Made available in DSpace on 2015-05-14T12:09:32Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 4820663 bytes, checksum: cc588b07b38e446793574dcf4b7b7b0c (MD5) Previous issue date: 2014-06-09 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The present study aims dissertative modeling and calibration of a real distribution system water, with emphasis on the identification of water losses. The case study was the supply system of Juatama community in Quixadá, located in the central region of the state of Ceará. The distribution network under study was recently installed and is operating with stability, which enabled the development of a model that successfully describes the real system. The calibration process was carried out through LenhsCalibra application, which uses an optimization algorithm based on the technique of genetic algorithms. The program allowed multivariate calibration, including how to search the demand variables and the roughness of pipes, whose values were adjusted using simulations from the actual flow levels and pressures. The calibrated model system showed satisfactory results, and identify the record of discharges used for cleaning of the network and network points higher than those with demands effectively, are consumed by customers. / O presente estudo dissertativo tem por objetivo a modelagem e calibração de um sistema de distribuição de água real, com ênfase na identificação das perdas de água. O estudo de caso foi o sistema de abastecimento da comunidade de Juatama, em Quixadá, localizada na região central do Estado do Ceará. A rede de distribuição em estudo foi instalada recentemente e vem operando com estabilidade, o que possibilitou o desenvolvimento de um modelo que descreve satisfatoriamente o sistema real. O processo de calibração foi realizado por meio do aplicativo LenhsCalibra, que utiliza um algoritmo de otimização baseado na técnica de algoritmos genéticos. O programa possibilitou a calibração multivariada, incluindo como variáveis de busca a demanda e a rugosidade das tubulações, cujos valores foram ajustados através de simulações a partir dos níveis de vazão e pressões reais. O modelo calibrado do sistema apresentou resultados satisfatórios, além de identificar o registro de descargas utilizadas para limpeza da rede e pontos na rede com demandas superiores às que, efetivamente, são consumidas pelos clientes.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Este trabalho apresenta um sistema multiagente para recomposiÃÃo au-tomÃtica de redes de distribuiÃÃo de energia elÃtrica. O sistema proposto à formado por trÃs tipos de agentes: agente dispositivo, agente alimentador e agente subesta-ÃÃo. Os agentes dispositivos estÃo associados aos equipamentos do sistema e sÃo responsÃveis pela coleta de informaÃÃes da rede; os agentes alimentadores sÃo responsÃveis pelo gerenciamento dos alimentadores do sistema; e, os agentes su-bestaÃÃes sÃo responsÃveis pelo gerenciamento da capacidade de suprimento da rede. SÃo apresentados os comportamentos e interaÃÃes dos agentes do sistema durante o processo de recomposiÃÃo, visando restabelecer a energia elÃtrica dos trechos desenergizados e nÃo defeituosos, afetados por falta no alimentador ou falta no transformador da subestaÃÃo. SÃo apresentados oito estudos de casos que testam diferentes situaÃÃes possÃveis de ser encontrada nos sistemas de distribuiÃÃo, como recomposiÃÃo mediante descoordenaÃÃo da proteÃÃo, recomposiÃÃo parcial do sistema devido as restriÃÃes operacionais do sistema e recomposiÃÃes para falta no transformador da subestaÃÃo. Para validaÃÃo dos casos testes foi desenvolvido um simulador que possibilita a simulaÃÃo de faltas em diferentes locais do sistema elÃtrico em estudo. AtravÃs do ambiente visual do simulador, onde à disponibilizado o diagrama unifilar do sistema com os estados dos equipamentos e a ferramenta de captura de mensagem do JADE, à possÃvel simular diversos cenÃrios e observar interaÃÃo dos agentes em busca da recomposiÃÃo do sistema. O sistema proposto à capaz de localizar a falta, isolar o trecho defeituoso e restaurar o sistema, considerando restriÃÃes operacionais e descoordenaÃÃo do sistema de proteÃÃo. / This work presents a multi-agent system for automatic restoration of power distribution networks. The proposed system consists of three types of agents: device agent, feeder agent and substation agent. Device agents are associated with system equipment and are responsible for information acquisition of the network; the feeder agents are responsible to manage the feeders; and the substations agents are accountable of manage the network supply capability. The behaviors and interactions of the system agents during the restoration process, aiming to restore the feeder sectors affected by but not in fault, are presented. Eight case studies are presented, which test different possible situations likely to be found in the distribution systems, such as restoration by uncoordinated protection, partial recovery of the system because of operating system restrictions and recomposition for faults in the transformer substation. To validate the test cases a simulator was developed, which allows the simulation of faults in different locations of the power system under study. Through the simulator, where there are the single line diagram of the system with the state of the equipment and the tool to capture message in JADE, is possible to simulate different scenarios and observe the interaction of agents in search of system restoration. The proposed system is able to locate and isolate the fault, and restore suitably the system, considering operating limits and uncoordinated system protection.

Esta dissertação apresenta uma metodologia de otimização do fluxo de potência em sistemas elétricos de subtransmissão utilizando duas técnicas da Computação Evolutiva, os Algoritmos Genéticos e as Estratégias Evolutivas. A metodologia decompõe o problema em duas partes e o trata seqüencialmente. A primeira parte procede com a otimização do fluxo de potência ativa e a segunda com a otimização do fluxo de potência reativa. São apresentadas as características e estruturas básicas dos Algoritmos Genéticos e das Estratégias Evolutivas. A técnica dos Algoritmos Genéticos é implementada no modelo de otimização do fluxo de potência ativa e a técnica das Estratégias Evolutivas no modelo de otimização do fluxo de potência reativa. As variáveis de controle dos modelos desenvolvidos são, respectivamente, os estados dos dispositivos de seccionamento e os níveis de tensão dos barramentos dos pontos de fronteira, associadas ao sistema analisado. Analisam-se os sistemas elétricos de subtransmissão que contêm múltiplos pontos de fronteira (conexão) com a Rede Básica e diversas possibilidades de configuração operativa. A metodologia proposta é aplicada a um sistema elétrico de subtransmissão real a fim de minimizar o custo dos encargos de uso dos sistemas de transmissão. Os resultados obtidos mostram a eficácia dos algoritmos desenvolvidos na busca das soluções desejadas. / This dissertation presents a power flow optimization methodology on subtransmission electric systems using two techniques of Evolutionary Computation, namely the Genetic Algorithms and the Evolution Strategies. The methodology splits the problem into two parts and treats it separately. On the first step it proceeds to optimize the active power flow and on the second step to optimize the reactive power flow. Characteristics and basic structures of the Genetic Algorithms and the Evolution Strategies are shown. The Genetic Algorithms technique is implemented on the active power flow optimization model and the Evolution Strategies technique on the reactive power flow optimization model. The control variables of developed models are, respectively, the switch states and the border point bar voltage levels, associated to the analyzed system. The subtransmission electric systems that have multiple border (connection) points to the Basic Network and many operative configuration possibilities are analyzed. The proposed methodology is applied to a real subtransmission electric system in order to minimizes the transmission system use duty costs. The obtained results show the efficacy of the developed algorithms in the search of desired solutions.

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-05-23T17:48:25Z No. of bitstreams: 1 andrelopesmarinhodossantos.pdf: 2400435 bytes, checksum: 2f58d7bcbbafebad1c3f9814b3568a23 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-05-24T17:37:03Z (GMT) No. of bitstreams: 1 andrelopesmarinhodossantos.pdf: 2400435 bytes, checksum: 2f58d7bcbbafebad1c3f9814b3568a23 (MD5) / Made available in DSpace on 2018-05-24T17:37:03Z (GMT). No. of bitstreams: 1 andrelopesmarinhodossantos.pdf: 2400435 bytes, checksum: 2f58d7bcbbafebad1c3f9814b3568a23 (MD5) Previous issue date: 2018-02-26 / O presente trabalho apresenta uma metodologia para o planejamento da operação de bancos de baterias em redes de distribuição, as quais contém a presença de geração distribuida proveniente de fontes renováveis de energia. Para tanto, o problema do fluxo ótimo de potência é solucionado com a inclusão da potência injetada ou absorvida pelas baterias como variável de otimização no modelo proposto. O objetivo é que a inserção de baterias impacte de forma a reduzir os custos de energia e os custos de confiabilidade da rede, e, consequentemente provocando a diminuição dos custos totais de operação do SDE em um horizonte de planejamento de longo prazo. A utilização da meta-heurística denominada SIA se deve a sua aplicabilidade em sistemas de grande porte, visto que, nestes casos, a busca exaustiva pela melhor solução torna-se inviável. Análises utilizando cinco tipos de baterias e sua inserção em quatro sistemas de distribuição conhecidos da literatura são realizados para a validação da metodologia proposta. Resultados apresentados demonstram a aplicabilidade da metodologia proposta, assim como a viabilidade de utilização de bancos de baterias em redes de distribuição de energia. / This work presents an application for the operation planning of battery storage systems in electricity distribution networks with penetration of distributed generation from renewable sources of energy. For this, the an optimal power flow algorithm is applied with the inclusion of the power supplied or absorbed by battery banks as an optimization variable in the developed model. The objective is that the battery banks insertion impacts on the reduction of energy and reliability costs of the network, and, as a consequence, to lead in the reduction of the total costs of the distribution network in a long term operation period. The choice for a meta-heuristic called SIA is due their ability to deal with large scale problems, in which an exhaustive search would not be feasible. Analysis using five battery types applied to four well known systems in literature are performed to validate the proposed methodology. Results presented demonstrate the applicability of the proposed methodology, as well as the feasibility of using battery banks in energy distribution networks.

Le raccordement des énergies renouvelables (ENR) aux réseaux de distribution peuvent nécessiter des travaux de renforcement coûteux et long à mettre en œuvre. Différentes solutions alternatives peuvent dans certains cas limiter l'ampleur des travaux à réaliser et donc leur montant et/ou leur durée. L’utilisation de telles solutions nécessite au préalable de réviser les méthodes de planification du réseau pour qu’elles puissent analyser leurs impacts technico-économiques. Cette thèse a pour objet d’apporter un cadre adapté à l’étude des leviers d’intégration des ENR à l’aide de nouvelles méthodes pour la planification pluriannuelle des réseaux de distribution. Comparée à l’état de l’art, l’approche adoptée présente l’avantage d’estimer les performances de ces leviers à moyen/long terme en considérant : 1) le comportement du gestionnaire de réseau de distribution, modélisé sous la forme d’une stratégie de planification multi-variables, 2) les interactions entre les réseaux de moyenne et basse tension, et 3) les incertitudes sur l’arrivée des ENR. Ces trois axes d’amélioration ont pu être abordés grâce à des méthodes de maîtrise du temps de calcul appliquées à l’estimation pluriannuelle de l’état électrique du réseau. Le potentiel de l’approche proposée est illustré via l’analyse technico-économique de plusieurs stratégies de planification incluant des leviers traditionnels et/ou des leviers d’effacement de production. Les travaux se concluent sur une première contribution sur l’optimisation des stratégies de planification compte tenu des incertitudes sur l’arrivée des ENR / The integration of Renewable Energy Sources (RES) into the distribution networks may require network reinforcements that can be expensive and take time. Different alternative solutions can limit the amount of work to be carried out and thus reduce their cost and/or duration. The use of such solutions requires modifying the network planning methods so as to analyze their techno-economic impacts. This research aims to provide a suitable framework for the study of RES-integration solutions using novel methods for the multi-year planning of distribution networks. Compared to the state of the art, the proposed approach provides the advantage of assessing the performance of these solutions in the medium/long run by considering: 1) the behavior of the distribution system operator, which is modeled as a multi-variable planning strategy, 2) the interactions between medium- and low-voltage networks, and 3) the uncertainties on the arrival of new RES. These three points could have been addressed by applying methods of reducing computation time to the multi-year estimation of the electrical network state. The potential of the proposed approach is illustrated through the techno-economic analysis of several planning strategies including traditional solutions and/or generation curtailment. The research concludes with a first contribution to the planning strategy optimization by taking into account the uncertainties on the arrival of new RES.

The aim of this thesis is to create a business plan for an existing company Design Bath, which operates as a wholesale and exclusive distributor of company PORCELANOSA Grupo on the Czech market of ceramic tiles. The plan is focused on building and extending current distribution network of PORCELANOSA Grupo products and should serve as a background for future decision making process and development of long-term strategy of company Design Bath. On the basis of this business plan we should be able to evaluate its feasibility. The theoretical part of this thesis contains basic introduction into business plans from theoretical point of view and market research methodology. The practical part includes the description of international and Czech market of ceramic tiles in order to understand the business opportunity. Description of competition, market research, proposal of suitable forms of distribution and financial plan are all included in the practical part in the way that the chapters logically follow each other. Financial plan revealed that the business plan is viable. Potential risks and conditions of successful realization complete the last part of the thesis.

Today’s power systems are based on a centralised system and distribution networks that are considered as passive terminations of transmission networks. The high penetration of Distributed Generation (DG) at the distribution network level has created many challenges for this structure. New tools and simulation approaches are required to address the subject and to quantify the dynamic characteristics of the system. A distribution network or part of it with DG, Active Distribution Network Cell (ADNC), can no longer be considered as passive. An equivalent dynamic model of ADNC is therefore extremely important, as it enables power system operators to quickly estimate the impact of disturbances on the power system’s dynamic behaviour. A dynamic equivalent model works by reducing both the complexity of the distribution network and the computation time required to run a full dynamic simulation. It offers a simple and low-order representation of the system without compromising distribution network dynamic characteristics and behaviour as seen by the external grid. This research aims to develop a dynamic equivalent model for ADNC. It focuses on the development of an equivalent model by exploiting system identification theory, i.e. the grey-box approach. The first part of the thesis gives a comprehensive overview and background of the dynamic equivalent techniques for power systems. The research was inspired by previous work on system identification theory. It further demonstrates the theoretical concept of system identification, system load modelling and the modelling of major types of DG. An equivalent model is developed, guided by the assumed structure of the system. The problem of equivalent model development is then formulated under a system identification framework, and the parameter estimation methodology is proposed. The validation results of the effectiveness and accuracy of the developed model are presented. This includes the estimation of the parameter model using a clustering algorithm to improve the computational performance and the analysis of transformer impedance effects on the ADNC responses. The evaluation of probability density function, eigenvalue analysis and parameter sensitivity analysis for the model parameters are also presented. Typical model parameters for different network topologies and configurations are identified. Finally, the developed equivalent model is used for a large power system application. The accuracy and robustness of the developed equivalent model are demonstrated under small and large disturbance studies for various types of fault and different fault locations.

To mitigate high voltages in transmission systems with low demands, traditional solutions often consider the installation of reactive power compensators. The deployment and tuning of numbers of VAr compensators at various locations may not be cost-effective. This thesis presents an alternative method that utilises existing parallel transformers in distribution networks to provide reactive power supports for transmission systems under low demands. The operation of parallel transformers in small different tap positions, i.e. with staggered taps, can provide a means of absorbing reactive power. The aggregated reactive power absorption from many pairs of parallel transformers could be sufficient to provide voltage support to the upstream transmission network. Network capability studies have been carried out to investigate the reactive power absorption capability through the use of tap stagger. The studies are based on a real UK High Voltage distribution network, and the tap staggering technique has been applied to primary substation transformers. The results confirm that the tap staggering method has the potential to increase the reactive power demand drawn from the transmission grid. This thesis also presents an optimal control method for tap stagger to minimise the introduced network loss as well as the number of tap switching operations involved. A genetic algorithm (GA) based procedure has been developed to solve the optimisation problem. The GA method has been compared with two alternative solution approaches, i.e. the rule-based control scheme and the branch-and-bound algorithm. The results indicate that the GA method is superior to the other two approaches. The economic and technical impacts of the tap staggering technique on the transmission system has been studied. In the economic analysis, the associated costs of applying the tap staggering method have been investigated from the perspective of transmission system operator. The IEEE Reliability Test System has been used to carry out the studies, and the results have been compared with the installation of shunt reactors. In the technical studies, the dynamic impacts of tap staggering or reactor switching on transmission system voltages have been analysed. From the results, the tap staggering technique has more economic advantages than reactors and can reduce voltage damping as well as overshoots during the transient states.

Integration of renewable energy systems by the utility, customers, and the third party into the electric power system, most especially in the MV and LV distribution networks grew over the last decade due to the liberalization of the electricity market, rising energy demand, and increasing environmental concern. The distributed rooftop PV system contributes to relieve the overall load, reduce losses, avoid conventional generation upgrade, and better matching of demand on the LV distribution network. Originally, the LV distribution network is designed for unidirectional current flow, that is from the substation to customers. However, a high penetration of rooftop solar PVs (with power levels typically ranging from 1 – 10 kW) may lead to the current flowing in the reverse direction and this could result in a sudden voltage rise. These negative impacts on the network have discouraged the distribution network operators (DNOs) to allow increased PV penetration in the LV distribution network because some customers load, and equipment are sensitive to voltage perturbation. Presently, the most applied voltage rise mitigation strategy for high rooftop solar PV penetration is the total disconnect from the LV distribution network when the voltage at the point of common coupling (PCC) goes above statutory voltage limits. However, the sudden disconnection of the PV system from the grid can cause network perturbation and affect the security of the network. This action may also cause voltage instability in the network and can reduce the lifetime of grid equipment such as voltage regulators, air conditioner etc. Due to this negative impact, different voltage rise mitigation strategies such as the active transformer with on load tap changers (OLTC), distributed battery energy storage system and reactive power support (D-STATCOM, etc.) have been used to curtail voltage rise in the distribution network. However, the implementation of D-STATCOM device on a radial LV distribution network results in high line current and losses. This may be detrimental to the distribution network. Therefore, in this thesis, a coordinated active power reduction (CAPR) strategy is proposed using a modified PWM PI current control strategy to ramp down the output power and voltage of a grid-tied voltage source inverter (VSI). In the proposed strategy, a reactive reference is generated based on the measured voltage level at the PCC using a threshold voltage algorithm to regulate the amplitude of the modulating signal to increase the off time of the high frequency signal which shut down the PV array momentary in an extremely short time and allow the VSI to absorb some reactive power through the freewheeling diode and reduce voltage. The proposed CAPR strategy was designed and simulated on a scaled down simple radial LV distribution network in MATLAB®/Simulink® software environment. The results show that the CAPR can ramp down the PV output power, reduce reverse power flow and reduce the sudden voltage rise at the point of common coupling (PCC) within ±5% of the standard voltage limit. The study also compares the performance of the proposed CAPR strategy to that of the distributed static compensator (D-STATCOM) and battery energy storage system (BESS) with respect to response time to curtail sudden voltage rise, losses and reverse power flow. The investigation shows that the D-STATCOM has the faster response time to curtail voltage rise. However, the voltage rise reduction is accompanied by high current, losses and reverse active power flow. The introduction of the BESS demonstrates better performance than the D- STATCOM device in terms of reverse power flow and losses. The CAPR strategy performs better than both D-STATCOM and BESS in terms of line losses and reverse power flow reduction.

The diploma thesis deals with the design of the connection of the Svratecko area with the distribution network of the company E.ON Distribuce, a.s.. The theoretical part describes the energy legislation and the individual standards on which the thesis is based. It also describes the concept of a 22 kV high voltage network. The practical part of the thesis is focused on the creation of line models in the program E-vlivy, which will supply the Svratecko area and the model of the monitored area. Outputs from the thesis will be used by E.ON Distribuce, a.s. to evaluate the connection of the Svratecko area.