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Hajeforosh, Seyede FatemehORCID iD iconorcid.org/0000-0002-2634-8852
Publications (10 of 11) Show all publications
Hajeforosh, S. F., Khatun, A. & Bollen, M. (2022). Enhancing the hosting capacity of distribution transformers for using dynamic component rating. International Journal of Electrical Power & Energy Systems, 142, Part A, Article ID 108130.
Open this publication in new window or tab >>Enhancing the hosting capacity of distribution transformers for using dynamic component rating
2022 (English)In: International Journal of Electrical Power & Energy Systems, ISSN 0142-0615, E-ISSN 1879-3517, Vol. 142, Part A, article id 108130Article in journal (Refereed) Published
Abstract [en]

With the increasing deployment of solar power, high photovoltaic (PV) penetration is expected to adversely impact the distribution grid. One of the challenges relates to the power flow and transfer capacity of the distribution transformers. Transformers might not have sufficient capacity to accommodate for all the downstream PV to feed back to a higher voltage level during sunny periods with low consumption. In this paper, we estimate the transformer hosting capacity considering dynamic thermal rating for residential consumption with increasing amounts of PV penetration. This paper analyzes the impact of PV integration and increased consumption on the aging of a transformer. The potential of dynamic rating to enhance transformer hosting capacity is studied under varying environmental conditions.

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Distribution Transformer, Dynamic Rating, Hosting Capacity, Overload, Renewable Energy System, Solar Power
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-90180 (URN)10.1016/j.ijepes.2022.108130 (DOI)000800400800003 ()2-s2.0-85129323471 (Scopus ID)
Funder
Swedish Energy Agency
Note

Validerad;2022;Nivå 2;2022-05-11 (sofila);

Funder: Skellefteå Kraft Elnät; Energiforsk AB

Available from: 2022-04-13 Created: 2022-04-13 Last updated: 2022-06-10Bibliographically approved
Hajeforosh, S. F. (2022). Multiple Aspects of Dynamic Rating in the Power System. (Doctoral dissertation). Luleå: Luleå University of Technology
Open this publication in new window or tab >>Multiple Aspects of Dynamic Rating in the Power System
2022 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Increased consumption and increased use of renewable energy make overhead lines and transformers more often congested. Dynamic rating (DR) uses a time-depending maximum permissible current instead of a long-term-fixed rating; it is an effective solution to upgrade the capacity of existing grid assets to minimize this congestion. Dynamic line rating (DLR) considers how the weather affects the thermal behavior of the conductor and therewith its rating; environmental parameters as well as conductor characteristics have to be considered. Likewise, dynamic rating of transformers (DTR) relies on a thermal assessment of the hottest spot in the transformer windings. The hot-spot temperature is dependent on the ambient temperature, loading, and transformer’s cooling system.

In this thesis, a number of lesser-studied aspects of DR are studied: stochastic modeling of the rating; relations between protection, reliability and rating; risk assessment for line selection when using DLR; and increased transformer hosting capacity (HC) in the presence of solar photovoltaic (PV).

In the first part of the work, the focus is on the stochastic modeling of DLR and its relation to the protection operation. Actual line rating is considered a random variable in the protection system for a more flexible decision-making. Different sources of uncertainties are modeled using suitable probability density functions. The method allows for a transparent trade-off between the risk of failure to take measures and the risk of unnecessary measures against overload. The results depicts that deterministic DLR could result in high probabilities of overloading or would require large safety margins. While, a stochastic approach will allow for both small margins and appropriate risks.  

A generic model is introduced to consider DLR reliability from two different viewpoints: errors and failures of components that would affect the calculation of the rating; and the impact of a DLR failure on the power system. The qualitative reliability study highlights that it is important to update the protection settings on a real-time basis. 

In the second part of the work, a risk assessment framework is proposed to select the minimum set of overhead lines for DLR implementation. Results show a possible increase of permissible hosting capacity (HC) for electric-vehicle charging by up to 80% (depending on the test system and initial data) with low interruption costs and reduced risk of congestion. Furthermore, the improvement in the transformer HC by using DTR has been quantified. The results indicate that depending on the HC performance indices, the transformer can be loaded beyond the normal operational limits up to 35% to host PV and up to 100% for increased consumption.

Place, publisher, year, edition, pages
Luleå: Luleå University of Technology, 2022
Series
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Keywords
Dynamic rating, Transmission lines, Overload Protection, Stochastic analysis, Hosting capacity, Transformers
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-90176 (URN)978-91-8048-063-5 (ISBN)978-91-8048-064-2 (ISBN)
Public defence
2022-06-10, Hörsal A, Campus Skellefteå, 97187, Skellefteå and Zoom, 09:00 (English)
Opponent
Supervisors
Available from: 2022-04-13 Created: 2022-04-13 Last updated: 2023-09-05Bibliographically approved
Hajeforosh, S. F., Bakhtiari, H. & Bollen, M. (2022). Risk Assessment Criteria for Utilizing Dynamic Line Rating in Presence of Electric Vehicles Uncertainty. Electric power systems research, 212, Article ID 108643.
Open this publication in new window or tab >>Risk Assessment Criteria for Utilizing Dynamic Line Rating in Presence of Electric Vehicles Uncertainty
2022 (English)In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 212, article id 108643Article in journal (Refereed) Published
Abstract [en]

Dynamic line rating (DLR) is a grid enhancing technology to enable a more effective use of transmission capacity of existing infrastructure.~The growth in load consumption along with a high integration of electric vehicles (EV) highlights the potential of DLR utilization for reducing the congestion costs and overloading risks.~Selecting the proper lines for DLR implementation is necessary to exploit optimally the benefits of DLR. In this paper, we propose risk assessment criteria to select proper lines for DLR implementation to minimize the system operation costs and the risk of overloading caused by high EV integration.A stochastic method is introduced to model the uncertain behavior of EV in charging stations. Furthermore, we analyze the impact of inherent uncertainties in DLR by comparing different DLR percentiles. The benefits of using DLR in different percentiles are then quantified in terms of supply and interruption costs.The results show improvements in system supply cost, system reliability, and operation risks. 

Place, publisher, year, edition, pages
Elsevier, 2022
Keywords
Dynamic Line Rating, Electric Vehicle, Electric Power Transmission, Optimization, Risk Assessment, Stochastic Approach
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-90181 (URN)10.1016/j.epsr.2022.108643 (DOI)000860499100007 ()2-s2.0-85134786687 (Scopus ID)
Funder
Swedish Energy Agency
Note

Validerad;2022;Nivå 2;2022-07-22 (sofila);

Funder: Skellefteå Kraft Elnät AB; Energiforsk AB

Available from: 2022-04-13 Created: 2022-04-13 Last updated: 2022-11-09Bibliographically approved
Hajeforosh, S. F. & Bollen, M. (2021). Increasing the Grid Capacity for Electric Vehicle Charging using Dynamic Rating. In: CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution: . Paper presented at 26th International Conference and Exhibition on Electricity Distribution (CIRED 2021), Online, September 20-23, 2021 (pp. 1777-1781). Institution of Engineering and Technology, Article ID 0068.
Open this publication in new window or tab >>Increasing the Grid Capacity for Electric Vehicle Charging using Dynamic Rating
2021 (English)In: CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution, Institution of Engineering and Technology, 2021, p. 1777-1781, article id 0068Conference paper, Published paper (Refereed)
Abstract [en]

With a noticeable increase in the number of electric vehicles\,(EVs) in coming years, lack of grid capacity may become a barrier for electrification of transportation. This study presents the application of dynamic rating to increase the available transfer capacity and to enable more increase in consumption. Through stochastic calculation the hourly available capacity has been estimated which then used to calculate the hosting capacity. In this sense, the probability of overloading considering different EV types is calculated. The results show that the probabilistic hosting capacity would be a better indication to estimate the minimum and maximum EV load demand in the coming hours.

Place, publisher, year, edition, pages
Institution of Engineering and Technology, 2021
Keywords
Curtailment, Dynamic Rating, Electric Power Transmission, Electric Vehicle Overloading, Hosting Capacity, Stochastic Method
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-90177 (URN)10.1049/icp.2021.1812 (DOI)
Conference
26th International Conference and Exhibition on Electricity Distribution (CIRED 2021), Online, September 20-23, 2021
Note

ISBN för värdpublikation: 978-1-83953-591-8 (elektroniskt)

Available from: 2022-04-13 Created: 2022-04-13 Last updated: 2022-04-29Bibliographically approved
Hajeforosh, S. F. & Bollen, M. (2021). Reliability Aspects of Dynamic Thermal Rating in the Power Grid. In: CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution: . Paper presented at 26th International Conference and Exhibition on Electricity Distribution (CIRED 2021), Online, September 20-23, 2021 (pp. 1086-1090). Institution of Engineering and Technology, Article ID 0024.
Open this publication in new window or tab >>Reliability Aspects of Dynamic Thermal Rating in the Power Grid
2021 (English)In: CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution, Institution of Engineering and Technology, 2021, p. 1086-1090, article id 0024Conference paper, Published paper (Refereed)
Abstract [en]

This paper is an overview of the components and failure modes that should be considered when studying the reliability of dynamic thermal rating (DTR) in the power system. A reliability study should include failure of a measurement device, failure of the communication, model inaccuracy, and failure of the control system. The presence of the DTR system increases the risks of unnecessary operation and lack of action in power system due to an error in DTR calculation. This impact is studied qualitatively in this paper; it is of great importance during operation and maintenance of the power system.

Place, publisher, year, edition, pages
Institution of Engineering and Technology, 2021
Keywords
Dynamic rating, Generic model, Power-system reliability, Power-system protection
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-90178 (URN)10.1049/icp.2021.1764 (DOI)
Conference
26th International Conference and Exhibition on Electricity Distribution (CIRED 2021), Online, September 20-23, 2021
Funder
Swedish Energy Agency
Note

 

ISBN för värdpublikation: 978-1-83953-591-8 (elektroniskt);

Funder: Skellefteå Kraft Elnät; Energiforsk

Available from: 2022-04-13 Created: 2022-04-13 Last updated: 2022-04-29Bibliographically approved
Hajeforosh, S. F. & Bollen, M. (2021). Uncertainties in radiation modelling for overhead lines and their impact on the ampacity. In: CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution: . Paper presented at 26th International Conference and Exhibition on Electricity Distribution (CIRED 2021), Online, September 20-23, 2021 (pp. 2366-2370). Institution of Engineering and Technology, Article ID 0039.
Open this publication in new window or tab >>Uncertainties in radiation modelling for overhead lines and their impact on the ampacity
2021 (English)In: CIRED 2021 - The 26th International Conference and Exhibition on Electricity Distribution, Institution of Engineering and Technology, 2021, p. 2366-2370, article id 0039Conference paper, Published paper (Refereed)
Abstract [en]

This paper gives a detailed analysis of the radiation terms in the heating balance for overhead conductors. The terms in the radiation balance determine the rating of an overhead line for use in dynamic line rating schemes. These radiation terms are often not considered and in which there is a relatively big uncertainty. The available knowledge and the different uncertainties are summarized, for radiation from the environment reaching the conductor, for thermal emission from the conductor and for heating of the conductor due to direct and indicated solar irradiation. The impact of the uncertainties on the uncertainty in line rating is quantified and it is concluded that the error made is around 10 % for low wind speed.

Place, publisher, year, edition, pages
Institution of Engineering and Technology, 2021
Keywords
Power transmission and distribution, Dynamic line rating, Radiation models, Ampacity
National Category
Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-90179 (URN)10.1049/icp.2021.1779 (DOI)
Conference
26th International Conference and Exhibition on Electricity Distribution (CIRED 2021), Online, September 20-23, 2021
Note

ISBN för värdpublikation: 978-1-83953-591-8 (elektroniskt);

Funder: Skellefteå Kraft; Energiforsk

Available from: 2022-04-13 Created: 2022-04-13 Last updated: 2022-04-29Bibliographically approved
Hajeforosh, S. & Bollen, M. H. .. (2021). Uncertainty analysis of stochastic dynamic line rating. Electric power systems research, 194, Article ID 107043.
Open this publication in new window or tab >>Uncertainty analysis of stochastic dynamic line rating
2021 (English)In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 194, article id 107043Article in journal (Refereed) Published
Abstract [en]

This paper presents an uncertainty analysis of lines equipped with dynamic line rating (DLR) that are exposed to operational overloading. Multiple sources of uncertainties are taken in to account to model the line rating probabilistically. The superiority of dynamic rating above static rating is confirmed in this paper. However, it is shown in this paper that when the uncertainties in line rating are not considered, DLR can result in a high probability of undetected overloading. Based on assumptions for the uncertainties in relevant weather parameters, the probability of overloading is calculated for three different loading profiles of a line, for each hour during an eight-year period. Guaranteeing a low probability of overloading, with a deterministic dynamic rating, will require a large margin and result in many hours during which unnecessary measures against overloading will be taken. A stochastic dynamic rating, as introduced in this paper, allows for a more transparent and hour-by-hour trade-off between failure to take measures and unnecessary measures against overloading.

Place, publisher, year, edition, pages
Elsevier, 2021
Keywords
Dynamic line rating, Electric power transmission, Overloading, Power system protection, Stochastic method
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-82730 (URN)10.1016/j.epsr.2021.107043 (DOI)000632386100010 ()2-s2.0-85099927161 (Scopus ID)
Note

Validerad;2021;Nivå 2;2021-02-01 (alebob)

Available from: 2021-02-01 Created: 2021-02-01 Last updated: 2022-04-13Bibliographically approved
Hajeforosh, S. F. & Bollen, M. (2020). Dynamisk belastningsförmåga av luftledningar: Överbelastningsskydd och tillförlitlighet. Sweden: Energiforsk
Open this publication in new window or tab >>Dynamisk belastningsförmåga av luftledningar: Överbelastningsskydd och tillförlitlighet
2020 (Swedish)Report (Other academic)
Abstract [sv]

Dynamisk belastningsförmåga är att sätt att möjliggöra en högre användning av överföringskapacitet av en luftledning utan att det finns en ökad risk att ledningen blir överbelastad. Från prognosen eller mätning av väderparametrar görs det en uppskattning av hur mycket ström en luftledning klarar.

Metoden har studerats förut och det pågår en hel del forskning kring detta. Det som dock får begränsat med uppmärksamhet är dynamisk belastningsförmågas roll i överbelastningsskydd, dess olika osäkerheter och tillförlitlighet. Det är dessa aspekter som var utgångspunkter för studien som presenteras i denna rapport.

Det visas att det finns en stor potential för dynamisk belastningsförmåga under vintermånaderna i Sverige, precis då som det behövs mer överföringsförmåga. Det möjliggör bland annat en större integrering av elbilsladdning i elnätet.

En metod för dynamisk belastningsförmåga i kombination med överbelastningsskydd har introducerats; sannolikheten att ledningen är överbelastat är kriteriet för att bedöma om det behövs åtgärder för att förebygga överbelastning. Denna stokastiska metod kan användas under driftplanering (till exempel dagen innan), under driften (till exempel för att bedöma driftsäkerheten) och som en skyddsåtgärd (i fall ingen av de förebyggande åtgärderna hjälper).

Belastningsförmågan och sannolikhet på överbelastning har beräknads för varje timme under en åttaårsperiod för en hypotetisk ledning till en hypotetisk stad i Norra Sverige, Belasteå. Alla ingångsparametrar var dock baserade på verklig data och inte hypotetiska alls.

Rapporten innehåller en diskussion angående en del förslag på tillämpningar och utvidgning av metoden. Där ingår det bland annat tillämpningar i det svenska elnätet, utveckling av liknade metoder för kablar och transformatorer, samt tillämpningar då ledartemperaturen mäts. 

Place, publisher, year, edition, pages
Sweden: Energiforsk, 2020. p. 39
Series
Energiforskrapport ; 2020:710
National Category
Energy Systems
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-82197 (URN)978-91-7673-710-1 (ISBN)
Projects
Stochastic models for future smart electricity transmission grids
Note

Finansiär: Skellefteå Kraft AB

Available from: 2021-01-07 Created: 2021-01-07 Last updated: 2021-06-16Bibliographically approved
Hajeforosh, S. F., Nazir, Z. & Bollen, M. (2020). Reliability Aspects of Battery Energy Storage in the Power Grid. In: Proceedings of 2020 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe) 26-28 October, 2020: . Paper presented at 10th IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe 2020), 26-28 October, 2020, Delft, The Netherlands (Virtual) (pp. 121-125). IEEE
Open this publication in new window or tab >>Reliability Aspects of Battery Energy Storage in the Power Grid
2020 (English)In: Proceedings of 2020 IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe) 26-28 October, 2020, IEEE, 2020, p. 121-125Conference paper, Published paper (Refereed)
Abstract [en]

This paper gives an overview of the components and failure modes that should be considered when studying the reliability of grid-size Battery Energy Storage System (BESS). Next to failures of the primary component, a reliability study should consider the failure of the protection, failure of the communication, and failure of the control system. After all the diagnosed failures, qualitative fault tree analysis (FTA) based on Boolean logic is introduced as a basis of further analysis. Storage installations have a number of applications, each of which requires a different look at the reliability. The following applications are discussed in the paper: improving supply reliability, compensation power flows, market participation and frequency control.

Place, publisher, year, edition, pages
IEEE, 2020
Keywords
Batteries, Energy storage, Fault tree analysis, Power system modeling, Power system reliability, Smart grids
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-81444 (URN)10.1109/ISGT-Europe47291.2020.9248757 (DOI)2-s2.0-85097337858 (Scopus ID)
Conference
10th IEEE PES Innovative Smart Grid Technologies Europe (ISGT-Europe 2020), 26-28 October, 2020, Delft, The Netherlands (Virtual)
Note

ISBN för värdpublikation: 978-1-7281-7100-5

Available from: 2020-11-18 Created: 2020-11-18 Last updated: 2024-02-20Bibliographically approved
Hajeforosh, S. F. & Bollen, M. H. J. (2020). Transmission Line Overloading Analysis Using Probabilistic Dynamic Line Rating. In: 2020 International Conference on Probabilistic Methods Applied to Power Systems (PMAPS): . Paper presented at 2020 International Conference on Probabilistic Methods Applied to Power Systems (PMAPS), 18-21 Augusti, 2020, Liege, Belgium (On-line). IEEE
Open this publication in new window or tab >>Transmission Line Overloading Analysis Using Probabilistic Dynamic Line Rating
2020 (English)In: 2020 International Conference on Probabilistic Methods Applied to Power Systems (PMAPS), IEEE, 2020Conference paper, Published paper (Refereed)
Abstract [en]

Load growth and addition of renewable energy generation occur in a way that makes the power grid being operated closer to its physical limits. Increasing the flexibility of the electrical power system is an essential step in ensuring a continued high reliability of the electricity supply. Dynamic line rating (DLR) can be utilized to increase the reliability of the system by ordering curtailment only when needed. In this paper, a probabilistic approach is introduced for the operational overload protection based on the probability distribution of the actual line capacity. That distribution is obtained by considering measurement and prediction errors in weather parameters as well as other uncertainties. The results indicate that probabilistic DLR based protection would allow operational decision-making based on a fair balance between dependability and security. This is not possible using the classical overload protection system.

Place, publisher, year, edition, pages
IEEE, 2020
Series
International Conference on Probabilistic Methods Applied to Power Systems (PMAPS), ISSN 2642-6730, E-ISSN 2642-6757
Keywords
Curtailment, Dynamic Line Rating, Protection, Probabilistic Approach, Uncertainty
National Category
Other Electrical Engineering, Electronic Engineering, Information Engineering
Research subject
Electric Power Engineering
Identifiers
urn:nbn:se:ltu:diva-80673 (URN)10.1109/PMAPS47429.2020.9183550 (DOI)000841883300045 ()2-s2.0-85091327402 (Scopus ID)
Conference
2020 International Conference on Probabilistic Methods Applied to Power Systems (PMAPS), 18-21 Augusti, 2020, Liege, Belgium (On-line)
Note

ISBN för värdpublikation: 978-1-7281-2822-1, 978-1-7281-2823-8

Available from: 2020-09-03 Created: 2020-09-03 Last updated: 2024-03-07Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-2634-8852

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