This dissertation is a systematic study of artificial neural networks (ANN) applications in power system restoration (PSR). PSR is based on available generation and load to be restored analysis. A literature review showed that the conventional PSR methods, i.e. the pre-established guidelines, the expert systems method, the mathematical programming method and the petri-net method have limitations such as the necessary time to obtain the PSR plan. ANN may help to solve this problem presenting a reliable PSR plan in a smaller time. Based on actual and past experiences, a PSR engine based on ANN was proposed and developed. Data from the Iowa 162 bus power system was used in the implementation of the technique. Reactive and real power balance, fault location, phase angles across breakers and intentional islanding were taken into account in the implementation of the technique. Constraints in PSR as thermal limits of transmission lines (TL), stability issues, number of TL used in the restoration plan and lockout breakers were used to create feasible PSR plans. To compare the time necessary to achieve the PSR plan with another technique a PSR method based on a breadth-search algorithm was implemented. This algorithm was also used to create training and validation patterns for the ANN used in the scheme. An algorithm to determine the switching sequence of the breakers was also implemented. In order to determine the switching sequence of the breakers the algorithm takes into account the most priority loads and the final system configuration generated by the ANN. The PSR technique implemented is composed by several pairs of ANN, each one assigned to an individual island of the system. The restoration of the system is done in parallel in each island. After each island is restored the tie lines are closed. The results encountered shows that ANN based schemes can be used in PSR helping the operators restore the system under the stressful conditions following a blackout. / Ph. D.

The interdependencies that exist within and between infrastructures can cause unexpected system properties to emerge when their components fail due to large disruptions. As witnessed following emergencies such as Hurricane Katrina, the complexities of these interdependencies make it very difficult to effectively recover infrastructure because of the challenges they create in prioritizing the most critical components for repair. The Joint Infrastructure Interdependencies Research Program was initiated by Public Safety Canada (PSC) and the Natural Sciences and Engineering Research Council of Canada (NSERC) in 2005 to research methods for remedying this problem. As a part of this research, the University of British Columbia (UBC) is developing an infrastructure interdependency simulator, named I2Sim, to simulate disasters and develop strategies for dealing with emergencies. Part of this development is to construct a model of the UBC electrical distribution system and interface it with I2Sim. In this research, a general methodology for such a model is presented, which employs an off-the-shelf powerflow modeling tool. In addition, a model of the UBC information technology infrastructure is developed to provide a second infrastructure model to demonstrate the electrical model's usefulness in multi-infrastructure disaster recovery simulations. Simulations with these models have shown that the recovery of this two-infrastructure system can be carried out more effectively following an earthquake if both infrastructures are considered together in the repair approach, rather than individually. This difference was on the order of thirty percent. To extend this research from electrical distribution systems to electrical bulk systems, an interdependency model of the British Columbia Transmission Corporation bulk power network and its communications system was also developed, along with a post-blackout restoration procedure. Using these, simulations of a post-blackout recovery were carried out to study the level of risk that communications outages may pose to the electrical network's recovery. These simulations revealed a correlation between restoration time and the number of communication points lost. This research also demonstrates there is value in combining the results of such simulations with risk evaluation tools. Together these results provided a clearer indication of where vulnerabilities exist.

The interdependencies that exist within and between infrastructures can cause unexpected system properties to emerge when their components fail due to large disruptions. As witnessed following emergencies such as Hurricane Katrina, the complexities of these interdependencies make it very difficult to effectively recover infrastructure because of the challenges they create in prioritizing the most critical components for repair. The Joint Infrastructure Interdependencies Research Program was initiated by Public Safety Canada (PSC) and the Natural Sciences and Engineering Research Council of Canada (NSERC) in 2005 to research methods for remedying this problem. As a part of this research, the University of British Columbia (UBC) is developing an infrastructure interdependency simulator, named I2Sim, to simulate disasters and develop strategies for dealing with emergencies. Part of this development is to construct a model of the UBC electrical distribution system and interface it with I2Sim. In this research, a general methodology for such a model is presented, which employs an off-the-shelf powerflow modeling tool. In addition, a model of the UBC information technology infrastructure is developed to provide a second infrastructure model to demonstrate the electrical model's usefulness in multi-infrastructure disaster recovery simulations. Simulations with these models have shown that the recovery of this two-infrastructure system can be carried out more effectively following an earthquake if both infrastructures are considered together in the repair approach, rather than individually. This difference was on the order of thirty percent. To extend this research from electrical distribution systems to electrical bulk systems, an interdependency model of the British Columbia Transmission Corporation bulk power network and its communications system was also developed, along with a post-blackout restoration procedure. Using these, simulations of a post-blackout recovery were carried out to study the level of risk that communications outages may pose to the electrical network's recovery. These simulations revealed a correlation between restoration time and the number of communication points lost. This research also demonstrates there is value in combining the results of such simulations with risk evaluation tools. Together these results provided a clearer indication of where vulnerabilities exist.

The interdependencies that exist within and between infrastructures can cause unexpected system properties to emerge when their components fail due to large disruptions. As witnessed following emergencies such as Hurricane Katrina, the complexities of these interdependencies make it very difficult to effectively recover infrastructure because of the challenges they create in prioritizing the most critical components for repair. The Joint Infrastructure Interdependencies Research Program was initiated by Public Safety Canada (PSC) and the Natural Sciences and Engineering Research Council of Canada (NSERC) in 2005 to research methods for remedying this problem. As a part of this research, the University of British Columbia (UBC) is developing an infrastructure interdependency simulator, named I2Sim, to simulate disasters and develop strategies for dealing with emergencies. Part of this development is to construct a model of the UBC electrical distribution system and interface it with I2Sim. In this research, a general methodology for such a model is presented, which employs an off-the-shelf powerflow modeling tool. In addition, a model of the UBC information technology infrastructure is developed to provide a second infrastructure model to demonstrate the electrical model's usefulness in multi-infrastructure disaster recovery simulations. Simulations with these models have shown that the recovery of this two-infrastructure system can be carried out more effectively following an earthquake if both infrastructures are considered together in the repair approach, rather than individually. This difference was on the order of thirty percent. To extend this research from electrical distribution systems to electrical bulk systems, an interdependency model of the British Columbia Transmission Corporation bulk power network and its communications system was also developed, along with a post-blackout restoration procedure. Using these, simulations of a post-blackout recovery were carried out to study the level of risk that communications outages may pose to the electrical network's recovery. These simulations revealed a correlation between restoration time and the number of communication points lost. This research also demonstrates there is value in combining the results of such simulations with risk evaluation tools. Together these results provided a clearer indication of where vulnerabilities exist. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Orientador: Andre Luiz Morelato França / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-04T08:14:44Z (GMT). No. of bitstreams: 1 Mota_LiaToledoMoreira_D.pdf: 2050832 bytes, checksum: 67d474d280eaf6b619b3f766e55b9010 (MD5) Previous issue date: 2005 / Resumo: Neste trabalho, foram desenvolvidos dois métodos para prever o comportamento da carga durante a reenergização de redes elétricas pós-blecaute total ou parcial e instantes posteriores. O primeiro consiste em um Método Heurístico Top-Down, baseado em regras extraídas da experiência de especialistas e eventos anteriores, caracterizado por uma capacidade de representação aproximada do comportamento da carga e por um baixo esforço computacional requerido em sua utilização. Nessa metodologia, as incertezas associadas às variáveis e regras são modeladas usando-se lógica fuzzy. O segundo método consiste em um Método Caixa-Branca Bottom-Up que permite a representação do comportamento da carga agregada de forma mais precisa, partindo-se da modelagem individual dos vários tipos de equipamentos e dos principais fenômenos físicos envolvidos na reenergização dos mesmos. Nessa metodologia, os modelos implementados levam em conta as parcelas de consumo residencial, comercial e industrial, bem como a classificação dos equipamentos quanto a seu tipo de controle (controlados termostaticamente, fixos e controlados manualmente). Testes e simulações foram realizados, visando a verificação da adequação dos métodos desenvolvidos, bem como uma análise comparativa entre eles, destacando vantagens e desvantagens da aplicação de cada um / Abstract: This work is focused on developing methods to forecast the load behavior during power systems restoration. Two methodologies were implemented. The first one is the Top-Down Heuristic Method, based on rules extracted from expert experiences and also on past events, that yields an approximate representation of the load behavior at a low computational effort. In this method, the uncertainties associated to the variables and rules are modeled using fuzzy logic. The second method is the Bottom-Up White-Box Method that alows a more adequate representation of the load behavior, by modelling both the functioning of individual equipments and the physical phenomena involved with the reenergization process. In this methodology, the implemented models take into account the residential, the commercial and the industrial consume parcels and the control type of each equipment (thermostatically controlled, fixed and manually controlled). Tests and simulations were carried out in order to verify the adequacy of the proposed methodologies and to compare the advantages and disadvantages of each one / Doutorado / Energia Eletrica / Doutor em Engenharia Elétrica

The work presented in this thesis was concerned with the implementation of a damage control method for U.S. Navy shipboard power systems (SPS). In recent years, the Navy has been seeking an automated damage control and power system management approach for future reconfigurable shipboard power systems. The methodology should be capable of representing the dynamic performance (differential algebraic description), the steady state performance (algebraic description), and the system reconfiguration routines (discrete events) in one comprehensive tool. The damage control approach should also be able to improve survivability, reliability, and security, as well as reduce manning through the automation of the reconfiguration of the SPS network. To this end, this work implemented a damage control method for a notional Next Generation Integrated Power System. This thesis presents a static implementation of a dynamic formulation of a new damage control method at the DC zonal Integrated Flight Through Power system level. The proposed method used a constrained binary genetic algorithm to find an optimal network configuration. An optimal network configuration is a configuration which restores all of the de-energized loads that are possible to be restored based on the priority of the load without violating the system operating constraints. System operating limits act as constraints in the static damage control implementation. Off-line studies were conducted using an example power system modeled in PSCAD, an electromagnetic time domain transient simulation environment and study tool, to evaluate the effectiveness of the damage control method in restoring the power system. The simulation results for case studies showed that, in approximately 93% of the cases, the proposed damage algorithm was able to find the optimal network configuration that restores the power system network without violating the power system operating constraints.

Orientador: Andre Luiz Morelato França / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de Computação / Made available in DSpace on 2018-08-04T08:13:24Z (GMT). No. of bitstreams: 1 Mota_AlexandredeAssis_D.pdf: 2550000 bytes, checksum: d1b87870a85e6720b234c4e11cce99a8 (MD5) Previous issue date: 2005 / Resumo: O sucesso da recomposição de sistemas interligados está diretamente associado à qualidade dos planos de recomposição. Esses planos descrevem as seqüências de ações de controle que devem ser tomadas para energizar as diferentes áreas geoelétricas do sistema após a ocorrência de blecautes totais ou parciais. Nesse contexto, o objetivo deste trabalho é propor uma metodologia para avaliação da qualidade de planos de recomposição, que permita o uso de ferramentas computacionais para avaliar a qualidade de forma automática e sob alguns critérios como (a) grau de flexibilidade quanto a imprevistos durante a execução, (b) índices de qualidade globais determinados a partir da representação do plano de recomposição através de grafos conexos e (c) facilidade de acesso, visualização, atualização e treinamento. Diferentes técnicas e métodos foram empregados para atingir esse objetivo (busca de caminho mínimo, utilização de índices nebulosos, métodos de caminho crítico - CPM/PERT), visando a determinação dos índices numéricos relacionados à qualidade do plano, tais como: duração total prevista para a recomposição, eficiência da fase fluente, evolução da carga interrompida e custos estimados para a interrupção / Abstract: A successful restoration depends on the quality of the restoration plans, that describe the sequence of control actions that must be executed to reenergize different areas (of the power system) just after total or partial blackouts. This work proposes a methodology to automatically evalute the quality of power system restoration plans, related to (a) the flexibility of the plan, (b) numerical quality indexes, extracted using a graph representation for the plan and (c) the easiness of use, visualization, training and access to restoration instructions. Different techniques and methods were used to achieve this goal (minimum path search, adoption of fuzzy indexes, critical path methods), focusing on the determination of numerical indexes that express the quality of the plan, such as total restoration duration, fluent phase efficiency, interrupted load evolution and estimated interruption costs / Doutorado / Energia Eletrica / Doutor em Engenharia Elétrica

No description available.

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2017-09-13T17:03:25Z No. of bitstreams: 1 Dissertacao Geração de manobras finais.pdf: 4641365 bytes, checksum: 7510c97c05590ec2f85789b4b018a86a (MD5) / Made available in DSpace on 2017-09-13T17:03:25Z (GMT). No. of bitstreams: 1 Dissertacao Geração de manobras finais.pdf: 4641365 bytes, checksum: 7510c97c05590ec2f85789b4b018a86a (MD5) Previous issue date: 2015-02-25 / No contexto da Companhia Hidro-Elétrica do São Francisco (CHESF), a recomposição do sistema elétrico está sujeita a falhas causadas por erros na interpretação, durante a execução em tempo real, das IOs (Instruções de Operação). Uma IO é um documento normativo que descreve o plano de recomposição de uma subestação; IOs são documentos complexos, caracterizados pelo uso de linguagem natural e estrutura limitada, o que possibilita a presença de ambiguidades no texto e favorece a ocorrência de erros de interpretação durante a execução. Qualquer instrução executada erradamente pode causar graves danos à rede elétrica, o que tende a atrasar ainda mais o processo de recomposição. A demora na restauração do sistema, porsuavez, causa enorme prejuízoà sociedade e perda de receita à companhia, em virtude da interrupção no fornecimento de energia elétrica. Este trabalho tem como objetivo propor uma solução inovadora para diminuir a quantidade de erros operacionais durante a execução de uma IO. A solução desenvolvida é composta por três passos fundamentais: (i) estruturação dos planos de recomposição da companhia utilizando uma linguagem de alto nível criada para este propósito; (ii) tradução dos planos estruturados em manobras de recomposição,compostas apenas por comando satômicos e (iii) exportação das manobras para uma ferramenta capaz de controlar a execução destas e auditá-as através do sistema SCADA da companhia. A validação da pesquisa foi conduzida em parceria com especialistas na recomposição do sistema elétrico da CHESF. Ao todo, seis IOs da CHESF foram convertidas para o modelo proposto, com o intuito de verificar a corretude da nova abordagem. Além disso,dois engenheiros da companhia analisaram e aprovaram o modelo de solução apresentado. Entre os principais benefícios da solução apontados pelos especialistas, destacam-se: (i) diminuição do esforço de manutenção dos planos de recomposição, (ii) diminuição dos erros de caráter técnico e de digitação na elaboração dos planos de recomposição e na interpretação das manobras e (iii) introdução de auditoria no fluxo de execução da manobra, o que automatiza parcialmente a tarefa e elimina a necessidade de análises em tempo real pelo operador. / In the context of the Companhia Hidro Elétrica do São Francisco (CHESF), power system restoration is subject to failures by virtue of mis interpretation,during real-time execution,of the OIs (Operation Instructions). An OI is a normative document that describes the power restoration plan of a electrical substation; OIs are complex documents, characterized by the use of natural language and poor structure, thus the text may contain ambiguities and the probability of misinterpretation is higher. Misinterpreting OI instructions during execution can severely harm the electrical grid, which tends to slow down the restorationprocess. The delay in this activity may cause enormous damage to the society and financial losses to the company, due to power supply interruption. Concerning this problem, this work presents an innovative approach to reduce operational errors when restoring the system. Our solution consists of three fundamental steps: (i) power restoration plans are structured through a high-level language created to serve this purpose; (ii) we translate these structured plans into switching sequences, composed of atomic commands and (iii) we export these final switching sequences to another existing tool, responsible for managing the execution of OIs in real time and auditing them by accessing the company’s SCADA system. The research was validated in partner ship with CHESF’s power system restoration specialists. Altogether, six CHESF’s operating OIs were converted to this approach, aiming to verify its correctness. Besides that, we presented the solution model to two engineers of the company, which analyzed and approved the proposed solution. As main advantages of the technique pointed out bythe specialists,standout: (i) itlowers themaintenance effortofthe power restoration plans; (ii) it decreases the number of technical errors and typographical errors on the power restoration plan generation and interpretation; (iii) it introduces auditing in the execution flow of the power restoration switching sequences, which partially automates the task and eliminates the need of real-time analysis by the operators.

After decades of routine operation, the hydropower industry faces new challenges. Large-scale integration of other renewable sources of generation in the power system accentuates the role of hydropower as a regulating resource. At the same time, an extensive reinvestment programme has commenced where many old components and apparatus are being refurbished or replaced. Introduction of new technical solutions in existing power plants requires good systems knowledge and careful consideration. Important tools for research, development and analysis are suitable mathematical models, numerical simulation methods and laboratory equipment. This doctoral thesis is devoted to studies of the electromechanical interaction between hydropower units and the power system. The work encompasses development of mathematical models, empirical methods for system identification, as well as numerical and experimental studies of hydropower generator and power system interaction. Two generator modelling approaches are explored: one based on electromagnetic field theory and the finite element method, and one based on equivalent electric circuits. The finite element model is adapted for single-machine infinite-bus simulations by the addition of a network equivalent, a mechanical equation and a voltage regulator. Transient simulations using both finite element and equivalent circuit models indicate that the finite element model typically overestimates the synchronising and damping properties of the machine. Identification of model parameters is performed both numerically and experimentally. A complete set of equivalent circuit parameters is identified through finite element simulation of standard empirical test methods. Another machine model is identified experimentally through frequency response analysis. An extension to the well-known standstill frequency response (SSFR) test is explored, which involves measurement and analysis of damper winding quantities. The test is found to produce models that are suitable for transient power system analysis. Both experimental and numerical studies show that low resistance of the damper winding interpole connections are vital to achieve high attenuation of rotor angle oscillations. Hydropower generator and power system interaction is also studied experimentally during a full-scale startup test of the Nordic power system, where multiple synchronised data acquisition devices are used for measurement of both electrical and mechanical quantities. Observation of a subsynchronous power oscillation leads to an investigation of the torsional stability of hydropower units. In accordance with previous studies, hydropower units are found to be mechanically resilient to subsynchronous power oscillations. However, like any other generating unit, they are dependent on sufficient electrical and mechanical damping. Two experimentally obtained hydraulic damping coefficients for a large Francis turbine runner are presented in the thesis.