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Dublin, Ireland

Igic P.,University of Swansea | Zhou Z.,University of Swansea | Knapp W.,TU Munich | MacEnri J.,ESB International | And 2 more authors.
IET Renewable Power Generation

Considerations of the electrical system configuration and the control strategy for the wave dragon (WD) multi-megawatt (MW) offshore wave energy converter (WEC) are presented in this study. The electrical system consists of 16-20 turbine-generator-AC/DC/AC converter units. The characteristics of the low-head water-turbine and generator control strategy enabling maximum energy capture and the best performance for the MW offshore wave energy power take-off system are described in detail. Simulation results from a single turbine-generator-frequency converter unit at different turbine heads are presented at the end of the study. © 2010 The Institution of Engineering and Technology. Source

O'Riordan J.,ESB International
IET Conference Publications

Using a case study outlined below the paper will demonstrate how an atypical distribution network configuration was employed to ensure security and continuity of supply in response to an increase in demand from a major single point load. The paper will highlight the options considered and the formalised process involved in delivering this request as well as the upgrades required to the protection on the local distribution and transmission networks. Source

Thiringer T.,Chalmers University of Technology | MacEnri J.,ESB International | Reed M.,Marine Current Turbines
IEEE Transactions on Sustainable Energy

This paper presents the power quality evaluation of a 1.2-MW tidal power plant. The results show that the unit works well and that the power quality impact is moderae to low and for future units which most likely will have more turbines, the power quality impact will be very low. The wind turbine power quality standard IEC 61400-21 was used in this investigation, and was adequate; however, regarding the connecting transients, there could be a need for a specific standard. It is found that the power level is well controlled at higher water speeds; the maximum 10-min power is found to be 1.21 MW. The maximum 2-s value is found to be 1.46 MW and the maximum 60-s value is found to be 1.30 MW. The reactive power exchange with the grid is negligible; at full load, the power factor is 0.99. The flicker coefficient is between 1 and 5, depending on the grid impedance angle. Finally, it can be said that the maximum total harmonic distortion (THD) for the voltages is found to be 1.2% and for the current 0.65% during operation with the complete power plant. © 2011 IEEE. Source

Scully S.,ESB International | O'Dowd N.P.,University of Limerick
Journal of Pressure Vessel Technology, Transactions of the ASME

This paper is concerned with the development of a methodology for thermomechanical analysis of high temperature, steam-pressurized P91 pipes in electrical power generation plant under realistic (measured) temperature and pressure cycles. In particular, these data encompass key thermal events, such as "load-following" temperature variations and sudden, significant fluctuations in steam temperatures associated with attemperation events and "trips" (sudden plant shut-down), likely to induce thermomechanical fatigue damage. An anisothermal elastic-plastic-creep material model for cyclic behavior of P91 is employed in the transient finite element (FE) model to predict the stress-strain-temperature cycles and the associated strain-rates. The results permit characterization of the behavior of pressurized P91 pipes for identification of the thermomechanical loading histories relevant to such components, for realistic, customized testing. This type of capability is relevant to design and analysis with respect to the evolving nature of power plant operating cycles, e.g., associated with more flexible operation of fossil fuel plant. © 2013 American Society of Mechanical Engineers. Source

MacEnri J.,ESB International | Reed M.,Marine Current Turbines | Thiringer T.,Chalmers University of Technology
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences

This paper presents the analysis of the study of the flicker emitted fromthe 1.2MWtidal energy converter (TEC), SeaGen, against varying tidal parameters. This paper outlines the main elements of the TEC itself, the environment it is located in and the measurement set up. In this paper, the flicker emitted by the TEC is compared with the different tidal parameters, including flood and ebb tides, tidal speed, water depth and turbulence strength and intensity. Flicker emissions have been calculated from measured data in over 90 measurement (10min) periods, and all of the tidal parameters vary significantly over that testing period. This allows for a detailed statistical and graphical analysis of the variation of flicker with the variation of the tidal parameters outlined above. It is found, with the exception of tidal speed, that there is no strong relationship between flicker emissions and any other tidal parameter. As SeaGen is an asymmetrical TEC with full blade pitching for flood and ebb generation, it was also found that the expected difference of flicker emissions owing to the effect of the submersed crossbeam was not significant. The TEC harmonic performance versus tidal speed is also presented. © 2013 The Author(s) Published by the Royal Society. All rights reserved. Source

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