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Impacts of different data averaging times on statistical analysis of distributed domestic photovoltaic systems
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: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 84, no 3, 492-500 p.Article in journal (Refereed) Published
Abstract [en]

The trend of increasing application of distributed generation with solar photovoltaics (PV-DG) suggests that a widespread integration in existing low-voltage (LV) grids is possible in the future. With massive integration in LV grids, a major concern is the possible negative impacts of excess power injection from on-site generation. For power-flow simulations of such grid impacts, an important consideration is the time resolution of demand and generation data. This paper investigates the impact of time averaging on high-resolution data series of domestic electricity demand and PV-DG output and on voltages in a simulated LV grid. Effects of 10-minutely and hourly averaging on descriptive statistics and duration curves were determined. Although time averaging has a considerable impact on statistical properties of the demand in individual households, the impact is smaller on aggregate demand, already smoothed from random coincidence, and on PV-DG output. Consequently, the statistical distribution of simulated grid voltages was also robust against time averaging. The overall judgement is that statistical investigation of voltage variations in the presence of PV-DG does not require higher resolution than hourly.

Place, publisher, year, edition, pages
2010. Vol. 84, no 3, 492-500 p.
Keyword [en]
Time averaging, Photovoltaics, Domestic electricity demand, Distribution grid, Low voltage, Power flow
National Category
Engineering and Technology
URN: urn:nbn:se:uu:diva-132903DOI: 10.1016/j.solener.2010.01.011ISI: 000276119000018OAI: oai:DiVA.org:uu-132903DiVA: diva2:359588

Correction in: Solar Energy, 2011, vol. 85, issue. 1, p. 214, doi:10.1016/j.solener.2010.11.015

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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