Advances in Modelling and Control of Wind and Hydrogenerators

Rapid deployment of wind and solar energy generation is going to result in a series of new problems with regards to the reliability of our electrical grid in terms of outages, cost, and life-time, forcing us to promptly deal with the challenging restructuring of our energy systems. Increased penetration of fluctuating renewable energy resources is a challenge for the electrical grid. Proposing solutions to deal with this problem also impacts the functionality of large generators. The power electronic generator interactions, multi-domain modelling, and reliable monitoring systems are examples of new challenges in this field. This book presents some new modelling methods and technologies for renewable energy generators including wind, ocean, and hydropower systems

Advances in Modelling and Control of Wind and Hydrogenerators

Rapid deployment of wind and solar energy generation is going to result in a series of new problems with regards to the reliability of our electrical grid in terms of outages, cost, and life-time, forcing us to promptly deal with the challenging restructuring of our energy systems. Increased penetration of fluctuating renewable energy resources is a challenge for the electrical grid. Proposing solutions to deal with this problem also impacts the functionality of large generators. The power electronic generator interactions, multi-domain modelling, and reliable monitoring systems are examples of new challenges in this field. This book presents some new modelling methods and technologies for renewable energy generators including wind, ocean, and hydropower systems

Evaluation of a fuzzy-expert system for fault diagnosis in power systems

A major problem with alarm processing and fault diagnosis in power systems is the reliance on the circuit alarm status. If there is too much information available and the time of arrival of the information is random due to weather conditions etc., the alarm activity is not easily interpreted by system operators. In respect of these problems, this thesis sets out the work that has been carried out to design and evaluate a diagnostic tool which assists power system operators during a heavy period of alarm activity in condition monitoring. The aim of employing this diagnostic tool is to monitor and raise uncertain alarm information for the system operators, which serves a proposed solution for restoring such faults. The diagnostic system uses elements of AI namely expert systems, and fuzzy logic that incorporate abductive reasoning. The objective of employing abductive reasoning is to optimise an interpretation of Supervisory Control and Data Acquisition (SCADA) based uncertain messages when the SCADA based messages are not satisfied with simple logic alone. The method consists of object-oriented programming, which demonstrates reusability, polymorphism, and readability. The principle behind employing objectoriented techniques is to provide better insights and solutions compared to conventional artificial intelligence (Al) programming languages. The characteristics of this work involve the development and evaluation of a fuzzy-expert system which tries to optimise the uncertainty in the 16-lines 12-bus sample power system. The performance of employing this diagnostic tool is assessed based on consistent data acquisition, readability, adaptability, and maintainability on a PC. This diagnostic tool enables operators to control and present more appropriate interpretations effectively rather than a mathematical based precise fault identification when the mathematical modelling fails and the period of alarm activity is high. This research contributes to the field of power system control, in particular Scottish Hydro-Electric PLC has shown interest and supplied all the necessary information and data. The AI based power system is presented as a sample application of Scottish Hydro-Electric and KEPCO (Korea Electric Power Corporation)

Advances in Modelling and Control of Wind and Hydrogenerators

Rapid deployment of wind and solar energy generation is going to result in a series of new problems with regards to the reliability of our electrical grid in terms of outages, cost, and life-time, forcing us to promptly deal with the challenging restructuring of our energy systems. Increased penetration of fluctuating renewable energy resources is a challenge for the electrical grid. Proposing solutions to deal with this problem also impacts the functionality of large generators. The power electronic generator interactions, multi-domain modelling, and reliable monitoring systems are examples of new challenges in this field. This book presents some new modelling methods and technologies for renewable energy generators including wind, ocean, and hydropower systems

Intelligent voltage dip mitigation in power networks with distributed generation

Includes bibliographical references.The need for ensuring good power quality (PQ) cannot be over-emphasized in electrical power system operation and management. PQ problem is associated with any electrical distribution and utilization system that experiences any voltage, current or frequency deviation from normal operation. In the current power and energy scenario, voltage-related PQ disturbances like voltage dips are a fact which cannot be eliminated from electrical power systems since electrical faults, and disturbances are stochastic in nature. Voltage dip tends to lead to malfunction or shut down of costly and mandatory equipment and appliances in consumers’ systems causing significant financial losses for domestic, commercial and industrial consumers. It accounts for the disruption of both the performance and operation of sensitive electrical and electronic equipment, which reduces the efficiency and the productivity of power utilities and consumers across the globe. Voltage dips are usually experienced as a result of short duration reduction in the r.m.s. (r.m.s.- root mean square) value of the declared or nominal voltage at the power frequency and is usually followed by recovery of the voltage dip after few seconds. The IEEE recommended practice for monitoring electric power quality (IEEE Std. 1159-2009, revised version of June 2009), provides definitions to label an r.m.s. voltage disturbance based upon its duration and voltage magnitude. These disturbances can be classified into transient events such as voltage dips, swells and spikes. Other long duration r.m.s. voltage variations are mains failures, interruption, harmonic voltage distortion and steady-state overvoltages and undervoltages. This PhD research work deals with voltage dip phenomena only. Initially, the present power network was not designed to accommodate renewable distributed generation (RDG) units. The advent and deployment of RDG over recent years and high penetration of RDG has made the power network more complex and vulnerable to PQ disturbances. It is a well-known fact that the degree of newly introduced RDG has increased rapidly and growing further because of several reasons, which include the need to reduce environmental pollution and global warming caused by emission of carbon particles and greenhouse gases, alleviating transmission congestion and loss reduction. RDG ancillary services support especially voltage and reactive power support in electricity networks are currently being recognized, researched and found to be quite useful in voltage dip mitigation

Hydrothermal processing of biogenic residues in Germany: A technology assessment considering development paths by 2030

The mining, processing, and use of finite natural resources is associated with significant interventions in the natural environment. Thus, these and other negative consequences make it necessary to reduce resource consumption. An important field of action is the more efficient use of biogenic residues as secondary raw materials. However, high water containing biomasses are still a problem since they need an energy- and cost-intensive pre-treatment for many conversion processes, which can make their use uneconomical. Hydrothermal processes (HTP) seem to be promising, since they require an aqueous environment for optimal processing anyway. Although technological progress within the industry is recognisable, however, to date HTP have not been established in industrial continuous operation in Germany. The core of this work is identifying reasons for this sluggish development and deriving appropriate recommendations for action. Based on the hypothesis that HTP can contribute to the efficient utilisation of biogenic residues in the future, potentials and obstacles for the development of HTP in Germany are identified using a literature review, expert survey, expert workshop, and SWOT analysis. To estimate the future potential of HTP in a systematic and structured way, a multi-criteria technology assessment approach is developed based on the results. To this end, assessment criteria for HTP are derived, weighted by expert judgment, and integrated into a transparent and structured procedure. In addition, mainly based on a Delphi-survey key factors of HTP development by 2030 in Germany are identified and three development alternatives for HTP in Germany by 2030 are derived. Using a system analysis and a comparative multi-criteria analysis at plant level, these scenarios are analysed for their possible future impact. Based on this methodology, the work shows that the production costs for the end products, the energy efficiency of the process, and the proportion of recycled phosphorus are of high relevance to the techno-economic success of HTP compared to reference systems, and they are therefore of high importance for its future development on the plant level. In addition, further key factors for the future development of HTP in Germany on the system level are found to be mainly in the political-legal (e.g. legal waste status of products from HTP) and techno-economic (e.g. cost-effective process water treatment) areas. According to this, important fields of action are the identification and use of cost reduction potentials (e.g. heat waste use), the development of system integrated decentralised plant concepts with integrated nutrient recycling (e.g. phosphorus), and the development of cost-effective ways to treat process water. System integration, cost-effective process water treatment, and nutrient recycling are all closely linked to production costs, investment costs, and potential revenues, and can contribute to improved process economics. For these areas, there is promising future potential to achieve higher competitiveness with reference technologies that are currently more economical.:Bibliographic description Curriculum Vitae Selbstständigkeitserklärung Danksagung List of Publications Contribution to the Publications Contents List of Acronyms List of Tables List of Figures Part I Introductory Chapters 1 Introduction and Background Hydrothermal processes: Introduction and status quo State of the art in the research field and knowledge gaps Objective and research framework Expected value added of this work 2 Materials and methods Derivation of HTP evaluation metrics and technology assessment tool Derivation of key HTP development factors and scenarios Performing the system-level scenario analysis Plant-level scenario analysis and test application of the assessment tool Derivation of core recommendations 3 Results and discussion Key development factors for HTP in Germany and scenarios System-level scenario analysis Test application of the assessment tool on plant level scenarios Recommendations Discussion 4 Conclusion and outlook Future research Further fields for the application of the developed methods 5 References Part II Appended Articles Paper I Paper II Paper III Paper IV Paper V Paper VIDer Abbau, die Verarbeitung und die Nutzung endlicher natürlicher Ressourcen sind mit erheblichen Eingriffen in die natürliche Umwelt verbunden. Diese und andere negative Folgen machen es daher erforderlich, den Ressourcenverbrauch zu senken. Ein wichtiges Handlungsfeld ist die effizientere Nutzung biogener Reststoffe als Sekundärrohstoffe. Stark wasserhaltige Biomassen sind jedoch ein Problem, da sie für viele Umwandlungsprozesse eine energie- und kostenintensive Vorbehandlung benötigen, was ihre Verwendung unwirtschaftlich machen kann. Hydrothermale Prozesse (HTP) scheinen für diese Reststoffe allerdings vielversprechend zu sein, da sie ohnehin eine wässrige Umgebung für eine optimale Verarbeitung benötigen. Obwohl der technologische Fortschritt innerhalb der Branche erkennbar ist, wurde HTP in Deutschland bisher nicht im industriellen Dauerbetrieb etabliert. Der Kern dieser Arbeit besteht darin, Gründe für diese schleppende Entwicklung zu ermitteln und geeignete Handlungsempfehlungen abzuleiten. Basierend auf der Hypothese, dass HTP in Zukunft zur effizienten Nutzung biogener Reststoffe beitragen können, werden Potenziale und Hindernisse für deren Entwicklung in Deutschland anhand einer Literaturrecherche, einer Expertenumfrage, eines Expertenworkshops und einer SWOT-Analyse ermittelt. Um das zukünftige Potenzial von HTP systematisch und strukturiert abzuschätzen, wird basierend auf den Ergebnissen ein multi-kriterieller Technologiebewertungsansatz entwickelt. Zu diesem Zweck werden Bewertungskriterien für HTP abgeleitet, nach Expertenmeinung gewichtet und in ein transparentes und strukturiertes Verfahren integriert. Darüber hinaus werden hauptsächlich auf der Grundlage einer Delphi-Umfrage Schlüsselfaktoren für die HTP-Entwicklung bis 2030 in Deutschland identifiziert und drei Entwicklungsalternativen für HTP in Deutschland bis 2030 abgeleitet. Mithilfe einer Systemanalyse und einer vergleichenden multi-kriteriellen Analyse auf Anlagenebene werden diese Szenarien auf ihre möglichen zukünftigen Auswirkungen hin analysiert. Basierend auf dieser Methodik zeigen sich als Ergebnisse, dass die Produktionskosten für die Endprodukte, die Energieeffizienz der Prozesse und der Anteil an recyceltem Phosphor für den techno-ökonomischen Erfolg von HTP im Vergleich zu Referenzsystemen von hoher Relevanz und daher auch von hoher Bedeutung für die zukünftige Entwicklung auf Anlagenebene sind. Darüber hinaus liegen weitere Schlüsselfaktoren für die künftige Entwicklung von HTP in Deutschland auf Systemebene hauptsächlich im politisch-rechtlichen (z. B. legalen Abfallstatus von Produkten aus HTP) und techno-ökonomischen (z. B. kostengünstige Prozesswasseraufbereitung)) Bereichen. Wichtige Handlungsfelder sind demnach die Ermittlung und Nutzung von Kostensenkungspotentialen (zB Abwärmenutzung), die Entwicklung systemintegrierter dezentraler Anlagenkonzepte mit integriertem Nährstoffrecycling (z.B. Phosphor) und die Entwicklung kostengünstiger Wege zur Prozesswasserbehandlung. Systemintegration, kostengünstige Prozesswasseraufbereitung und Nährstoffrecycling hängen eng mit Produktionskosten, Investitionskosten und potenziellen Einnahmen zusammen und können zu einer verbesserten Wirtschaftlichkeit der Prozesse beitragen. Für diese Bereiche besteht ein vielversprechendes Zukunftspotenzial für eine höhere Wettbewerbsfähigkeit zu Referenztechnologien, die derzeit noch wirtschaftlicher sind.:Bibliographic description Curriculum Vitae Selbstständigkeitserklärung Danksagung List of Publications Contribution to the Publications Contents List of Acronyms List of Tables List of Figures Part I Introductory Chapters 1 Introduction and Background Hydrothermal processes: Introduction and status quo State of the art in the research field and knowledge gaps Objective and research framework Expected value added of this work 2 Materials and methods Derivation of HTP evaluation metrics and technology assessment tool Derivation of key HTP development factors and scenarios Performing the system-level scenario analysis Plant-level scenario analysis and test application of the assessment tool Derivation of core recommendations 3 Results and discussion Key development factors for HTP in Germany and scenarios System-level scenario analysis Test application of the assessment tool on plant level scenarios Recommendations Discussion 4 Conclusion and outlook Future research Further fields for the application of the developed methods 5 References Part II Appended Articles Paper I Paper II Paper III Paper IV Paper V Paper V

Architecture for intelligent power systems management, optimization, and storage.

The management of power and the optimization of systems generating and using power are critical technologies. A new architecture is developed to advance the current state of the art by providing an intelligent and autonomous solution for power systems management. The architecture is two-layered and implements a decentralized approach by defining software objects, similar to software agents, which provide for local optimization of power devices such as power generating, storage, and load devices. These software device objects also provide an interface to a higher level of optimization. This higher level of optimization implements the second layer in a centralized approach by coordinating the individual software device objects with an intelligent expert system thus resulting in architecture for total system power management. In this way, the architecture acquires the benefits of both the decentralized and centralized approaches. The architecture is designed to be portable, scalable, simple, and autonomous, with respect to devices and missions. Metrics for evaluating these characteristics are also defined. Decentralization achieves scalability and simplicity through modularization using software device objects that can be added and deleted as modules based on the devices of the power system are being optimized. Centralization coordinates these software device objects to bring autonomy and intelligence of the whole power system and mission to the architecture. The centralization approach is generic since it always coordinates software device objects; therefore it becomes another modular component of the architecture. Three example implementations illustrate the evolution of this power management system architecture. The first implementation is a coal-fired power generating station that utilized a neural network optimization for the reduction of nitrogen oxide emissions. This illustrates the limitations of this type of black-box optimization and serves as a motivation for developing a more functional architecture. The second implementation is of a hydro-generating power station where a white-box, software agent approach illustrates some of the benefits and provides initial justification of moving towards the proposed architecture. The third implementation applies the architecture to a vehicle to grid application where the previous hydro-generating application is ported and a new hybrid vehicle application is defined. This demonstrates portability and scalability in the architecture, and linking these two applications demonstrates autonomy. The simplicity of building this application is also evaluated

Evaluation of integration of pumped storage units in an isolated network

Tese de mestrado. Engenharia Eletrotécnica e de Computadores (Área de especialização em Sistemas de Energia). 2006. Faculdade de Engenharia. Universidade do Port

Nuclear Power Plants

This book covers various topics, from thermal-hydraulic analysis to the safety analysis of nuclear power plant. It does not focus only on current power plant issues. Instead, it aims to address the challenging ideas that can be implemented in and used for the development of future nuclear power plants. This book will take the readers into the world of innovative research and development of future plants. Find your interests inside this book

Low-head pumped hydro storage: A review of applicable technologies for design, grid integration, control and modelling

To counteract a potential reduction in grid stability caused by a rapidly growing share of intermittent renewable energy sources within our electrical grids, large scale deployment of energy storage will become indispensable. Pumped hydro storage is widely regarded as the most cost-effective option for this. However, its application is traditionally limited to certain topographic features. Expanding its operating range to lowhead scenarios could unlock the potential of widespread deployment in regions where so far it has not yet been feasible. This review aims at giving a multi-disciplinary insight on technologies that are applicable for low-head (2-30 m) pumped hydro storage, in terms of design, grid integration, control, and modelling. A general overview and the historical development of pumped hydro storage are presented and trends for further innovation and a shift towards application in low-head scenarios are identified. Key drivers for future deployment and the technological and economic challenges to do so are discussed. Based on these challenges, technologies in the field of pumped hydro storage are reviewed and specifically analysed regarding their fitness for low-head application. This is done for pump and turbine design and configuration, electric machines and control, as well as modelling. Further aspects regarding grid integration are discussed. Among conventional machines, it is found that, for high-flow low-head application, axial flow pump-turbines with variable speed drives are the most suitable. Machines such as Archimedes screws, counter-rotating and rotary positive displacement reversible pump-turbines have potential to emerge as innovative solutions. Coupled axial flux permanent magnet synchronous motor-generators are the most promising electric machines. To ensure grid stability, grid-forming control alongside bulk energy storage with capabilities of providing synthetic inertia next to other ancillary services are required