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Impacts of distributed photovoltaics on network voltages: Stochastic simulations of three Swedish low-voltage distribution grids
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. (Built Environment Energy Systems Group (BEESG))
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics.
Helsinki University of Technology.
Helsinki University of Technology.
2010 (English)In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 80, no 12, 1562-1571 p.Article in journal (Refereed) Published
Abstract [en]

The continuously increasing application of distributed photovoltaics (PV-DG) in residential areas around the world calls for detailed assessment of distribution grid impacts. Both photovoltaic generation and domestic electricity demand exhibit characteristic variations on short and long time scales and are to a large extent negatively correlated, especially at high latitudes. This paper presents a stochastic methodology for simulation of PV-DG impacts on low-voltage (LV) distribution grids, using detailed generation and demand models. The methodology is applied to case studies of power flow in three existing Swedish LV grids to determine load matching, voltage levels and network losses at different PV-DG penetration levels. All studied LV grids can handle significant amounts of PV-DG, up to the highest studied level of 5 kWp PV per household. However, the benefits of PV-DG in terms of relative improvement of on-site reduction of demand, mitigated voltage drops and reduced losses were most significant at a penetration level of 1 kWp PV per household.

Place, publisher, year, edition, pages
2010. Vol. 80, no 12, 1562-1571 p.
Keyword [en]
Distributed generation, Photovoltaics, Low voltage, Distribution grids, Power flow
National Category
Engineering and Technology
URN: urn:nbn:se:uu:diva-132904DOI: 10.1016/j.epsr.2010.07.007ISI: 000282404500022OAI: oai:DiVA.org:uu-132904DiVA: diva2:359589
Available from: 2010-10-28 Created: 2010-10-28 Last updated: 2016-04-18Bibliographically approved
In thesis
1. System Studies and Simulations of Distributed Photovoltaics in Sweden
Open this publication in new window or tab >>System Studies and Simulations of Distributed Photovoltaics in Sweden
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Grid-connected photovoltaic (PV) capacity is increasing worldwide, mainly due to extensive subsidy schemes for renewable electricity generation. A majority of newly installed systems are distributed small-scale systems located in distribution grids, often at residential customers. Recent developments suggest that such distributed PV generation (PV-DG) could gain more interest in Sweden in the near future. With prospects of decreasing system prices, an extensive integration does not seem impossible.

In this PhD thesis the opportunities for utilisation of on-site PV generation and the consequences of a widespread introduction are studied. The specific aims are to improve modelling of residential electricity demand to provide a basis for simulations, to study load matching and grid interaction of on-site PV and to add to the understanding of power system impacts.

Time-use data (TUD) provided a realistic basis for residential load modelling. Both a deterministic and a stochastic approach for generating different types of end-use profiles were developed. The models are capable of realistically reproducing important electric load properties such as diurnal and seasonal variations, short time-scale fluctuations and random load coincidence.

The load matching capability of residential on-site PV was found to be low by default but possible to improve to some extent by different measures. Net metering reduces the economic effects of the mismatch and has a decisive impact on the production value and on the system sizes that are reasonable to install for a small-scale producer.

Impacts of large-scale PV-DG on low-voltage (LV) grids and on the national power system were studied. Power flow studies showed that voltage rise in LV grids is not a limiting factor for integration of PV-DG. Variability and correlations with large-scale wind power were determined using a scenario for large-scale building-mounted PV. Profound impacts on the power system were found only for the most extreme scenarios.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2010. 110 p.
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 781
Photovoltaics, Solar energy, Distributed generation, Load modelling, Time-use data, Markov chain, Power flow, Power system
National Category
Other Engineering and Technologies
Research subject
Engineering Science
urn:nbn:se:uu:diva-132907 (URN)978-91-554-7931-2 (ISBN)
Public defence
2010-12-10, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Felaktigt tryckt som Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology 711Available from: 2010-11-18 Created: 2010-10-28 Last updated: 2011-03-21Bibliographically approved

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Publisher's full texthttp://www.sciencedirect.com/science/article/B6V30-50RV8GM-1/2/8e96f766580535cd1fcd8768b6852b51

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