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  • 1. Duvnjak Zarkovic, Sanja
    et al.
    Weiss, Xavier
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Addressing Data Deficiencies in Outage Reports: A Qualitative and Machine Learning Approach2024Conference paper (Other academic)
    Abstract [en]

    This study investigates outage statistics in the Swedish power system. More specifically, this paper delves into the critical analysis and enhancement of data quality, focusing on inconsistencies and missing values, i.e. unknown outage causes and unidentified faulty equipment. By carefully examining the data, noticeable gaps and deficiencies are revealed. Thus, a format for improving outage reporting using a database with 3 relations (outage summary, outage breakdown and customer breakdown) is proposed. In addition to a qualitative analysis of the data, various machine learning algorithms are explored and tested for their capability to predict the unknown values within the dataset, thereby offering a twofold solution: enhancing the accuracy of outage data and facilitating deeper, more accurate analytical capabilities. The findings and proposals within this work not only illuminate the current challenges within outage data management but also pave the way for more robust, data-driven decision-making in outage management and policy formation. 

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  • 2.
    Duvnjak Zarkovic, Sanja
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Security of Electricity Supply in Power Systems: Establishing a Global Framework for Assessing Power System Health and Analyzing Outage Statistics in Sweden2024Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The primary objective of this thesis is to enhance the security of electricity supply by providing a holistic perspective and introducing a comprehensive framework for assessing power system health. This novel approach aims for a thorough evaluation of the system’s overall performance and well-being, using the physical dimensions of the security of supply as the foundation for a power system health index. 

    After establishing the theoretical framework, relevant and available data is collected in order to analyze and understand the system’s performance. By analyzing outage statistics in Sweden, the research identifies specific trends and performance metrics that can be further investigated and segmented according to various criteria. The insights gained from this research can, in turn, be used to inform proactive maintenance strategies and capacity planning, ultimately mitigating the risks of outages and ensuring a more reliable electricity supply. 

    Outage statistics are furthermore analyzed from the aspect of data quality, focusing on inconsistencies and missing values in the outage reports, i.e. unknown outage causes and unidentified faulty equipment. By carefully examining the data, noticeable gaps and deficiencies are revealed. Thus, a format for improving outage reporting using a database with 3 relations (outage summary, outage breakdown and customer breakdown) is proposed. In addition to a qualitative analysis of the data, various machine learning algorithms are explored and tested for their capability to predict the unknown values within the dataset, thereby offering a twofold solution: enhancing the accuracy of outage data and facilitating deeper, more accurate analytical capabilities. The findings and proposals within this work highlight the current challenges within outage data management and also lay the groundwork for a more comprehensive, data-driven approach in outage management and policy development. 

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  • 3.
    Habib, Md Zakaria
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Duvnjak Zarkovic, Sanja
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Shayesteh, Ebrahim
    Swedish Natl Grid Svenska Kraftnät, Sundbyberg, Sweden..
    Distributed fault-passage indicators versus central fault location: Comparison for reliability centred planning of resonant-earthed distribution systems2023In: Energy Reports, E-ISSN 2352-4847, Vol. 9, p. 1731-1742Article in journal (Refereed)
    Abstract [en]

    Fault location methods are crucial for reducing fault restoration time, and thus improving a network's system average interruption duration index (SAIDI) and customer outage cost. Resonant-earthed systems pose problems for traditional fault location methods, leading to poor accuracy and a need for additional complexity. In this context, methods that detect fault direction (fault-passage indicators, FPI) at multiple points in the network may show advantages over a central distance-estimation method using fault locators (FL) of poor accuracy. This paper includes a comparative study of these two major fault location methods, comparing the reliability benefit from a varied number of FPIs or a central method. The optimal placement of the fault locating devices is found by formulating a mixed-integer linear programming (MILP) optimization approach that minimizes both outage and investment costs and assesses SAIDI. This approach has been tested on an example distribution system. However, to justify the universality of the algorithm, the RBTS reliability test system has also been analysed. The comparison of location methods and placement method of FPIs are useful for reliability centred planning of resonant-earthed distribution systems where fault location is to be used. Results show that a small number of FPIs that give accurate identification of direction may give more cost effective increase in reliability than a distance estimate by FL with typical levels of inaccuracy.

  • 4.
    Duvnjak Zarkovic, Sanja
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Outage Statistics and Trends in Sweden – What does data tell us?2023In: Energy Proceedings / [ed] Prof. Jinyue Yan, 2023Conference paper (Refereed)
    Abstract [en]

    Data analysis plays a pivotal role in identifying patterns and relationships within data sets. By examining historical outage statistics in power systems, trends in system performance can be revealed, contributing to a better understanding of its behavior. Furthermore, by understanding the past performance of the power system, utility companies can make better decisions to enhance system reliability and resilience. This study investigates outage statistics in the Swedish power system from 2009 to 2019 and examines in depth the reporting mechanism. The data is clustered and analyzed according to three different criteria: voltage level of the breaking device, cause of the failure, and faulty equipment. Although the presented overview highlights key trends in system performance, the analysis has uncovered issues related to data quality and availability, such as missing values and inconsistencies that require further attention.

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  • 5.
    Duvnjak Zarkovic, Sanja
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Integrated reliability centered distribution system planning — Cable routing and switch placement2021In: Energy Reports, E-ISSN 2352-4847, Vol. 7, p. 3099-3115Article in journal (Refereed)
    Abstract [en]

    Distribution utilities aim to operate and plan their network in a secure and economical way. The prime focus of this work is to assist utilities by developing a new integrated approach which considers the impacts of system reliability in distribution system planning (DSP). This approach merges different problems together and solves them in a two-stage process, as follows: 1. cable routing and optimal location and number of switching devices (circuit breakers and reclosers); 2. optimal location and number of tie switches. Moreover, the possibility of installing different cable options, with different prices and capacities, is included. The optimization algorithm is designed using mixed-integer programming (MIP). The developed algorithm analytically evaluates relationships between different components in the system and dynamically updates reliability indices, failure rate and restoration time, of every node in the system. This approach has been tested on two distribution systems. Despite the complexity and the exhaustiveness of the problem, MIP converges and provides the optimal solution for every studied scenario. The results show that an integrated approach enables utilities to obtain more comprehensive solutions. Moreover, by understanding the impact of parameter variation enables utilities to categorize their priorities in the decision making process and optimally invest in distribution network with respect to reliability.

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  • 6.
    Duvnjak Zarkovic, Sanja
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Onshore wind farm - Reliability centered cable routing2021In: Electric power systems research, ISSN 0378-7796, E-ISSN 1873-2046, Vol. 196, p. 107201-Article in journal (Refereed)
    Abstract [en]

    Designing an onshore wind farm is a complex planning process that requires various stages to be completed. The prime focus of this work is to assist planners and experts in finding the optimal cable layout of the onshore wind farm. The optimization algorithm is designed using mixed integer linear programming (MILP). The MILP algorithm takes into account system reliability, power transfer capacities and power quality issue. The novelty in this optimization algorithm is to simultaneously minimize cable installation cost and the cost of lost energy production and therefore maximize the reliability of the system. Additionally, the algorithm supports the optimal selection among different cable options, with different features, prices and capacities. By calculating voltage increase at the point of connection (POC), power quality issue is considered as well. The designed algorithm provides optimal results for four different wind farm layouts. Every layout is tested for three different case scenarios, where different number and type of cables are considered. The results show that more cable options contribute in lowering the total costs. Moreover, cables with higher capacity can help in improving the power quality issue.

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  • 7. Karlsson, Anders
    et al.
    Duvnjak Zarkovic, Sanja
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Johansson, Joar
    Ellevio AB.
    Nordström, Lars
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Shayesteh, Ebrahim
    Svenska Kraftnät, Stockholm, Sweden.
    STRATEGIES FOR IMPLEMENTING MONITORING AND REMOTE CONTROL EQUIPMENT IN AN URBAN DISTRIBUTION NETWORK2021Conference paper (Refereed)
    Abstract [en]

    This paper develops a strategy of where and how to install and implement communication and remote control systems in the distribution network, with respect to lowering customer interruption cost and reliability indices. The aim is to evaluate and update customer restoration time based on the proposed level of automation in the system. Three different automation levels are considered: 1) ordinary secondary substation, that is not connected to the SCADA/DMS system; 2) monitored secondary substation that sends certain information to SCADA/DMS system; 3) monitored secondary substation with the addition of remotely controlled switching device. The developed strategy has been tested on three different models: 1) reference test system; 2) real feeder network; 3) small grid. Based on the results and the developed framework, the best strategy for implementing monitoring and remote control equipment is presented in the paper. It has been shown that the design of the system affects the results and the strategy. Moreover, secondary substations in models are highly dependent on each other’s configuration and level of automation. 

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  • 8.
    Hou, Novalie
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS).
    Duvnjak Zarkovic, Sanja
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    The Swedish Power System Resilience against Bad Weather Conditions2021Conference paper (Refereed)
    Abstract [en]

    As a result of global warming, the frequency of bad weather events has increased raptly, but so has the demand for more reliable power supply. This study investigates the Swedish power distribution system’s resilience towards certain weather conditions such as wind, lightning, rain etc. The input data is all unplanned disturbances gathered from the Swedish energy companies (Energiföretagen Sverige) between 2015 and 2019. After sorting and analyzing the data, the results are then compared to the weather data from SMHI (Swedish Meteorological and Hydrological Institute). The results show that on average 21% of unplanned outages are related to weather conditions in Sweden. Of the weather phenomena studied, wind and lightning are significantly affecting the resilience of the power system. One way to prevent outages, especially in lower voltage distribution systems, where most disturbances occur, is to improve the maintenance of the system.

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  • 9.
    Habib, Md Zakaria
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hoq, Md Tanbhir
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Duvnjak Zarkovic, Sanja
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Impact of the fault location methods on SAIDI of a resonant-earthed distribution system2020In: 2020 IEEE International Conference on Power Systems Technology, POWERCON 2020, Institute of Electrical and Electronics Engineers Inc. , 2020Conference paper (Refereed)
    Abstract [en]

    Reliability indices of a distribution system can be improved by reducing failure rate and restoration time. A resonant-earthed distribution system has a low failure rate because numerous transient faults become self-extinguishing. However, in such networks, it can be difficult and time-consuming to locate nontransient faults resulting in aggravating the restoration time. This paper analyzes how different fault location methods affect the restoration time and SAIDI. Two major fault location methods are modeled for the calculation of the reliability indices and then applied to a radial feeder of a medium-voltage distribution system. The results show that SAIDI varies depending on the applied fault location method and its accuracy. The influence of fault location methods on labour costs is also discussed.

  • 10.
    Duvnjak Zarkovic, Sanja
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Security of Electricity Supply in Power Distribution System: Optimization Algorithms for Reliability Centered Distribution System Planning2020Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The importance of electricity in everyday life and demands to improve the reliability of distribution systems force utilities to operate and plan their networks in a more secure and economical manner. With higher demands on reliability from both customers and regulators, a big pressure has been put on the security of electricity supply which is considered as a fundamental requirement for modern societies. Thus, efficient solutions for reliability and security of supply improvements are not just of increasing interest, but also have significant socio-economic relevance. Distribution system planning (DSP) is one of the major activities of distribution utilities to deal with reliability enhancement.

    This thesis deals with developing optimization algorithms, which aim is to min- imize customer interruption costs, and thus maximize the reliability of the system. This is implemented either by decreasing customer interruption duration, frequency of customer interruptions or both. The algorithms are applied on a single or multi- ple DSP problems. Mixed-integer programming has been used as an optimization approach.

    It has been shown that solving and optimizing each one of the DSP problems contributes greatly to the reliability improvement, but brings certain challenges. Moreover, applying algorithms on multiple and integrated DSP problems together leads to even bigger complexity and burdensome. However, going toward this inte- grated approach results in a more appropriate and realistic DSP model.

    The idea behind the optimization is to achieve balance between reliability and the means to achieve this reliability. It is a decision making process, i.e. a trade-off between physical and pricing dimension of security of supply.

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  • 11.
    Duvnjak Zarkovic, Sanja
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Stankovic, Stefan
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electric Power and Energy Systems.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Reliability improvement of distribution system through distribution system planning: MILP vs. GA2019In: 2019 IEEE Milan PowerTech, 2019Conference 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.

  • 12.
    Duvnjak Zarkovic, Sanja
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    On the Security of Electricity Supply in Power Distribution Systems2018In: 2018 IEEE International Conference on Probabilistic Methods Applied to Power Systems (PMAPS), IEEE conference proceedings, 2018, article id 8440489Conference paper (Refereed)
    Abstract [en]

    Security of electricity supply has become a fundamental requirement for modern societies. However, attempts to define and evaluate security of supply have differed from one another. This paper reviews relevant studies in order to give a comprehensive explanation of the security of supply concept. The paper includes theory, assessment, methodology, regulations, data and practical issues associated with the security of supply and power system reliability. Special focus is given to the methodologies used for improving the reliability and security of supply in power distribution systems.

  • 13.
    Duvnjak Zarkovic, Sanja
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering and Fusion Science.
    Defining Power System Health: Framework and Process towards a System Health IndexManuscript (preprint) (Other academic)
    Abstract [en]

    The health index has traditionally been devised and calculated for individual assets within a power system. This index provides vital details about an asset’s overall health and allows for a standardized comparison among various assets. However, the intricate nature of power systems poses significant challenges when trying to adapt this methodology for a broader, global power system health index. To tackle this obstacle, this paper proposes an innovative framework for evaluating power system health. The framework’s primary purpose is either to monitor the performance of a power system within a defined jurisdiction (such as a country, region, or utility) over time and identify trends/changes or to compare the performance across various jurisdictions. This paper further presents a comprehensive overview of key concepts that play a vital role in determining power system health. These include the driving factors, performance metrics, and associated costs, all of which are under the careful supervision of asset management. Special attention is given to the physical dimensions of the security of electricity supply, which represent the performance-based aspect of power system health and constitute the foundation for the power system health index. Each performance-based dimension is thoroughly reviewed, and a list of relevant key performance indicators is provided for every dimension. 

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  • 14.
    Habib, Md Zakaria
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. Swedish Energy Agency (SWEGRIDS).
    Duvnjak Zarkovic, Sanja
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Taylor, Nathaniel
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Distributed fault-passage indicators versus central fault location: comparison for reliability centered planning of resonant-earthed distribution systemsManuscript (preprint) (Other academic)
    Abstract [en]

    Fault location methods are crucial for reducing fault restoration time, and thus improving a network's system average interruption duration index (SAIDI) and customer outage cost. Resonant-earthed systems pose problems for traditional fault location methods, leading to poor accuracy and a need for additional complexity. In this context, methods that detect fault direction (fault-passage indicators, FPI) at multiple points in the network may show advantages over a central distance-estimation method using fault locators (FL) of poor accuracy. This paper includes a comparative study of these two major fault location methods, comparing the reliability benefit from a varied number of FPIs or a central method. The optimal placement of the fault locating devices is found by formulating a mixed-integer linear programming (MILP) optimization approach that minimizes both outage and investment costs and assesses SAIDI. This approach has been tested on an example distribution system. However, to justify the universality of the algorithm, the RBTS reliability test system has also been analysed. The comparison of location methods and placement method of FPIs are useful for reliability centred planning of resonant-earthed distribution systems where fault location is to be used. Results show that a small number of FPIs that give accurate identification of direction may give more cost effective increase in reliability than a distance estimate by FL with typical levels of inaccuracy.

  • 15.
    Duvnjak Zarkovic, Sanja
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Onshore Wind Farm - Reliability Centered Cable RoutingManuscript (preprint) (Other academic)
    Abstract [en]

    Onshore wind farm design requires various stages to be completed. Due to complexity, these stages can not be unified as one planning process. Rather, every design step is considered separately. The prime focus of this work is to assist planners and experts in finding the optimal cable layout of the onshore wind farm. The optimization algorithm is designed using a mixed integer linear programming (MILP). The MILP algorithm takes into account system relia- bility, power transfer capacities and power quality issue. Beside minimizing cable installation cost, the novelty in this optimization algorithm is to mini- mize the cost of lost energy production and therefore maximize the reliability of the system. Additionally, the algorithm supports the optimal selection among different cable options, with different features, prices and capacities. By calcu- lating voltage increase at the point of connection (POC), power quality issue is considered as well. The designed algorithm provides optimal results for four different wind farm layouts. Every layout is tested for three different case sce- narios, where different number and type of cables are considered. The results show that more cable options contribute in lowering the total costs. Moreover, cables with higher capacity can help in improving the power quality issue.

  • 16.
    Duvnjak Zarkovic, Sanja
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Reliability Centered Distribution System Planning - Cable Routing and Switch PlacementManuscript (preprint) (Other academic)
    Abstract [en]

    Distribution utilities aim to operate and plan their network in a secure and economical way. The prime focus of this work is to assist utilities by developing a new integrated approach which considers the impacts of system reliability in distribution system planning (DSP). This approach merges different problems together and solves them in a two-stage process, as follows: 1. cable routing and optimal location and number of reclosers; 2. optimal location and number of tie switches. The optimization algorithm is designed using a mixed integer programming (MIP). The developed approach has been tested on 2 distribution systems and for each system 18 different case scenarios have been conducted, making an overall of 36 simulations. Despite the complexity and the exhaustiveness of the problem, MIP converges and provides optimal solution within reasonable time for every scenario. The results show that without sufficient number of reclosers, drastically changing the cable layout can worsen the reliability. Moreover, the benefit of tie switch placement is very susceptible to the network outline (cable layout and number and position of reclosers). With more layout changes and bigger number of reclosers, the benefit of tie switches becomes more significant.

  • 17.
    Habib, Md Zakaria
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Duvnjak Zarkovic, Sanja
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Taylor, Nathaniel
    KTH, Superseded Departments (pre-2005), Electrical Systems. KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering.
    Hilber, Patrik
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Shayesteh, Ebrahim
    KTH, School of Electrical Engineering and Computer Science (EECS), Electrical Engineering, Electromagnetic Engineering. KTH Royal Institute of Technology.
    Reliability Centered Planning of a Resonant-earthed Distribution System with Focus on the Fault Location MethodsManuscript (preprint) (Other academic)
    Abstract [en]

    Fault location methods help to reduce the restoration time and thus improve the SAIDI (System average interruption duration index) of the network. Besides that, restoration time has a direct impact on customer outage cost. Traditional fault location methods struggle to perform adequately and need additional features for a resonant-earthed system. This paper assists in the reliability centred planning of such a system with the focus on fault location methods. Two major fault location methods are modelled for the study. The optimal placement of the fault locating devices is found by formulating a MILP optimization approach that minimizes both outage and investment cost and asses SAIDI. Moreover, a comparative study among the fault location methods is done to find the best case for an actual resonant-earthed distribution system.

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