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Publications (5 of 5) Show all publications
Duvnjak Zarkovic, S., Stankovic, S., Shayesteh, E. & Hilber, P. (2019). Reliability improvement of distribution system through distribution system planning: MILP vs. GA. In: 2019 IEEE Milan PowerTech: . Paper presented at 2019 IEEE Milan PowerTech.
Open this publication in new window or tab >>Reliability improvement of distribution system through distribution system planning: MILP vs. GA
2019 (English)In: 2019 IEEE Milan PowerTech, 2019Conference paper, Published paper (Refereed)
Abstract [en]

Distribution system planning (DSP) is very important because it can result in reliability enhancement and large cost savings for both utilities and consumers. DSP is a complex nonlinear problem, which can be solved with different optimization methods. This paper compares two such optimization methods, conventional (mixed-integer linear programming - MILP) and meta-heuristic (genetic algorithm - GA), applied to the DSP problem: construction of feeders in distribution power system from scratch. The main objective of DSP is to minimize the total cost, where both the investment and operational outage costs are considered, while the reliability of the whole system is maximized. DSP problem is applied to an actual distribution system. Solution methods are outlined, and computational results show that even though GA gives reasonably good results in faster computation time, MILP provides a better optimal solution with simpler implementation.

Keywords
Distribution system, distribution system planning, edge-sets, genetic algorithm, mixed-integer programming, power system reliability
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-259601 (URN)10.1109/PTC.2019.8810515 (DOI)2-s2.0-85072341947 (Scopus ID)
Conference
2019 IEEE Milan PowerTech
Funder
SweGRIDS - Swedish Centre for Smart Grids and Energy Storage, CP26
Note

QC 20190930

Available from: 2019-09-18 Created: 2019-09-18 Last updated: 2019-09-30Bibliographically 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: 2018-10-19Bibliographically approved
Stankovic, S. & Söder, L. (2018). Optimal Power Flow Based on Genetic Algorithms and Clustering Techniques. In: 2018 POWER SYSTEMS COMPUTATION CONFERENCE (PSCC): . Paper presented at 2018 POWER SYSTEMS COMPUTATION CONFERENCE (PSCC). IEEE
Open this publication in new window or tab >>Optimal Power Flow Based on Genetic Algorithms and Clustering Techniques
2018 (English)In: 2018 POWER SYSTEMS COMPUTATION CONFERENCE (PSCC), IEEE , 2018Conference paper, Published paper (Refereed)
Abstract [en]

Optimal power flow problems have been studied extensively for the past decades. Two approaches for solving the problem 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 search space when calculating power flows. The proposed method is compared against similar methods showing considerable improvement.

Place, publisher, year, edition, pages
IEEE, 2018
Keywords
Continuous Newton-Raphson, Convex Optimization, Genetic Algorithm, K-means, Optimal Power Flow
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Identifiers
urn:nbn:se:kth:diva-238163 (URN)10.23919/PSCC.2018.8442583 (DOI)000447282400057 ()2-s2.0-85054015733 (Scopus ID)
Conference
2018 POWER SYSTEMS COMPUTATION CONFERENCE (PSCC)
Note

QC 20181107

Available from: 2018-11-07 Created: 2018-11-07 Last updated: 2020-02-17Bibliographically 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
Stankovic, S. & Söder, L. (2017). Identification of Reactive Power Provision Boundaries of a Distribution Grid with DFIGs to a Transmission Grid. 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. Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>Identification of Reactive Power Provision Boundaries of a Distribution Grid with DFIGs to a Transmission Grid
2017 (English)In: 2017 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2017 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2017Conference paper, Published paper (Refereed)
Abstract [en]

Development of the distribution grids brings alsonew challenges. With efficient exploitation of all the availableresources in the grid, many related problems can be solved. Theproblem addressed in this paper is becoming more and morecommon in the practice. There is a need to control reactivepower exchange between the grids of different voltage levels. Thisneed becomes more pronounced with increasing penetration ofdistributed generation and cables in the system. But, the causeof the problem can be also a part of its solution. This papershows that it is possible to control the reactive power exchangeto a noticeable extent using the distributed generation locatedin the grid and the on-load tap changers. The results have beenobtained from the analysis of a representative model of Swedishdistribution network with installed DFIG wind turbines. Whilenot going deeper into the control strategies, the reactive powerboundaries of the system are identified. Critical elements arefound for different case scenarios. Solutions on adjustment ofreactive power capabilities of the grid are proposed.

Place, publisher, year, edition, pages
Institute of Electrical and Electronics Engineers (IEEE), 2017
Series
IEEE PES Innovative Smart Grid Technologies Conference Europe, ISSN 2165-4816
Keywords
DFIG, reactive power provision, radial distribution grid, voltage control, wind power
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electrical Engineering
Identifiers
urn:nbn:se:kth:diva-219933 (URN)10.1109/ISGTEurope.2017.8260119 (DOI)000428016500028 ()2-s2.0-85046290526 (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 20171214

Available from: 2017-12-14 Created: 2017-12-14 Last updated: 2019-01-15Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0002-5263-1950

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