The increasing awareness on the effect of carbon emissions in our planet has led to several countries to adopt targets for their reduction. One way of contributing to this aim is to use and distribute electricity more efficiently. In this context, Conservation Voltage Reduction (CVR), a well-known technique that takes advantage of the positive correlation between voltage and demand to reduce energy consumption, is gaining renewed interest. This technique saves energy by only reducing customer voltages, without relying on customer actions and, therefore, can be controlled by the Distribution Network Operator (DNO). CVR not only brings benefits to the electricity system by reducing generation requirements (fewer fossil fuel burning and carbon emissions), but also to customers, as energy bill reductions. The extent to which CVR can bring benefits mainly depends on the customers load composition and their voltages. While the former dictates the voltage-demand correlation, the latter constraints the voltage reduction that can be applied without violating statutory limits. Although CVR has been studied for many years, most of the studies neglect the time-varying voltage-demand characteristic of loads and/or do not assess end customer voltages. While these simplifications could be used to estimate CVR benefits for fixed and limited voltage reductions, realistic load and network models are needed to assess the performance of active CVR schemes, where voltages are actively managed to be close to the minimum limit. Moreover, distribution networks have been traditionally designed with limited monitoring and controllability. Therefore, CVR has been typically implemented by adopting conservative voltage reductions from primary substations, for both American and European-style networks. However, as new infrastructure is deployed in European-style LV networks (focus of this work), such as monitoring and on-load tap changers (OLTCs), the opportunity arises to actively manage voltages closer to end customer (unlocking further energy savings). Although these technologies have shown to effectively control voltages in LV networks, their potential for CVR has not been assessed before. Additionally, most CVR studies were performed in a context where distributed generation (DG) was not common. However, this has changed in many countries, with residential photovoltaic (PV) systems becoming popular. As this is likely to continue, the interactions of residential PV and CVR need to be studied. This thesis contributes to address the aforementioned literature gaps by: (i) proposing a simulation framework to characterise the time-varying voltage-demand correlation of individual end customers; (ii) developing a process to model real distribution networks (MV and LV) from DNO data; (iii) adopting a Monte Carlo-based quantification process to cater for the uncertainties related to individual customer demand; (iv) assessing the CVR benefits that can be unlocked with new LV infrastructure and different PV conditions. To accomplish (iv), first, a simple yet effective rule-based scheme is proposed to actively control voltages in OLTC-enabled LV networks without PV and using limited monitoring. It is demonstrated that by controlling voltages closer to customers, annual energy savings can increase significantly, compared to primary substation voltage reductions. Also, to understand the effect of PV on CVR, a centralized, three-phase AC OPF-based CVR scheme is proposed. This control, using monitoring, OLTCs and capacitors across MV and LV networks, actively manages voltages to minimize energy consumption in high PV penetration scenarios whilst considering MV-LV constraints. Results demonstrate that without CVR, PV systems lead to higher energy imports for customers without PV, due to higher voltages. Conversely, the OPF-based CVR scheme can effectively manage voltages throughout the day, minimising energy imports for all customers. Moreover, if OLTCs at secondary substations are available (and managed in coordination with the primary substation OLTC), these tend to regulate customer voltages close to the minimum statutory limit (lower tap positions), while the primary OLTC delivers higher voltages to the MV network to also reduce MV energy losses.

Submitted by Geyciane Santos (geyciane_thamires@hotmail.com) on 2015-06-18T14:20:29Z No. of bitstreams: 1 Dissertação- Jhonathan Araújo Oliveira.pdf: 17407325 bytes, checksum: 9ed1cb282822c8dd666684f5cc5e0219 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-19T21:10:55Z (GMT) No. of bitstreams: 1 Dissertação- Jhonathan Araújo Oliveira.pdf: 17407325 bytes, checksum: 9ed1cb282822c8dd666684f5cc5e0219 (MD5) / Approved for entry into archive by Divisão de Documentação/BC Biblioteca Central (ddbc@ufam.edu.br) on 2015-06-19T21:12:04Z (GMT) No. of bitstreams: 1 Dissertação- Jhonathan Araújo Oliveira.pdf: 17407325 bytes, checksum: 9ed1cb282822c8dd666684f5cc5e0219 (MD5) / Made available in DSpace on 2015-06-19T21:12:04Z (GMT). No. of bitstreams: 1 Dissertação- Jhonathan Araújo Oliveira.pdf: 17407325 bytes, checksum: 9ed1cb282822c8dd666684f5cc5e0219 (MD5) Previous issue date: 2013-09-24 / Scalability and high demand for resources are the main challenges that content providers face in multimedia applications based on networks. For instance, YouTube is one of the most popular delivery systems video on demand, the users send 100 hours of video every minute to its servers and more than four billion hours of video are watched every month. The CDN-P2P systems is widely recognized as a scalable alternative for multimedia content delivery in the Internet. In these systems, the peers from a peerto- peer network (P2P) share their resources thus reducing the demands on the network infrastructure for content delivery (CDN). Moreover, the CDN server to guarantee the availability of content when the peers contributions are limited by the churn, or when the content is is unprecedented to the peers of the P2P network. However, CDN-P2P systems alone do not guarantee the effectiveness of the services, since the peers output that are the only holders of a particular contents can generate congestion around the CDN server and degrade the quality of users experience. This dissertation investigates the contribution of stable peers for availability content on the on the P2P slice form a CDN-P2P system designed to distribute videos similar to those distributed by YouTube. In this way, the data were collected from the real YouTube Web site, exploring the potential of the users that have been access the playlists to characterize the stability of the peers in the system. The assumption about the effectiveness of playlists viewers int the availability content, due to the increased of the stay connnected of these users in the system and the possible popularity of contents shared by them. It was found that when a large number of the peers players pairs of the playlists spend long sessions connected, the improvement of the availability of content was in 60%. Additionally, in scenarios of low participation of players in playlists, its was the improvement outperformed in 20%. Furthermore, we evaluated how the build policies of the mesh impact the distribution system when the peers are grouped and identified as ordinaries and stable. These policies structure the portion of the P2P system through the criterias that are employed on arrival, maintenance and management of the connections of the peers, thus reducing the demands on the CDN server. / A escalabilidade e a alta demanda por recursos são os principais desafios que os provedores de conteúdo enfrentam na viabilização de aplicações multimídia baseadas em redes. No YouTube, por exemplo, um dos mais populares sistemas de distribuição de vídeo sob demanda, são enviadas 100 horas de vídeo a cada minuto aos seus servidores e mais de quatro bilhões de horas de vídeo são assistidas a cada mês. Sistemas CDN-P2P têm sido apontados como uma alternativa escalável para distribuição de conteúdo multimídia na Internet. Nesses sistemas, os pares da rede par-a-par (P2P) compartilham seus recursos, diminuindo as demandas sobre a infraestrutura da rede de distribuição de conteúdo (CDN). Por outro lado, os servidores da CDN garantem a disponibilidade de conteúdo quando as contribuições dos pares são limitadas pelo churn, ou quando o conteúdo for inédito aos pares da rede P2P. Contudo, sistemas CDN-P2P, por si só, não garantem a efetividade dos serviços, visto que a saída de pares que são os únicos detentores de um determinado conteúdo pode gerar congestionamento ao redor do servidor da CDN e degradar a qualidade de experiência dos usuários. Nesta dissertação investiga-se a contribuição de pares estáveis para disponibilidade de conteúdo na parte P2P de um sistema CDN-P2P concebido para distribuir vídeos similares aos distribuídos pelo YouTube. Para isso, dados reais foram coletados do site YouTube, explorando-se o potencial de usuários que acessam playlists para caracterizar a estabilidade dos pares no sistema. A suposição acerca da efetividade dos tocadores de playlists na disponibilidade de conteúdo deve-se Ao maior tempo de permanência desses usuários no sistema e á possível popularidade dos conteúdos por eles compartilhados. Verificou-se que quando um número grande de pares tocadores de playlists passam longas sessões conectados, a melhoria na disponibilidade de conteúdo foi de 60%. Adicionalmente em cenários de baixa participação dos tocadores de playlists a melhoria superou 20%. Em seguida, avaliou-se de que forma políticas de formação da malha impactam o sistema de distribuição estudado quando os pares são agrupados e identificados como estáveis e comuns. Estas políticas estruturam a porçãoP2P do sistema através de critérios que são empregados na chegada, na manutenção e gerência das conexões dos pares, diminuindo assim as exigências sobre o servidor da CDN.

Submitted by Sandro Camargo (sandro.camargo@unipampa.edu.br) on 2015-05-09T19:03:09Z No. of bitstreams: 1 107110001.pdf: 3453553 bytes, checksum: fb266cf11dce80833ef41b2adb20cd21 (MD5) / Made available in DSpace on 2015-05-09T19:03:09Z (GMT). No. of bitstreams: 1 107110001.pdf: 3453553 bytes, checksum: fb266cf11dce80833ef41b2adb20cd21 (MD5) Previous issue date: 2012-10-19 / As distribuidoras de energia elétrica devem estar preparadas para restabelecer o fornecimento de forma ágil, sempre respeitando os critérios de segurança e os índices de continuidade e qualidade compatíveis com o estabelecido na legislação vigente. A possibilidade de localizar defeitos remotamente acelera o processo de restabelecimento. Apesar dos próprios relés e religadores microprocessados fornecerem uma indicação com base na impedância de curto-circuito, ela não é precisa para sistemas de distribuição, uma vez que as redes apresentam várias bifurcações (ramais) protegidas por elementos fusíveis e diferentes bitolas de condutores. Entretanto, atualmente há vários métodos como revelam as pesquisas, que tentam estabelecer maior precisão dos dados e resultados ali envolvidos, buscando criar uma inovação e satisfação às empresas do setor elétrico. Assim, a proposta deste projeto é desenvolver uma metodologia diferencial para localização de faltas em redes de distribuição a partir de estudos da rede combinados com a monitoração remota de dispositivos de proteção (relés e religadores microprocessados). Estas variáveis de entrada: corrente de carga (corrente pré-falta), corrente de curto-circuito, corrente pós-falta; serão obtidas em tempo real pelo SCADA no momento da ocorrência de uma falta na rede. As medidas obtidas serão comparadas e classificadas por Mapas Auto-Organizáveis ou SOM (Self-Organizing Map) de acordo com os padrões de dados simulados pelos estudos da rede. A partir do método proposto será possível estimar o local do defeito ocorrido na rede elétrica por meio do mapa que melhor se identifica com os dados medidos. Essa pesquisa foi aplicada no estudo de caso de uma concessionária da região central gaúcha, a qual alcançou resultados bastante satisfatórios, obtidos a partir de dados reais. / The power utilities must be prepared to restore the supply in an agile way constantly respecting the safety criteria and indexes of continuity and quality consistent with the current legislation. The ability to remotely locate defects accelerates this healing process. Despite own microprocessor relays and reclosers provide an indication based on the short circuit impedance, it is not applicable to distribution systems, since the networks present various bifurcations (branch lines) protected by fuse elements and different wire gauges. However, today there are several methods such as surveys show, trying to establish more precisely the data and results here involved, seeking to create an innovation and satisfaction to the electric companies. Thus, the aim of this project is to develop a methodology for distinct fault location in distribution feeders. It will combine network studies with remote monitoring of protective devices (microprocessor relays and reclosers). These input variables: load current (pre-fault current), short circuit current, post-fault current; will be obtained in real time by SCADA when a fault occurs in the network. These measures will be compared and ranked by Self- Organizing Maps (SOM) according to the patterns obtained by simulation studies of the network. With this method, it will be possible to assess the location of the defect occurring in the power grid, identifying the best map that resembles with the measured data. This research was applied in a power utility in the South of Brazil as case study, which achieved satisfactory results obtained from real data.

Este trabalho apresenta a metodologia, o desenvolvimento e testes de um sistema de automação independente, baseado em Redes Neurais Artificiais, para redução de perdas técnicas em redes de distribuição subterrâneas reticuladas por meio do controle ótimo dos bancos de capacitores presentes na rede. A metodologia proposta contempla funcionalidades típicas de Redes Inteligentes, incluindo soluções práticas para o posicionamento de sensores de corrente em redes subterrâneas, coleta de medições de campo e transmissão para o Centro de Operação da Distribuição e controle em tempo real dos equipamentos de campo (bancos de capacitores). Portanto este trabalho consiste na implementação da solução através de baixo custo de investimento na mitigação do controle do fator de potência nos pontos de entrega ao consumidor, sendo que com isto ocorrem melhorias nos indicadores de qualidade e confiabilidade atendendo aos requisitos regulamentares e contratuais de fornecimento das distribuidoras. Para validação da metodologia proposta, foram utilizados os dados da concessionária de energia AES Eletropaulo sobre a Rede de Distribuição Subterrânea Reticulada do centro da cidade de São Paulo. As etapas da metodologia proposta e os principais aspectos do desenvolvimento do sistema são também descritos, bem como os testes realizados para comprovação dos resultados e validação do sistema. / This work presents the methodology, development and testing of an independent automation system, based on Artificial Neural Networks, to reduce technical losses in reticulated underground distribution networks by means of the optimal control of the capacitor banks present in the network. The proposed methodology includes typical functionalities of Intelligent Networks, including practical solutions for the positioning of current sensors in underground networks, collection of field measurements and transmission to the Distribution Operation Center and real-time control of field equipment (capacitors banks). Therefore, this work consists in the implementation of the solution through a low cost of investment in the mitigation of the control of the power factor in the points of delivery to the consumer, and with this there are improvements in the indicators of quality and reliability taking into account the regulatory and contractual requirements of supply of the distributors. The energy concessionaire AES Eletropaulo had great participation in this research project, providing the necessary data of the Reticulated Underground Distribution Network of the city center of São Paulo. The steps of the proposed methodology and the main aspects of system development are also described, as well as the tests performed to prove the results and validate the system.

Os sistemas elétricos de distribuição estão evoluindo rapidamente devido à penetração de geração distribuída e ao crescimento na utilização de avançadas estruturas de medição e sistemas de gerenciamento de distribuição de energia elétrica. Esta evolução traz consigo novos desafios devido à intermitência da geração, a qual pode gerar impactos indesejáveis nos sistemas de distribuição, como a interação de diferentes harmônicos. As Unidades de Medição Fasorial (PMUs) tem potencial para desempenhar um importante papel no monitoramento de sistemas elétricos de distribuição por meio dos fasores com medidas temporalmente sincronizadas de tensão e corrente em vários locais do sistema, oferecendo assim inúmeras possibilidades para estimar o estado de uma rede de distribuição. Porém, para serem utilizadas amplamente em redes de distribuição, é necessário que as PMUs apresentem um menor custo e possuam algumas características funcionais exclusivas para o uso nestas redes. Assim, o objetivo desta tese consiste no desenvolvimento de uma unidade de medição fasorial de baixo custo com características originais para o uso no nível de distribuição de energia elétrica, tais como medição fasorial nas redes de média e baixa tensão utilizando a modelagem dos transformadores e a identificação e estimação dos parâmetros da causa de ocorrência de distúrbios elétricos. Para isso, foram construídos dois protótipos da unidade de medição fasorial proposta neste trabalho, visando verificar a sincronização na medição de fasores de tensão e corrente. Os protótipos também foram acoplados à rede com diferentes combinações de impedância e alimentaram variadas cargas, onde foi possível através das técnicas implementadas nos equipamentos identificar e estimar os parâmetros elétricos da origem (rede ou carga) da ocorrência de variações na tensão e potência fornecidas pela rede distribuição. / Power distribution systems are evolving at a high pace largely due to the proliferation of distributed energy resources and the growing utilization of advanced metering infrastructures and distribution management system. This evolution is also leading to new challenges due large penetration of intermittent distributed generation, which can lead to noticeable impacts on distribution feeders. Phasor Measurement Units (PMUs) have the potential to play an essential role in power distribution system monitoring. For providing synchronized measurements of voltage and current phasors at various system locations, PMUs offer numerous possibilities for ascertaining information relating to the state of the power distribution system. However, to be used widely in power distribution systems, its necessary that PMUs get a low cost and have some exclusive features for these systems. Thus, the main objective of this thesis have consisted of developing a low cost Phasor Measurement Unit with original features proposed for distribution level, such as compatibility with low and medium voltage power networks using transformer modeling and also the identification and parameter estimation of the cause of electrical disturbances. So, they were built two prototypes of the Phasor Measurement Unit, in order to verify the synchronization in the measurement of voltage and current phasors. The prototypes were also coupled to the network with different combinations of impedance and they fed varying loads, where it was possible through the techniques implemented in the equipment identify and estimate electrical parameters of the cause (network or load) of variations in voltage and power supplied by the network distribution.

Les travaux de la thèse se focalisent sur la protection des réseaux de distribution HTA en présence des générateurs distribués (éoliennes, fermes solaires,...). Dans un premier temps, un état de l’art a été réalisé sur les comportements des générateurs en creux de tension, leurs impacts sur le système de protection et les pistes de solution proposées pour y remédier. L’étape suivante est la mise au point d’algorithmes directionnels de détection de défauts, sans mesure de tension. Ces algorithmes s’appuient sur la décomposition en composantes symétriques des courants mesurés. Ces relais doivent empêcher le déclenchement intempestif de protections de surintensité dû au courant de défaut provenant des générateurs distribués. Ils sont moins coûteux par rapport à ceux traditionnels car les capteurs de tension, qui sont indispensables pour ces derniers, peuvent être enlevés. Après détection d’un défaut sur critère de seuil simple (max de I ou max de I résiduel), la direction est évaluée à l’aide d’un algorithme en delta basé sur les rapports courants inverse-homopolaire ou inverse-direct, selon le type de défaut (monophasé ou biphasé). En se basant sur ces rapports, un classifieur SVM (Support Vector Machines), entrainé préalablement à partir des simulations, donne ensuite l’estimation de la direction du défaut (amont ou aval par rapport au relais). La bonne performance de ces algorithmes a été montrée dans la thèse pour différents paramètres du réseau et en présence de différents types de générateurs. Le développement de tels algorithmes favorise la mise en œuvre des protections en réseau, qui pourraient être installées dans les futurs Smart Grids. / This research focuses on the protection of MV distribution networks with Distributed Generators (DGs), such as wind farms or photovoltaic farms, etc. First, the state of art is carried out on fault behaviour of DGs, their impacts on protection system and the mitigation solutions. Next, algorithms are developed for directional relays without voltage sensors. Based on the symmetrical component method, these algorithms help the overcurrent protections to avoid the false tripping issue due to fault contribution of DGs. With the suppression of voltage sensors, such directional relays become cheaper in comparison with the traditional ones. Following the fault detection (the phase or residual current reaches the pick-up value) and depending on fault type (line-to-ground or line-to-line fault), the ratios between the variation (before and during fault) of negative-zero sequence or negative-positive sequence currents are calculated. From these ratios, a SVM (Support Vector Machines) classifier estimates the fault direction (upstream or downstream the detector). The classifier is trained beforehand from transient simulations. This survey shows good performances of the directional algorithms with different network parameters and different kinds of DGs. Such algorithms could be implemented in protections along the feeders in the future smart grids.

En la actualidad, la cobertura de agua potable en el país aún es insuficiente, sobre todo en las zonas rurales del país; de manera similar este problema se presenta en las zonas periurbanas de Lima. Tal como en La Rinconada de Pamplona Alta que se encuentra ubicada en el distrito San Juan de Miraflores, el cual no cuenta con servicio básico de agua potable, el abastecimiento de este recurso se realiza mediante camiones cisterna y son almacenados en tanques, bidones, baldes, etc. Es por ello, que la presente investigación plantea una propuesta de diseño del sistema de abastecimiento de agua potable para la zona de estudio, para lo cual se toma en consideración que el caudal requerido será brindado por SEDAPAL. Debido a que la topografía de la zona de estudio presenta pendientes pronunciadas es necesario utilizar válvulas reductoras de presión, cuya localización se realiza a través de la aplicación del Algoritmo Genético Multiobjetivo, el cual en su codificación incluye el uso del Epanet Programmer’s Toolkit, que viene a ser una biblioteca dinámica (DLL) de funciones que permite a los programadores personalizar el motor de cálculo de EPANET para sus necesidades específicas. En ese sentido, el método utilizado plantea una propuesta de mejora en el proceso de diseño del sistema de abastecimiento de agua potable en La Rinconada de Pamplona Alta del distrito de San Juan de Miraflores. Para lo cual, se utilizó el programa EPANET en la simulación y cálculo hidráulico de la red de distribución por ser un programa de comprobada eficacia y de uso libre. Por otro lado, el resultado del análisis hidráulico de los proyectos de agua potable que se realizan en el país tanto por métodos manuales iterativos o con ayuda de programas de simulación, muchas veces no cumplen con las exigencias del rango de presiones admisibles establecido por el Reglamento Nacional de Edificaciones, lo cual se traduce por un lado en costos de cumplir programas de mantenimiento que suplan estas deficiencias y por otro lado posibles roturas de tuberías o fugas de agua debido a altas presiones. Es por ello que se busca cumplir con los requisitos exigidos por las normas de diseño y a la vez brindar una adecuada presión de servicio, para lo cual se hace uso del Algoritmo Genético Multiobjetivo en el diseño de la red para la zona de estudio, lo cual conllevaría a un ahorro en los costos de operación y mantenimiento. Finalmente el diseño propuesto para el sistema de abastecimiento de agua potable en La Rinconada de Pamplona Alta está conformado por el reservorio RAP-1 que abastece mediante una línea de aducción a cuatro zonas de presión y el reservorio RRP-3 que abastece por otra línea de aducción a tres zonas de presión debido a que la topografía presenta desniveles considerables. Adicionalmente, con el uso de un subprograma incluido en el Algoritmo Genético Multiobjetivo se logró asignar los caudales de demanda de manera automática en todos los nodos de la red de distribución contribuyendo a la mejora en el proceso de diseño mediante el programa EPANET. / At present, the coverage of drinking water in the country is still insufficient, especially in rural areas of the country; similarly, this problem occurs in the peri-urban areas of Lima. Such as the La Rinconada area of Pamplona Alta which is located in the San Juan de Miraflores district that does not have a basic potable water service, the supply of this resource is done by tank trucks and stored in tanks, drums, buckets, etc. It is for this reason that the present investigation proposes a design proposal for the potable water supply system for the study area, for which it is taken into consideration that the required flow will be provided by SEDAPAL. Because the topography of the study area presents steep slopes, it is necessary to use pressure reducing valves, which are localized through the application of the Multiobjective Genetic Algorithm, which in its coding includes the use of the Epanet Programmer's Toolkit, which comes to be a dynamic library (DLL) of functions that allows programmers to customize the EPANET calculation engine for their specific needs. In this sense, the method used proposes a proposal for improvement in the design process of the potable water supply system in La Rinconada de Pamplona Alta in the district of San Juan de Miraflores. For which, the EPANET program was used in the simulation and hydraulic calculation of the distribution network as it is a program of proven effectiveness and free use. On the other hand, the result of the hydraulic analysis of drinking water projects carried out in the country either by iterative manual methods or with the help of simulation programs, often does not meet the requirements of the range of admissible pressures established by the Regulation. National Building, which translates on the one hand in costs of carrying out maintenance programs that supply these deficiencies and on the other hand possible pipe breaks or water leaks due to high pressures. That is why it seeks to meet the requirements of the design standards and at the same time provide adequate service pressure, for which the Multiobjective Genetic Algorithm is used in the design of the network for the study area, which it would lead to savings in operation and maintenance costs. Finally, the proposed design for the drinking water supply system in La Rinconada de Pamplona Alta is made up of the RAP-1 reservoir that supplies four pressure zones through an adduction line and the RRP-3 reservoir that supplies another line of water. adduction to three pressure zones because the topography presents considerable differences in level. Additionally, with the use of a subprogram included in the Multiobjective Genetic Algorithm, it was possible to assign the demand flows automatically in all nodes of the distribution network contributing to the improvement in the design process through the EPANET program. / Tesis

Aging infrastructure and personnel, combined with stricter financial constraints has put maintenance, or more popular Asset Management, at the top of the agenda for most power utilities. At the same time the industry reports that this area is not properly supported by information systems. Today’s power utilities have very comprehensive and complex portfolios of information systems that serve many different purposes. A common problem in such heterogeneous system architectures is data management, e.g. data in the systems do not represent the true status of the equipment in the power grid or several sources of data are contradictory. The research presented in this thesis concerns how this industrial problem can be better understood and approached by novel use of the ontology standardized in the Common Information Model defined in IEC standards 61970 & 61968. The theoretical framework for the research is that of data management using ontology based frameworks. This notion is not new, but is receiving renewed attention due to emerging technologies, e.g. Service Oriented Architectures, that support implementation of such ontological frameworks. The work presented is empirical in nature and takes its origin in the ontology available in the Common Information Model. The scope of the research is the applicability of the CIM ontology, not as it was intended i.e. in systems integration, but for analysis of business processes, legacy systems and data. The work has involved significant interaction with power distribution utilities in Sweden, in order to validate the framework developed around the CIM ontology. Results from the research have been published continuously, this thesis consists of an introduction and summary and papers describing the main contribution of the work. The main contribution of the work presented in this thesis is the validation of the proposition to use the CIM ontology as a basis for analysis existing legacy systems. By using the data models defined in the standards and combining them with established modeling techniques we propose a framework for information system management. The framework is appropriate for analyzing data quality problems related to power systems maintenance at power distribution utilities. As part of validating the results, the proposed framework has been applied in a case study involving medium voltage overhead line inspection. In addition to the main contribution, a classification of the state of the practice system support for power system maintenance at utilities has been created. Second, the work includes an analysis and classification of how high performance Wide Area communication technologies can be used to improve power system maintenance including improving data quality. / QC 20100614

The overall goal of this research is to develop an integrated system dynamics framework for sustainable management of municipal water and wastewater systems. Canadian municipalities have traditionally relied on grants received from senior levels of government to finance construction of water supply and wastewater collection infrastructure. User fees for water and wastewater services were determined so as to recover only the operating expenditures with no allowance to recoup the capital costs of infrastructure. As the infrastructure assets started approaching the end of their service life, investments needed to rehabilitate these assets were deferred in the expectation of receiving further grants for this purpose. Hence, a significant backlog of deteriorated infrastructure has accumulated over the years. Recently enacted regulations require that all expenditures incurred on provision of water and wastewater services should ultimately be financed from user fee based revenues. Another piece of legislation provides for establishment of service performance standards. Urban water and wastewater systems involve interconnections among physical infrastructure, financial, and socio-political factors. Several interacting feedback loops are formed due to these interconnections and render the management of water and wastewater infrastructure as a complex, dynamic problem. Existing asset management tools in the literature are found inadequate to capture the influence of feedback loops. A novel system dynamics approach is used to develop a demonstration model for water and wastewater network management. Model results for a case study show significance of feedback loops for financial sustainability of the system. For example, user fees have to be substantially increased to achieve financial sustainability, especially when price elasticity of water demand is considered. A detailed causal loop diagram for management of wastewater collection networks is presented. The causal loop diagram lays out qualitative causal relationships among system components and identifies multiple interacting feedback loops. Based on this causal loop diagram, a system dynamics model comprised of a wastewater pipes sector, a finance sector, and a consumers sector, is developed. Policy levers are included in the model to facilitate formulation of different financing and rehabilitation strategies for the wastewater collection network. Financial and service performance indicators included in the model allow comparison of different financing and rehabilitation strategies. Data requirements for implementation of the model are discussed. The wastewater collection network model is implemented for a case study of a medium-sized Canadian municipality with a substantial backlog of deteriorated pipes. A methodology for parameterization of the model using existing data sources is presented. Simulation results indicate that different financing strategies ranging from no borrowing to full utilization of debt capacity can achieve similar total life-cycle costs but with significantly varying impacts for consumers in terms of service performance and financial burden. A detailed causal loop diagram for management of a watermain distribution network is employed to identify feedback loops. The causal loop diagram is then developed into a system dynamics model comprised of watermain pipes, financial, and consumer sectors. Data requirements for implementation of the model are discussed.

Ο σκοπός αυτής της διπλωματικής εργασίας ήταν η μελέτη και η καταγραφή των σφαλμάτων που έχουν προκληθεί από ποικίλες αιτίες στο Δίκτυο Διανομής (Μέση Τάση) της Ηλεκτρικής Ενέργειας της νήσου Κρήτης και πιο συγκεκριμένα στο εναέριο δίκτυο αυτού. Για την κατανόηση όμως του λόγου που οι εν λόγω αιτίες οδήγησαν σε σφάλματα, αλλά και για να έχουμε μια πιο πλήρη εικόνα επί του αντικειμένου, έπρεπε αρχικά να γίνει μια συνοπτική παρουσίαση ενός τυπικού συστήματος ηλεκτρικής ενέργειας, αφού πρώτα αναλυθεί στα επιμέρους τμήματά του. Εν συνεχεία αναλύουμε λεπτομερώς την διαμόρφωση των δικτύων διανομής και τον βασικό εξοπλισμό από τον οποίο αποτελείται. Ακολούθως μελετούμε τα εναέρια δίκτυα διανομής μέσης τάσης παρουσιάζοντας πλήρως όλα τα στοιχεία που συμβάλλουν στην ομαλή διανομή της ηλεκτρικής ενέργειας στον καταναλωτή. Στο επόμενο βήμα παρουσιάζουμε την IEEE οδηγία για τη συμπεριφορά έναντι κεραυνών των εναέριων γραμμών διανομής ηλεκτρικής ενέργειας, μιας και οι επικρατούντες κλιματολογικές - περιβαλλοντολογικές συνθήκες είναι από τις βασικές αιτίες πρόκλησης σφαλμάτων στα εναέρια δίκτυα. Τέλος, παρουσιάζουμε τα σφάλματα που έχουν καταγραφεί στα ημερήσια δελτία σημαντικών μη προγραμματισμένων διακοπών της νήσου Κρήτης για τα έτη από το 2005 έως το 2009. / The aim of this diploma thesis was the examination and comprehension of the aerial distribution networks of electrical power. In the beginning we briefly analyzed the electric power systems (power stations, transmission networks, distribution networks). After that we thoroughly examined the configuration of the distribution networks with the observation of the ways the networks are planned and their equipment, which is used for their protection and for the connection between them. Afterwards we examined the aerial distribution networks of medium voltage, by fully presenting all the elements which contribute in the normal distribution of the electric flow to the customers. Finally we present the faults that have happened to the middle voltage distribution circuit of the island Crete and we compare them with the theoretical number of faults, according the IEEE guide in order to come to some useful conclusions.