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  • 1.
    Abran, Eszter
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Andersson, Elin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Intäktsanalys av vindkraft som reglerresurs: Med och utan batterilager2023Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    In order to ensure a stable power system, a balance between production and consumption at every given moment is necessary. An indication of this balance is the system frequency, which deviates from its nominal value in case of imbalance. With an increasing share of weather dependent energy in the Nordic synchronous system, such as wind power, the need for stabilizing services are becoming even more crucial. Ancillary services are a way of keeping the frequency stabilized, they are provided by different actors in the power system with flexible production or consumption. This contributes to increasing or decreasing the input and output of energy to the system when needed. Ancillary services are procured in separate markets that are structured and designed by the transmission system operator, Svenska kraftnät.

    This thesis investigates wind power and its potential of providing ancillary services in the Swedish power system. The report presents two different studies which are performed based on two specific wind farms in Sweden. Firstly, the possibility of providing ancillary services by the wind farms alone are considered with emphasis on the economic profitability. A model is used to present a theoretical maximum of income based on historical production and market data from 2022. The second study has an additional aspect of combining the wind farms with a battery energy storage system (BESS), creating a hybrid system, to examine the potential improvement of income for the company. Due to the production being dependent on weather conditions, the BESS can provide additional contribution when needed. The second study is performed using an optimization model in order to optimize the use of the BESS for the simulated period.

    The results presented an increase of revenues when participating on the ancillary service markets for both studies. The first study showed that down regulating services were the most profitable, this being FCR-D down and aFRR down. With the hybrid system, the profitability was even more significant. It demonstrated a big potential of participating on the FFR market during the summer and FCR-D during winter. Furthermore, the hybrid system also showed an increase in participation on the up-regulating markets. Without the BESS, the windfarm is forced to curtail production toparticipate in the up-regulating markets, which proved to be less profitable than participating on down-regulating markets. The results also give an understanding of the cycling of the BESS and how this affects the results and the BESS lifetime. With coming market development, the conditions on the ancillary service markets is expected to change, the effect of this is considered in a sensitivity analysis. Finally, the studies collectively show the opportunity for wind power to contribute to stabilizing the power system and ensuring the security of energy supply in the Nordicsynchronous system.

    Ladda ner fulltext (pdf)
    fulltext
  • 2.
    Agerhäll, Isabella
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Flexibilitet i elsystemet: En undersökning om hur flexibilitet lokalt kan samverka med de nationella stödtjänstmarknaderna2022Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The Swedish power system is facing a lot of change in the near future. A system which is built around nuclear- and hydropower now contains more and more intermittent power sources such as wind and solar. In addition, Sweden is entering a second electrification era, where the electricity use is predicted to increase substantially. This means the need for flexibility in the power system is bigger than ever and is going to increase.

    The power system needs to be in balance at every instance. The same amount of energy that is produced also needs to be consumed. This balance, or imbalance, affects the frequency in the system and there are balancing markets in place to handle disturbances in the frequency.Flexible solutions outside these balancing markets can also be valuable since they can lower costs for power use and prevent unnecessary investments in the power grids.

    This thesis was written in cooperation with the municipal energy company Gävle Energi. The cases it is built on are both cases in and around Gävle. The study is based on two cases: One case where a local hauling company is interested in a combination of solar power, electric charging for vehicles, and a battery storage. The hauling company plans to electrify parts of their fleet and will by doing so increase their power use. The second case regards the building of a gasturbine for electricity production in Gävle Energi’s grid.

    Both cases examine how the balancing markets can be used to motivate investments in flexible solutions. The hauling company can lower their power peaks by using a battery storage and the battery storage can also be used to sell capacity on the balancing market FCR-D. Through planning when heavy duty charging and regular vehicle charging is done, unnecessary power peaks can be avoided. The study shows that a battery storage can in fact be profitable and bring benefits to both the hauling company and the national energy system.

    The second case, the gas turbine, is based on income from both the spot market and the balancing market mFRR which is then compared to the price for gas. The income from mFRR was varied between 140-250% of the prices from 2021 and the gas price was varied from 800-2100 SEK. The results show that the prices for mFRR need to increase a lot for the turbine to be profitable and the gas turbine could perhaps be more beneficial if combined with other solutions. The case has a lot of insecurities as the turbine runs very few hours per year (only 10 hours would have been profitable in 2021). It becomes vital that the bidding is won these hours, which is hard to predict.

    Ladda ner fulltext (pdf)
    Flexibilitet_i_elsystemet
  • 3.
    Aguilar, J. A.
    et al.
    Univ Libre Bruxelles, Sci Fac, CP 230, B-1050 Brussels, Belgium..
    Allison, P.
    Ohio State Univ, Dept Phys, Ctr Cosmol & Astroparticle Phys, Columbus, OH 43210 USA..
    Beatty, J. J.
    Ohio State Univ, Dept Phys, Ctr Cosmol & Astroparticle Phys, Columbus, OH 43210 USA..
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Besson, D.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA.;Natl Nucl Res Univ MEPhI, Kashirskoe Shosse 31, Moscow 115409, Russia..
    Bingefors, Nils
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Botner, Olga
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Bouma, S.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Buitink, S.
    Vrije Univ Brussel, Inst Astrophys, Pleinlaan 2, B-1050 Brussels, Belgium..
    Carter, K.
    Calif Polytechn State Univ, Phys Dept, San Luis Obispo, CA 93407 USA..
    Cataldo, M.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Clark, B. A.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Curtis-Ginsberg, Z.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Connolly, A.
    Ohio State Univ, Dept Phys, Ctr Cosmol & Astroparticle Phys, Columbus, OH 43210 USA..
    Dasgupta, P.
    Univ Libre Bruxelles, Sci Fac, CP 230, B-1050 Brussels, Belgium..
    De Kocker, S.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    De Vries, K. D.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Deaconu, C.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    DuVernois, M. A.
    Univ Wisconsin Madison, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin Madison, Dept Phys, Madison, WI 53703 USA..
    Glaser, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Hallgren, Allan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Hallmann, S.
    DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Hanson, J. C.
    Whittier Coll, Whittier, CA 90602 USA..
    Hendricks, B.
    Penn State Univ, Dept Astron & Astrophys, Dept Phys, University Pk, PA 16801 USA..
    Hokanson-Fasig, B.
    Univ Wisconsin Madison, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin Madison, Dept Phys, Madison, WI 53703 USA..
    Hornhuber, C.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Hughes, K.
    Karle, A.
    Univ Wisconsin Madison, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin Madison, Dept Phys, Madison, WI 53703 USA..
    Kelley, J. L.
    Univ Wisconsin Madison, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin Madison, Dept Phys, Madison, WI 53703 USA..
    Klein, S. R.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Krebs, R.
    Lahmann, R.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Latif, U.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Magnuson, M.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Meures, T.
    Univ Wisconsin Madison, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin Madison, Dept Phys, Madison, WI 53703 USA..
    Meyers, Z. S.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Mulrey, K.
    Vrije Univ Brussel, Inst Astrophys, Pleinlaan 2, B-1050 Brussels, Belgium..
    Nelles, A.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Novikov, A.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Oberla, E.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Oeyen, B.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Pandya, H.
    Vrije Univ Brussel, Inst Astrophys, Pleinlaan 2, B-1050 Brussels, Belgium..
    Plaisier, I.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Pyras, L.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Ryckbosch, D.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Scholten, O.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium.;Univ Groningen, Kapte Inst, Groningen, Netherlands..
    Seckel, D.
    Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Smith, D.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Southall, D.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Torres, J.
    Ohio State Univ, Dept Phys, Ctr Cosmol & Astroparticle Phys, Columbus, OH 43210 USA..
    Toscano, S.
    Tosi, D.
    Univ Wisconsin Madison, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin Madison, Dept Phys, Madison, WI 53703 USA..
    Van den Broeck, D. J.
    Vrije Univ Brussel, Inst Astrophys, Pleinlaan 2, B-1050 Brussels, Belgium.;Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Ndhoven, N. Van E.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Vieregg, A. G.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Welling, C.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Wissel, S.
    Calif Polytechn State Univ, Phys Dept, San Luis Obispo, CA 93407 USA.;Penn State Univ, Dept Astron & Astrophys, Dept Phys, University Pk, PA 16801 USA..
    Young, R.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Zink, A.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Hardware Development for the Radio Neutrino Observatory in Greenland (RNO-G)2022Ingår i: 37th International Cosmic Ray Conference, ICRC2021 / [ed] Keilhauer, B Kappes, A, Proceedings of Science , 2022, artikel-id 1058Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Radio Neutrino Observatory in Greenland (RNO-G) is designed to make the first observations of ultra-high energy neutrinos at energies above 10 PeV, playing a unique role in multi-messenger astrophysics as the world's largest in-ice Askaryan radio detection array. The experiment will be composed of 35 autonomous stations deployed over a 5 x 6 km grid near NSF Summit Station in Greenland. The electronics chain of each station is optimized for sensitivity and low power, incorporating 150 - 600 MHz RF antennas at both the surface and in ice boreholes, low-noise amplifiers, custom RF-over-fiber systems, and an FPGA-based phased array trigger. Each station will consume 25 W of power, allowing for a live time of 70% from a solar power system. The communications system is composed of a high-bandwidth LTE network and an ultra-low power LoRaWAN network. I will also present on the calibration and DAQ systems, as well as status of the first deployment of 10 stations in Summer 2021.

    Ladda ner fulltext (pdf)
    fulltext
  • 4.
    Aguilar, J. A.
    et al.
    Univ Libre Bruxelles, Sci Fac CP230, B-1050 Brussels, Belgium..
    Allison, P.
    Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Dept Phys, Columbus, OH 43210 USA..
    Beatty, J. J.
    Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Dept Phys, Columbus, OH 43210 USA..
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Besson, D.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA.;Natl Nucl Res Univ MEPhI, Kashirskoe Shosse 31, Moscow 115409, Russia..
    Bingefors, Nils
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Botner, Olga
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Bouma, S.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Buitink, S.
    Vrije Univ Brussel, Astrophys Inst, Pleinlaan 2, B-1050 Brussels, Belgium..
    Carter, K.
    Calif Polytech State Univ San Luis Obispo, Phys Dept, San Luis Obispo, CA 93407 USA..
    Cataldo, M.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Clark, B. A.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Curtis-Ginsberg, Z.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Connolly, A.
    Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Dept Phys, Columbus, OH 43210 USA..
    Dasgupta, P.
    Univ Libre Bruxelles, Sci Fac CP230, B-1050 Brussels, Belgium..
    de Kockere, S.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    de Vries, K. D.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Deaconu, C.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    DuVernois, M. A.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Glaser, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Hallgren, Allan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Hallmann, S.
    DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Hanson, J. C.
    Whittier Coll, Whittier, CA 90602 USA..
    Hendricks, B.
    Penn State Univ, Dept Phys, Dept Astron & Astrophys, University Pk, PA 16801 USA..
    Hokanson-Fasig, B.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Hornhuber, C.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Hughes, K.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Karle, A.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Kelley, J. L.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Klein, S. R.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Krebs, R.
    Penn State Univ, Dept Phys, Dept Astron & Astrophys, University Pk, PA 16801 USA..
    Lahmann, R.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Latif, U.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Meures, T.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Meyers, Z. S.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Mulrey, K.
    Vrije Univ Brussel, Astrophys Inst, Pleinlaan 2, B-1050 Brussels, Belgium..
    Nelles, A.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Novikov, A.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Oberla, E.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Oeyen, B.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Pandya, H.
    Vrije Univ Brussel, Astrophys Inst, Pleinlaan 2, B-1050 Brussels, Belgium..
    Plaisier, I
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Pyras, L.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Ryckbosch, D.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Scholten, O.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium.;Univ Groningen, KVI Ctr Adv Radiat Technol, Groningen, Netherlands..
    Seckel, D.
    Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Smith, D.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Southall, D.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Torres, J.
    Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Dept Phys, Columbus, OH 43210 USA..
    Toscano, S.
    Univ Libre Bruxelles, Sci Fac CP230, B-1050 Brussels, Belgium..
    Tosi, D.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Van den Broeck, D. J.
    Vrije Univ Brussel, Astrophys Inst, Pleinlaan 2, B-1050 Brussels, Belgium.;Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    van Eijndhoven, N.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Vieregg, A. G.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Welling, C.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Wissel, S.
    Calif Polytech State Univ San Luis Obispo, Phys Dept, San Luis Obispo, CA 93407 USA.;Penn State Univ, Dept Phys, Dept Astron & Astrophys, University Pk, PA 16801 USA..
    Young, R.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Zink, A.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Reconstructing the neutrino energy for in-ice radio detectors2022Ingår i: European Physical Journal C, ISSN 1434-6044, E-ISSN 1434-6052, Vol. 82, nr 2, artikel-id 147Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Since summer 2021, the Radio Neutrino Observatory in Greenland (RNO-G) is searching for astrophysical neutrinos at energies > 10 PeV by detecting the radio emission from particle showers in the ice around Summit Station, Greenland. We present an extensive simulation study that shows how RNO-G will be able to measure the energy of such particle cascades, which will in turn be used to estimate the energy of the incoming neutrino that caused them. The location of the neutrino interaction is determined using the differences in arrival times between channels and the electric field of the radio signal is reconstructed using a novel approach based on Information Field Theory. Based on these properties, the shower energy can be estimated. We show that this method can achieve an uncertainty of 13% on the logarithm of the shower energy after modest quality cuts and estimate how this can constrain the energy of the neutrino. The method presented in this paper is applicable to all similar radio neutrino detectors, such as the proposed radio array of IceCube-Gen2.

    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 5.
    Aguilar, J. A.
    et al.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Allison, P.
    Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Dept Phys, Columbus, OH 43210 USA..
    Beatty, J. J.
    Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Dept Phys, Columbus, OH 43210 USA..
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Besson, D.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA.;Natl Nucl Res Univ MEPhI, Kashirskoe Shosse 31, Moscow 115409, Russia..
    Bingefors, Nils
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Botner, Olga
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Buitink, S.
    Vrije Univ Brussel, Astrophys Inst, Pl Laan 2, B-1050 Brussels, Belgium..
    Carter, K.
    Calif Polytech State Univ San Luis Obispo, Dept Phys, San Luis Obispo, CA 93407 USA..
    Clark, B. A.
    Michigan State Univ, Dept Phys & Astron, E Lansing, MI 48824 USA..
    Connolly, A.
    Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Dept Phys, Columbus, OH 43210 USA..
    Dasgupta, P.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    de Kockere, S.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    de Vries, K. D.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Deaconu, C.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    DuVernois, M. A.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Feigl, N.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Garcia-Fernandez, D.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Glaser, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Hallgren, Allan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Hallmann, S.
    DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Hanson, J. C.
    Whittier Coll, Whittier, CA 90602 USA..
    Hendricks, B.
    Penn State Univ, Dept Phys, Dept Astron & Astrophys, University Pk, PA 16801 USA..
    Hokanson-Fasig, B.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Hornhuber, C.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Hughes, K.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Karle, A.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Kelley, J. L.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Klein, S. R.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Krebs, R.
    Penn State Univ, Dept Phys, Dept Astron & Astrophys, University Pk, PA 16801 USA..
    Lahmann, R.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Magnuson, M.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Meures, T.
    Univ Wisconsin, Wisconsin IceCube Particle Astrophys Ctr WIPAC, Madison, WI 53703 USA.;Univ Wisconsin, Dept Phys, Madison, WI 53703 USA..
    Meyers, Z. S.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Nelles, A.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Novikov, A.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Oberla, E.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Oeyen, B.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Pandya, H.
    Vrije Univ Brussel, Astrophys Inst, Pl Laan 2, B-1050 Brussels, Belgium..
    Plaisier, I
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Pyras, L.
    DESY, Platanenallee 6, D-15738 Zeuthen, Germany.;Humboldt Univ, Unter Linden 6, D-10117 Berlin, Germany..
    Ryckbosch, D.
    Univ Ghent, Dept Phys & Astron, B-9000 Ghent, Belgium..
    Scholten, O.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Seckel, D.
    Univ Delaware, Dept Phys & Astron, Newark, DE 19716 USA..
    Smith, D.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Southall, D.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Torres, J.
    Ohio State Univ, Ctr Cosmol & AstroParticle Phys, Dept Phys, Columbus, OH 43210 USA..
    Toscano, S.
    Univ Libre Bruxelles, Sci Fac, CP230, B-1050 Brussels, Belgium..
    Van den Broeck, D. J.
    Vrije Univ Brussel, Astrophys Inst, Pl Laan 2, B-1050 Brussels, Belgium.;Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    van Eijndhoven, N.
    Vrije Univ Brussel, Dienst ELEM, B-1050 Brussels, Belgium..
    Vieregg, A. G.
    Univ Chicago, Enrico Fermi Inst, Kavli Inst Cosmol Phys, Dept Phys, Chicago, IL 60637 USA..
    Welling, C.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany.;DESY, Platanenallee 6, D-15738 Zeuthen, Germany..
    Wissel, S.
    Calif Polytech State Univ San Luis Obispo, Dept Phys, San Luis Obispo, CA 93407 USA.;Penn State Univ, Dept Phys, Dept Astron & Astrophys, University Pk, PA 16801 USA..
    Young, R.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Zink, A.
    Friedrich Alexander Univ Erlangen Nuremberg, Erlangen Ctr Astroparticle Phys ECAP, D-91058 Erlangen, Germany..
    Design and sensitivity of the Radio Neutrino Observatory in Greenland (RNO-G)2021Ingår i: Journal of Instrumentation, E-ISSN 1748-0221, Vol. 16, nr 3, artikel-id P03025Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article presents the design of the Radio Neutrino Observatory Greenland (RNO-G) and discusses its scientific prospects. Using an array of radio sensors, RNO-G seeks to measure neutrinos above 10 PeV by exploiting the Askaryan effect in neutrino-induced cascades in ice. We discuss the experimental considerations that drive the design of RNO-G, present first measurements of the hardware that is to be deployed and discuss the projected sensitivity of the instrument. RNO-G will be the first production-scale radio detector for in-ice neutrino signals.

  • 6.
    Aihara, Aya
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Aeroacoustic Prediction for Vertical Axis Wind Turbines2021Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis investigates the aerodynamic and aeroacoustic prediction of vertical axis wind turbines, using computational fluid dynamics simulations. Noise pollution from wind turbines is one of the disadvantages of wind energy, calling for strategies to reduce noise levels. Yet for vertical axis wind turbines in particular, there is insufficient knowledge of how to identify sound sources and mitigate the sound level. The aim of this study is to predict aerodynamic noise, using large eddy simulation and acoustic analogy, so as to better understand the mechanism of sound generation for vertical axis wind turbines. First, the prediction method is validated for a static single blade in stall. This model is able to capture the dominant frequency, but it does not well reproduce the broadband characteristics. Next, the aerodynamic behavior of the 12 kW H-rotor vertical axis wind turbine is studied, whereby the focus is on the importance of properly modeling the strut influence for an accurate prediction of the blade forces. To achieve this, the flow field is solved for three different tip speed ratios. The results show that the struts significantly affect on the force distribution along the blade. The reduction of the blade force is observed to occur not only at the attachment points of the struts, but also over a large area of the blade section in the downwind side where the blade interacts with the wake created in the upwind. Finally, the noise radiated from the vertical axis wind turbine operating at high tip speed ratio is predicted. Measurements are conducted to validate the prediction, with the experimental data representing the broadband noise characteristics dominant at around 800 Hz. The prediction reproduces the sound pressure level observed at a radial distance of 1.4 rotor diameter, with a few decibels difference. However, these discrepancies become more pronounced at double distance, which can be considered to arise due to the effect of the ground reflection being ignored. The simulation furthermore indicates, that the main sound sources are emitted when the blade rotates in the downwind. It is suggested that future work should properly consider the atmospheric turbulence for more accurate predictions.

    Delarbeten
    1. LES prediction for acoustic noise of airfoil at high angle of attack
    Öppna denna publikation i ny flik eller fönster >>LES prediction for acoustic noise of airfoil at high angle of attack
    2020 (Engelska)Konferensbidrag, Muntlig presentation med publicerat abstract (Refereegranskat)
    Nationell ämneskategori
    Strömningsmekanik och akustik
    Identifikatorer
    urn:nbn:se:uu:diva-426027 (URN)10.2514/6.2020-1723 (DOI)
    Konferens
    AIAA Scitech 2020 Forum
    Tillgänglig från: 2020-11-23 Skapad: 2020-11-23 Senast uppdaterad: 2021-12-28
    2. Numerical prediction of noise generated from airfoil in stall using LES and acoustic analogy
    Öppna denna publikation i ny flik eller fönster >>Numerical prediction of noise generated from airfoil in stall using LES and acoustic analogy
    2021 (Engelska)Ingår i: Noise & Vibration Worldwide, ISSN 0957-4565, E-ISSN 2048-4062, Vol. 52, nr 10, s. 295-305Artikel i tidskrift (Övrigt vetenskapligt) Published
    Abstract [en]

    This article presents the aerodynamic noise prediction of a NACA 0012 airfoil in stall region using Large Eddy Simulation and the acoustic analogy. While most numerical studies focus on noise for an airfoil at a low angle of attack, prediction of stalled noise has been made less sufficiently. In this study, the noise of a stalled airfoil is calculated using the spanwise correction where the total noise is estimated from the sound source of the simulated span section based on the coherence of turbulent flow structure. It is studied for the airfoil at the chord-based Reynolds number of 4.8 × 105 and the Mach number of 0.2 with the angle of attack of 15.6° where the airfoil is expected to be under stall condition. An incompressible flow is resolved to simulate the sound source region, and Curle’s acoustic analogy is used to solve the sound propagation. The predicted spectrum of the sound pressure level observed at 1.2 m from the trailing edge of the airfoil is validated by comparing measurement data, and the results show that the simulation is able to capture the dominant frequency of the tonal peak. However, while the measured spectrum is more broadband, the predicted spectrum has the tonal character around the primary frequency. This difference can be considered to arise due to insufficient mesh resolution.

    Ort, förlag, år, upplaga, sidor
    Sage Publications, 2021
    Nyckelord
    Acoustics, noise; airfoil, computational fluid dynamics, LES, Curle’s acoustic analogy
    Nationell ämneskategori
    Strömningsmekanik och akustik
    Identifikatorer
    urn:nbn:se:uu:diva-426035 (URN)10.1177/09574565211030706 (DOI)
    Tillgänglig från: 2020-11-23 Skapad: 2020-11-23 Senast uppdaterad: 2023-03-13Bibliografiskt granskad
    3. A numerical study of strut influence on blade forces of vertical axis wind turbine using computational fluid dynamics simulation
    Öppna denna publikation i ny flik eller fönster >>A numerical study of strut influence on blade forces of vertical axis wind turbine using computational fluid dynamics simulation
    (Engelska)Ingår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824Artikel i tidskrift (Övrigt vetenskapligt) Submitted
    Nationell ämneskategori
    Strömningsmekanik och akustik
    Identifikatorer
    urn:nbn:se:uu:diva-426033 (URN)
    Tillgänglig från: 2020-11-23 Skapad: 2020-11-23 Senast uppdaterad: 2020-12-07
    4. Comparison of three-dimensional numerical methods for modeling of strut effect on aerodynamic forces of a vertical axis wind turbine
    Öppna denna publikation i ny flik eller fönster >>Comparison of three-dimensional numerical methods for modeling of strut effect on aerodynamic forces of a vertical axis wind turbine
    (Engelska)Ingår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824Artikel i tidskrift (Övrigt vetenskapligt) Submitted
    Nationell ämneskategori
    Strömningsmekanik och akustik
    Identifikatorer
    urn:nbn:se:uu:diva-426034 (URN)
    Tillgänglig från: 2020-11-23 Skapad: 2020-11-23 Senast uppdaterad: 2020-12-07
    5. Aeroacoustic noise prediction of a vertical axis wind turbine using Large Eddy Simulation
    Öppna denna publikation i ny flik eller fönster >>Aeroacoustic noise prediction of a vertical axis wind turbine using Large Eddy Simulation
    2021 (Engelska)Ingår i: International Journal of Aeroacoustics, ISSN 1475-472X, E-ISSN 2048-4003, Vol. 20, nr 8, s. 959-978Artikel i tidskrift (Övrigt vetenskapligt) Published
    Abstract [en]

    This study investigates the numerical prediction for the aerodynamic noise of the vertical axis wind turbine using large eddy simulation and the acoustic analogy. Low noise designs are required especially in residential areas, and sound level generated by the wind turbine is therefore important to estimate. In this paper, the incompressible flow field around the 12 kW straight-bladed vertical axis wind turbine with the rotor diameter of 6.5 m is solved, and the sound propagation is calculated based on the Ffowcs Williams and Hawkings acoustic analogy. The sound pressure for the turbine operating at high tip speed ratio is predicted, and it is validated by comparing with measurement. The measured spectra of the sound pressure observed at several azimuth angles show the broadband characteristics, and the prediction is able to reproduce the shape of these spectra. While previous works studying small-scaled vertical axis wind turbines found that the thickness noise is the dominant sound source, the loading noise can be considered to be a main contribution to the total sound for this turbine. The simulation also indicates that the received noise level is higher when the blade moves in the downwind than in the upwind side.

    Ort, förlag, år, upplaga, sidor
    Sage PublicationsSAGE Publications, 2021
    Nyckelord
    Vertical axis wind turbine, acoustics, aerodynamic noise, CFD, LES
    Nationell ämneskategori
    Strömningsmekanik och akustik
    Identifikatorer
    urn:nbn:se:uu:diva-426037 (URN)10.1177/1475472X211055179 (DOI)000721550900001 ()
    Forskningsfinansiär
    Swedish National Infrastructure for Computing (SNIC)Vetenskapsrådet, 2020/5-321
    Tillgänglig från: 2020-11-23 Skapad: 2020-11-23 Senast uppdaterad: 2024-01-15Bibliografiskt granskad
    Ladda ner fulltext (pdf)
    fulltext
    Ladda ner (jpg)
    presentationsbild
  • 7.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    LES prediction for acoustic noise of airfoil at high angle of attack2020Konferensbidrag (Refereegranskat)
  • 8.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Numerical prediction of noise generated from airfoil in stall using LES and acoustic analogy2021Ingår i: Noise & Vibration Worldwide, ISSN 0957-4565, E-ISSN 2048-4062, Vol. 52, nr 10, s. 295-305Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    This article presents the aerodynamic noise prediction of a NACA 0012 airfoil in stall region using Large Eddy Simulation and the acoustic analogy. While most numerical studies focus on noise for an airfoil at a low angle of attack, prediction of stalled noise has been made less sufficiently. In this study, the noise of a stalled airfoil is calculated using the spanwise correction where the total noise is estimated from the sound source of the simulated span section based on the coherence of turbulent flow structure. It is studied for the airfoil at the chord-based Reynolds number of 4.8 × 105 and the Mach number of 0.2 with the angle of attack of 15.6° where the airfoil is expected to be under stall condition. An incompressible flow is resolved to simulate the sound source region, and Curle’s acoustic analogy is used to solve the sound propagation. The predicted spectrum of the sound pressure level observed at 1.2 m from the trailing edge of the airfoil is validated by comparing measurement data, and the results show that the simulation is able to capture the dominant frequency of the tonal peak. However, while the measured spectrum is more broadband, the predicted spectrum has the tonal character around the primary frequency. This difference can be considered to arise due to insufficient mesh resolution.

    Ladda ner fulltext (pdf)
    fulltext
  • 9.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Karl, Bolin
    The Marcus Wallenberg Laboratory, Department of Engineering Mechanics, KTH, Sweden.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Aeroacoustic noise prediction of a vertical axis wind turbine using Large Eddy Simulation2021Ingår i: International Journal of Aeroacoustics, ISSN 1475-472X, E-ISSN 2048-4003, Vol. 20, nr 8, s. 959-978Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    This study investigates the numerical prediction for the aerodynamic noise of the vertical axis wind turbine using large eddy simulation and the acoustic analogy. Low noise designs are required especially in residential areas, and sound level generated by the wind turbine is therefore important to estimate. In this paper, the incompressible flow field around the 12 kW straight-bladed vertical axis wind turbine with the rotor diameter of 6.5 m is solved, and the sound propagation is calculated based on the Ffowcs Williams and Hawkings acoustic analogy. The sound pressure for the turbine operating at high tip speed ratio is predicted, and it is validated by comparing with measurement. The measured spectra of the sound pressure observed at several azimuth angles show the broadband characteristics, and the prediction is able to reproduce the shape of these spectra. While previous works studying small-scaled vertical axis wind turbines found that the thickness noise is the dominant sound source, the loading noise can be considered to be a main contribution to the total sound for this turbine. The simulation also indicates that the received noise level is higher when the blade moves in the downwind than in the upwind side.

    Ladda ner fulltext (pdf)
    fulltext
  • 10.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. Uppsala Univ, Dept Elect Engn, Div Elect, Uppsala, Sweden..
    Mendoza, Victor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. Hexicon, Slupskjulsvagen 30, S-11149 Stockholm, Sweden..
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    A numerical study of strut and tower influence on the performance of vertical axis wind turbines using computational fluid dynamics simulation2022Ingår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824, Vol. 25, nr 5, s. 897-913Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper presents the influence of the strut and the tower on the aerodynamic force of the blade for the vertical axis wind turbine (VAWT). It has been known that struts degrade the performance of VAWTs due to the inherent drag losses. In this study, three-dimensional Reynolds-averaged Navier-Stokes simulations have been conducted to investigate the effect of the strut and the tower on the flow pattern around the rotor region, the blade force distribution, and the rotor performance. A comparison has been made for three different cases where only the blade; both the blade and the strut; and all of the blade, the strut, and the tower are considered. A 12-kW three-bladed H-rotor VAWT has been studied for tip speed ratio of 4.16. This ratio is relatively high for this turbine, so the influence of the strut is expected to be crucial. The numerical model has been validated first for a single pitching blade and full VAWTs. The simulations show distinguished differences in the force distribution along the blade between two cases with and without struts. Since the wake from the struts interacts with the blades, the tangential force is reduced especially in the downwind side when the struts are considered. The calculated power coefficient is decreased by 43 %, which shows the importance of modeling the strut effect properly for accurate prediction of the turbine performance. The simulations also indicate that including the tower does not yield significant difference in the force distribution and the rotor power.

    Ladda ner fulltext (pdf)
    fulltext
  • 11.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik.
    Mendoza, Victor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    A numerical study of strut influence on blade forces of vertical axis wind turbine using computational fluid dynamics simulationIngår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824Artikel i tidskrift (Övrigt vetenskapligt)
  • 12.
    Aihara, Aya
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Mendoza, Victor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. Hexicon AB, Ostra Jarnvagsgatan 27, S-11120 Stockholm, Sweden..
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Comparison of Three-Dimensional Numerical Methods for Modeling of Strut Effect on the Performance of a Vertical Axis Wind Turbine2022Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 7, artikel-id 2361Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper compares three different numerical models to evaluate their accuracy for predicting the performance of an H-rotor vertical-axis wind turbine (VAWT) considering the influence of struts. The strut of VAWTs is one factor that makes the flow feature around the turbine more complex and thus influences the rotor performance. The focus of this study is placed on analyzing how accurately three different numerical approaches are able to reproduce the force distribution and the resulting power, taking the strut effect into account. For the 12 kW straight-bladed VAWT, the blade force is simulated at three tip speed ratios by the full computational fluid dynamics (CFD) model based on the Reynolds-averaged Navier-Stokes (RANS) equations, the actuator line model (ALM), and the vortex model. The results show that all the models do not indicate a significant influence of the struts in the total force over one revolution at low tip speed ratio. However, at middle and high tip speed ratio, the RANS model reproduces the significant decrease of the total tangential force that is caused due to the strut. Additionally, the RANS and vortex models present a clear influence of the struts in the force distribution along the blade at all three tip speed ratios investigated. The prediction by the ALM does not show such distinctive features of the strut impact. The RANS model is superior to the other two models for predicting the power coefficient considering the strut effect, especially at high tip speed ratio.

    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 13. Aihara, Aya
    et al.
    Mendoza, Victor
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Comparison of three-dimensional numerical methods for modeling of strut effect on aerodynamic forces of a vertical axis wind turbineIngår i: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824Artikel i tidskrift (Övrigt vetenskapligt)
  • 14.
    Al Kzair, Christian
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    SiC MOSFET function in DC-DC converter2020Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis evaluate the state of art ROHM SCT3080KR silicon carbide mosfet in a synchronous buck converter. The converter was using the ROHM P02SCT3040KR-EVK-001 evaluation board for driving the mosfets in a half bridge configuration. Evaluation of efficiency, waveforms, temperature and a theoretical comparison between a silicon mosfet (STW12N120K5) is done. For the efficiency test the converter operate at 200 V input voltage and 100 V output voltage at output currents of 7 A to 12 A, this operation was tested at switching frequencies of 50 kHz, 80 kHz and 100 kHz. The result of the efficiency test showed an efficiency of 98-97 % for 50 kHz, 97.7-96.4 % for 80 kHz and 97-96.2 % for the 100 kHz test. The temperature test shows a small difference in comparison of the best case scenario and the worst case scenario, temperature ranges from 25.5 to 33.5 °C for the high side mosfet while the low side mosfet temperature ranges from 29.8 to 35 °C. The waveform test was conducted at 50 kHz and 100 kHz for output currents of 4 A and 12 A (at 200 V input and 100 V output). The result of the waveform test shows a rise and fall time of the voltages in range of 10-12 ns while the current rise and fall time was 16 ns for the 4 A test and 20 ns for the 12 A test. Overall SiC mosfet show a clear advantage over silicon mosfet in terms of efficiency and high power capabilities.

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  • 15.
    Al Obeid, Karar
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Barr, Anton
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Energieffektivisering av Scanias automationsindustri: En studie som syftar till att förbättra Scanias verktyg, MDC-EE och utförs för att eliminera icke värdegivande tillförd energi för en bearbetningsmaskin och industriell tvättmaskin.2022Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Scania have set a goal to reduce 25% of its energy usages in the production to provide sustainable transport solution by 2025. Scania have studied their current production processes over the years for energy efficiency and have developed a tool named Machine Data Card - Energy Efficiency (MDC-EE) for a group of equipment (e.g., washing machine, machine tool). The developed MDC-EE for an equipment, consist of six levels and allows suppliers to grade their product according to Scania’s standard. This means that Scania can choose an energy efficient solution in the early procurement phase of a new equipment or facilities.

    We have studied two existing machines (i.e., a washing machine and a machine tool) at Scania with the energy efficiency method (i.e., MDC-EE) and propose improvements for energy efficiency. Later we evaluated the MDC-EE method and proposes improvement opportunities so the method can be generalised.

    A yearly saving of about 83 MWh can be achieved on the two machines by optimizing their operation time in relation to the real need in the process. Therefore, Scania has the possibility to save a large amount of energy, with little or no investment cost, if those improvements are implemented in machines like the examined units. 

    We continued to focus on the improvement opportunities on Scania’s energy efficiency method and suggests new definitions for different MDC-EE by clarifying the existing MDC-EE levels. In addition, we introduced an energy classing so that an equipment can be assessed by considering both operation time and installed power for all MDC-EE levels. 

    For the time being there is no information about which components should prioritized to increase the energy efficiency in a machine. If MDC-EE is used together with a weight factor, the correct components can be prioritized. As a recommendation, we suggested that Scania should continue working on a new method, based on the weighting factor, so that components can be prioritized in the initial stage of procurement.  

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  • 16.
    Alfredsson, Hampus
    et al.
    RISE Research Institutes of Sweden.
    Ollas, Patrik
    RISE Research Institutes of Sweden.
    Ghaem Sigarchian, Sara
    RISE Research Institutes of Sweden.
    Aalhuizen, Christoffer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Leijon, Jennifer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Thomas, Karin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Transportation Goes Electric – Exploring the Potential of Smart Charging Strategies for Airports2023Konferensbidrag (Refereegranskat)
    Abstract [en]

    Transport electrification continuously increases globally and propagates to new, even-larger vehicle applications due to decreased costs, battery technology improvements, and charging infrastructure rollout. This work highlights the importance of strategic planning for large electric vehicle charging nodes, like depots, terminals, airports and ports. Specifically from the perspective of predicting future power requirements and how to satisfy energy demand using a combination of smart charging algorithms, local photovoltaic electricity production and battery energy storage systems. A case study is presented where developed tools and models are applied to an airport for high-power charging of future electric aircraft.

  • 17.
    Ali, Roni
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Helelektriska tunga lastbilar: En studie om påverkan på elnätet2023Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Sweden has ambitious climate goals, such as the overarching goal, the 2045 goal. The goal is for Sweden to have zero net emissions of greenhouse gases by 2045 at the latest. In order to achieve the overall climate goal and the interim targets, electrification of society is an important component.

    The industrial sector and the transport sector each account for about a third of Sweden’s emissions, where the conversion to electricity is an important solution. The electrification of passenger cars and buses has meant that emissions from domestic transport have decreased every year, and in order to achieve the interim target of 70 percent lower emissions of greenhouse gases in 2030 compared to 2010, the electrification of heavy duty trucks is one of the key components.

    However, there are long-term challenges with the power grid and already today grid owners have capacity challenges. Regional grid owners cannot increase their power subscription, while local grid owners cannot grant new connections.

    Regarding the electrification of long-haul transportation, there are challenges in terms of charging infrastructure. Truck drivers operate on a strict schedule, and minimizing down time is crucial to keep costs down. By law, truck drivers must take a 45-minute break after 4.5 hours of driving time, which means that during this break it is desirable to recharge the vehicle before departure. This means that high power demands are placed on the charging infrastructure that exists to be able to transmit the desired energy.

     

    A new standard, the Megawatt Charging System (MCS), which meets the high power requirements has been developed and is included in pilot projects. The maximum power that the charging standard can deliver is 3.75 MW.

    The results of the thesis show that these high-power chargers place high demands on thepower grid. When connecting a charging station with MCS charging points to the grid, it may require local upgrading of lines and transformers, but also upgrading in otherparts of the network. Examples of such upgrades are reactive power compensation to be able to support the network locally at peak loads to obtain voltage levels within stable voltage ranges, but also upgrades of lines and transformers to be able to deliver the desired power.

    Integration of a battery storage in connection with a charging station relieves the powergrid and its components. However, it is important to highlight that since the battery needs to be recharged, this means that a more even power requirement is needed. However, the  maximum load on both transformers and lines is reduced, which can be a desirable effect when a charging station of the same nature is put into operation.

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  • 18.
    Andersson, Emil
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. World Wide Wind Tech AS, Alesund, Norway.
    Goude, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Vortex filament method 3D analysis of design parameters for counter-rotating axis floating tilted turbine2023Ingår i: EERA DeepWind conference 2023 / [ed] Tande, J. O. G.; Kvamsdal, T.; Muskulus, M., Institute of Physics Publishing (IOPP), 2023, artikel-id 012001Konferensbidrag (Refereegranskat)
    Abstract [en]

    The Counter-Rotating Axis Floating Tilted turbine (CRAFT) is a new design for floating off-shore wind power, which utilizes a low center of gravity and allows the tower to tilt to mitigate costs for platforming.

    In this study, 3D simulations of the CRAFT have been performed to investigate the effect from the tower's tilt angle on the aerodynamics of the turbine using a vortex filament method. Due to lack of empirical data of the CRAFT, the method has been benchmark tested against a previous project on a vertical axis wind turbine.

    Using this method, the blades' twist angle has been set to achieve good lift-to-drag ratio along the entire blade. Furthermore, the blades' chord length has been determined for optimal Tip Speed Ratio (TSR) 6 when the tower is tilted 30 degrees from vertical position.

    The CRAFT has been simulated vertically and tilted 15°, 30° and 45°, for TSRs ranging between 4 and 9. The power coefficients (CP) and normal forces have been determined, and velocity plots are presented to show how the near-wake develops.

    The results from this study serves as a basis for further development and design of the CRAFT.

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  • 19.
    Andersson, Tim
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Akram, Muhammad Arsal
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Carlnäs, Carl-Henrik
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Salisbury, Tiffany
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Evaluation of potential marine current turbine sites in North American waters2020Självständigt arbete på grundnivå (kandidatexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    Suitable locations for marine current power generation were scouted. The specific turbines considered in this project are vertical axis turbines and require an water velocity of 0.8 m/s to start and has a system efficiency of 20%. In the beginning of the project focus was directed towards areas along Florida's coastal line with high water velocities tapping into the Gulf Stream. Data found the velocities did not meet the water speed requirements. Following this observation, it was decided to discontinue further research in the Florida region and divert the attention towards waters in Alaska. There current velocities were found to be significantly higher. Because velocities vary over time marine current power is not relevant in Alaska, but rather the closely related technology tidal power. Two areas in Alaska distinguished themselves, Cook Inlet and Aleutian Islands.Potential power and annual energy extraction were estimated for turbine stations at each site. A battery energy storage system was implemented to counteract varying water velocities. The most promising site could steadily deliver 269 kW and an annual energy production of 2.44 GWh per turbine.

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  • 20.
    Andersson-Gran, Hilda
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Övertoner i lågspänningsnätet: Påverkan från storskalig introduktion av solcellsanläggningar och elfordonsladdning2021Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The number of solar panel systems and electric vehicle charging in the low voltage grid is increasing rapidly, due to climate- and environmental targets. These nonlinear loads inject harmonics into the grid, which could impact power quality as well as the wear and life of power grid components, such as transformers and cables. The Swedish network operator Ellevio wants to investigate the possible effects that can arise from a largescale introduction of this equipment in the grid, in terms of harmonics. The aim of this master thesis has been to evaluate the compatibility of equipment emission standards and requirements for power quality, and through different calculation methods assess the potential impact from high penetration of devices in the same network.

    The results show that converters of both EV and PV are able to keep emission levels well below the equipment standard limits. Even by full penetration of a network the aggregated effect of these loads will not alone have a significant impact on neither power quality nor components in terms of wear, losses or capacity. However, in networks experiencing unusually high background levels in combination with high emissions from other loads, the PV and EV emissions could be a contributing factor to a state where individual transformers would be affected or single harmonic voltage limits would be violated. This is considered a very rare case, and thus not something that would serve as a basis for the dimensioning of the low voltage grid. Instead, increased knowledge will help assessing such a scenario and give better support for solving the individual cases that do arise.

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  • 21.
    Anker, A.
    et al.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Barwick, S. W.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Besson, D. Z.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA.;Natl Res Nucl Univ MEPhI, Moscow Engn Phys Inst, Moscow 115409, Russia..
    Bingefors, Nils
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Garcia-Fernandez, D.
    DESY, D-15738 Zeuthen, Germany.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Gaswint, G.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Glaser, C.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA.;Uppsala Univ, Dept Phys & Astron, SE-75237 Uppsala, Sweden..
    Hallgren, Allan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Hanson, J. C.
    Whittier Coll Dept Phys, Whittier, CA 90602 USA..
    Klein, S. R.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Kleinfelder, S. A.
    Univ Calif Irvine, Dept Elect Engn & Comp Sci, Irvine, CA 92697 USA..
    Lahmann, R.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Latif, U.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Meyers, Z. S.
    DESY, D-15738 Zeuthen, Germany.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Nam, J.
    Natl Taiwan Univ, Dept Phys, Taipei 10617, Taiwan.;Natl Taiwan Univ, Leung Ctr Cosmol & Particle Astrophys, Taipei 10617, Taiwan..
    Novikov, A.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA.;Natl Res Nucl Univ MEPhI, Moscow Engn Phys Inst, Moscow 115409, Russia..
    Nelles, A.
    DESY, D-15738 Zeuthen, Germany.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Paul, M. P.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Persichilli, C.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Plaisier, I
    DESY, D-15738 Zeuthen, Germany.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Tatar, J.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA.;Univ Calif Irvine, Res Cyberinfrastruct Ctr, Irvine, CA 92697 USA..
    Wang, S-H
    Natl Taiwan Univ, Dept Phys, Taipei 10617, Taiwan.;Natl Taiwan Univ, Leung Ctr Cosmol & Particle Astrophys, Taipei 10617, Taiwan..
    Welling, C.
    DESY, D-15738 Zeuthen, Germany.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Probing the angular and polarization reconstruction of the ARIANNA detector at the South Pole2020Ingår i: Journal of Instrumentation, E-ISSN 1748-0221, Vol. 15, nr 9, artikel-id P09039Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The sources of ultra-high energy (UHE) cosmic rays, which can have energies up to 10(20) eV, remain a mystery. UHE neutrinos may provide important clues to understanding the nature of cosmic-ray sources. ARIANNA aims to detect UHE neutrinos via radio (Askaryan) emission from particle showers when a neutrino interacts with ice, which is an efficient method for neutrinos with energies between 10(16) eV and 10(20) eV. The ARIANNA radio detectors are located in Antarctic ice just beneath the surface. Neutrino observation requires that radio pulses propagate to the antennas at the surface with minimum distortion by the ice and firn medium. Using the residual hole from the South Pole Ice Core Project, radio pulses were emitted from a transmitter located up to 1.7 km below the snow surface. By measuring these signals with an ARIANNA surface station, the angular and polarization reconstruction abilities are quantified, which are required to measure the direction of the neutrino. After deconvolving the raw signals for the detector response and attenuation from propagation through the ice, the signal pulses show no significant distortion and agree with a reference measurement of the emitter made in an anechoic chamber. Furthermore, the signal pulses reveal no significant birefringence for our tested geometry of mostly vertical ice propagation. The origin of the transmitted radio pulse was measured with an angular resolution of 0.37 degrees indicating that the neutrino direction can be determined with good precision if the polarization of the radio-pulse can be well determined. In the present study we obtained a resolution of the polarization vector of 2.7 degrees. Neither measurement show a significant offset relative to expectation.

  • 22.
    Anker, A.
    et al.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Barwick, S. W.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Besson, D. Z.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA.;Natl Res Nucl Univ MEPhI, Moscow Engn Phys Inst, Moscow 115409, Russia..
    Bingefors, Nils
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Garcia-Fernandez, D.
    DESY, D-15738 Zeuthen, Germany.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Gaswint, G.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Glaser, C.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Hallgren, Allan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Hanson, J. C.
    Whittier Coll, Dept Phys, Whittier, CA 90602 USA..
    Klein, S. R.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Kleinfelder, S. A.
    Univ Calif Irvine, Dept Elect Engn & Comp Sci, Irvine, CA 92697 USA..
    Lahmann, R.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Latif, U.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA..
    Nam, J.
    Natl Taiwan Univ, Dept Phys, Taipei 10617, Taiwan.;Natl Taiwan Univ, Leung Ctr Cosmol & Particle Astrophys, Taipei 10617, Taiwan..
    Novikov, A.
    Univ Kansas, Dept Phys & Astron, Lawrence, KS 66045 USA.;Natl Res Nucl Univ MEPhI, Moscow Engn Phys Inst, Moscow 115409, Russia..
    Nelles, A.
    DESY, D-15738 Zeuthen, Germany.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Paul, M. P.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Persichilli, C.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Plaisier, I
    DESY, D-15738 Zeuthen, Germany.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    Prakash, T.
    Lawrence Berkeley Natl Lab, Berkeley, CA 94720 USA..
    Shively, S. R.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA..
    Tatar, J.
    Univ Calif Irvine, Dept Phys & Astron, Irvine, CA 92697 USA.;Univ Calif Irvine, Res Cyberinfrastruct Ctr, Irvine, CA 92697 USA..
    Unger, Elisabeth
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Högenergifysik.
    Wang, S-H
    Natl Taiwan Univ, Dept Phys, Taipei 10617, Taiwan.;Natl Taiwan Univ, Leung Ctr Cosmol & Particle Astrophys, Taipei 10617, Taiwan..
    Welling, C.
    DESY, D-15738 Zeuthen, Germany.;Friedrich Alexander Univ Erlangen Nurnberg, ECAP, D-91058 Erlangen, Germany..
    A search for cosmogenic neutrinos with the ARIANNA test bed using 4.5 years of data2020Ingår i: Journal of Cosmology and Astroparticle Physics, E-ISSN 1475-7516, nr 3, artikel-id 053Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The primary mission of the ARIANNA ultra-high energy neutrino telescope is to uncover astrophysical sources of neutrinos with energies greater than 10(16) eV. A pilot array, consisting of seven ARIANNA stations located on the surface of the Ross Ice Shelf in Antarctica, was commissioned in November 2014. We report on the search for astrophysical neutrinos using data collected between November 2014 and February 2019. A straight-forward template matching analysis yielded no neutrino candidates, with a signal efficiency of 79%. We find a 90% confidence upper limit on the diffuse neutrino flux of E-2 Phi = 1.7 x 10(-6) GeV cm(-2) s(-1) sr(-1) for a decade wide logarithmic bin centered at a neutrino energy of 10(18),eV, which is an order of magnitude improvement compared to the previous limit reported by the ARIANNA collaboration. The ARIANNA stations, including purpose built cosmic-ray stations at the Moore's Bay site and demonstrator stations at the South Pole, have operated reliably. Sustained operation at two distinct sites confirms that the flexible and adaptable architecture can be deployed in any deep ice, radio quiet environment. We show that the scientific capabilities, technical innovations, and logistical requirements of ARIANNA are sufficiently well understood to serve as the basis for large area radio-based neutrino telescope with a wide field-of-view.

  • 23.
    Anttila, Sara
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Döhler, Jéssica
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Oliveira, Janaína Goncalves de
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. Univ Fed Juiz de Fora, Dept Elect Energy, BR-36036330 Juiz De Fora, Brazil..
    Boström, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Grid Forming inverters: A review of the state of the art of key elements for microgrid operation2022Ingår i: Energies, E-ISSN 1996-1073, Vol. 15, nr 15, artikel-id 5517Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    In the past decade, inverter-integrated energy sources have experienced rapid growth, which leads to operating challenges associated with reduced system inertia and intermittent power generation, which can cause instability and performance issues of the power system. Improved control schemes for inverters are necessary to ensure the stability and resilience of the power system. Grid-forming inverters dampen frequency fluctuations in the power system, while grid-following inverters can aggravate frequency problems with increased penetration. This paper aims at reviewing the role of grid-forming inverters in the power system, including their topology, control strategies, challenges, sizing, and location. In order to facilitate continued research in this field, a comprehensive literature review and classification of the studies are conducted, followed by research gaps and suggestions for future studies.

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  • 24.
    Archetti, Joao A. G.
    et al.
    Univ Fed Juiz de Fora, Multiplatform Simulat Lab, Elect Engn Program, BR-36036900 Juiz De Fora, MG, Brazil..
    de Oliveira, Leonardo W.
    Univ Fed Juiz de Fora, Multiplatform Simulat Lab, Elect Engn Program, BR-36036900 Juiz De Fora, MG, Brazil..
    Oliveira, Janaína Goncalves de
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. Univ Fed Juiz de Fora, Multiplatform Simulat Lab, Elect Engn Program, BR-36036900 Juiz De Fora, MG, Brazil..
    Hardware-in-the-Loop Volt-Watt and Volt-VAr Control for Distribution Systems with High Penetration of Renewables2023Ingår i: Journal of Control Automation and Electrical Systems, ISSN 2195-3880, Vol. 34, nr 1, s. 177-188Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work aims to validate in control hardware in the loop (CHIL) simulations new voltage profile control strategies in distribution systems with different levels of photovoltaic penetration. The proposed control is implemented through intelligent inverters with control functions that act through voltage sensitivity. The Volt-VAr (V-V) and Volt-Watt (V-W) functions act in the local voltage control being implemented in a complementary way. The simulations are performed in real time, using the real-time digital simulator. Residential load profiles, solar irradiance and temperature curves are discretized hourly over a daily period, with the intention of making the emulation more realistic. Voltage source converters were implemented in RSCAD software. The contribution of this article points to the performance of the Volt-Watt (V-W) control function in single-stage inverters, which allows the maximum generation of instantaneous active power, acting directly on the maximum power point tracking algorithm, this strategy being validated by the CHIL simulation. The results show that the Volt-VAr and Volt-Watt control functions, acting at different levels of photovoltaic penetration, were effective in preventing the voltage profiles from violating the critical level imposed by the regulatory standard. Leading to the conclusion that its implementation directly in photovoltaic inverters entails a low cost and a complementary solution for the new challenges of electrical systems.

  • 25.
    Archetti, Joao Antonio Guedes
    et al.
    Univ Fed Juiz de Fora, Elect Engn Program, Multiplatform Simulat Lab, Juiz De Fora, MG, Brazil..
    Silva Junior, Dalmo C.
    Univ Fed Juiz de Fora, Elect Engn Program, Multiplatform Simulat Lab, Juiz De Fora, MG, Brazil.;Acad Univ Ctr, Juiz De Fora, MG, Brazil..
    de Medeiros, Lucio
    Lactec Inst, Curitiba, PR, Brazil..
    Salamanca, Henry L. L.
    Lactec Inst, Curitiba, PR, Brazil..
    Fuchs, Leonardo
    Lactec Inst, Curitiba, PR, Brazil..
    de Oliveira, Leonardo Willer
    Univ Fed Juiz de Fora, Elect Engn Program, Multiplatform Simulat Lab, Juiz De Fora, MG, Brazil..
    Gonçalves de Oliveira, Janaína
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. Univ Fed Juiz de Fora, Elect Engn Program, Multiplatform Simulat Lab, Juiz De Fora, MG, Brazil..
    Real time validation of a control system for microgrids with distributed generation and storage resources2023Ingår i: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 223, artikel-id 109683Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Faced with a scenario in which the increase in renewable energy generated near consumer centers can cause problems for the operation of the electrical network, the present work proposes a real-time simulation model for automation and control systems of electrical distribution networks with microgrids, distributed generation, and storage resources. The proposed model consists of a hardware-in-the-loop control with the aid of a simulation tool in conjunction with a Real-Time Digital Simulator (RTDS) and considers the dynamic behavior of switched elements and inverters. A communication platform using TCP/IP protocol between RTDS (power system) and MatLab/Simulink (optimization algorithms) allows the operation of the network in grid-connected and islanded mode, guaranteeing the computational time for experimental implementation. For the first mode, an algorithm is proposed to solve an optimal dispatch energy storage system problem. Second mode, an algorithm is proposed to solve a load shedding problem. The objective is to operate the microgrids optimally and evaluate the performance of a storage system based on real data from the state of Parana, in Brazil. Results show that the optimization algorithms are experimentally applicable, obtaining reasonable computational time to find optimal solutions and an assertive decision-making to meet the objectives. Thus, the proposed framework is a potential tool to validate algorithms for active management of microgrids in real-time simulation.

  • 26.
    Arevalo, Liliana
    et al.
    ABB Power Grids HVDC, Res & Dev, Ludvika, Sweden..
    Lobato, André
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Hettiarachchi, Pasan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Rahman, Mahbubur
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Attachment process of the discharge of competing grounded electrodes - Experimental observations and modeling2021Ingår i: 2021 35th International Conference on Lightning Protection (ICLP) and XVI International Symposium On Lightning Protection (SIPDA), IEEE, 2021Konferensbidrag (Refereegranskat)
    Abstract [en]

    The lightning attachment discharge process theory is based on studies of the physics of the discharge obtained from high voltage laboratory tests. The process of propagation of positive and negative discharges has been studied independently and then the gathered information has been used to understand and explain the lightning attachment development. In this paper, an experimental set-up is built to describe the dynamic behavior of positive and negative discharges. Electrodes of different dimensions placed at different distances are used as grounded electrodes and a high voltage electrode is subject to negative switching impulses. Test results allow to identify different stages of the dynamic process of attachment of the discharge between a downward negative discharge and a positive upward leader discharge. The principles of physics of discharge for positive and negative polarities are used to model the laboratory test measurements. The model can reproduce in an accurate manner majority of the dynamic processes of the discharge. In addition, statistical results of the effect of nearby and competing upward discharges is obtained.

  • 27.
    Arghandeh, Reza
    et al.
    Department of Electrical Engineering and Computer Science, Western Norway University of Applied Sciences, Bergen, Norway;StormGeo AS, Bergen, Norway.
    Uzunoglu, Bahri
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    D’Arco, Salvatore
    Department of Energy Systems, SINTEF Energy Research, Trondheim, Norway.
    Ozguven, Eren Erman
    FAMU-FSU College of Engineering, Tallahassee, FL, USA.
    Data Driven Reliable and Resilient Energy System Against Disasters2021Ingår i: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 18, nr 3, s. 2075-2077Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Disasters Such As Hurricanes, Earthquakes, Wildfires, Etc. Are Felt Most Acutely At local and regional levels. These events have exposed weaknesses in how well-prepared infrastructure operators are to keep their services and provide resilient responses. Outages and service disruptions are largely due to the inability of the affected city infrastructure (i.e., power grids) to cope with random and dynamic disruptive events, translating into resilience deficiencies. A significant challenge is the lack of data availability, sharing, and analysis for emergency planning, and restoration. The Special Section (SS) on Data-driven Reliable and Resilient Energy System Against Disasters in the IEEE Transactions on Industrial Informatics aims to address the data-driven approaches for power systems and infrastructure reliability and resilience during small- and large-scale extreme weather events or natural disasters. The specific aim is to utilize the advancements in data mining and data processing to minimize catastrophic conditions that affect the quality of critical infrastructure operations, quality of life, and economic activities.

  • 28.
    Arvidsson, Emil
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Future Nordic Grid Frequency Quality: A quantitative simulation study of current and potential frequency control methods with emphasis on synthetic inertia2021Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The power grid faces stability problems due to loss of inertia. The ancillary services balancing the system must be improved to maintain stability. In contrast to earlier studies, this thesis estimates how the future grid frequency quality in both the short and long term is affected by different control methods, using an ensemble of quality measures. The thesis uses conventional one-area models for the power grid and FCR-N (frequency containment reserve – normal operation) but develops new models for FCR-D (– disturbed operation), FFR (fast frequency reserve), and synthetic inertia (SI). To acquire proper input data the thesis uses an inverse model of the power grid to compute the momentary load disturbance, i.e., the difference between load and generation, from the grid frequency. The thesis makes a difference between proportional and derivative SI, where the latter is the one commonly associated with the term SI. The results show that derivative SI can improve some quality measures but requires very high power capacity. In contrast, proportional SI improves almost every measure the most, for a fraction of the required capacity. Derivative SI is therefore worth less from a system perspective. However, it is shown that the quality measures improved by derivative SI are related to hydropower wear and tear, making it more interesting for hydro power owners. Moreover, FFR gives no benefit to long time quality measures. Considering the short-term analysis where a large disturbance occurs, FFR gives almost no benefit and risks worsening the stability. Also, for the large disturbance, proportional SI performs the best. The results are limited by the small number of simulations that were performed and can only provide indications of trends. A more solid conclusion, however, is that one cannot expect transmission system operators (TSO) to introduce an ancillary service that builds on derivative SI.

    Ladda ner fulltext (pdf)
    Future Nordic Grid Frequency Quality
  • 29.
    Arvidsson, Maria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    On Electrification of Heavy-Duty Trucks: A Grid Impact Analysis of Grid Integration of a High-Power Charging Station2022Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The Swedish transport sector will need to undergo a major restructuring to achieve the established climate and environmental goals. The biggest change is that fossil fuels will be phased out and a larger part of the vehicle fleet will be electrified. This study deals with the electrification of heavy-duty trucks and how high-power charging stations affect the local electricity grid. Charging of heavy-duty trucks depends largely on the logistics of the transport system, which reduces the demand flexibility of power. High-power charging entails a risk of increased power peaks, which can affect the bus-voltage profiles, losses and loads on grid components.

    This thesis has been conducted as general study based on the case with the high-power charging station at Vädermotet in the area Hisingen of Gothenburg. The purpose was to build a generic model of the electricity grid at Hisingen and then investigate the consequences of high-power charging for the grid for two charging scenarios: the first scenario with four ABB Terra 360 chargers, and the second scenario with six ABB Terra 360 chargers and one MCS. The electricity network model and simulations were performed in PSS®SINCAL. The two charging scenarios, as well as the scenario before chargers were installed, were then simulated for three different system-load cases: maximum, average, and low load.

    The results showed that high-power charging of trucks had the biggest impacts for the voltage profiles during the case of low load. For the medium load and maximum load cases, the effect of the high-power charge decreased. Furthermore, electricity network losses increased for the low load case, but decreased slightly for the average and maximum load case. The reason was a more even load balance between the bus that connected the charging station to the grid and the rest of the network for the average and maximum load cases. In summary, the study indicated that grid implementation of a high-power charging station will have consequences for the local power system. However, the magnitude of the effects is not validated and can therefore only be regarded as indications. The outcome can be partly explained by the assumptions and simplifications of the model compared to the real system.

    Ladda ner fulltext (pdf)
    fulltext
  • 30. Asad, M.
    et al.
    Majdi, Saman
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Vorobiev, A.
    Jeppson, K.
    Isberg, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Stake, J.
    Graphene FET on Diamond for High-Frequency Electronics2022Ingår i: IEEE Electron Device Letters, ISSN 0741-3106, E-ISSN 1558-0563, Vol. 43, nr 2, s. 300-303Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transistors operating at high frequencies are the basic building blocks of millimeter-wave communication and sensor systems. The high charge-carrier mobility and saturation velocity in graphene can open way for ultra-fast field-effect transistors with a performance even better than what can be achieved with III-V-based semiconductors. However, the progress of high-speed graphene transistors has been hampered by fabrication issues, influence of adjacent materials, and self-heating effects. Here, we report on the improved performance of graphene field-effect transistors (GFETs) obtained by using a diamond substrate. An extrinsic maximum frequency of oscillation fmax of up to 54 GHz was obtained for a gate length of 500 nm. Furthermore, the high thermal conductivity of diamond provides an efficient heat-sink, and the relatively high optical phonon energy of diamond contributes to an increased charge-carrier saturation velocity in the graphene channel. Moreover, we show that GFETs on diamond exhibit excellent scaling behavior for different gate lengths. These results promise that the GFET-on-diamond technology has the potential of reaching sub-terahertz frequency performance.

  • 31.
    Asseh, Samir
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Small-scale wave energy converter for wave tank facility2023Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    A small-scale wave energy converter was designed and built for teaching and academic purposes to be used at The Division for Electricity, in the Ångström Laboratory at Uppsala University. The design of the power take-off (PTO) makes use of magnets passing through a copper coil for electricity generation. The magnets are attached by a string to the floating buoy in the small-scale wave tank which leads to a joint oscillation. Design parameters are executed using COMSOL Multiphysics which illustrates the total voltage output generated as well as the total magnetic field. Simulations and calculations in MATLAB were performed to extract the expected damping coefficient and plots of the buoy position compared to the wave amplitude. Lastly, a PTO prototype were built and compared with the simulations. The PTO shows electricity generation with the aid of a voltmeter showcasing the voltage. Additional information on future improvements to further aid teaching and academic understanding of wave energy converter are mentioned in the final section of this study.

    Ladda ner fulltext (pdf)
    fulltext
  • 32.
    Backéus, Jonas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Ombyggnad av Klockarforsen2021Självständigt arbete på avancerad nivå (masterexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The water level at Hjälta power station in Faxälven varies depending on the water flow that passes through the power station. The varying water level causes head losses, lesser energy generation and loss of income. The varying water level is caused by a short but narrow and shallow part of the river, known as Klockarforsen. To increase the water flow and decrease the resulting head losses, it is possible to dredge the stream bed in Klockarforsen in order to achieve a greater depth. 

    By using a sonar to map the bathymetry in Klockarforsen, it has been possible to create a model of this part of the river. The model has been constructed and processed in ArcGIS and HEC-RAS, in order to examine how a dredging would affect the water level, head losses, energy generation, income and retention water levels. 

    The results show that a dredging to a depth of four or six meters could raise the water level and the head height at Hjälta power station with an average of 0.32 and 0.41 meters, respectively. During the period between 2014-2019, 1.11-3.84 GWh more energy would have been generated annually if Klockarforsen had been dredged. Which means that the income for the power station would have increased by between MSEK 0.39-1.3 per year. The increased energy generation and income are considerable, but in terms of how much energy and income is generated annually, the figures are more modest. The energy production and income increase by between 0.13-0.3 percent annually. 

    Ladda ner fulltext (pdf)
    fulltext
  • 33.
    Baharin, Shamsul Ammar Shamsul
    et al.
    Univ Teknikal Malaysia Melaka, Ctr Technol Disaster Risk Reduct CDR, Fak Teknol & Kejuruteraan Elekt & Komputer, Durian Tunggal 76100, Melaka, Malaysia..
    Ahmad, Mohd Riduan
    Univ Teknikal Malaysia Melaka, Ctr Technol Disaster Risk Reduct CDR, Fak Teknol & Kejuruteraan Elekt & Komputer, Durian Tunggal 76100, Melaka, Malaysia..
    Akbar, Muhammad A'mmar Jamal
    Adv Micro Devices AMDs, Bayan Lepas 11900, Pulau Pinang, Malaysia..
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Electromagnetic Interference From Natural Lightning on 4G Communication Links2024Ingår i: IEEE Access, E-ISSN 2169-3536, Vol. 12, s. 14870-14881Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, microwave radiation pulses emitted from natural lightning have been found to interfere with the Fourth Generation Long Term Evolution (4G LTE) mobile communication data transmission. Two sets of measurement instruments have been synchronized where lightning electric field sensor together with 4G LTE network were evaluated its performance under two conditions namely fair-weather (four cases) and storm (four lightning cases). The microwave radiation emitted from lightning was directly measured without the use of a mixer and down-convertor to ensure the preservation of information such as the number of pulses and amplitude. A client-server architecture has been set up for data transmission utilizing User Datagram Protocol (UDP) where the packets have been generated by using Internet Performance Working Group Third Version (Iperf3) platform. Under fair-weather conditions, the 4G LTE connection at both the client and server nodes demonstrated stability and experienced minimal impact. On the other hand, natural lightning electromagnetic interference disrupted the 4G LTE communication links. Among the four reported storms, three storms have affected the 4G LTE data transmission. The first and fourth storms resulted in a complete connection drop to zero, lasting for 4 minutes and 2 seconds and for 44 seconds, respectively. The observation of hundreds microwave radiation pulses, each characterized by individual oscillating features suggests a potential disruption to packet transmission. Moreover, negative could-to-ground (-CG) and intra-cloud (IC) lightning flashes have been identified as the primary sources of interference to the 4G LTE data transmission. This information could be useful for future studies and for developers working on improving the reliability and performance of 4G LTE networks, particularly in areas prone to thunderstorms.

    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 34.
    Baharin, Shamsul Ammar Shamsul
    et al.
    Univ Tekn Malaysia Melaka, Atmospher & Lightning Res Lab, Ctr Telecommun Res & Innovat CeTRI, Fak Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Malaysia..
    Ahmad, Mohd Riduan
    Univ Tekn Malaysia Melaka, Atmospher & Lightning Res Lab, Ctr Telecommun Res & Innovat CeTRI, Fak Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Malaysia..
    Al-Shaikhli, Taha Raad Khaleel
    Univ Tekn Malaysia Melaka, Atmospher & Lightning Res Lab, Ctr Telecommun Res & Innovat CeTRI, Fak Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Malaysia..
    Sabri, Muhammad Haziq Mohammad
    Univ Tenaga Nas, Inst Power Engn, Coll Engn, Jalan IKRAM UNITEN, Kajang 43000, Selangor, Malaysia..
    Al-Kahtani, Ammar Ahmed
    Univ Tenaga Nas, Inst Power Engn, Coll Engn, Jalan IKRAM UNITEN, Kajang 43000, Selangor, Malaysia..
    Mohamad, Sulaiman Ali
    Univ Kebangsaan Malaysia, Inst Climate Change, Bangi 43600, Selangor, Malaysia..
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Sidik, Muhammad Abu Bakar
    Univ Sriwijaya UNSRI, Dept Elect Engn, Sumatera Selatan 30662, Indonesia..
    Microwave and Very High Frequency Radiations of The First Narrow Initial Breakdown2021Ingår i: 2021 35TH INTERNATIONAL CONFERENCE ON LIGHTNING PROTECTION (ICLP) AND XVI INTERNATIONAL SYMPOSIUM ON LIGHTNING PROTECTION (SIPDA), IEEE Institute of Electrical and Electronics Engineers (IEEE), 2021Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper reports the observation of microwave and very high frequency (VHF) radiation pulses associated with the first narrow (<10us) initial breakdown (IB) pulses of ten negative cloud-to-ground (-CG) flashes. The centre frequency of microwave and VHF sensors was 0.97 GHz and 60 MHz, respectively. We found that all microwave pulses were the initiation event led the first VHF pulses ranging between 0.03187 and 2.57968 mu s and led the first narrow IB pulses ranging between 0.02382 and 2.70202 mu s. Half of the VHF pulses were observed to lead the first narrow IB pulses ranging between 0.03453 and 0.128 mu s. Moreover, polarity of microwave radiation pulses was always positive while the polarity of the first narrow IB pulses always negative. On the other hand, half of VHF radiation pulses had the same polarity as microwave radiation pulses.

  • 35.
    Baharin, Shamsul Ammar Shamsul
    et al.
    Univ Tekn Malaysia Melaka, Ctr Telecommun Res & Innovat CeTRI, Atmospher & Lightning Res Lab, Fak Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Melaka, Malaysia..
    Ahmad, Mohd Riduan
    Univ Tekn Malaysia Melaka, Ctr Telecommun Res & Innovat CeTRI, Atmospher & Lightning Res Lab, Fak Kejuruteraan Elekt & Kejuruteraan Komputer, Durian Tunggal 76100, Melaka, Malaysia..
    Al-Shaikhli, Taha Raad Khaleel
    Al Nisour Univ Coll, Dept Comp Tech Engn, Baghdad, Iraq..
    Sidik, Muhammad Abu Bakar
    Univ Sriwijaya UNSRI, Dept Elect Engn, Sumatera Selatan 30662, Indonesia..
    Sabri, Muhammad Haziq Mohammad
    Univ Tenaga Nasl UNITEN, Inst Power Engn, Jalan IKRAM UNITEN, Kajang 43000, Selangor, Malaysia..
    Al-Kahtani, Ammar Ahmed Nasser
    Univ Tenaga Nasl UNITEN, Inst Power Engn, Jalan IKRAM UNITEN, Kajang 43000, Selangor, Malaysia..
    Mohammad, Sulaiman Ali
    Univ Kebangsaan Malaysia, Inst Climate Change, Bangi 43600, Selangor, Malaysia..
    Lu, Gaopeng
    Chinese Acad Sci, Inst Atmospher Phys, Key Lab Middle Atmosphere & Global Environm Obser, Beijing 100029, Peoples R China..
    Zhang, Hongbo
    Chinese Acad Sci, Inst Atmospher Phys, Key Lab Middle Atmosphere & Global Environm Obser, Beijing 100029, Peoples R China..
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Microwave radiation associated with stepped leaders of negative cloud-to-ground flashes2022Ingår i: Atmospheric research, ISSN 0169-8095, E-ISSN 1873-2895, Vol. 270, artikel-id 106091Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, Very-High Frequency (VHF) and microwave radiation pulses associated with stepped leader pulses (conventional breakdown) are examined. A total of 100 stepped leader pulses (SLPs) with the associated 100 quiet periods (QPs) from ten negative cloud-to-ground (CG) flashes within the reversal distance (<8 km) have been analyzed. The QP is defined as the period between two SLPs when no electrical activity within the fast antenna sensor bandwidth was detected. The measurement system is made up of fast antenna (FA) and slow antenna (SA) sensors, a VHF sensor (60 MHz center frequency with 40 MHz bandwidth), and a microwave sensor (0.97 GHz center frequency with 20 MHz bandwidth). The waveforms were sampled at 2.5 GHz (400 ps). The total durations of the SLPs and QPs were 2.648 +/- 1.152 mu s and 2.708 +/- 1.670 mu s, respectively. All microwave and VHF radiation waveforms have been detected as clear individual oscillating pulses. The key finding is that the microwave radiation can be classified into three categories based on the total number of detected individual oscillating pulses during the QP. Two microwave pulses detected during the QP (Category 1) are suggested to be associated with the electron avalanche/corona process at the tip of an existing negative leader and a space stem. The VHF pulses associated with the microwave pulses are suggested to be emitted by propagating streamers. On the other hand, a single microwave pulse detected during the QP (Category 2) is suggested to be emitted by the electron avalanche/corona process of a space stem. The VHF pulses associated with the microwave pulse are suggested to be emitted by propagating streamers. In both categories, 70% of the microwave radiation pulses have been observed to precede VHF radiation pulses with an average lead time of 0.848 +/- 1.336 mu s. The head-on collision of a downward propagating negative streamer and an upward propagating positive streamer (from space stem) emitted significant microwave radiation. A new negative leader was formed when the head-on collision took place. The microwave radiation pulses emitted by the head-on collision process were observed to precede SLPs with an average lead time of 0.423 +/- 0.378 mu s. Around 80% of the microwave radiation pulses preceded VHF radiation pulses with average lead time of 0.540 +/- 0.596 mu s. Therefore, microwave and VHF radiation pulses are suggested to be emitted by different processes of the electrical breakdown mechanism. The microwave radiation is emitted by electron avalanche/corona/head-on collision while the VHF radiation is emitted by propagating streamers.

  • 36.
    Baharin, Shamsul Ammar Shamsul
    et al.
    Univ Tekn Malaysia Melaka, Ctr Telecommun Res & Innovat CeTRI, Atmospher Sci & Disaster Management Res Grp ThorRG, Fak Kejuruteraan Elekt Kejuruteraan Komputer, Melaka 76100, Malaysia..
    Ahmad, Mohd Riduan
    Univ Tekn Malaysia Melaka, Ctr Telecommun Res & Innovat CeTRI, Atmospher Sci & Disaster Management Res Grp ThorRG, Fak Kejuruteraan Elekt Kejuruteraan Komputer, Melaka 76100, Malaysia..
    Sabri, Muhammad Haziq Mohammad
    Univ Tenaga Nas, Inst Power Engn IPE, Jalan IKRAM UNITEN, Kajang Selangor 43000, Malaysia..
    Alammari, Ammar
    Univ Tekn Malaysia Melaka, Ctr Telecommun Res & Innovat CeTRI, Atmospher Sci & Disaster Management Res Grp ThorRG, Fak Kejuruteraan Elekt Kejuruteraan Komputer, Melaka 76100, Malaysia..
    Al-Kahtani, Ammar Ahmed Nasser
    Univ Tenaga Nas, Inst Sustainable Energy ISE, Jalan IKRAM UNITEN, Kajang Selangor 43000, Malaysia..
    Lu, Gaopeng
    Chinese Acad Sci, Inst Atmospher Phys, Key Lab Middle Atmosphere & Global Environm Observ, Beijing 100029, Peoples R China..
    Kawasaki, Zen
    Osaka Univ, Grad Sch Engn, 1 1 Yamadaoka, Suita, Osaka 5650871, Japan..
    Cooray, Vernon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Microwave radiation associated with positive narrow bipolar events2023Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, E-ISSN 1879-1824, Vol. 242, artikel-id 105998Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, we examined seven isolated positive Narrow Bipolar Events (NBEs), one positive NBE that initiated an IC flash progressed to a single-stroke Cloud-to-Ground (CG) flash, and one positive NBE that initiated an IC flash. Seven NBEs have been accompanied by significant Very-High Frequency (VHF) and microwave radiation pulses. We recorded all NBEs from two measurement stations (ST1 and ST2) separated at 13.3 km apart which consisted of fast antenna (FA) and slow antenna (SA) sensors, a magnetic field (B-field) sensor, a VHF sensor (60 MHz), and a microwave sensor (0.97 GHz). The waveforms were sampled at 2.5 GHz (400 ps). The key finding is that all microwave radiation pulses have been found to precede both the VHF radiation pulses and NBEs with average lead time of 63 +/- 39 ns and 122 +/- 143 ns, respectively. In comparison to stepped leader pulses or SLPs (conventional breakdown), the average lead time of microwave to VHF for NBEs (fast breakdown) was 88% faster compared to the average lead time of microwave to VHF for SLPs. Moreover, the average lead time of VHF to NBEs was 56% faster when compared to the average lead time of VHF to SLPs. The VHF interferometer map for an isolated NBE (NBE6) showed upward propagation of VHF radiation sources (fast negative breakdown) with initiation altitude, total length of the VHF radiation sources propagation, and estimated velocity were 10.2 +/- 0.3 km, 2.9 +/- 0.6 km, and 1.8 x 108 and 2.8 x 108 ms-1, respectively. On the other hand, interferometer map for an NBE that initiated a single-stroke CG (NBE3) showed bidirectional fast streamers propagation with initiation altitude, total length of the VHF radiation sources propagation, and estimated velocity were 14.0 +/- 0.4 km, 2.9 +/- 0.82 km, and 1.6 x 108 and 2.8 x 108 ms-1, respectively. Clearly, the microwave and VHF radiation pulses associated with positive NBEs have been emitted by different processes of fast breakdown mechanism. Therefore, it can be suggested that the microwave radiation is emitted by electron avalanches/corona while the VHF ra-diation is emitted by fast propagating streamers.

  • 37.
    Bankefors, John
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Day-ahead modelling of the electricity balancing market: A study of linear machine learning models used for modelling predictions of mFRR volumes2024Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The study aimed to define and investigate relevant parameters affecting manual frequency restoration reserve (mFRR) volumes of the balancing market in the Finnish price area. It also aimed to find suitable models and investigate Day-ahead prediction possibilities of mFRR volumes. Parameters related to mFRR volumes Day-ahead predictions were identified in several earlier studies where of nine parameters were investigated. The correlations between mFRR volumes and the different parameters were investigated using Spearman’s correlation. Different linear machine learning models for Day-ahead predictions of mFRR volumes were builtand tested in Python. The resulting models used for predicting mFRR volumes in Python were one ARIMAX model and one SARIMAX model. The models were validated with a walk-forward method where Day-ahead predictions were conducted monthly for one year. The accuracy of the predictions was measured by the validation parameters Mean Absolute Value, Root Mean Square Error and Median Absolute Deviation. Results from the study show that it is difficult to predict absolute activated mFRR volumes. Although, it might be possible to predict that mFRR volumes will be activated or not, up- or down regulated to some extent. One explanation of the difficulties in predicting mFRR volumes is dueto mFRR being a balancing product whose function is to regulate disturbances in the electricity grid.

    Ladda ner fulltext (pdf)
    MasterThesis_JohnBankefors_2024
  • 38.
    Barankova, Hana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. BB Plasma Design AB, SE-75643 Uppsala, Sweden..
    Bardos, Ladislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. BB Plasma Design AB, SE-75643 Uppsala, Sweden..
    Amorphous Carbon Coatings on Glass for High Voltage Protection2022Ingår i: ECS Journal of Solid State Science and Technology, ISSN 2162-8769, E-ISSN 2162-8777, Vol. 11, nr 5, artikel-id 053003Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Radio frequency Hollow Cathode based hybrid process integrating both Physical Vapor Deposition and Plasma Enhanced Chemical Vapor Deposition was used for deposition of amorphous carbon on glass samples. The films were subjected to high voltage pulses and the performance was compared with uncoated glass samples to test the protection ability of the films, the ability to prevent the deteriorating effects of corona flashovers/arcs. In contrast to the uncoated glass the well adherent carbon films with thicknesses between 3.5 and 17 mu m exhibited an excellent protection of the glass substrate against the flashovers/arc damages in both polarities of the electric field with voltages up to 300 kV.

    Ladda ner fulltext (pdf)
    fulltext
  • 39.
    Barankova, Hana
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. BB Plasma Design AB, Uppsala, Sweden..
    Bardos, Ladislav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära. BB Plasma Design AB, Uppsala, Sweden..
    Reactive process and hysteresis effect in magnetron with magnetized hollow cathode enhanced target2020Ingår i: Contributions to Plasma Physics, ISSN 0863-1042, E-ISSN 1521-3986, Vol. 60, nr 9, artikel-id e202000023Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The hysteresis effect in the reactive process was investigated in the magnetron with a magnetized hollow cathode enhanced target (HoCET) in which the target is coupled with the hollow cathode magnetized by the magnetic field of the magnetron. The process, where both the magnetron and hollow cathode plasmas are combined, is compared to the magnetron sputtering. The hysteresis curve in the magnetized HoCET magnetron, recording the titanium emission intensity versus varying content of nitrogen in the gas mixture exhibits a local maximum on the increasing part of the curve. The hysteresis curve is shifted to lower contents of nitrogen than the hysteresis curve for the magnetron. It is concluded that more efficient utilization of the reactive gas takes place in this device.

    Ladda ner fulltext (pdf)
    fulltext
  • 40.
    Bardos, Ladislav
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Barankova, Hana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Radio frequency powered spiral hollow cathodes2020Ingår i: Vacuum, ISSN 0042-207X, E-ISSN 1879-2715, Vol. 175, artikel-id 109241Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Potential usage of the radio frequency (RF) spiral hollow electrodes in comparison with the compact hollow cathodes was examined for coating and other surface processing treatments. Most properties were found similar to the compact RF hollow cathodes. The non-conventional shapes of spiral hollow cathodes can be suitable for the inner coating in narrow tubes and pipes. Small diameter spiral cathodes can generate focused high-density ion flux capable of rapid etching of the substrate.

  • 41.
    Bardos, Ladislav
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Barankova, Hana
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Shaping od the flame geometry by non-conventional cold plasma arrangements2020Ingår i: Plasma Research Express, E-ISSN 2516-1067, Vol. 2, nr 3, artikel-id 035014Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Experimental examination of possibility to affect the shapes of flames under combustion of the liquified petroleum gas (LPG) were performed by several non-conventional cold atmospheric plasma arrangements. The lateral fused hollow cathode, the microwave surface wave plasma jet and the combination of these systems confirmed possibility of an efficient control of the flame shapes, increasing stability of flames and broadening of their front parts.

    Ladda ner fulltext (pdf)
    fulltext
  • 42.
    Bender, Anke
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Environmental Effects from Wave Power: Artificial Reefs and Incidental No-take Zones2022Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Marine renewable technologies have rapidly been developing over the past decade. Wave power is one of the renewable sources and has the potential securing the renewable electricity production. However, all renewable energy extraction affects the environment in some way and for a true sustainable energy generation, environmental effects need to be investigated. Beside uncertain effects from the technologies to habitats or organisms e.g., collision risks, electromagnetic fields, noise, past studies have also shown benefits on diversity, size and abundance of species around marine renewable technologies as a result of habitat creation by the devices and fishery exclusion in designated offshore park areas.

    This thesis deals with environmental effects from heaving point-absorber wave energy converters developed at Uppsala University and deployed on the Swedish west coast at the Lysekil research site and the Sotenäs Project wave power park over a period of four years. The scope was the investigation of artificial reef effects from wave power foundations on local mobile, mega and macrofauna during visual inspections using scuba diving on the first hand. On the second hand, the effects from the incidental no-take zone on decapods and two sea pen species were investigated applying cage fishing and ROV seabed surveys. A third focus was on environmental monitoring around MRE sites and monitoring of MRE installations, both in an experimental and theoretical approach.

    In the Lysekil research site, the results highlight that abundance and diversity can be enhanced locally around wave power foundations compared to control areas. The abundance and size of decapods were not significantly different within the wave power park and up to a distance of 360 m outside of it. In the Sotenäs Project wave power park a positive effect on Nephrops norvegicus size and burrow density but not on abundance was found on a scale of up to 1230 m. Sea pen abundance was enhanced inside the wave power park. However, interannual variation was strong.

    In conclusion, wave power foundations can influence abundance and diversity of marine organisms around foundations on a very local scale (meters). With the methods in this study, the investigations did not reveal strong effects on the abundance and size of decapods on a larger scale up to 1230 m away from foundations as a result of the no-take zone. However, a focus should be put on a further development of environmental monitoring routines around MRE sites and their evaluation.

    Delarbeten
    1. Colonisation of wave power foundations by mobile mega- and macrofauna - a 12 year study
    Öppna denna publikation i ny flik eller fönster >>Colonisation of wave power foundations by mobile mega- and macrofauna - a 12 year study
    2020 (Engelska)Ingår i: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 161, artikel-id 105053Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Environmental impacts from wave energy generators on the local mobile mega- and macrofauna community have been investigated in the Lysekil project by Uppsala University. Offshore renewable energy installations provide hard, artificial substrates, and as such, they could act as artificial reefs. Foundations with manufactured holes served as complex habitats and foundations without served as non-complex. In this long-term study, SCUBA surveys of mobile fauna in the years 2007, 2008 and 2016-2019 were analyzed. The results show a distinct reef effect on the foundations with significant greater species richness, total number of individuals, greater values of the Shannon-Wiener biodiversity index, and greater abundance of specific reef fauna. Complex foundations accommodated a greater abundance of brown crabs than non-complex foundations, other taxa did not show differences between the two foundation types. A successional increase of species richness, numbers of individuals and Shannon-Wiener biodiversity could be revealed from the first to the second survey period. Inter-annual variation was visible throughout all taxa and years.

    Ort, förlag, år, upplaga, sidor
    Elsevier BV, 2020
    Nyckelord
    Offshore renewable energy, Artificial reefs, Wave power, Reef effect, Habitat complexity, Long-term study, Cancer pagurus, Environmental effects, Community composition, Biodiversity
    Nationell ämneskategori
    Ekologi
    Identifikatorer
    urn:nbn:se:uu:diva-424486 (URN)10.1016/j.marenvres.2020.105053 (DOI)000579495700016 ()32871461 (PubMedID)
    Forskningsfinansiär
    Energimyndigheten, 40857-1StandUp
    Tillgänglig från: 2020-11-09 Skapad: 2020-11-09 Senast uppdaterad: 2022-02-02Bibliografiskt granskad
    2. Effects of a Wave Power Park with No-Take Zone on Decapod Abundance and Size
    Öppna denna publikation i ny flik eller fönster >>Effects of a Wave Power Park with No-Take Zone on Decapod Abundance and Size
    2021 (Engelska)Ingår i: Journal of Marine Science and Engineering, E-ISSN 2077-1312, Vol. 9, nr 8, s. 864-, artikel-id 864Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Past studies have revealed higher levels of biodiversity, total abundance, and size ofindividuals around offshore installations of renewable energy. This study investigated the effectsof Lysekil wave power park (area 0.5 km2) on the abundance and carapace size of decapods at theSwedish west coast. For that purpose, decapods were caught with cages during four consecutivesummers. Two types of cages were applied to catch a wide range of decapod species and sizes. Theabundance and size of decapods were not significantly different within the wave power park and upto a distance of 360 m outside of it. The catch rate, i.e., number of decapods caught in 24 h, was notsignificantly different among sampling locations but revealed inter-annual variation for both cagetypes. The results suggest a limited role of the incidental no-take zone of the small Lysekil wavepower park on the abundance and size of local decapods. However, neither were negative impacts,such as decreasing abundances or smaller carapace sizes, discovered. As an increase in the numberof marine renewable energy production sites is foreseen, a scaled-up and larger study addressingMPA networks and other environmental interactions should be considered.

    Ort, förlag, år, upplaga, sidor
    MDPIMDPI AG, 2021
    Nyckelord
    marine renewable energy, wave energy, marine protected area (MPA), no-take zone, co-location, environmental effects, mid-term study
    Nationell ämneskategori
    Biologiska vetenskaper Annan elektroteknik och elektronik
    Identifikatorer
    urn:nbn:se:uu:diva-450186 (URN)10.3390/jmse9080864 (DOI)000690541200001 ()
    Forskningsfinansiär
    Energimyndigheten, 40857-1
    Tillgänglig från: 2021-08-13 Skapad: 2021-08-13 Senast uppdaterad: 2024-01-15Bibliografiskt granskad
    3. Effects from wave power generators on the distribution of two sea pen species on the Swedish west coast
    Öppna denna publikation i ny flik eller fönster >>Effects from wave power generators on the distribution of two sea pen species on the Swedish west coast
    2019 (Engelska)Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Global electricity demand doubled between 1990 and 2016 and several countries are planning for a significant increase in offshore renewable energies along the European coast. In 2015 renewable energy accounted for more than half of the new generating capacity installed in the power sector worldwide. These activities bring up an increased interest about possible environmental impacts or additional values of the new technologies. The Wave Energy Park "Sotenäs Project" is located on the west coast of Sweden, 120 km north of Gothenburg, and was the site for environmental impact studies from wave energy generators on two sea pen species, Virgularia mirabilis (Müller, 1776) and Pennatula phosphorea (Linnaeus, 1758). Sea pens and burrowing mega fauna communities are designated threatened or declining habitats or species by the OSPAR convention. Investigations of those taxa in relation to marine renewable energies are thereby both interesting and important. A ROV aided seabed survey in the wave power park and respective control areas were primarily conducted to assess Nephrops norvegicus (Linnaeus, 1758) abundance and video footages were used to compare the abundance of the two sea pen species within the same area. Preliminary results show a significant difference between the transects and years. However, a clear increased number of individuals inside the wave power park for the two sea pen species compared to the control transects were not identified. Long-term observations and complementary studies are necessary in order to draw firm conclusions.

    Serie
    Proceedings of the 13th European Wave and Tidal Energy Conference, ISSN 2309-1983 ; 1240-1
    Nyckelord
    Environmental Studies, Marine Renewable Energy, Sea Pens, Pennatula phosphorea, Virgularia mirabilis, ROV Survey, Wave power
    Nationell ämneskategori
    Miljövetenskap Teknik och teknologier
    Forskningsämne
    Biologi med inriktning mot zooekologi
    Identifikatorer
    urn:nbn:se:uu:diva-394315 (URN)
    Konferens
    13th European Wave and Tidal Energy Conference, 1–6 September 2019, Napoli, Italy
    Forskningsfinansiär
    Energimyndigheten
    Tillgänglig från: 2019-10-07 Skapad: 2019-10-07 Senast uppdaterad: 2022-02-02Bibliografiskt granskad
    4. Effects of distance from a wave power park with no-take zone on Nephrops norvegicus abundance, size and burrow density
    Öppna denna publikation i ny flik eller fönster >>Effects of distance from a wave power park with no-take zone on Nephrops norvegicus abundance, size and burrow density
    (Engelska)Manuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The introduction of marine renewable energy parks often comes along with restrictions, such as prohibition of marine traffic or fishing. The Norway lobster, Nephrops norvegicus, is an ecologically relevant and economically important species, which potentially could benefit from such restrictions. This study investigated the effects of the no-take zone of a wave power park (0.8 km2) after its establishment (2014−2015), on the abundance, size, and burrow density of N. norvegicus on the west coast of Sweden. For four summers (2016−2018, 2020), the abundance and size of N. norvegicus was quantified by deployment of fishing cages inside the wave power park as well as along a 1230 m long transects to the east and west of it. Furthermore, the abundance of N. norvegicus burrows were recorded by a remote operating vehicle (ROV) along the same transects. N. norvegicus abundance, size and burrow density were expected to decrease with distance from the wave power park. During the study period, the number of N. norvegicus slightly increased, by 0.03 individuals every 100 m. Interannual variation of distance-dependent change in abundance resulted in up to 45.6 % fewer individuals in one km distance from the wave park in 2016 but in turn 25.8 % more individuals in one km distance from the wave park in 2018. Carapace length slightly decreased throughout the study, on average by 0.03 cm for every 100 m distance from the wave power park. Interannual variation of distance-dependent change in carapace length varied by one order of magnitude, resulting up to 10.6 % smaller individuals per km distance from the park in 2017. Overall, the number of N. norvegicus burrows decreased with distance, by 0.7 burrows every 100 m. Variation of distance-dependent change in burrow abundance resulted in 26.1 and 45.2 % more burrows in 2016 and 2017, respectively. The results suggest a benefit for the size and burrow density of N. norvegicus and a limited role for the number of individuals from the small and newly introduced incidental no-take zone of the Sotenäs Project wave power park. 

    Nyckelord
    Marine protected area; Marine renewable energy; Wave energy; Wave power; Cage fishing; ROV; Decapod; Benthos; Skagerrak; Norway lobster; Nephrops norvegicus
    Nationell ämneskategori
    Biologiska vetenskaper
    Identifikatorer
    urn:nbn:se:uu:diva-466348 (URN)
    Tillgänglig från: 2022-01-31 Skapad: 2022-01-31 Senast uppdaterad: 2022-02-02
    5. Effects of Wave Energy Generators on Nephrops Norvegicus
    Öppna denna publikation i ny flik eller fönster >>Effects of Wave Energy Generators on Nephrops Norvegicus
    2018 (Engelska)Ingår i: AWTEC 2018 Proceedings, 2018, artikel-id 283Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    Wave energy research is primarily focused on the technical developments of energy conversion but the parallel evaluation of environmental effects related to wave energy is also essential and reflects sustainable development of renewable energy. At the west coast of Sweden, 120 km north of Gothenburg, the Wave Energy Park “Sotenäs Project” is located. This area has been the location of environmental impact studies from wave energy generators on the macro crustacean species Nephrops norvegicus (Linnaeus, 1758), the Norway lobster. The Norway lobster is an ecologically as well as economically important species in Sweden and across Europe. The aim of this preliminary study was to detect possible positive or negative effects on numbers of individuals by the presence of the wave energy generators and the created “no take” zone. For that purpose, ROV aided seabed recordings of the characteristic Norway lobster burrow entrances were conducted inside the Wave Energy Park and respective control areas in 2016 and 2017. Preliminary results do not show a clear distinct result between the different transects and years. Long-term observations and complementary studies are necessary to draw conclusions and outweigh extreme and rare events of annual one-time samplings.

    Nationell ämneskategori
    Naturvetenskap Teknik och teknologier
    Forskningsämne
    Biologi
    Identifikatorer
    urn:nbn:se:uu:diva-361412 (URN)
    Konferens
    4th Asian Wave and Tidal Energy Conference (AWTEC 2018), Sep. 9-13 2018, Taipei, Taiwan
    Tillgänglig från: 2018-09-24 Skapad: 2018-09-24 Senast uppdaterad: 2022-02-02Bibliografiskt granskad
    6. A Review of Methods and Models for Environmental Monitoring of Marine Renewable Energy
    Öppna denna publikation i ny flik eller fönster >>A Review of Methods and Models for Environmental Monitoring of Marine Renewable Energy
    2017 (Engelska)Ingår i: Proceedings of the 12th European Wave and Tidal Energy Conference, EWTEC , 2017Konferensbidrag, Publicerat paper (Refereegranskat)
    Abstract [en]

    A continued expansion of the marine renewable energy sector will result in an increased demand in monitoring the natural marine environment. This may be due to a basic scientific interest but is foremost linked to the requirement of pre- and post-construction studies in relation to environmental impact assessments and consenting processes for marine renewable energy projects. With focus on wave and tidal power, but without attempting to provide a comprehensive list, we review methods, technologies and other scientific tools used for monitoring and predicting possible impacts from marine energy installations, on both population and behavioural levels. This includes traditional methods such as fishing gear, like nets and cages, modern technologies such as platforms with multi parameter equipment and the use of deterministic models. This paper is intended to serve as an overview for technology developers as well as authorities, regulators and decision makers with interests in general techniques, and naturally for scientists and consultants commonly being executors of studies and monitoring programs. By giving relevant and up to date references this paper may also be useful for finding more detailed information on study methods and variants. Finally, we give recommendations on where development of technologies is needed in order to face future requirements.

    Ort, förlag, år, upplaga, sidor
    EWTEC, 2017
    Nyckelord
    Environmental monitoring, Monitoring techniques and platforms, Models, Impact assessment, Wave power, Tidal power, Offshore windpower, Marine renewable energy
    Nationell ämneskategori
    Teknik och teknologier Marin teknik
    Identifikatorer
    urn:nbn:se:uu:diva-330179 (URN)
    Konferens
    European Wave and Tidal Energy Conference (EWTEC, 7th Aug -1st Sept 2017, Cork, Ireland
    Tillgänglig från: 2017-09-27 Skapad: 2017-09-27 Senast uppdaterad: 2022-02-02Bibliografiskt granskad
    7. Deployment and Maintenance of Wave Energy Converters at the Lysekil Research Site: A Comparative Study on the Use of Divers and Remotely-Operated Vehicles
    Öppna denna publikation i ny flik eller fönster >>Deployment and Maintenance of Wave Energy Converters at the Lysekil Research Site: A Comparative Study on the Use of Divers and Remotely-Operated Vehicles
    Visa övriga...
    2018 (Engelska)Ingår i: Journal of Marine Science and Engineering, E-ISSN 2077-1312, Vol. 6, nr 2, artikel-id 39Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Ocean renewable technologies have been rapidly developing over the past years. However, current high installation, operation, maintenance, and decommissioning costs are hindering these offshore technologies to reach a commercialization stage. In this paper we focus on the use of divers and remotely-operated vehicles during the installation and monitoring phase of wave energy converters. Methods and results are based on the wave energy converter system developed by Uppsala University, and our experience in offshore deployments obtained during the past eleven years. The complexity of underwater operations, carried out by either divers or remotely-operated vehicles, is emphasized. Three methods for the deployment of wave energy converters are economically and technically analyzed and compared: one using divers alone, a fully-automated approach using remotely-operated vehicles, and an intermediate approach, involving both divers and underwater vehicles. The monitoring of wave energy converters by robots is also studied, both in terms of costs and technical challenges. The results show that choosing an autonomous deployment method is more advantageous than a diver-assisted method in terms of operational time, but that numerous factors prevent the wide application of robotized operations. Technical solutions are presented to enable the use of remotely-operated vehicles instead of divers in ocean renewable technology operations. Economically, it is more efficient to use divers than autonomous vehicles for the deployment of six or fewer wave energy converters. From seven devices, remotely-operated vehicles become advantageous.

    Nationell ämneskategori
    Marin teknik
    Identifikatorer
    urn:nbn:se:uu:diva-348816 (URN)10.3390/jmse6020039 (DOI)000436558500011 ()
    Forskningsfinansiär
    StandUpEU, FP7, Sjunde ramprogrammet, 607656Energimyndigheten
    Tillgänglig från: 2018-04-17 Skapad: 2018-04-17 Senast uppdaterad: 2022-02-02Bibliografiskt granskad
    8. Use of Multibeam Imaging Sonar for Observation Of Marine Mammals and Fish on a Marine Renewable Energy Site
    Öppna denna publikation i ny flik eller fönster >>Use of Multibeam Imaging Sonar for Observation Of Marine Mammals and Fish on a Marine Renewable Energy Site
    2022 (Engelska)Ingår i: PLOS ONE, E-ISSN 1932-6203, Vol. 17, nr 12, artikel-id e0275978Artikel i tidskrift (Refereegranskat) Published
    Abstract [en]

    Environmental data is crucial for planning, permitting, execution and post construction monitoring of marine renewable energy projects. In harsh conditions in which marine renewable energy is harvested, integrated monitoring platforms comprising multibeam imaging sonar systems coupled with other sensors can provide multi-dimensional data of the marine environment surrounding marine renewable energy installations. The aim of this study was to test the possibilities of observing the occurrence of fish and marine mammals using a multibeam imaging sonar system deployed at a wave power test site. The results obtained from a ten-day data set proved the platform as suitable for long time underwater monitoring and also revealed that the occurrence of fish and marine mammals was distributed across characteristic time and space domains. Large fish [>0.4 m] frequently occurred at night-time and near the benthic zone. Small fish [<0.2 m] frequently occurred during daylight and within the pelagic zone. The occurrence of seals was periodically distributed along a daily cycle, with intervals of 1 – 2 hours between maxima and minima. In conclusion, the use of multibeam imaging sonar can be a reliable technique for the qualitative and quantitative observations of fish and marine mammals in general and at marine renewable energy sites specifically, including protected and economically important species.

    Ort, förlag, år, upplaga, sidor
    Public Library of Science (PLoS), 2022
    Nyckelord
    Environmental monitoring, Multibeam imaging sonar, Fish, Marine mammals, Renewable energy, Wave power, Lysekil research site
    Nationell ämneskategori
    Annan elektroteknik och elektronik
    Forskningsämne
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-368877 (URN)10.1371/journal.pone.0275978 (DOI)000925168900007 ()36516145 (PubMedID)
    Forskningsfinansiär
    EU, FP7, Sjunde ramprogrammet, 607656Carl Tryggers stiftelse för vetenskaplig forskning J. Gust. Richert stiftelseStandUp
    Tillgänglig från: 2018-12-10 Skapad: 2018-12-10 Senast uppdaterad: 2023-04-21Bibliografiskt granskad
    Ladda ner fulltext (pdf)
    UUThesis_A-Bender-2022
    Ladda ner (jpg)
    presentationsbild
    Ladda ner (pdf)
    omslag
  • 43.
    Bender, Anke
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Langhamer, Olivia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Francisco, Francisco
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Forslund, Johan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Hammar, Linus
    Octopus Ink Research & Analysis, Lysekil, Sweden.
    Sundberg, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Molander, Sverker
    Chalmers University of Technology, Gothenburg, Sweden.
    Imaging-sonar observations of salmonid interactions with a vertical axis instream turbine2023Ingår i: Rivers Research and Applications: an international journal devoted to river research and management, ISSN 1535-1459, E-ISSN 1535-1467Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Anthropogenic activities and their influences on aquatic systems is an important topic, especially considering the growing interest in using the earth's resources in a sustainable way. One of those anthropogenic activities is the introduction of renewable technologies into the aquatic environment such as instream turbines. Environmental studies around those technologies are often still ongoing due to their novelty. During the spring of 2018, juvenile individuals of two salmonid species, Atlantic salmon and brown trout were released upstream a vertical axis instream turbine in the river Dal (Dalälven) in eastern Sweden. The aim of this study was to investigate the swimming behavior of the salmonids around a small-scale prototype vertical axis instream turbine. The swimming pattern and the possible response of avoiding the vertical axis instream turbine were documented with a multi beam sonar. A control area, next to the turbine, was used as reference. No consistent results were shown for trout as they were passing the control area with a statistically high variation, and specimens were rarely observed in proximity of the turbine, neither if the turbine was operating nor at stand still. Salmon clearly avoided the operating turbine, but did not avoid the turbine when it was at stand still, and was often observed swimming straight through the turbine area. These findings indicate that operating this type of instream turbine in a river affects the swimming behavior of Atlantic salmon but is unlikely to affect its migration paths. For brown trout, the statistical results are inconclusive, although data indicate a response of avoiding the turbine. The species are in little risk to suffer physical harm as no fish entered the rotating turbine, despite very turbid water conditions.

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  • 44.
    Bender, Anke
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Langhamer, Olivia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Molis, Markus
    nstitute of Arctic and Marine Biology, UiT The Arctic University of Norway, P.O. Box 6050 Langnes, 9037 Tromsø, Norway.
    Sundberg, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Effects of a Wave Power Park with No-Take Zone on Decapod Abundance and Size2021Ingår i: Journal of Marine Science and Engineering, E-ISSN 2077-1312, Vol. 9, nr 8, s. 864-, artikel-id 864Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Past studies have revealed higher levels of biodiversity, total abundance, and size ofindividuals around offshore installations of renewable energy. This study investigated the effectsof Lysekil wave power park (area 0.5 km2) on the abundance and carapace size of decapods at theSwedish west coast. For that purpose, decapods were caught with cages during four consecutivesummers. Two types of cages were applied to catch a wide range of decapod species and sizes. Theabundance and size of decapods were not significantly different within the wave power park and upto a distance of 360 m outside of it. The catch rate, i.e., number of decapods caught in 24 h, was notsignificantly different among sampling locations but revealed inter-annual variation for both cagetypes. The results suggest a limited role of the incidental no-take zone of the small Lysekil wavepower park on the abundance and size of local decapods. However, neither were negative impacts,such as decreasing abundances or smaller carapace sizes, discovered. As an increase in the numberof marine renewable energy production sites is foreseen, a scaled-up and larger study addressingMPA networks and other environmental interactions should be considered.

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  • 45.
    Bender, Anke
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Langhamer, Olivia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Molis, Markus
    Institute of Arctic and Marine Biology, UiT The Arctic University of Norway.
    Sundberg, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Effects of distance from a wave power park with no-take zone on Nephrops norvegicus abundance, size and burrow densityManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    The introduction of marine renewable energy parks often comes along with restrictions, such as prohibition of marine traffic or fishing. The Norway lobster, Nephrops norvegicus, is an ecologically relevant and economically important species, which potentially could benefit from such restrictions. This study investigated the effects of the no-take zone of a wave power park (0.8 km2) after its establishment (2014−2015), on the abundance, size, and burrow density of N. norvegicus on the west coast of Sweden. For four summers (2016−2018, 2020), the abundance and size of N. norvegicus was quantified by deployment of fishing cages inside the wave power park as well as along a 1230 m long transects to the east and west of it. Furthermore, the abundance of N. norvegicus burrows were recorded by a remote operating vehicle (ROV) along the same transects. N. norvegicus abundance, size and burrow density were expected to decrease with distance from the wave power park. During the study period, the number of N. norvegicus slightly increased, by 0.03 individuals every 100 m. Interannual variation of distance-dependent change in abundance resulted in up to 45.6 % fewer individuals in one km distance from the wave park in 2016 but in turn 25.8 % more individuals in one km distance from the wave park in 2018. Carapace length slightly decreased throughout the study, on average by 0.03 cm for every 100 m distance from the wave power park. Interannual variation of distance-dependent change in carapace length varied by one order of magnitude, resulting up to 10.6 % smaller individuals per km distance from the park in 2017. Overall, the number of N. norvegicus burrows decreased with distance, by 0.7 burrows every 100 m. Variation of distance-dependent change in burrow abundance resulted in 26.1 and 45.2 % more burrows in 2016 and 2017, respectively. The results suggest a benefit for the size and burrow density of N. norvegicus and a limited role for the number of individuals from the small and newly introduced incidental no-take zone of the Sotenäs Project wave power park. 

  • 46.
    Bender, Anke
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Langhamer, Olivia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Sundberg, Jan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Colonisation of wave power foundations by mobile mega- and macrofauna - a 12 year study2020Ingår i: Marine Environmental Research, ISSN 0141-1136, E-ISSN 1879-0291, Vol. 161, artikel-id 105053Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Environmental impacts from wave energy generators on the local mobile mega- and macrofauna community have been investigated in the Lysekil project by Uppsala University. Offshore renewable energy installations provide hard, artificial substrates, and as such, they could act as artificial reefs. Foundations with manufactured holes served as complex habitats and foundations without served as non-complex. In this long-term study, SCUBA surveys of mobile fauna in the years 2007, 2008 and 2016-2019 were analyzed. The results show a distinct reef effect on the foundations with significant greater species richness, total number of individuals, greater values of the Shannon-Wiener biodiversity index, and greater abundance of specific reef fauna. Complex foundations accommodated a greater abundance of brown crabs than non-complex foundations, other taxa did not show differences between the two foundation types. A successional increase of species richness, numbers of individuals and Shannon-Wiener biodiversity could be revealed from the first to the second survey period. Inter-annual variation was visible throughout all taxa and years.

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  • 47.
    Bengtson, Mattias
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Optimering av energisystem för fjällstugor utanför elnätet: En fallstudie av fyra stugor i Abiskoområdet2020Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The Swedish Tourist Association, STF, is an organization which strives to make the Swedish nature more accessible to people. Since its founding, STF has been a key player in the development of the tourism in the Swedish mountain regions. Today the organization have 44 mountain cabins along the Swedish mountain range, and a majority of the huts are completely off-grid with no other connection to them but hiking trails. To accommodate for the needs of hikers and skiers throughout the year, the huts need electricity for lighting and in many cases cash registers and satellite modems to run small shops selling simple commodities. Many of the huts use solar energy combined with lead acid batteries, but not all of them can make it through the year without the use of a backup gasoline generator. This master thesis analyzes the different energy systems of four huts run by STF and using solar radiance data from PVGIS to calculate whether or not they are self-sufficient throughout the year using only solar energy. In the cases where the huts were found not to be self-sufficient, suggestions on actions that STF could implement to optimize the systems were found. For two out of the four huts, the thesis found that they were not self-sufficient, but after optimizing the energy systems with new energy saving appliances as well as tilting the solar panels between the winter and summer seasons, all four huts were found to be able to reach self-sufficiency.

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  • 48.
    Bengtsson, Jacob
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Moberg Safaee, Benjamin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Minimising Battery Degradation And Energy Cost For Different User Scenarios In V2G Applications: An Integrated Optimisation Model for BEVs2023Självständigt arbete på avancerad nivå (yrkesexamen), 20 poäng / 30 hpStudentuppsats (Examensarbete)
    Abstract [en]

    The functionality to both charge and discharge energy from and to the power grid to a Battery Electric Vehicle (BEV) is referred to as Vehicle-to-Grid (V2G). This allows the customer to buy energy when the spot price is low and sell energy when the price is high to make a profit, called energy arbitrage. However, when the battery is charging, discharging, or idling for storage, battery degradation occurs due to chemical properties and reactions.

    This thesis developed a mathematical optimisation model in Python, using the modelling language Pyomo. Mathematical equations are used to integrate energy arbitrage and degradation data to reduce the total cost in terms of degradation and energy by finding an optimised charge and discharge pattern. The model allows different user scenarios to be analysed by changing inputs such as charger power, battery cost or daily driving distance. When using V2G technology, the State-of-Charge (SoC) level of BEVs battery packs can be adjusted to find SoC levels which minimise the battery degradation, while allowing the user to make a profit from energy arbitrage. The result shows that the V2G charging protocol, compared to protocols without a bidirectional charger could be beneficial for the simulated time periods, by both reducing degradation and the total energy cost. The results also indicate that the degradation cost of the battery is often the determining factor in the decision of when to charge or discharge, i.e., the substantial cost-saving strategy is to control the storage and cycle degradation to reduce the total degradation, rather than controlling the energy arbitrage.

    The model and the result of this thesis can be used by car manufacturers to learn more about how battery cell types behave in V2G mode and influence further work on V2G control.

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  • 49.
    Bengtsson, Rhodel
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för materialvetenskap, Tillämpad mekanik. Uppsala University.
    Gamstedt, Kristofer
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för materialvetenskap, Tillämpad mekanik.
    Florisson, Sara
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för materialvetenskap, Tillämpad mekanik.
    Bernhoff, Hans
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Feasiblity of wooden towers for offshore wind turbines: Creep and fatigue predictionsManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Long-term experiences with vertical axis wind turbines constructed with wood are positive, and show that wood towers are a viable alternative to conventional steel towers on land. Wood is a renewable material in contrast to steel and concrete and could steer a more sustainable use of raw material for future wind farms. The obvious drawback of moisture-induced softening and degradation in off-shore settings can be mitigated by efficiently sealing the tower using a barrier coating. In that case, fatigue sensitivity and creep deformations are the main design concerns. In this paper through finite element simulations of a floating tilted vertical-axis wind turbine, it was shown that fatigue issues can be resolved with proper design of the mast and the blade joints keeping the stress concentrations at bay. The numerical results also indicated that creep displacements are negligible. The review and calculations reinforce the assumption that the fast developments seen in timber high-rise building can also be expected for off-shore wind turbine towers. 

  • 50.
    Benkowski, Gustav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för elektroteknik, Elektricitetslära.
    Cutting Tool Container Inspection: Stereo vision and monocular artificial intelligence depth estimation at Sandvik Coromant2024Självständigt arbete på grundnivå (yrkesexamen), 10 poäng / 15 hpStudentuppsats (Examensarbete)
    Abstract [en]

    This thesis explores and evaluates solutions for the inspection of cutting tool containers at Sandvik Coromant, focusing on the transition from current vision systems utilizing infrared (IR) light to new methods compatible with recycled polypropylene (PP) plastic containers.

    The primary goal is to evaluate the effectiveness of stereo vision and artificial intelligence (AI) for depth estimation, ensuring that the containers are properly populated with cutting tools. Various methods and algorithms are tested to determine their accuracy and speed, to meet the time requirements of the production line at Sandvik Coromant.

    The results indicate that, while traditional IR-based systems excel in processing speed and robustness, monocular artificial intelligence methods offer adaptability that could be utilized with the new container material. Future work will involve further optimization and real-world testing to confirm these findings. 

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