Change search
Link to record
Permanent link

Direct link
BETA
Alternative names
Publications (10 of 337) Show all publications
Söder, L., Lund, P. D., Koduvere, H., Bolkesjø, T. F., Rossebø, G. H., Rosenlund-Soysal, E., . . . Blumberga, D. (2018). A review of demand side flexibility potential in Northern Europe. Renewable & sustainable energy reviews, 91, 654-664
Open this publication in new window or tab >>A review of demand side flexibility potential in Northern Europe
Show others...
2018 (English)In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 91, p. 654-664Article, review/survey (Refereed) Published
Abstract [en]

The number of regional and national power systems with a high share of wind and solar power in the world is quickly increasing. The background for this development is improved technology, decreasing costs, and increased concern regarding environmental problems of competing technologies such as fossil fuels. For the future there are large possibilities for increasing the renewable electricity share. However, variable renewable power production has to be balanced. Demand side flexibility offers an interesting approach to the balancing issues. The aim of this paper is to compare flexibility potentials and how they were estimated in seven Northern European countries in order to compare general challenges and results as well as the connection between used method and results. The total flexibility is estimated to 12–23 GW in a system with a total peak load of 77 GW.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Balancing, Demand side management, Flexibility, Solar power, Wind power
National Category
Energy Systems
Identifiers
urn:nbn:se:kth:diva-227514 (URN)10.1016/j.rser.2018.03.104 (DOI)000434919600045 ()2-s2.0-85045627732 (Scopus ID)
Note

QC 20180516

Available from: 2018-05-16 Created: 2018-05-16 Last updated: 2018-07-02Bibliographically approved
Ren, G., Wan, J., Liu, J., Yu, D. & Söder, L. (2018). Analysis of wind power intermittency based on historical wind power data. Energy, 150, 482-492
Open this publication in new window or tab >>Analysis of wind power intermittency based on historical wind power data
Show others...
2018 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 150, p. 482-492Article in journal (Refereed) Published
Abstract [en]

As wind power provides an increasingly larger share of electricity supply, the challenges caused by wind power intermittency have become more and more prominent. A better understanding of wind power intermittency would contribute to mitigate it effectively. In the present study, the definition of wind power intermittency is given firstly. Based on the definition, wind power intermittency is quantified by duty ratio of wind power ramp (DRWPR). This index provides system operators quantitative insights into wind power intermittency. Furthermore, some characteristics of wind power intermittency can be extracted by the index, such as the differences between wind speed intermittency and wind power intermittency, the differences of wind power intermittency between different scales and so on. The wind power intermittency of a Chinese wind farm is studied in detail based on the proposed index and historical data.

Place, publisher, year, edition, pages
Elsevier, 2018
Keywords
Characteristics, Duty ratio, Forecasting, Intermittency, Ramp event, wind power
National Category
Energy Systems
Identifiers
urn:nbn:se:kth:diva-227592 (URN)10.1016/j.energy.2018.02.142 (DOI)000431748400038 ()2-s2.0-85042848108 (Scopus ID)
Note

QC 20180518

Available from: 2018-05-18 Created: 2018-05-18 Last updated: 2018-05-31Bibliographically approved
Stankovic, S. & Söder, L. (2018). Analytical Estimation of Reactive Power Capability of a Radial Distribution System. IEEE Transactions on Power Systems
Open this publication in new window or tab >>Analytical Estimation of Reactive Power Capability of a Radial Distribution System
2018 (English)In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679Article in journal (Refereed) Published
Abstract [en]

The control of reactive power exchange between grids of different voltage levels has always been a concern for system operators. With production moving from the transmission to the distribution level, its importance increases. This paper proposes a novel approach to estimate reactive power capability of the grid as a whole. A linearized analytical model for an estimation of available reactive power exchange at the interface between two grids has been developed. The maximum estimation error for the scenarios we tested was only 2%. The model gives the relation between important grid parameters and the supported reactive power. The conclusions drawn from the model are confirmed on typical Swedish distribution network with scattered wind power and small industry consumers. Common scenarios in development of distribution grids are applied to show relevant parameters influence. One studied scenario is replacement of overhead lines with cables. It is shown that this particular change enhances the reactive power capability of the grid which is directly seen from the analytical analysis without running any optimal power flow. The analytical model proposed in this paper gives fundamental understanding of the reactive power capability of radial distribution grids.

Keywords
distribution grid, reactive power capability, reactive power management, voltage control, wind power
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-231395 (URN)
Projects
Volatile
Note

QC 20180627

Available from: 2018-06-27 Created: 2018-06-27 Last updated: 2018-06-27Bibliographically approved
Stankovic, S. & Söder, L. (2018). Optimal Power Flow Based on Genetic Algorithms and Clustering Techniques. In: Power Systems Computational Conference PSCC 2018: . Paper presented at Power Systems Computational Conference PSCC 2018.
Open this publication in new window or tab >>Optimal Power Flow Based on Genetic Algorithms and Clustering Techniques
2018 (English)In: Power Systems Computational Conference PSCC 2018, 2018Conference paper, Published paper (Refereed)
Abstract [en]

Optimal power flow problems have been studied extensively for the past decades. Two approaches for solving theproblem have been distinguished: mathematical programming and evolutionary algorithms. The first is fast but is not converging to a global optimum for every case. The second ones are robust but time-consuming. This paper proposes a method that combines both approaches to eliminate their flaws and take advantage of their benefits. The method uses properties of genetic algorithms to group their chromosomes around optima in the search space. The centers of these groups are identified by clustering techniques and furthermore used as initial points for gradient based search methods. At the end, the proposed method finds global optimum and its closest local optima. Continuous Newton-Raphson method is used to overcome ill-conditioned points in a search space when calculating power flows. The proposed method is compared against similar methods showing considerable improvement.

Keywords
Continuous Newton-Raphson, Convex Optimization, Genetic Algorithm, K-means, Optimal Power Flow
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-231394 (URN)
Conference
Power Systems Computational Conference PSCC 2018
Projects
Volatile
Note

QC 20180627

Available from: 2018-06-27 Created: 2018-06-27 Last updated: 2018-06-27Bibliographically approved
Herre, L., Söder, L. & Mathieu, J. L. (2018). The Flexibility of Thermostatically ControlledLoads as a Function of Price Notice Time. In: : . Paper presented at Power Systems Computation Conference (PSCC) 2018. Dublin
Open this publication in new window or tab >>The Flexibility of Thermostatically ControlledLoads as a Function of Price Notice Time
2018 (English)Conference paper, Published paper (Refereed)
Abstract [en]

Due to increased use of variable renewable energy sources, more capacity for balancing and ancillary services (AS) is required. Non-generating resources such as thermostatically controlled loads (TCLs) can arbitrage energy prices and provide AS due to their thermal energy storage capacity. This paper explores the impact of energy/AS price notice time, i.e. the time between when the price is announced and when it takes effect, on the TCL energy consumption and AS capacity bids, and quantifies trade-offs between notice time and flexibility. We first optimize the energy consumption and AS capacity offers at a given notice time, varied from 24 hours ahead to real-time. We then introduce uncertainty in TCL availability, formulate the stochastic optimization problem, and evaluate how the trade-offs change. We find that price notice time impacts TCL profits, but does not significantly affect the total AS capacity offered over the day. However, AS capacity offers are impacted by uncertainty, which is likely to increase with notice time.

Place, publisher, year, edition, pages
Dublin: , 2018
Keywords
ancillary services, demand response, electricity prices, notice time, thermostatically controlled loads
National Category
Energy Systems
Identifiers
urn:nbn:se:kth:diva-231946 (URN)
Conference
Power Systems Computation Conference (PSCC) 2018
Funder
Swedish Energy Agency, 76178
Note

QC 20180717

Available from: 2018-07-05 Created: 2018-07-05 Last updated: 2018-07-17Bibliographically approved
Huang, Y. & Söder, L. (2017). Assessing the impact of incentive regulation on distribution network investment considering distributed generation integration. International Journal of Electrical Power & Energy Systems, 89, 126-135
Open this publication in new window or tab >>Assessing the impact of incentive regulation on distribution network investment considering distributed generation integration
2017 (English)In: International Journal of Electrical Power & Energy Systems, ISSN 0142-0615, E-ISSN 1879-3517, Vol. 89, p. 126-135Article in journal (Refereed) Published
Abstract [en]

In a deregulated power system, incentive regulations for network owners are designed to direct the network investment. An innovative method that assesses the incentive regulation in distribution networks is proposed in this paper. The method quantifies the interplay between incentive regulation, network investment, and network performances. It allows regulators and the distribution system operators (DSOs) evaluating the economic effects of investments within the incentive regulation framework. Considered network investments include the investment in network infrastructure and performance improving. The assessment is based on a network investment optimization model considering multi-period optimal power flow and regulatory constraints. The main contributions of this paper include the modeling of the incentive regulations and the quantification of the impacts of incentive regulation on network infrastructure investment and performance improving investment. 

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Network investment, Distributed generation, Incentive regulation, Revenue cap regulation, Performance incentive regulation
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-201705 (URN)10.1016/j.ijepes.2017.01.018 (DOI)2-s2.0-85012078042 (Scopus ID)
Funder
StandUp
Note

QC 20170221

Available from: 2017-02-14 Created: 2017-02-14 Last updated: 2017-11-29Bibliographically approved
Nilsson, M., Söder, L. & Ericsson, G. (2017). Balancing Strategies Evaluation Framework Using Available Multi-Area Data. IEEE Transactions on Power Systems
Open this publication in new window or tab >>Balancing Strategies Evaluation Framework Using Available Multi-Area Data
2017 (English)In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679Article in journal (Refereed) Published
Abstract [en]

The penetration of variable RES, the deregulation of electricity markets, and the expansion of HVDC- transmission capacities all increase the variability, uncertainty, and imbalances for System Operators (SOs) to handle. Meanwhile, frequency quality has deteriorated and occurrence of balancing problems has increased. Therefore, there is an increased need for SOs to improve their balancing strategies. In this paper we present a new balancing evaluation framework. The main idea of the framework is to be applicable for real and large power systems and provide support for SOs when comparing already used balancing strategies with new ones using historical available data. This is important as only comparatively low-resolution data measurements, such as hourly-mean-values for production, consumption, and HVDC-transmission are stored in many power systems. The framework consists of model building, system parameter identification, testing different strategies and targets supporting the corporate missions of the SOs. In a case study, the framework is tested for a real power system where the model set-up mimics measured frequency accurately. The case study illustrates how the framework can be used to evaluate the impact of different balancing strategies on a series of selected targets which support the cooperate missions of ENTSO-E.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Keywords
Balancing strategies, imbalance, multi-area, power system control, power system modeling, sustainable development, renewable energy sources, variability, uncertainty
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-221217 (URN)10.1109/TPWRS.2017.2736604 (DOI)000425530300012 ()2-s2.0-85028959814 (Scopus ID)
Note

QC 20180116

Available from: 2018-01-16 Created: 2018-01-16 Last updated: 2018-03-14Bibliographically approved
Stankovic, S. & Söder, L. (2017). Cable Impact on Integration of Wind and Solar Power. In: : . Paper presented at ELKRAFT Conference. Goteborg, Sweden
Open this publication in new window or tab >>Cable Impact on Integration of Wind and Solar Power
2017 (English)Conference paper, Poster (with or without abstract) (Refereed)
Place, publisher, year, edition, pages
Goteborg, Sweden: , 2017
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-219934 (URN)
Conference
ELKRAFT Conference
Note

QC 20171214

Available from: 2017-12-14 Created: 2017-12-14 Last updated: 2017-12-14Bibliographically approved
Söder, L., Pellinger, C., Lopez-Botet Zulueta, M., Milligan, M., Kiviluoma, J., Flynn, D., . . . O’Neill, B. (2017). Comparison of Integration Studies of 30-40 percent Energy Share from Variable Renewable Sources. In: 16th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power Plants, Berlin, 2017, article id WIW17-049: . Paper presented at 16th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power Plants, Berlin 25-27 October.
Open this publication in new window or tab >>Comparison of Integration Studies of 30-40 percent Energy Share from Variable Renewable Sources
Show others...
2017 (English)In: 16th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power Plants, Berlin, 2017, article id WIW17-049, 2017Conference paper, Published paper (Other academic)
Abstract [en]

The amount of wind and solar power in the world is quickly increasing. The background for this development is improved technology, decreased costs for the units, and increased concern regarding environmental problems of competing technologies such as fossil fuels. For the future there are large possibilities for increasing shares. However there have been questions raised concerning the challenges of integrating larger shares of variable renewable power such as wind and solar power. Because of this many studies have been performed concerning larger amounts of variable generation for different regions in the world. The aim of this paper is to compare seven of these ones in order to identify general challenges and results as well as the connection between used method and results. 

Keywords
Wind power, solar power, integration, power system, power transmission, frequency control, balancing of wind power.
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-225381 (URN)
Conference
16th International Workshop on Large-Scale Integration of Wind Power into Power Systems as well as on Transmission Networks for Offshore Wind Power Plants, Berlin 25-27 October
Note

QC 20180411

Available from: 2018-04-03 Created: 2018-04-03 Last updated: 2018-04-11Bibliographically approved
Nilsson, M., Söder, L., Eriksson, R., Ghandari, M. & Ericsson, G. (2017). Designing new proactive control-room strategies to decrease the need for automatic reserves. In: 2017 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2017 - Proceedings: . Paper presented at 2017 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2017, Torino, Italy, 26 September 2017 through 29 September 2017.
Open this publication in new window or tab >>Designing new proactive control-room strategies to decrease the need for automatic reserves
Show others...
2017 (English)In: 2017 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2017 - Proceedings, 2017Conference paper, Published paper (Refereed)
Abstract [en]

Maintaining automatic reserve capacities is essential for a sustainable and reliable power system. Today, many power systems experience more frequent frequency deviations coming from increased power variations. This implies an increased utilization of automatic reserves. To decrease frequency deviations, one can increase the automatic reserve capacities. However, the solution tends to be costly and ineffective. Therefore, it is urgent to develop better solutions to cease this trend. Here we have designed new proactive control-room strategies to decrease the need for automatic reserves. We design strategies for a process called Re-Scheduling of Generation and for the Tertiary Frequency Control process. The new control-room strategies are tested using an intra-hour model comparing already used strategies against new ones. It is shown that the historical used strategies are well executed. Nevertheless, results show that the proactive TFC-strategy using a forecasted frequency as control parameter would improve system security significantly.

Keywords
Control-Room Strategies, ENTSO-E, Intra-hour Simulation, Tertiary Frequency Control.
National Category
Control Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-221218 (URN)10.1109/ISGTEurope.2017.8260179 (DOI)000428016500088 ()2-s2.0-85046284932 (Scopus ID)978-1-5386-1953-7 (ISBN)
Conference
2017 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2017, Torino, Italy, 26 September 2017 through 29 September 2017
Note

QC 20180116

Available from: 2018-01-16 Created: 2018-01-16 Last updated: 2018-06-01Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-8189-2420

Search in DiVA

Show all publications