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- Leijon, Mats, 1958-, et al.
(author)
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A wave power unit, a buoy, use of a wave power unit and a method for producing electric energy
- 2008
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Patent (pop. science, debate, etc.)abstract
- The invention relates to a wave power unit with a buoy, adapted to float on a water surface. An electric generator is connected to the buoy through connection means. According to the invention the buoy when floating on a water surface and when seen in a direction perpendicular to the water surface has the shape of a closed loop enclosing an inner opening. The invention also relates to a buoy for a wave power unit, which buoy has the corresponding features as above. Further, the invention relates to the use of the invented wave power unit and to a method for producing electric energy with the invented wave power unit.
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2. |
- Manyahi, M. J., et al.
(author)
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Transient response of transformer with XLPE insulation cable winding design
- 2005
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In: International Journal of Electrical Power & Energy Systems. - : Elsevier BV. - 0142-0615 .- 1879-3517. ; 27:1, s. 69-80
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Journal article (peer-reviewed)abstract
- Significant advances in XLPE insulation cables that have higher electric field strength withstand capability have made it possible to apply these high voltage (HV) cables as windings in generators and transformers. Therefore, the recent advent of HV generator (Powerformer) that can be connected directly to the power transmission line has motivated the design of HV transformer (Dryformer) that performs one step transformation from transmission to distribution voltage levels. Since the dryformer will be connected directly to transmission lines, they will be subjected to transients resulting from direct and indirect lightning strikes as well as fast switching surges from Gas insulated circuit breakers. This paper presents the results of experimental studies on the cable winding power transformer (Dryformer) to study its response to various transients. Experimental investigations have been carried to obtain the transformer model parameters based on terminal measurement of admittance functions using Network Analyser, and hence for comparing the model predictions with experimentally obtained responses. The model has been successfully used in estimating the dryformer transient responses at its terminals due to surge application of various front times and peak amplitudes that are representative of lightning and switching caused transients. Experiment and simulation results show that there are considerable differences in the transient response characteristics of dryformer windings as compared to that of transformers with traditional winding design. These differences on transient responses are discussed in perspective of their basic difference in winding design features.
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