Studies in Electrical Machines & Wind Turbines associated with developing Reliable Power Generation

The publications listed in date order in this document are offered for the Degree of Doctor of Science in Durham University and have been selected from the author’s full publication list. The papers in this thesis constitute a continuum of original work in fundamental and applied electrical science, spanning 30 years, deployed on real industrial problems, making a significant contribution to conventional and renewable energy power generation. This is the basis of a claim of high distinction, constituting an original and substantial contribution to engineering science

Wave and tidal generation devices: reliability and availability

To some extent the wave and tidal generation industry is following in the wake of the wind industry, learning from the growing experience of offshore wind farm deployment. This book combines wind industry lessons with wave and tidal field knowledge to explore the main reliability and availability issues facing this growing industry

Axial flux distribution in laminated steel cores, with particular reference to the end region magnetic field of large turbo-generators

This thesis describes a new approach to the consideration of leakage fields in the end regions of large rotating electrical machines. In particular the approach is applied to the axial field developed at the ends of stator cores both inside and outside their laminated steel structure. The method considers individually the magnetic sources of axial flux. The sources involved are the winding currents, surface polarities of the magnetised core and the eddy currents and volume polarities within the core. Mathematical expressions are derived for the sources and their geometrical behaviour is then investigated as the design and dimensions of both windings and core are altered. Measurements are made of axial flux inside and outside cylindrical, slotless, laminated cores excited with a rotating field. The experiments are scaled to show the effects on axial flux in a fullsize machine of winding design, core geometry, core s:..:iration and eddy currents. The measurements are in good agreement rn th predictions made in air and on the core end using the source expressions. Axial flux is reduced as winding overhang and radius are reduced. The penetration of axial flux inside the core is shown to be independent of winding design but for a given frequency that penetration increases as the core is saturated. The behaviour of eddy currents in the core is shown to be controlled by the homogenised axial permeability of the core.</p

Long-term research challenges in wind energy – a research agenda by the European Academy of Wind Energy

The European Academy of Wind Energy (eawe), representing universities and institutes with a significant wind energy programme in 14 countries, has discussed the long-term research challenges in wind energy. In contrast to research agendas addressing short- to medium-term research activities, this eawe document takes a longer-term perspective, addressing the scientific knowledge base that is required to develop wind energy beyond the applications of today and tomorrow. In other words, this long-term research agenda is driven by problems and curiosity, addressing basic research and fundamental knowledge in 11 research areas, ranging from physics and design to environmental and societal aspects. Because of the very nature of this initiative, this document does not intend to be permanent or complete. It shows the vision of the experts of the eawe, but other views may be possible. We sincerely hope that it will spur an even more intensive discussion worldwide within the wind energy community.Wind EnergyTeam Raf Van de PlasDC systems, Energy conversion & StorageEconomics of Technology and Innovatio