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

Condition-based maintenance in hydroelectric plants: A systematic literature review

Industrial maintenance has become an essential strategic factor for profit and productivity in industrial systems. In the modern industrial context, condition-based maintenance guides the interventions and repairs according to the machine’s health status, calculated from monitoring variables and using statistical and computational techniques. Although several literature reviews address condition-based maintenance, no study discusses the application of these techniques in the hydroelectric sector, a fundamental source of renewable energy. We conducted a systematic literature review of articles published in the area of condition-based maintenance in the last 10 years. This was followed by quantitative and thematic analyses of the most relevant categories that compose the phases of condition-based maintenance. We identified a research trend in the application of machine learning techniques, both in the diagnosis and the prognosis of the generating unit’s assets, being vibration the most frequently discussed monitoring variable. Finally, there is a vast field to be explored regarding the application of statistical models to estimate the useful life, and hybrid models based on physical models and specialists’ knowledge, of turbine-generators

Proceeding Of Mechanical Engineering Research Day 2016 (MERD’16)

This Open Access e-Proceeding contains a compilation of 105 selected papers from the Mechanical Engineering Research Day 2016 (MERD’16) event, which is held in Kampus Teknologi, Universiti Teknikal Malaysia Melaka (UTeM) - Melaka, Malaysia, on 31 March 2016. The theme chosen for this event is ‘IDEA. INSPIRE. INNOVATE’. It was gratifying to all of us when the response for MERD’16 is overwhelming as the technical committees received more than 200 submissions from various areas of mechanical engineering. After a peer-review process, the editors have accepted 105 papers for the e-proceeding that cover 7 main themes. This open access e-Proceeding can be viewed or downloaded at www3.utem.edu.my/care/proceedings. We hope that these proceeding will serve as a valuable reference for researchers. With the large number of submissions from the researchers in other faculties, the event has achieved its main objective which is to bring together educators, researchers and practitioners to share their findings and perhaps sustaining the research culture in the university. The topics of MERD’16 are based on a combination of fundamental researches, advanced research methodologies and application technologies. As the editor-in-chief, we would like to express our gratitude to the editorial board and fellow review members for their tireless effort in compiling and reviewing the selected papers for this proceeding. We would also like to extend our great appreciation to the members of the Publication Committee and Secretariat for their excellent cooperation in preparing the proceeding of MERD’16

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

Hydrodynamic and control optimization for a heaving point absorber wave energy converter

The thesis aims at studying the non-linear performance of a designed 1/50 scale point absorber wave energy converter (PAWEC) in heave motion. In particular, designs of the PAWEC geometry and control strategy are considered to optimize the power capture. Experimental and computational fluid dynamics (CFD) data are provided to evaluate the studies. Specifically, this thesis can be summarized into four parts.Firstly, a numerical wave tank (NWT) is constructed in a commercial CFD package ANSYS/LS-DYNA. The main objective associated with the NWT is to closely reproduce the physical wave-PAWEC interactions. To achieve this, physical experimental data from two specified WECs are provided to verify the capability of the NWT. One of the devices is the PAWEC designed at University of Hull. Free decay, excitation force and water splashing tests, etc., are conducted. As a result, the developed NWT is validated to be capable of representing the non-linear behaviors of the PAWEC compared with the costly physical experiments. The second part focuses on investigating the extent to which the non-linear hydrodynamic characteristics of the PAWEC need to be considered. By comparing with the CFD data from a series of tests, a non-linear mathematical modeling involving a quadratic viscous term is verified. The results show that the non-linear PAWEC behavior for the conditions of large oscillations (e.g., near resonance or at a large wave heights) can only be predicted realistically by considering a correct viscous effect. This study highlights that the linear counterpart derived from potential flow code ANSYS/AQWA fails to describe the PAWEC behavior and would mislead the control strategy and power take-off (PTO) designs. Additionally, the results show that the viscous damping is significantly larger than the inviscid radiation damping for the flat-bottom cylindrical heaving PAWEC.It is found that the viscous effect can induce clear energy losses during device oscillations which is unwanted for a PAWEC system. Therefore, in the third part, besides the originalflat-bottom PAWEC, two streamline-bottom counterparts are proposed to improve the capability of power capture. Free motion tests are conducted in the NWT regarding the three different geometric devices. The results indicate that for the streamlined devices, the added mass and hydrodynamic damping decrease by up to 60% compared with the flat-bottom device. More importantly by simulating PTO system in the NWT, it is found that there exists a clear mutual interaction among the designs of the device geometry and PTO damping. Applying a proper PTO damping to the streamlined PAWEC can prominently improve the optimal power absorption efficiency by up to 70% underboth regular and irregular waves, compared with the flat-bottom PAWEC. Finally, a fuzzy logic control strategy with particle swarm optimization algorithm (PSO-FLC) is implemented on the developed non-linear modeling to adaptively tune the PTO damping for power absorption maximization. The fuzzy rule base is initialized according to the power capture characteristics achieved through the NWT tests. PSO algorithm is then used to search for more efficient rules. It is found that applying a well-designed fuzzy inference system can adaptively tune the PTO damping for power capture optimization in contrast to the passive control with constant PTO damping