Electro-mechanical modelling of tidal arrays
The aim of this study is to present, compare and improve the options of power transmission for tidal current arrays. The potential to generate low or zero carbon power from the world’s tides is increasing as technology moves forward. The technically available tidal current energy resource, the resou...
Published in: | 7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014) |
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Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
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The University of Edinburgh
2018
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Online Access: | http://hdl.handle.net/1842/31089 |
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Edinburgh Research Archive (ERA - University of Edinburgh) |
op_collection_id |
ftunivedinburgh |
language |
English |
topic |
tidal energy tidal arrays electrical modelling long distance control induction generator control permanent magnet generator control system optimisation power harmonic filters filter design |
spellingShingle |
tidal energy tidal arrays electrical modelling long distance control induction generator control permanent magnet generator control system optimisation power harmonic filters filter design Sousounis, Marios Charilaos Electro-mechanical modelling of tidal arrays |
topic_facet |
tidal energy tidal arrays electrical modelling long distance control induction generator control permanent magnet generator control system optimisation power harmonic filters filter design |
description |
The aim of this study is to present, compare and improve the options of power transmission for tidal current arrays. The potential to generate low or zero carbon power from the world’s tides is increasing as technology moves forward. The technically available tidal current energy resource, the resource that can be captured using existing technology, in the United Kingdom can supply a significant amount of the UK electricity demand. Even though tidal current devices have similarities to offshore wind turbines in many aspects, a number of characteristics differentiate the approach needed regarding power transmission and drive-train design. Some of these characteristics are: predictable direction and speed of the tidal current, predetermined available area in a tidal channel, less swept area due higher density of water, continuous underwater operation and smaller distances to shore. This thesis is based on the hypothesis that tidal current energy can be harnessed using today’s technology in an efficient manner. Technology progression never stops and as new materials and methods become available the cost of utilising tidal current energy will drop in the years to come. However, the research question that has to be asked is whether using today’s technology tidal arrays can be an alternative source of electrical power. In order to respond to this research question electromechanical models of tidal current devices have been developed in detail, from resource to the grid connection, using mathematical linear and non-linear programming in MATLAB/Simulink. The tidal models developed include the tidal resource, the tidal turbine with pitch control, geared induction and synchronous generators, the power electronics with the generator controller, the grid side controller, the cables for power transmission, the filters and the grid connection. All the modelling aspects of this study are presented in Chapter 3. Single tidal current devices were compared using different generator technologies, squirrel cage induction generator or permanent magnet synchronous generator, and different location of the power converters, in the nacelle near the generator or many kilometres apart from the generator. Regarding the generator technology, results showed that even though differences are minor, the permanent magnet synchronous generators are more efficient. Regarding the location of the power converters results showed that positioning the power converters in the nacelle always yields fewer electrical losses but component accessibility is minimised due to the underwater operation of the tidal current device. A key focus aspect of the study is the power transmission option with onshore converters which is presented in detail. Using this concept it is possible to generate electricity from tidal current devices but at the same time keep the highest possible system reliability despite the continuous underwater operation. This concept has been used in the first demonstration tidal current arrays developed by Andritz Hydro Hammerfest. What is more, data provided by Andritz Hydro Hammerfest were utilised in order to validate the simulation models. In this study a step forward is taken regarding the concept of keeping the converter dry and controlling the tidal current generator from afar. An algorithm is developed to design power harmonic filters for systems that use long distance controls. Power harmonic filters allow the long distance control system to operate reliably under all conditions but generate significant electrical losses. The power harmonic filter design algorithm presented in this thesis estimates the exact filter parameters so that the filter ensures maximum system reliability and generate minimum possible losses. In addition tidal array topologies using this concept are developed. The final part of this thesis compares a number of different tidal array topologies based on resource to grid efficiency and component accessibility for maintenance. Results showed that when tidal current devices are clustered per four turbines on offshore platforms it is efficient to use as many clusters as possible connected to a single cable whose both ends are connected to the grid. Locating the power converters in the nacelle yields fewer electrical losses compared to locating the power converters on the offshore platform. However, the difference is minimised because the distance between the tidal current device and the offshore platform is the least possible. Having the power converters on an offshore platform is beneficial in terms of accessibility for maintenance and operation because they are not underwater. The results and the methodology from this thesis can be extended to other offshore renewable energy systems such as the wind and wave. In addition, this study can be used as a stepping stone for decision making by tidal current developers. |
author2 |
Shek, Jonathan Mueller, Markus Engineering and Physical Sciences Research Council (EPSRC) |
format |
Doctoral or Postdoctoral Thesis |
author |
Sousounis, Marios Charilaos |
author_facet |
Sousounis, Marios Charilaos |
author_sort |
Sousounis, Marios Charilaos |
title |
Electro-mechanical modelling of tidal arrays |
title_short |
Electro-mechanical modelling of tidal arrays |
title_full |
Electro-mechanical modelling of tidal arrays |
title_fullStr |
Electro-mechanical modelling of tidal arrays |
title_full_unstemmed |
Electro-mechanical modelling of tidal arrays |
title_sort |
electro-mechanical modelling of tidal arrays |
publisher |
The University of Edinburgh |
publishDate |
2018 |
url |
http://hdl.handle.net/1842/31089 |
genre |
Hammerfest |
genre_facet |
Hammerfest |
op_relation |
M. C. Sousounis, J. K. H. Shek and M. A. Mueller, "Modelling and control of tidal energy conversion systems with long distance converters," 7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014), Manchester, 2014, pp. 1-6. doi:10.1049/cp.2014.0367. M. C. Sousounis, J. K. H. Shek, R. C. Crozier and M. A. Mueller, "Comparison of permanent magnet synchronous and induction generator for a tidal current conversion system with onshore converters," 2015 IEEE International Conference on Industrial Technology (ICIT), Seville, 2015, pp. 2481-2486. doi:10.1109/ICIT.2015.7125463. M. C. Sousounis, J. K. H. Shek and M. A. Mueller, "Filter Design for Cable Overvoltage and Power Loss Minimization in a Tidal Energy System With Onshore Converters," in IEEE Transactions on Sustainable Energy, vol. 7, no. 1, pp. 400-408, Jan. 2016. doi:10.1109/TSTE.2015.2424258. M. C. Sousounis, J. K. H. Shek and M. A. Mueller, "Modelling, control and frequency domain analysis of a tidal current conversion system with onshore converters," in IET Renewable Power Generation, vol. 10, no. 2, pp. 158-165, 2 2016. doi:10.1049/iet-rpg.2014.0331. http://hdl.handle.net/1842/31089 |
op_doi |
https://doi.org/10.1049/cp.2014.0367 https://doi.org/10.1109/ICIT.2015.7125463 https://doi.org/10.1109/TSTE.2015.2424258 https://doi.org/10.1049/iet-rpg.2014.0331 |
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7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014) |
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ftunivedinburgh:oai:era.ed.ac.uk:1842/31089 2023-05-15T16:32:51+02:00 Electro-mechanical modelling of tidal arrays Sousounis, Marios Charilaos Shek, Jonathan Mueller, Markus Engineering and Physical Sciences Research Council (EPSRC) 2018-07-04 application/pdf http://hdl.handle.net/1842/31089 en eng The University of Edinburgh M. C. Sousounis, J. K. H. Shek and M. A. Mueller, "Modelling and control of tidal energy conversion systems with long distance converters," 7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014), Manchester, 2014, pp. 1-6. doi:10.1049/cp.2014.0367. M. C. Sousounis, J. K. H. Shek, R. C. Crozier and M. A. Mueller, "Comparison of permanent magnet synchronous and induction generator for a tidal current conversion system with onshore converters," 2015 IEEE International Conference on Industrial Technology (ICIT), Seville, 2015, pp. 2481-2486. doi:10.1109/ICIT.2015.7125463. M. C. Sousounis, J. K. H. Shek and M. A. Mueller, "Filter Design for Cable Overvoltage and Power Loss Minimization in a Tidal Energy System With Onshore Converters," in IEEE Transactions on Sustainable Energy, vol. 7, no. 1, pp. 400-408, Jan. 2016. doi:10.1109/TSTE.2015.2424258. M. C. Sousounis, J. K. H. Shek and M. A. Mueller, "Modelling, control and frequency domain analysis of a tidal current conversion system with onshore converters," in IET Renewable Power Generation, vol. 10, no. 2, pp. 158-165, 2 2016. doi:10.1049/iet-rpg.2014.0331. http://hdl.handle.net/1842/31089 tidal energy tidal arrays electrical modelling long distance control induction generator control permanent magnet generator control system optimisation power harmonic filters filter design Thesis or Dissertation Doctoral PhD Doctor of Philosophy 2018 ftunivedinburgh https://doi.org/10.1049/cp.2014.0367 https://doi.org/10.1109/ICIT.2015.7125463 https://doi.org/10.1109/TSTE.2015.2424258 https://doi.org/10.1049/iet-rpg.2014.0331 2021-08-08T12:09:49Z The aim of this study is to present, compare and improve the options of power transmission for tidal current arrays. The potential to generate low or zero carbon power from the world’s tides is increasing as technology moves forward. The technically available tidal current energy resource, the resource that can be captured using existing technology, in the United Kingdom can supply a significant amount of the UK electricity demand. Even though tidal current devices have similarities to offshore wind turbines in many aspects, a number of characteristics differentiate the approach needed regarding power transmission and drive-train design. Some of these characteristics are: predictable direction and speed of the tidal current, predetermined available area in a tidal channel, less swept area due higher density of water, continuous underwater operation and smaller distances to shore. This thesis is based on the hypothesis that tidal current energy can be harnessed using today’s technology in an efficient manner. Technology progression never stops and as new materials and methods become available the cost of utilising tidal current energy will drop in the years to come. However, the research question that has to be asked is whether using today’s technology tidal arrays can be an alternative source of electrical power. In order to respond to this research question electromechanical models of tidal current devices have been developed in detail, from resource to the grid connection, using mathematical linear and non-linear programming in MATLAB/Simulink. The tidal models developed include the tidal resource, the tidal turbine with pitch control, geared induction and synchronous generators, the power electronics with the generator controller, the grid side controller, the cables for power transmission, the filters and the grid connection. All the modelling aspects of this study are presented in Chapter 3. Single tidal current devices were compared using different generator technologies, squirrel cage induction generator or permanent magnet synchronous generator, and different location of the power converters, in the nacelle near the generator or many kilometres apart from the generator. Regarding the generator technology, results showed that even though differences are minor, the permanent magnet synchronous generators are more efficient. Regarding the location of the power converters results showed that positioning the power converters in the nacelle always yields fewer electrical losses but component accessibility is minimised due to the underwater operation of the tidal current device. A key focus aspect of the study is the power transmission option with onshore converters which is presented in detail. Using this concept it is possible to generate electricity from tidal current devices but at the same time keep the highest possible system reliability despite the continuous underwater operation. This concept has been used in the first demonstration tidal current arrays developed by Andritz Hydro Hammerfest. What is more, data provided by Andritz Hydro Hammerfest were utilised in order to validate the simulation models. In this study a step forward is taken regarding the concept of keeping the converter dry and controlling the tidal current generator from afar. An algorithm is developed to design power harmonic filters for systems that use long distance controls. Power harmonic filters allow the long distance control system to operate reliably under all conditions but generate significant electrical losses. The power harmonic filter design algorithm presented in this thesis estimates the exact filter parameters so that the filter ensures maximum system reliability and generate minimum possible losses. In addition tidal array topologies using this concept are developed. The final part of this thesis compares a number of different tidal array topologies based on resource to grid efficiency and component accessibility for maintenance. Results showed that when tidal current devices are clustered per four turbines on offshore platforms it is efficient to use as many clusters as possible connected to a single cable whose both ends are connected to the grid. Locating the power converters in the nacelle yields fewer electrical losses compared to locating the power converters on the offshore platform. However, the difference is minimised because the distance between the tidal current device and the offshore platform is the least possible. Having the power converters on an offshore platform is beneficial in terms of accessibility for maintenance and operation because they are not underwater. The results and the methodology from this thesis can be extended to other offshore renewable energy systems such as the wind and wave. In addition, this study can be used as a stepping stone for decision making by tidal current developers. Doctoral or Postdoctoral Thesis Hammerfest Edinburgh Research Archive (ERA - University of Edinburgh) 7th IET International Conference on Power Electronics, Machines and Drives (PEMD 2014) 4.3.02 4.3.02 |