a proposição de mecanismos de melhoria dos índices de desligamento. / This study is intended to explore the main causes of failure in 15kV switchgears, restricted to primary equipments making the interface between the Utility and the consumers. Discovering the reasons of the failures, the individual failure rates of each components was noted, as following: switches and its acessories, circuit breakers and its coils, overcurrent relays, current and voltage transformers, auxiliary circuits, etc. Analyzing the failure rates of many possible configurations of eighteen particular models, a mathematical failure rate study was achieved. A Brazilian standards, used by Energy Companies like AES-ELETROPAULO, ESCELSA and CPFL, was used to achieve the results and a optimized model could be proposed. Based on the acquired experienced during this study, it was possible to offer new techniques to decrease the failure rates.

Este trabalho apresenta as principais causas de desligamento de cubículos classe 15kV, restringindo-se aos cubículos conhecidos como cabines primárias, que fazem a interface entre a rede das concessionárias de energia e os consumidores primários. Conhecidas as razões pelas quais as cabines desligam, verificou-se quais são as taxas de falha presumidas para os componentes individuais como: chaves seccionadoras e seus acessórios, disjuntores e suas bobinas, relés de proteção de sobrecorrente, transformadores de corrente e de potencial, componentes de serviços auxiliares, etc. Para avaliar a taxa de falhas das diversas configurações possíveis foram estabelecidos dezoito modelos específicos e estudadas matematicamente suas taxas de falha. Para tanto, foram utilizados os padrões estabelecidos pelas concessionárias Brasileiras como AES-ELETROPAULO, ESCELSA e CPFL, além da proposição de modelo que pode ser considerado como OTIMIZADO. Com base na experiência adquirida com os modelos estudados foi possível ainda a proposição de mecanismos de melhoria dos índices de desligamento. / This study is intended to explore the main causes of failure in 15kV switchgears, restricted to primary equipments making the interface between the Utility and the consumers. Discovering the reasons of the failures, the individual failure rates of each components was noted, as following: switches and its acessories, circuit breakers and its coils, overcurrent relays, current and voltage transformers, auxiliary circuits, etc. Analyzing the failure rates of many possible configurations of eighteen particular models, a mathematical failure rate study was achieved. A Brazilian standards, used by Energy Companies like AES-ELETROPAULO, ESCELSA and CPFL, was used to achieve the results and a optimized model could be proposed. Based on the acquired experienced during this study, it was possible to offer new techniques to decrease the failure rates.

Este trabalho apresenta um estudo de proteção de sobrecorrente de redes primárias aéreas de distribuição de energia elétrica através de uma abordagem probabilística. Abordagens convencionais para o problema de proteção de sobrecorrente não levam em conta a natureza probabilística das principais variáveis envolvidas: tipo da falta, localização da falta e impedância de defeito para faltas envolvendo a terra. Neste caso, por exemplo, torna-se muito difícil avaliar as conseqüências de situações nas quais a coordenação total entre os dispositivos não pode ser alcançada por alguma razão. A abordagem probabilística permite, por outro lado, quantificar o risco de não haver coordenação entre dois dispositivos de proteção adjacentes. Esta informação é extremamente valiosa para os engenheiros de proteção na fase de projeto da rede elétrica. No trabalho, a metodologia probabilística é apresentada em detalhe e sua aplicação é ilustrada através de alguns estudos de aplicação, nos quais procurou-se avaliar a influência dos principais parâmetros do modelo na coordenação dos dispositivos de proteção. / This work describes the study of distribution system overcurrent protection through a probabilistic approach. Conventional approaches for overcurrent protection do not consider the probabilistic nature of the main variables involved, such as fault location, fault type and fault impedance for faults involving the ground. In this case, for instance, it is very difficult to assess the impact of situations where full coordination cannot be attained for some reason. The probabilistic approach, on the other hand, allows quantifying the risk of two adjacent protective devices operating in a non-coordinated way. This information is extremely valuable for electrical engineers at design level. In this work, the proposed methodology is illustrated through a few detailed application studies, including various sensitivity analyzes for assessing the influence of model parameters on the coordination of protective devices.

Este trabalho apresenta um estudo de proteção de sobrecorrente de redes primárias aéreas de distribuição de energia elétrica através de uma abordagem probabilística. Abordagens convencionais para o problema de proteção de sobrecorrente não levam em conta a natureza probabilística das principais variáveis envolvidas: tipo da falta, localização da falta e impedância de defeito para faltas envolvendo a terra. Neste caso, por exemplo, torna-se muito difícil avaliar as conseqüências de situações nas quais a coordenação total entre os dispositivos não pode ser alcançada por alguma razão. A abordagem probabilística permite, por outro lado, quantificar o risco de não haver coordenação entre dois dispositivos de proteção adjacentes. Esta informação é extremamente valiosa para os engenheiros de proteção na fase de projeto da rede elétrica. No trabalho, a metodologia probabilística é apresentada em detalhe e sua aplicação é ilustrada através de alguns estudos de aplicação, nos quais procurou-se avaliar a influência dos principais parâmetros do modelo na coordenação dos dispositivos de proteção. / This work describes the study of distribution system overcurrent protection through a probabilistic approach. Conventional approaches for overcurrent protection do not consider the probabilistic nature of the main variables involved, such as fault location, fault type and fault impedance for faults involving the ground. In this case, for instance, it is very difficult to assess the impact of situations where full coordination cannot be attained for some reason. The probabilistic approach, on the other hand, allows quantifying the risk of two adjacent protective devices operating in a non-coordinated way. This information is extremely valuable for electrical engineers at design level. In this work, the proposed methodology is illustrated through a few detailed application studies, including various sensitivity analyzes for assessing the influence of model parameters on the coordination of protective devices.

No description available.

The smooth and reliable operation of key infrastructure components like water distribution systems, electric power systems, and telecommunications is essential for a nation?s economic growth and overall security. Tragic events such as the Northridge earthquake and Hurricane Katrina have shown us how the occurrence of a disaster can cripple one or more such critical infrastructure components and cause widespread damage and destruction. Technological advancements made over the last few decades have resulted in these infrastructure components becoming highly complicated and inter-dependent on each other. The development of tools which can aid in understanding this complex interaction amongst the infrastructure components is thus of paramount importance for being able to manage critical resources and carry out post-emergency recovery missions. The research work conducted as a part of this thesis aims at studying the effects of fire (a calamitous event) on the electrical distribution network of a city. The study has been carried out on a test bed comprising of a virtual city named Micropolis which was modeled using a Geographic Information System (GIS) based software package. This report describes the designing of a separate electrical test bed using Simulink, based on the GIS layout of the power distribution network of Micropolis. It also proposes a method of quantifying the damage caused by fire to the electrical network by means of a parameter called the Load Loss Damage Index (LLDI). Finally, it presents an innovative graph theoretic approach for determining how to route power across faulted sections of the electrical network using a given set of Normally Open switches. The power is routed along a path of minimum impedance. The proposed methodologies are then tested by running numerous simulations on the Micropolis test bed, corresponding to different fire spread scenarios. The LLDI values generated from these simulation runs are then analyzed in order to determine the most damaging scenarios and to identify infrastructure components of the city which are most crucial in containing the damage caused by fire to the electrical network. The conclusions thereby drawn can give useful insights to emergency response personnel when they deal with real-life disasters.

No description available.