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Case study of upgrading potential for a small hydro power station
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Division for Electricity and Lightning Research.
2005 (English)In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 30, no 7, 1091-1099 p.Article in journal (Refereed) Published
Abstract [en]

Schemes for upgrading hydro power are formed in many parts of the world. Small hydro power (<15 MW) constitutes a fraction of all hydro power, but upgrading can still be worthwhile. In this article, a small generating station in Sweden, with two generators, is simulated with new generators. The voltage is increased by introducing a cable wound stator, thereby the transformers can be excluded, and more efficient generators are introduced with a higher power factor. These improvements lead to an active power increase from 8.9 to 9.4 MW per generator, which means an increased total annual production by 4.2 GW h.

Place, publisher, year, edition, pages
2005. Vol. 30, no 7, 1091-1099 p.
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:uu:diva-94694DOI: 10.1016/j.renene.2004.08.006OAI: oai:DiVA.org:uu-94694DiVA: diva2:168643
Available from: 2006-09-01 Created: 2006-09-01 Last updated: 2017-12-14Bibliographically approved
In thesis
1. Electric Energy Conversion Systems: Wave Energy and Hydropower
Open this publication in new window or tab >>Electric Energy Conversion Systems: Wave Energy and Hydropower
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Electric energy conversion is an important issue in today's society as our daily lives largely depend on the supplies of energy. Two energy sources are studied for conversion in the present thesis, ocean waves and hydropower. The work focuses on the generator and the transmission of its output to the electric grid.

Different approaches have been used, over the years, to convert the energy in ocean waves, and the method presently used is based on a point absorber (buoy) directly coupled to a linear generator on the seabed. A varying alternating voltage is induced with such configuration, where both the amplitude and the frequency changes continuously. The target is to connect several units in a farm, and thereby decrease the fluctuations in power production. This is shown to be possible to accomplish with a rectifier connected to each generator. Transmission systems can be designed with converters and transformers to connect the farm to the electric grid onshore. Several aspects of the concept are considered as well as interconnection issues. Analytical calculations verified by finite element simulations and measured data are used to model the behaviour of a linear generator. A series expanded expression for the ideal no-load flux and EMF (electromotive force) is derived, which can be developed into an analytical transmission design tool.

Hydropower has been used for more than a century. Today many of the stations from the mid 1900's are up for refurbishment. Studies with finite element calculations show that a higher electric efficiency can be obtained with a high voltage cable wound generator.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2006. 59 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 202
Keyword
Engineering physics, Ocean wave power, renewable energy, linear generator, farm simulation, Teknisk fysik
Identifiers
urn:nbn:se:uu:diva-7081 (URN)91-554-6617-6 (ISBN)
Public defence
2006-09-22, Siegbahnsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15
Opponent
Supervisors
Available from: 2006-09-01 Created: 2006-09-01 Last updated: 2013-07-31Bibliographically approved

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Leijon, Mats

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