No description available.

<p>This thesis presents the mechanical design and dimensioning of a pressure vessel, which is to be used as housing for a marine substation in a wave power park. A concept for generation of electricity from ocean waves is being developed at the Division of electricity at Uppsala University. The concept is based on the use of a permanent magnet linear generator, placed on the seabed, connected via a line to a buoy at the surface. The generated electricity from a group of generators is transmitted in sea cables to a marine substation where conversion and transformation takes place before the electricity is transmitted to shore. To reduce the risk of water leakage, the gas pressure inside the marine substation is larger than the surrounding water pressure. The substation can be pressurized before submersion, which requires the housing to be designed as a pressure vessel. The pressure vessel has been dimensioned with formula based methods according to EN 13445, the European standard for unfired pressure vessels. The construction has been based on modifying a standard pressure tank. The housing has been designed for installation and sealing of a large number of electrical connectors. The connectors have been placed in a way that allows for future cable coupling with remotely operated vehicles and simplifies maintenance of the substation. Another design consideration has been to facilitate submersion by reducing the buoyancy of the substation.</p>

This thesis presents the mechanical design and dimensioning of a pressure vessel, which is to be used as housing for a marine substation in a wave power park. A concept for generation of electricity from ocean waves is being developed at the Division of electricity at Uppsala University. The concept is based on the use of a permanent magnet linear generator, placed on the seabed, connected via a line to a buoy at the surface. The generated electricity from a group of generators is transmitted in sea cables to a marine substation where conversion and transformation takes place before the electricity is transmitted to shore. To reduce the risk of water leakage, the gas pressure inside the marine substation is larger than the surrounding water pressure. The substation can be pressurized before submersion, which requires the housing to be designed as a pressure vessel. The pressure vessel has been dimensioned with formula based methods according to EN 13445, the European standard for unfired pressure vessels. The construction has been based on modifying a standard pressure tank. The housing has been designed for installation and sealing of a large number of electrical connectors. The connectors have been placed in a way that allows for future cable coupling with remotely operated vehicles and simplifies maintenance of the substation. Another design consideration has been to facilitate submersion by reducing the buoyancy of the substation.

No description available.

No description available.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1980. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 345-354).

Shelf tidal streams are accelerated by coastal features, such as headlands and islands. In the search for sustainable forms of electricity generation, such locations may become attractive for tidal stream power. For many prospective sites, however, little is known about the intricacies of the local tidal dynamics: knowledge which is crucial to understanding the resource and the potential environmental consequences of its extraction. This thesis explores tidal stream energy in the Pentland Firth (Scotland, UK). This channel contains some of the most promising tidal stream energy sites in the world and is set to become host to the first large-scale arrays of tidal stream turbines, but its detailed characteristics were previously unknown. A hydrodynamic model was used to investigate the complex tidal dynamics of the Pentland Firth. This demonstrated, for the first time, the hydrodynamic mechanisms driving the exceptionally fast tidal currents through this channel. The model was then refined at a key site within the Pentland Firth, the Inner Sound. The results provided insight into complex flow characteristics, such as displacement and misalignment of peak flood and ebb tides, which must be considered when contemplating the exploitation of this energy resource. Tidal stream turbines were simulated in the hydrodynamic model. Artificial energy extraction was parameterised at the sub-grid-scale via added seabed drag. Turbine drag of varying magnitude was represented by a novel analytical model based on published characteristics of horizontal axis turbines. This new formulation reflects the non-linear dynamics of tidal turbine operation. Using the new turbine model, arrays of turbines were simulated within the Inner Sound. Complex interactions between the dynamics of energy extraction and flow required individual turbines to be parameterised in-concert with all other turbines in the array. This required extra effort, but offered enhanced insight into the behaviour of turbine arrays. Accounting for nonlinear turbine dynamics at high current speeds limited the magnitude of peak energy dissipation. Tidal stream velocities decreased both upstream and downstream of the extraction zone and were accelerated around it. At peak energy extraction, changes in tidal velocity were detectable several kilometres from the array, but were confined to the shallow waters of the Inner Sound and its environs. Implications for array modelling are discussed in the context of environmental impact assessments.

<p>At the Division for Electricity at Uppsala University a new marine substation for waveenergy is being built. The marine substation is required to connect the wave energyconverters to the grid. In this thesis a part of the main circuit for the marinesubstation is assembled and tested. Furthermore, a part of the measurement system isdesigned and a prototype is built and evaluated. The test results from the set-up ofthe main circuit agree well with simulations done in MATLAB Simulink. A detailed listof components combined with a finished CAM-model for a measurement card arepresented along with interface cards and shielding solutions.</p>

At the Division for Electricity at Uppsala University a new marine substation for waveenergy is being built. The marine substation is required to connect the wave energyconverters to the grid. In this thesis a part of the main circuit for the marinesubstation is assembled and tested. Furthermore, a part of the measurement system isdesigned and a prototype is built and evaluated. The test results from the set-up ofthe main circuit agree well with simulations done in MATLAB Simulink. A detailed listof components combined with a finished CAM-model for a measurement card arepresented along with interface cards and shielding solutions.

Wave energy converters (WECs) are relatively new power sources under rapiddevelopment. WECs utilize permanent magnets to generate power and theperformance of these magnets have a great impact on the produced effects in theWECs. This paper is primarily constructed to investigate the magnetic and mechanicalproperties of a specific kind of permanent magnets, referred to as Y40. The paperalso gives a comprehensive review of magnetic materials in general, slightly focusingon magnetic stability. Literature studies has been made to get an understanding ofhow the Y40 magnets will perform under external influences such as reversed field,temperature change and mechanical stress. Further, a compression test has beenmade to examine the Y40s solidity. From the results of the tests and from theinformation provided in literature it is considered to be little to no risk for the Y40sto lose magnetization due to external influences. However, because of theirassembled structure, the Y40 magnets are very likely to break in their joints duringpressure lower than what is expected in the WECs.