uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Field Measurements and System Identification of Three Frequency Controlling Hydropower Plants
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. (Hydropower)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity. (Hydropower)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Electricity.
2015 (English)In: IEEE transactions on energy conversion, ISSN 0885-8969, E-ISSN 1558-0059, Vol. 30, no 3, 1061-1068 p.Article in journal (Refereed) Published
Abstract [en]

The dynamic behaviour of hydropower plants participating in primary frequency control is investigated in this paper through frequency response, step response and setpoint change tests on three Swedish hydropower plants. Grey-box system identification is used to estimate the parameters of simple linear models suitable for power system analysis and the major shortcomings of the linear models are discussed. It is found that frequency response tests with sinusoidal input signals give more reliable information about the dynamics of the plants than step response tests. It is also shown that backlash in the runner and guide vane regulating mechanisms are of great importance for the dynamic behaviour of the plants, and that the incremental gain from guide vane opening to power varies considerably with the operation point.

Place, publisher, year, edition, pages
2015. Vol. 30, no 3, 1061-1068 p.
Keyword [en]
hydropower, system identification, frequency control, field measurements
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
URN: urn:nbn:se:uu:diva-237793DOI: 10.1109/TEC.2015.2425915ISI: 000360439300026OAI: oai:DiVA.org:uu-237793DiVA: diva2:768921
Available from: 2014-12-05 Created: 2014-12-05 Last updated: 2017-12-05Bibliographically approved
In thesis
1. A hydropower perspective on flexibility demand and grid frequency control
Open this publication in new window or tab >>A hydropower perspective on flexibility demand and grid frequency control
2014 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The production and consumption of electricity on the power grid has to balance at all times. Slow balancing, over days and weeks, is governed by the electricity market and carried out through production planning.  Fast balancing, within the operational hour, is carried out by hydropower plants operating in frequency control mode. The need of balancing power is expected to increase as more varying renewable energy production is connected to the grid, and the deregulated electricity market presents a challenge to the frequency control of the grid.

The first part of this thesis suggests a method to quantify the need for balancing or energy storage induced by varying renewable energy sources. It is found that for high shares of wind and solar power in the system, the energy storage need over a two-week horizon is almost 20% of the production.

The second and third part of the thesis focus on frequency control. In the second part, measurements from three Swedish hydropower plants are compared with the behaviour expected from commonly used power system analysis hydropower models. It is found that backlash in the guide vane and runner regulating mechanisms has a large impact on the frequency control performance of the plants.

In the third part of the thesis, the parameters of the primary frequency control in the Nordic grid are optimised with respect to performance, robustness and actuator work. It is found that retuning of the controller parameters can improve the performance and robustness, with a reasonable increase of the actuator work. A floating deadband in the controller is also discussed as a means to improve performance without increasing the actuator work.

Place, publisher, year, edition, pages
Uppsala: Uppsala universitet, 2014. 57 p.
Series
UURIE / Uppsala University, Department of Engineering Sciences, ISSN 0349-8352 ; 339-14L
Keyword
hydropower, frequency control, balancing
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-237798 (URN)
Presentation
2014-12-01, ITC1211, Uppsala, 14:00 (English)
Opponent
Supervisors
Available from: 2014-12-11 Created: 2014-12-05 Last updated: 2015-10-08Bibliographically approved
2. The Frequency of the Frequency: On Hydropower and Grid Frequency Control
Open this publication in new window or tab >>The Frequency of the Frequency: On Hydropower and Grid Frequency Control
2017 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Variations in the electricity consumption and production connected to the power system have to be balanced by active control. Hydropower is the most important balancing resource in the Nordic system, and will become even more important as the share of variable renewable energy sources increases. This thesis concerns balancing of active power, especially the real-time balancing called frequency control. The thesis starts in a description of the situation today, setting up models for the behaviour of hydropower units and the power system relevant to frequency control, and comparing the models with experiments on several hydropower units and on the response of the Nordic grid. It is found that backlash in the regulating mechanisms in hydropower units have a strong impact on the quality of the delivered frequency control. Then, an analysis of what can be done right now to improve frequency control and decrease its costs is made, discussing governor tuning, filters and strategies for allocation of frequency control reserves. The results show that grid frequency quality could be improved considerably by retuning of hydropower governors. However, clear technical requirements and incentives for good frequency control performance are needed. The last part of the thesis concerns the impact from increased electricity production from variable renewable energy sources. The induced balancing need in terms of energy storage volume and balancing power is quantified, and it is found that with large shares of wind power in the system, the energy storage need over the intra-week time horizon is drastically increased. Reduced system inertia due to higher shares of inverter connected production is identified as a problem for the frequency control of the system. A new, linear synthetic inertia concept is suggested to replace the lost inertia and damping. It is shown that continuously active, linear synthetic inertia can improve the frequency quality in normal operation and decrease wear and tear of hydropower units delivering frequency control.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2017. 105 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1460
Keyword
hydropower, frequency control, governors, power system stability, inertia, primary control
National Category
Engineering and Technology Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Engineering Science with specialization in Science of Electricity
Identifiers
urn:nbn:se:uu:diva-308441 (URN)978-91-554-9769-9 (ISBN)
Public defence
2017-02-07, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 09:00 (English)
Opponent
Supervisors
Available from: 2017-01-13 Created: 2016-11-25 Last updated: 2017-01-17

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Saarinen, LinnNorrlund, PerLundin, Urban

Search in DiVA

By author/editor
Saarinen, LinnNorrlund, PerLundin, Urban
By organisation
Electricity
In the same journal
IEEE transactions on energy conversion
Electrical Engineering, Electronic Engineering, Information Engineering

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 483 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf