The increasing penetration of renewable energy in the power system grid makes it one of the most important topics in electricity generation, now and into the future. Tidal current energy is one of the most rapidly growing technologies for generating electric energy. Within that frame, tidal current energy is surging to the fore. Forecasting is the first step in dealing with future generations of the tidal current power systems. The doubly-fed induction generator (DFIG) and the direct drive permanent magnet synchronous generator (DDPMSG) are the most commonly used generators associated with tidal current turbines. The aim of the present work is to propose a forecasting technique for tidal current speed and direction and to develop dedicated control strategies for the most commonly used generators, enabling the turbines to act as an active component in the power system. This thesis is divided into two parts. The first part proposes a hybrid model of an artificial neural network (ANN) and a Fourier series model based on the least squares method (FLSM) for monthly forecasting of tidal current speed magnitude and direction. The proposed hybrid model is highly accurate and outperforms both the ANN and the FLSM alone. The model is validated and shown to perform better than other models currently in use. This study was done using data collected from the Bay of Fundy, Nova Scotia, Canada, in 2008. The second part of the thesis describes the overall dynamic models of the tidal current turbine driving either a DFIG or a DDPMSG connected to a single machine infinite bus system, including controllers used to improve system stability. Two models are tested and validated, and two proportional integral (PI) controllers are proposed for each machine to control the output power of the tidal current turbine. The controllers are tested using a small signal stability analysis method for the models, and prove the robustness of the tidal current turbine using two different types of generators over those without controllers. The controller gain ranges are also investigated to establish zones of stability. Overall results show the advantages of using a DDPMSG over a DFIG.

Abstract Energy is one of the most important factors that continue to influence the shape of civilization in the 21st Century. The cost and availability of energy significantly impacts our quality of life, the health of national economies and the stability of our environment. In recent years there has been a significant global commitment to develop clean and alternative forms of energy resources and it is envisioned that by 2020 10% of world energy will be supplied from renewable resources, and there is an expectation that this value will grow to 50% by 2050. Among renewable energy resources, wind generation technology has matured considerably, and wind is fairly distributed around the globe and therefore available to world communities. In the last decade, wind generation has been the fastest growing energy source globally. However more penetration of wind energy into existing power networks raises concern for power system operators and regulators. Traditionally wind energy convertors do not participate in frequency regulation or Automatic Generation Control (AGC) services, and therefore large penetration of wind power into the power systems can result in a reduction of total system inertia and robustness of the frequency response to the disturbances. The research presented in this thesis covers some of the operational and design aspects of frequency control and AGC services in power systems with mixed generation resources. The thesis examines the operation of the Doubly Fed Induction Generator (DFIG) with a modified inertial loop control considering single-area and two-area frequency control, both primary control and AGC. The thesis presents new, small-perturbation, linear, dynamic, mathematical models for the simulation of primary regulation services and AGC services for single-area and two-area power systems with a mix of conventional and non-conventional DFIG-based wind generators. In order to improve the performance of the frequency regulation and AGC services of the above systems, a parameter optimization technique based on the minimization of the Integral of Squared Errors (ISE) is applied to determine the optimal settings for the proportional-integral (PI) controller gains of the DFIG machines. The thesis presents analytical studies with various perturbations to demonstrate the effectiveness and participation of DFIG-based wind generators in frequency support services and draws some important conclusions. Variation in DFIG penetration levels, and wind speed levels (strong wind and weak wind) on system frequency control performance, has also been examined in the thesis.

abstract: This thesis is focused on the study of wind energy integration and is divided into two segments. The first part of the thesis deals with developing a reliability evaluation technique for a wind integrated power system. A multiple-partial outage model is utilized to accurately calculate the wind generation availability. A methodology is presented to estimate the outage probability of wind generators while incorporating their reduced power output levels at low wind speeds. Subsequently, power system reliability is assessed by calculating the loss of load probability (LOLP) and the effect of wind integration on the overall system is analyzed. Actual generation and load data of the Texas power system in 2008 are used to construct a test case. To demonstrate the robustness of the method, relia-bility studies have been conducted for a fairly constant as well as for a largely varying wind generation profile. Further, the case of increased wind generation penetration level has been simulated and comments made about the usability of the proposed method to aid in power system planning in scenarios of future expansion of wind energy infrastructure. The second part of this thesis explains the development of a graphic user interface (GUI) to demonstrate the operation of a grid connected doubly fed induction generator (DFIG). The theory of DFIG and its back-to-back power converter is described. The GUI illustrates the power flow, behavior of the electrical circuit and the maximum power point tracking of the machine for a variable wind speed input provided by the user. The tool, although developed on MATLAB software platform, has been constructed to work as a standalone application on Windows operating system based computer and enables even the non-engineering students to access it. Results of both the segments of the thesis are discussed. Remarks are presented about the validity of the reliability technique and GUI interface for variable wind speed conditions. Improvements have been suggested to enable the use of the reliability technique for a more elaborate system. Recommendations have been made about expanding the features of the GUI tool and to use it to promote educational interest about renewable power engineering. / Dissertation/Thesis / M.S. Electrical Engineering 2012

No description available.

Detta examensarbete behandlar ett uppsamlingsnät för en ny vindkraftpark som planeras i norra Sverige av företaget AB.Parken skall bestå av 101 stycken vindkraftverk som skall förbindas samman med ett kabelnät och anslutas till en transformatorstation. Rapporten behandlar två förslag på hur nätet skall dimensioneras och förläggas. Uppdelningen av vindkraftverken i kluster illustreras av kartor och enlinjescheman.Valda förläggningsätt och dimensioneringar motiveras med kabelberäkningar och grundläggande teori gällande kabeldimensionering. Kabeltyp samt längder för båda förslagens samtliga radialer presenteras i tabeller tillsammans med en enklare kostnads jämförelse.Simuleringar för uppsamlingsnäten utförs i programmet Power World Simulator. För att kontrollera riktigheten i värdena från simuleringen utförs kontrollberäkningar på en radial med pi-modellen.Beräkningarna visar att dimensioneringen är utförd så förluster och spänningsökningar är väl inom gränsvärden för båda förslagen. Uppsamlingsnätets totala reaktiva tillskott är väl inom gränserna för vad vindkraftverken kan kompensera för.Förslag på fortsatt arbete för detta projekt vore att se över konstruktionen av transformatorstationen samt skydd för uppsamlingsnätet. / This report contains a suggestion for a projected wind farm in northern Sweden.The farm contains 101 wind turbines that shall be connected together with a collection grid and connected to a substation.The report contains two different suggestions of dimension and location of the cables for the grid. The turbines are divided into clusters and shown in maps and single line diagramsChosen suggestions and dimensions are reasoned with calculations and basic theory regarding cable sizing. The chosen cable types and lengths for both suggestions are shown in table form, together with a simplified cost comparison.After simulations have been run in power world simulator programme, the values was checked for authenticity with the π-circuit formula.The calculations shows that the selection of cables have accomplished low losses, and the increase of voltage is well within limits for both suggestions.The contribution of reactive power in the collection grid is also within the limits of what the wind turbines can compensate.A suggestion for future work on this project could be the design and dimension of the substation and the safety equipment.

O aumento da demanda energética mundial e a necessidade de obtenção de energia por fontes renováveis abriram espaço para discussão sobre vantagens e desvantagens relacionadas às diversas tecnologias de geração existentes. Dados mostram um crescimento significativo do percentual da geração eólica no sistema energético mundial tornando factível o investimento em tecnologias que possam atender às diferenças de aplicação para cada região. Este trabalho apresenta inicialmente as principais características das arquiteturas construtivas dos geradores eólicos listando e apresentando seus principais equipamentos e funções, em seguida são apresentados métodos de controle e proteção aerodinâmica e as principais topologias aplicadas na geração eólica de energia. A discussão das vantagens e desvantagens de cada topologia apontou o gerador Doubly Fed Induction Generator (DFIG) aplicado em sistemas de velocidade variável como uma tecnologia que se destaca pelo seu alto nível de controle e pelo ganho relacionado ao conversor back-to-back de apenas 30% da capacidade de geração da máquina. No trabalho o controle do conversor back-to-back foi testado e validado por simulações e os ajustes dos controladores obtidos pelo método do modelo simétrico ótimo. Em seguida, são apresentados os dispositivos básicos de proteção correlacionados ao monitoramento de corrente, tensão e fluxo de potência e discutidas suas limitações na topologia com o gerador DFIG. No final do trabalho a proteção diferencial é apresentada e aplicada sobre o gerador DFIG e simulações de falta são realizadas em diferentes condições de funcionamento da máquina de modo a obter dados que possam apontar a melhor parametrização deste dispositivo de proteção. / The world energetic demand increase and the generation renewable necessity allowed the dialogue about the advantages and disadvantages of generations technologies existing. Many data shows an significant increase of wind generation inside the world energetic system allowing the investment in technologies to work at the characteristics existing in each place. This study shows the main constructive characteristics in the wind generation showing their main equipments and functions. After, the control and protection aerodynamic methods are shown together with the main topologies in the wind generation. The discussion about the advantages and disadvantages of this topologies showed the DFIG generator working in variable speeds systems like an efficient technology because your accurate control and the low cost of back-to-back frequency inverter. In this study the control of back-to-back converter was tested end validated and the drivers parameters was calculated with the method of the optimal symmetric model. then, are showed some basic protections devices linked with current, voltage and power flow monitoring and yours limitations are discussed in the DFIG topology. In the end the differential protection is showed and applied in the DFIG machine then fault simulations are make to obtain data to produce the best configuration parameters of differential protection.

O aumento da demanda energética mundial e a necessidade de obtenção de energia por fontes renováveis abriram espaço para discussão sobre vantagens e desvantagens relacionadas às diversas tecnologias de geração existentes. Dados mostram um crescimento significativo do percentual da geração eólica no sistema energético mundial tornando factível o investimento em tecnologias que possam atender às diferenças de aplicação para cada região. Este trabalho apresenta inicialmente as principais características das arquiteturas construtivas dos geradores eólicos listando e apresentando seus principais equipamentos e funções, em seguida são apresentados métodos de controle e proteção aerodinâmica e as principais topologias aplicadas na geração eólica de energia. A discussão das vantagens e desvantagens de cada topologia apontou o gerador Doubly Fed Induction Generator (DFIG) aplicado em sistemas de velocidade variável como uma tecnologia que se destaca pelo seu alto nível de controle e pelo ganho relacionado ao conversor back-to-back de apenas 30% da capacidade de geração da máquina. No trabalho o controle do conversor back-to-back foi testado e validado por simulações e os ajustes dos controladores obtidos pelo método do modelo simétrico ótimo. Em seguida, são apresentados os dispositivos básicos de proteção correlacionados ao monitoramento de corrente, tensão e fluxo de potência e discutidas suas limitações na topologia com o gerador DFIG. No final do trabalho a proteção diferencial é apresentada e aplicada sobre o gerador DFIG e simulações de falta são realizadas em diferentes condições de funcionamento da máquina de modo a obter dados que possam apontar a melhor parametrização deste dispositivo de proteção. / The world energetic demand increase and the generation renewable necessity allowed the dialogue about the advantages and disadvantages of generations technologies existing. Many data shows an significant increase of wind generation inside the world energetic system allowing the investment in technologies to work at the characteristics existing in each place. This study shows the main constructive characteristics in the wind generation showing their main equipments and functions. After, the control and protection aerodynamic methods are shown together with the main topologies in the wind generation. The discussion about the advantages and disadvantages of this topologies showed the DFIG generator working in variable speeds systems like an efficient technology because your accurate control and the low cost of back-to-back frequency inverter. In this study the control of back-to-back converter was tested end validated and the drivers parameters was calculated with the method of the optimal symmetric model. then, are showed some basic protections devices linked with current, voltage and power flow monitoring and yours limitations are discussed in the DFIG topology. In the end the differential protection is showed and applied in the DFIG machine then fault simulations are make to obtain data to produce the best configuration parameters of differential protection.

Made available in DSpace on 2016-08-31T13:33:44Z (GMT). No. of bitstreams: 1 SauloLR_Dissert.pdf: 2026827 bytes, checksum: 844a5bebdb8c74bcc97253da6842843e (MD5) Previous issue date: 2015-08-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work is carried out a detailed study of the electrical and mechanical behavior of a doubly fed induction machine that operates as wind generator (DFIG), when it is faced with disturbances from both the grid as wind variations. The dynamic analysis becomes closer to the wind turbine connection to a three-phase electrical network containing several bars. The wind turbine has a classical control system, commonly found in the literature, which is to use PI controllers. From the junction of the control system, the power grid model and the turbine model, serial information will be analyzed. The way the system is designed makes possible, simply, changes of parameters and characteristics of the systems, making it possible to perform simulation of many different wind turbines. By the representation adopted of the electrical grid, it was possible to simulate different types of disturbances, enabling a detailed analysis of the system response in front of the disturbances / Nesse trabalho é realizado um estudo detalhado do comportamento elétrico e mecânico de uma máquina de indução duplamente alimentada que opera como gerador eólico (DFIG), quando esta se encontra diante de perturbações provenientes tanto da rede elétrica quanto de variações de vento. A análise da dinâmica torna-se mais detalhada com a conexão do aerogerador a uma rede elétrica trifásica que contem diversas barras. O aerogerador possui um sistema clássico de controle, comumente encontrado na literatura, que é a utilização de controladores do tipo PI. A partir da junção do sistema de controle, do modelo da rede elétrica e do modelo do aerogerador, uma série de dados serão analisados, tais como velocidade de rotação, corrente e potências fornecidas pelo DFIG, tensão elétrica nos barramentos, dentre outros. Ao utilizar uma representação trifásica na rede elétrica, qualquer forma de perturbação elétrica é facilmente implementada e analisada. A forma como o sistema foi elaborado viabiliza, de maneira simples, modificações de parâmetros e características dos sistemas, tornando possível realizar simulação de diversos modelos de aerogeradores. Através da representação adotada na rede elétrica, foi possível simular diferentes tipos de perturbações, viabilizando uma análise detalhada da resposta do sistema diante das mesmas

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-04-25T14:57:44Z No. of bitstreams: 1 thainansantostheodoro.pdf: 6277443 bytes, checksum: 64fdae570574b42d13c86c42cedaca9e (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-04-25T15:29:25Z (GMT) No. of bitstreams: 1 thainansantostheodoro.pdf: 6277443 bytes, checksum: 64fdae570574b42d13c86c42cedaca9e (MD5) / Made available in DSpace on 2017-04-25T15:29:25Z (GMT). No. of bitstreams: 1 thainansantostheodoro.pdf: 6277443 bytes, checksum: 64fdae570574b42d13c86c42cedaca9e (MD5) Previous issue date: 2016-09-05 / Esta dissertação apresenta uma técnica de simulação híbrida no domínio do tempo de programas de transitórios eletromecânicos e eletromagnéticos usando o MatLab/ Simulink, a qual confere eficiência computacional e precisão, tanto na análise de sistemas de potência, quanto de controle, sobretudo em situações nas quais fenômenos eletromagnéticos e eletromecânicos se sobrepõe, como é o caso da integração de grandes parques eólicos. Para que ocorra a interação entre os dois programas é necessário a adequação das grandezas de fasores para formas de onda e vice versa, assim, é apresentada uma nova abordagem de extração de fasores instantâneos a partir do DSOGI com boa eficiência computacional com perda desprezível de informações. A comunicação regular entre os programas é feita através do protocolo de comunicação baseado na plataforma TCP/IP, que possibilita a representação de modelos distribuídos e a divisão do esforço computacional. São apresentados resultados de simulação para a integração de um parque eólico, representado por um aerogerador DFIG, à uma rede de 29 barras e 7 geradores. Todo o sistema foi representado em um programa de transitórios eletromagnéticos para comparação com os resultados do programa híbrido. Os resultados se mostraram encorajadores já que houve diminuição de quase 70% do tempo de processamento. / This dissertation presents a hybrid simulation technique in the time domain of electromechanical and electromagnetic transient programs using the MatLab/Simulink, which confers computational efficiency and precision, in both power system and control analysis, mainly in situations where electromagnetic and electromechanical phenomena overlap, such as the integration of large wind farms. In order to guarantee the interaction between the two programs it is necessary to adapt the phasor magnitudes to waveforms and vice versa, thus, a new approach is presented for the extraction of instantaneous phasors using the DSOGI approach, with good computational efficiency and negligible loss of information. The regular communication between the programs is done through the communication protocol based on the TCP/IP platform, which allows the representation of distributed models and enables the division of computational effortt between computers. Simulation results are presented for the integration of a wind farm, represented by a DFIG, to a network of 29 bars and 7 generators. The entire system was represented in an electromagnetic transient program for comparison with the results of the hybrid program. The results were encouraging since there was a decrease of almost 70 % of the processing time.

Quang Ninh province, Vietnam has a rich wind power resources. This type of energy will be soon utilized for generating power to supply all industrial sites including mining corporations. Because of geological characteristics, wind power stations are located near the 6kV grid of mining areas, therefore it needs to make the analysis about the connection ability of wind power generators to the grids. The paper presents the connection model of a wind turbine and 6kV grids. Based on this model, the simulations of system’s possible operating mode are implemented. The conclusions about the suitable operating modes of wind turbine are pointed out to give the operators and grid managers a general observation for the possibility of connecting a wind turbine to 6kV grid / Tỉnh Quảng Ninh là một trong những địa phương giàu tiềm năng về năng lượng gió. Theo phân tích, loại năng lượng này sẽ sớm được đưa vào cung cấp điện năng cho các khu công nghiệp trong đó có các công ty than. Do đặc thù địa lý, các trạm phát phong năng được đặt khá gần các lưới điện 6kV của mỏ, vì thế cần tiến hành phân tích khả năng kết nối trực tiếp các máy phát điện gió với lưới điện này. Bài báo giới thiệu mô hình kết nối máy phát điện gió với lưới 6kV. Các mô phỏng về các chế độ vận hành có thể có của lưới cũng được thực hiện. Các kết luận về chế độ vận hành thích hợp của tua bin gió được đúc rút để giúp người vận hành, các nhà quản lý lưới điện có được cái nhìn tổng quan về khả năng kết nối tua bin gió với lưới điện 6kV.