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Publications (10 of 362) Show all publications
Nycander, E. (2020). Curtailment analysis for the Nordic power system considering transmission capacity, inertia limits and generation flexibility. Renewable Energy, 152, 942-960
Open this publication in new window or tab >>Curtailment analysis for the Nordic power system considering transmission capacity, inertia limits and generation flexibility
2020 (English)In: Renewable Energy, Vol. 152, p. 942-960Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Elsevier, 2020
National Category
Engineering and Technology
Identifiers
urn:nbn:se:kth:diva-268058 (URN)10.1016/j.renene.2020.01.059 (DOI)
Available from: 2020-02-16 Created: 2020-02-16 Last updated: 2020-02-16
Herre, L., Mathieu, J. L. & Söder, L. (2020). Impact of Market Timing on the Profit of a Risk-Averse Load Aggregator. IEEE Transactions on Power Systems
Open this publication in new window or tab >>Impact of Market Timing on the Profit of a Risk-Averse Load Aggregator
2020 (English)In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679Article in journal (Refereed) Published
Abstract [en]

Non-generating resources such as thermostatically controlled loads (TCLs) can arbitrage energy prices and provide balancing reserves when aggregated due to their thermal energy storage capacity. An aggregator that wants to quantify this flexibility in order to place optimal bids before gate closure, would be affected by market timing. The market timing can be quantified by parameters such as lead time and contract period. This paper explores the impact of market timing on TCL aggregate power consumption and reserve capacity bids and quantifies trade-offs between market timing and flexibility. We first optimize the power consumption and reserve capacity offers at given lead times and contract periods, varying from 24 hours ahead to real-time. We then introduce uncertainty in prices and TCL availability, formulate a two-stage chance-constrained optimization problem of a risk-averse aggregator, implement it on a rolling horizon basis, and evaluate how the trade-offs change. The results show that shorter lead times and contract periods positively impact TCL profit as well as flexibility if the prediction horizon is sufficiently long. The proposed method can be used by aggregators to decide on optimal bids and incentive payments to consumers to reward flexibility.

Place, publisher, year, edition, pages
IEEE, 2020
Keywords
balancing reserves, chance-constrained optimization, load aggregator, rolling horizon optimization, thermostatically controlled loads
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-267713 (URN)10.1109/TPWRS.2020.2971866 (DOI)
Note

QC 20200214

Available from: 2020-02-14 Created: 2020-02-14 Last updated: 2020-02-14Bibliographically approved
Söder, L., Tomasson, E., Estanqueiro, A., Flynn, D., Hodge, B.-M., Kiviluoma, J., . . . de Vries, L. (2020). Review of wind generation within adequacy calculations and capacity markets for different power systems. Renewable & sustainable energy reviews, 119, Article ID 109540.
Open this publication in new window or tab >>Review of wind generation within adequacy calculations and capacity markets for different power systems
Show others...
2020 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 119, article id 109540Article, review/survey (Refereed) Published
Abstract [en]

The integration of renewable energy sources, including wind power, in the adequacy assessment of electricity generation capacity becomes increasingly important as renewable energy generation increases in volume and replaces conventional power plants. The contribution of wind power to cover the electricity demand is less certain than conventional power sources; therefore, the capacity value of wind power is smaller than that of conventional plants. This article presents an overview of the adequacy challenge, how wind power is handled in the regulation of capacity adequacy, and how wind power is treated in a selection of jurisdictions. The jurisdictions included in the overview are Sweden, Great Britain, France, Ireland, United States (PJM and ERCOT), Finland, Portugal, Spain, Norway, Denmark, Belgium, Germany, Italy and the Netherlands.

Place, publisher, year, edition, pages
PERGAMON-ELSEVIER SCIENCE LTD, 2020
Keywords
Adequacy, Capacity credit, Capacity markets, Market integration, Power system, Wind power
National Category
Environmental Engineering
Identifiers
urn:nbn:se:kth:diva-269449 (URN)10.1016/j.rser.2019.109540 (DOI)000512406900017 ()2-s2.0-85075946844 (Scopus ID)
Note

QC 20200310

Available from: 2020-03-10 Created: 2020-03-10 Last updated: 2020-03-10Bibliographically approved
Söder, L., Tomasson, E., Estanqueiro, A., Flynn, D., Hodge, B.-M. -., Kiviluoma, J., . . . de Vries, L. (2020). Review of wind generation within adequacy calculations and capacity markets for different power systems. Renewable and Sustainable Energy Reviews, 119, Article ID 109540.
Open this publication in new window or tab >>Review of wind generation within adequacy calculations and capacity markets for different power systems
Show others...
2020 (English)In: Renewable and Sustainable Energy Reviews, Vol. 119, article id 109540Article in journal (Refereed) Published
Abstract [en]

The integration of renewable energy sources, including wind power, in the adequacy assessment of electricity generation capacity becomes increasingly important as renewable energy generation increases in volume and replaces conventional power plants. The contribution of wind power to cover the electricity demand is less certain than conventional power sources; therefore, the capacity value of wind power is smaller than that of conventional plants.

This article presents an overview of the adequacy challenge, how wind power is handled in the regulation of capacity adequacy, and how wind power is treated in a selection of jurisdictions. The jurisdictions included in the overview are Sweden, Great Britain, France, Ireland, United States (PJM and ERCOT), Finland, Portugal, Spain, Norway, Denmark, Belgium, Germany, Italy and the Netherlands.

Keywords
dequacy Capacity credit Capacity markets Market integration Power system Wind power
National Category
Energy Engineering
Identifiers
urn:nbn:se:kth:diva-268198 (URN)10.1016/j.rser.2019.109540 (DOI)000512406900017 ()2-s2.0-85075946844 (Scopus ID)
Note

QC 20200406

Available from: 2020-04-06 Created: 2020-04-06 Last updated: 2020-04-06Bibliographically approved
Nycander, E. & Söder, L. (2019). Comparison of stochastic and deterministic security constrained optimal power flow under varying outage probabilities. In: 2019 IEEE Milan PowerTech, PowerTech 2019: . Paper presented at 2019 IEEE Milan PowerTech, PowerTech 2019; Milan; Italy; 23 June 2019 through 27 June 2019. Institute of Electrical and Electronics Engineers (IEEE), Article ID 8810833.
Open this publication in new window or tab >>Comparison of stochastic and deterministic security constrained optimal power flow under varying outage probabilities
2019 (English)In: 2019 IEEE Milan PowerTech, PowerTech 2019, Institute of Electrical and Electronics Engineers (IEEE), 2019, article id 8810833Conference paper, Published paper (Refereed)
Abstract [en]

Increasing penetration of renewables and focus on cost efficiency means that power systems are operated closer to security limits. It has been suggested that the traditional N-l approach to security is unsatisfactory as it does not consider the likelihood and severity of contingencies. In this paper we investigate a stochastic version of security-constrained optimal power flow (S-SCOPF), which considers outage probabilities when deciding the optimal dispatch. Both a priori dispatch costs and realized real time costs are considered to evaluate the usefulness of the S-SCOPF a s opposed to the deterministic SCOPF (D-SCOPF). For low outage probabilities the S-SCOPF gives lower total costs, achieved by reducing the security for contingency situations. For high outage probabilities the two methods give the same dispatch. The robustness of the S-SCOPF to errors in the outage probability is also investigated. Underestimating the true outage probability results in the S-SCOPF giving higher total costs.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
Keywords
OPF, Probabilistic security, SCOPF
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-262637 (URN)10.1109/PTC.2019.8810833 (DOI)2-s2.0-85072337547 (Scopus ID)9781538647226 (ISBN)
Conference
2019 IEEE Milan PowerTech, PowerTech 2019; Milan; Italy; 23 June 2019 through 27 June 2019
Note

QC 20191017

Available from: 2019-10-17 Created: 2019-10-17 Last updated: 2019-10-17Bibliographically approved
Herre, L., Matusevičius, T., Olauson, J. & Söder, L. (2019). Exploring Wind Power Prognosis Data on Nord Pool: The Case of Sweden and Denmark. IET Renewable Power Generation
Open this publication in new window or tab >>Exploring Wind Power Prognosis Data on Nord Pool: The Case of Sweden and Denmark
2019 (English)In: IET Renewable Power Generation, ISSN 1752-1416, E-ISSN 1752-1424, ISSN 1752-1416Article in journal (Refereed) Published
Abstract [en]

A good understanding of forecast errors is imperative for greater penetration of wind power, as it can facilitate planning and operation tasks. Oftentimes, public data is used for system studies without questioning or verifying its origin. In this paper, we propose a methodology to verify public data with the example of wind power prognosis published by Nord Pool. We focus on Swedish data and identify a significant bias that increases over the forecast horizon. In order to explore the origin of this bias, we first compare against Danish forecast and then describe the underlying structure behind the submission processes of this data. Based on the balance settlement structure, we reveal that Swedish "wind power prognoses" on Nord Pool are in fact rather wind production plans than technical forecasts. We conclude with the recommendation for improved communication and transparency with respect to terminology of public data on Nord Pool. We stress the importance for the research community to check publicly available input data before further use. Furthermore, the root-mean-square error and the spatio-temporal correlation between the errors in the bidding areas at different horizons is presented. Even with this compromised data, a stronger correlation is identified in neighbouring areas.

Keywords
wind power forecasts, forecast anaylsis, vindkraftspognoser, analys av vindkraftsprognoser
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering Energy Systems
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-241639 (URN)10.1049/iet-rpg.2018.5086 (DOI)000462942900006 ()2-s2.0-85063728250 (Scopus ID)
Note

QC 20190124

Available from: 2019-01-24 Created: 2019-01-24 Last updated: 2019-04-29Bibliographically approved
Crosara, A., Tomasson, E. & Söder, L. (2019). Generation Adequacy in the Nordic and Baltic Area: The Potential of Flexible Residential Electric Heating. In: Proceedings of 2019 IEEE PES Innovative Smart Grid Technologies Europe, ISGT-Europe 2019: . Paper presented at 2019 IEEE PES Innovative Smart Grid Technologies Europe, ISGT-Europe 2019; University Politehnica of Bucharest, Bucharest; Romania; 29 September 2019 through 2 October 2019. Institute of Electrical and Electronics Engineers (IEEE), Article ID 8905720.
Open this publication in new window or tab >>Generation Adequacy in the Nordic and Baltic Area: The Potential of Flexible Residential Electric Heating
2019 (English)In: Proceedings of 2019 IEEE PES Innovative Smart Grid Technologies Europe, ISGT-Europe 2019, Institute of Electrical and Electronics Engineers (IEEE), 2019, article id 8905720Conference paper, Published paper (Refereed)
Abstract [en]

Generation adequacy is a concern in today's electricity market where intermittent renewable energy sources are rapidly becoming a greater share of the generation mix. This paper focuses on the North-European power system that is comprised of the system areas of the Nord Pool spot market. Sequential Monte Carlo Simulation is applied to assess the generation adequacy of this multi-area system for several future scenarios defined within the Nordic Flex4RES project. The paper gives insights into the characteristics of these adequacy problems that the system could face in a more sustainable future and quantifies their magnitude. Finally, some solutions based on the demand flexibility of residential electric heating are discussed.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2019
Keywords
EENS, Generation Adequacy, LOLE, Nord Pool, Sequential Monte Carlo Simulation
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-267910 (URN)10.1109/ISGTEurope.2019.8905720 (DOI)2-s2.0-85075900367 (Scopus ID)9781538682180 (ISBN)
Conference
2019 IEEE PES Innovative Smart Grid Technologies Europe, ISGT-Europe 2019; University Politehnica of Bucharest, Bucharest; Romania; 29 September 2019 through 2 October 2019
Note

QC 20200217

Available from: 2020-02-17 Created: 2020-02-17 Last updated: 2020-02-17Bibliographically approved
Crosara, A., Tomasson, E. & Söder, L. (2019). Generation Adequacy in the Nordic and Baltic Region: Case Studies from 2020 to 2050: Flex4RES Project Report. Stockholm: KTH Royal Institute of Technology
Open this publication in new window or tab >>Generation Adequacy in the Nordic and Baltic Region: Case Studies from 2020 to 2050: Flex4RES Project Report
2019 (English)Report (Other academic)
Abstract [en]

Generation adequacy is a concern in today's electricity market where intermittent renewable energy sources are rapidly becoming a greater share of the generation mix. This study focuses on the Nordic and Baltic power system that is comprised of the system areas of the Nord Pool spot market. Sequential Monte Carlo Simulation is applied to assess the generation adequacy of this multi-area system for several future case studies, based on scenarios defined within the Nordic Flex4RES project. The report gives insights into the characteristics of these adequacy problems that the system could face in a more sustainable future, quantifies their magnitude and presents their characteristics. Finally, a solution based on the demand flexibility of residential electric heating is discussed, as a way to counter capacity deficit problems.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2019. p. 33
Keywords
Generation Adequacy, Reliability, Electricity Market, Monte Carlo Simulation
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-254940 (URN)
Projects
Flex4RES
Note

QC 20190724

Available from: 2019-07-09 Created: 2019-07-09 Last updated: 2019-07-26Bibliographically approved
Divshali, P. H. & Söder, L. (2019). Improving PV Dynamic Hosting Capacity Using Adaptive Controller for STATCOMs. IEEE transactions on energy conversion, 34(1), 415-425
Open this publication in new window or tab >>Improving PV Dynamic Hosting Capacity Using Adaptive Controller for STATCOMs
2019 (English)In: IEEE transactions on energy conversion, ISSN 0885-8969, E-ISSN 1558-0059, Vol. 34, no 1, p. 415-425Article in journal (Refereed) Published
Abstract [en]

High penetrations of renewable energy sources (RES) in distribution grids lead to new challenges in voltage regulation. These challenges are not just limited to the steady-state voltage rise, but they are extended to rapid voltage changes due to wind speed variations and moving clouds, casting shadows on photovoltaic panels. According to EN50160 in low-voltage (LV) grids, the steady-state voltage should not exceed 1.1 pu (static characteristic), and rapid voltage changes should be kept less than 0.05 pu (dynamic characteristic). These two characteristics may limit the maximum amount of RES that can be installed in LV grids, called, respectively, the static hosting capacity (SHC) and dynamic hosting capacity (DHC). Although existing research just evaluated SHC in distribution grids, high-penetrated RES grids can be faced with such large voltage changes, which cause a smaller DHC than the SHC. This paper studies both SHC and DHC in distribution grids and proposes an adaptive controller for static synchronous compensators to regulate the steady-state and dynamic voltage while avoiding the unnecessary increase in the reactive power. The simulation results in some German distribution grids show considerable effects of the proposed adaptive controller on improving both SHC and DHC.

Place, publisher, year, edition, pages
IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2019
Keywords
Distribution grids, dynamic voltage regulation, hosting capacity, reactive power, renewable energy sources (RESs)
National Category
Environmental Engineering
Identifiers
urn:nbn:se:kth:diva-247822 (URN)10.1109/TEC.2018.2873057 (DOI)000460332600041 ()2-s2.0-85054469916 (Scopus ID)
Note

QC 20190327

Available from: 2019-03-27 Created: 2019-03-27 Last updated: 2020-03-09Bibliographically approved
Nycander, E., Söder, L., Eriksson, R. & Hamon, C. (2019). Minimising wind power curtailments using OPF considering voltage stability. The Journal of Engineering (18), 5064-5068
Open this publication in new window or tab >>Minimising wind power curtailments using OPF considering voltage stability
2019 (English)In: The Journal of Engineering, ISSN 1872-3284, E-ISSN 2051-3305, no 18, p. 5064-5068Article in journal (Refereed) Published
Abstract [en]

As the amount of wind power in power systems has increased, it has become necessary to curtail wind power in some high-penetration situations. In order to assess the need for curtailment arising from voltage stability considerations the authors develop a security constrained optimal power flow (SCOPF) for minimising the expected curtailment. The authors find that with a very high wind penetration and wind farms operating at unity power factor curtailment becomes necessary to satisfy voltage limits. In this case, the optimal solution in the studied system is to curtail at a single bus rather than curtailing by a smaller amount at several buses. However, allowing for reactive power production from wind farms reduces the need for curtailments.

Place, publisher, year, edition, pages
INST ENGINEERING TECHNOLOGY-IET, 2019
Keywords
load flow, wind power plants, wind power, reactive power, power system security, power factor, minimising wind power curtailments, OPF considering voltage stability, power systems, high-penetration situations, voltage stability considerations, optimal power flow, expected curtailment, high wind penetration, wind farms, unity power factor curtailment, voltage limits, reactive power production
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-260206 (URN)10.1049/joe.2018.9371 (DOI)000482590000074 ()
Note

QC 20190930

Available from: 2019-09-30 Created: 2019-09-30 Last updated: 2019-09-30Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8189-2420

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