Change search
Refine search result
12345 51 - 100 of 201
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 51.
    Gómez, Francisco José
    et al.
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Statnett SF, Oslo.
    Olsen, Svein
    Statnett SF, Oslo.
    A Modelica-based execution and simulation engine for automated power system model validation2014In: Innovative Smart Grid Technologies Conference Europe (ISGT-Europe), 2014 IEEE PES, 2014, p. 1-6Conference paper (Refereed)
    Abstract [en]

    Power systems model information exchange and the simulation of user defined models is a challenge for Transmission System Operators (TSOs) due to the use of different simulation software with specific data format and models strongly coupled to the simulation software's numerical routines. The use of Open Source software for simulation and modelling can help to decouple power system models from simulation tools. This work describes the design of a software tool following the Free/Libre Open Source Software philosophy to simulate equation-based models and implement a standard data format for model information exchange.

  • 52.
    Gómez, Francisco José
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Statnett SF, Oslo.
    Olsen, Svein
    Statnett SF, Oslo.
    Binding CIM and Modelica for Consistent Power System Dynamic Model Exchange and Simulation2015Conference paper (Refereed)
    Abstract [en]

    The Common Information Model (CIM) is considered the most prominent data model for power systems information exchange between Transmission System Operators (TSO), facilitating coordination of TSO for steady-state operation. However, information exchange should also consider power systems dynamic models required to perform dynamic simulations so to coordinate TSOs operations under emergency conditions. This work describes the design and implementation of a mapping between CIM and Modelica. The Modelica models provide a strict mathematical representation of power system dynamic models using a standardized modeling language. The proposed solution combines both modeling languages, thus providing a CIM-compliant unambiguous power system model exchange and simulation solution considering both steady-state and dynamic models.

  • 53.
    Gómez, Francisco José
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Vanfretti, Luigi
    Renssellaer Polytechnic Institute, Troy, NY 12180, United States.
    Olsen, Svein
    Statnett SF, Oslo.
    CIM-Compliant Power System Dynamic Model-to-Model Transformation and Modelica Simulation2018In: IEEE Transactions on Industrial Informatics, ISSN 1551-3203, E-ISSN 1941-0050, Vol. 14, no 9, p. 3989-3996, article id 8231176Article in journal (Refereed)
    Abstract [en]

    European regulations on information exchange have put new requirements on analysis tools, the main one being the adoption of the IEC Common Information Model (CIM) that may help interoperability across applications. This paper proposes the use of Model-Driven Software Engineering (MDSE) methods to meet these new requirements. Specifically, this paper shows how to apply Model-to-Model (M2M) transformations. The M2M method presented herein allows to work directly with the information and mathematical description and computer implementation of dynamic models, independent from specific analysis tools. The M2M method proposed requires the development of a mapping between CIM/UML and the Modelica language, which allows to derive Modelica models of physical power systems for dynamic simulations. 

  • 54. Haddadi, Aboutaleb
    et al.
    Hooshyar, Hossein
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Mahseredjian, Jean
    Dufou, Christian
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    A first step towards the implementation and software-to-software validation of an active distribution network model2017Conference paper (Refereed)
  • 55.
    Hasan, Md Rokibul
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. SF, Norwegian Transmission System Operator, Norway .
    Li, Wei
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Khan, Naveed Ahmad
    Generic High Level VSC-HVDC Grid Controls and Test Systems for Offline and Real Time Simulation2014In: 9th International: 2014 Electric Power Quality and Supply Reliability Conference, PQ 2014 - Proceedings, IEEE Computer Society, 2014, p. 57-64Conference paper (Refereed)
    Abstract [en]

    This article describes generic high level control models for VSC-HVDC grid systems. An average value model of the voltage source converter (VSC) is used; it includes the vector current control strategy. As an improvement to traditional conventional high-level control systems, this paper includes dc voltage, negative sequence current and dc voltage droop control loops. To validate the controller's performances, two tests systems were developed: a point-to-point link and a four-terminal DC grid. Both offline and real-time simulations are carried out for several test scenarios. A methodology for calibrating controller parameters is presented and used to tune the controls of each test system considering the different scenarios presented. All simulation models were developed in SimPowerSystem/Simulink and prepared using the RT-LAB software from Opal-RT for real-time simulation; real-time simulation performance of the simulation models is also discussed.

  • 56.
    Honeth, Nicholas
    et al.
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Saleem, Arshad
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Zhu, Kun
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Nordström, Lars
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Decentralized topology inference of electrical distribution networks2012In: 2012 IEEE PES Innovative Smart Grid Technologies, ISGT 2012, IEEE , 2012Conference paper (Refereed)
    Abstract [en]

    Power system operation and control relies heavily on models for decision making. Topology is a critical part of producing these models and maintaining up-to-date topologies of electrical distribution networks is a resource consuming and challenging task. This paper proposes a methodology and system architecture for inference of electrical topology using process and model data from IEC 61850 compliant substation automation devices. A system of autonomous intelligent agents communicating via an overlay network is proposed where agents are capable of communicating on the IEC 61850 station bus. An algorithm for topology inference using structured exchange and comparison of process and model information is developed. The capabilities of structured information exchange and interfacing of substation automation devices enables plug-and-play operation of the topology inference requiring minimal prior knowledge of electrical network structure. Decentralized topology inference forms the basis for future work in operation and management of active distribution networks.

  • 57.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Baran, M. E.
    Firouzi, Seyed Reza
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    PMU-assisted overcurrent protection for distribution feeders employing solid state transformers2017In: Sustainable Energy, Grids and Networks, ISSN 0284-4354, E-ISSN 2352-4677, Vol. 10, p. 26-34Article in journal (Refereed)
  • 58.
    Hooshyar, Hossein
    et al.
    North Carolina State University, Raleigh, NC, United States .
    Baran, Mesut E.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Coordination assessment of overcurrent relays in distribution feeders with high penetration of PV systems2013In: 2013 IEEE Grenoble Conference PowerTech, POWERTECH 2013, IEEE , 2013, p. 6652117-Conference paper (Refereed)
    Abstract [en]

    This paper investigates the impact of Photovoltaic (PV) systems on the coordination between overcurrent relays in a PV-dominated distribution feeder. The paper shows under what conditions and how significant the PV systems affect the coordination. The paper also proposes a method for assessing the coordination in such feeders. Performance of the proposed methods has been assessed by simulations on a sample distribution feeder.

  • 59.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Mahmood, Farhan
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    HIL simulation of a distribution system reference model2014In: 11th Nordic Conference on Electricity Distribution System Management and Development (NORDAC), Statnett , 2014Conference paper (Refereed)
  • 60.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Mahmood, Farhan
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Specification and implementation of a reference grid for distribution network dynamic studies2014In: 2014 IEEE PES General Meeting | Conference & Exposition, IEEE , 2014, p. 1-5Conference paper (Refereed)
    Abstract [en]

    This paper presents the IDE4L project reference grid model developed to perform real-time hardware-in-the-loop simulations. The simulations will be carried out to study distribution network dynamics and to evaluate the techniques developed in IDE4L project for TSO/DSO interactions. Performance of the grid model is shown by sample simulation results.

  • 61.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Mahmood, Farhan
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Statnett SF, Norway.
    Baudette, Maxime
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Specification, implementation, and hardware-in-the-loop real-time simulation of an active distribution grid2015In: Sustainable Energy, Grids and Networks, ISSN 0284-4354, E-ISSN 2352-4677, Vol. 3Article in journal (Refereed)
    Abstract [en]

    This paper presents the IDE4L project reference grid model developed to serve as a benchmark for studies on distribution grid dynamics within the project. The paper demonstrates a MATLAB/Simulink implementation of the reference grid to be used in real-time hardware-in-the-loop simulations. The simulations will be carried out to study distribution grid dynamics and to evaluate the techniques developed in IDE4L project for TSO/DSO interactions. Performance of the grid model is shown through sample real-time simulation results and a hardware-in-the-loop setup for PMU-based grid monitoring applications.

  • 62.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering and Computer Science (EECS), Electric Power and Energy Systems.
    A SGAM-based architecture for synchrophasor applications facilitating TSO/DSO interactions2017In: 2017 IEEE Power and Energy Society Innovative Smart Grid Technologies Conference, ISGT 2017, IEEE, 2017, article id 8085977Conference paper (Refereed)
    Abstract [en]

    Distribution grid dynamics are becoming increasingly complex due to the transition of these networks from passive to active networks. This transition requires increasing the observability and awareness of the interactions between Transmission and Distribution (T&D) grids, particularly to guarantee adequate operational security. As part of the work carried out in the EU-funded IDE4L project, a specific use case, containing PMU-based monitoring functions, has been defined to support the architecture design of a distribution grid automation system. As a result, the architecture can accommodate for synchrophasor applications that provide key dynamic information extraction and exchange between DSO and TSO. This paper presents the use case and the portion of the IDE4L architecture that accommodates for scenarios that exploit synchrophasors for monitoring applications.

  • 63.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Statnett SF, Norway.
    Multiphase unbalanced power flow and fault analysis of distribution networks with high penetration of inverter-interfaced DERs2015In: 2015 Ieee Jordan Conference on Applied Electrical Engineering and Computing Technologies (Aeect), Institute of Electrical and Electronics Engineers (IEEE), 2015Conference paper (Refereed)
    Abstract [en]

    The traditional power flow and fault analysis methods fail to meet the requirements in both performance and accuracy aspects in the distribution network applications. This is due to the unbalanced multiphase nature of the distribution network and also due to the emerging penetration of renewable generation at the distribution level. This paper proposes a comprehensive method for power flow solution and fault analysis of multiphase unbalanced distribution networks with high penetration of inverter-interfaced DERs. Also, the self-protection scheme employed for the inverter of the DERs is also formulated in the proposed method. Performance of the proposed method has been assessed by simulations on a sample distribution network.

  • 64.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Power flow solution for multiphase unbalanced distribution networks with high penetration of photovoltaics2013In: ELECO 2013 - 8th International Conference on Electrical and Electronics Engineering, IEEE conference proceedings, 2013, p. 167-171Conference paper (Refereed)
    Abstract [en]

    Power flow analysis on a Photovoltaic System (PV)dominated distribution network is rather different than a conventional distribution system. This paper proposes a new three-phase power flow solution for such networks that considers the multiphase unbalanced nature of distribution systems together with different system topologies. Power flow contributions of PVs and different types of loads are also considered. The performance of the proposed method has been assessed by simulations on a sample distribution network.

  • 65.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Dufour, Christian
    Delay-free parallelization for real-time simulation of a large active distribution grid model2016Conference paper (Refereed)
    Abstract [en]

    Parallel computations for real-time simulation of large power system models is conventionally performed by using propagation delays embedded in line models. However, using the same approach to simulate distribution grids results in modelling inaccuracies, due to the short lengths of most distribution feeders. This paper illustrates the drawbacks of the delay-based parallelization technique by assessing the dynamic response of a large active distribution grid model and applies a delay-free parallelization technique (i.e. the State-Space-Nodal algorithm) to address inaccuracy issues inherent to the delay-based approach.

  • 66.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Mahmood, Farhan
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Singh, Ravi Shankar
    KTH.
    Singh, Narender
    KTH.
    Bidadfar, Ali
    KTH.
    Firouzi, Seyed Reza
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Synchrophasor applications facilitating interactions in transmission and distribution operations2017In: 2017 IEEE Manchester PowerTech, Powertech 2017, IEEE, 2017, article id 7980917Conference paper (Refereed)
    Abstract [en]

    Dynamics of distribution grids are becoming more and more complex to analyze due to their transition from passive networks to active ones. This has necessitated the increase of observability between Transmission and Distribution (T&D) grids for operational security and real-time security assessment. This paper presents an overview of the IDE4L project, funded by the European Commission, where a system of PMU data-based monitoring applications has been developed to facilitate TSO-DSO interactions.

  • 67.
    Johannesson, Niclas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Bogodorova, Tetiana
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Vanfretti, Luigi
    Rensselaer Polytech Inst, Elect Comp & Syst Dept, Troy, NY USA.
    Identifying Low-Order Frequency-Dependent Transmission Line Model Parameters2017In: 2017 IEEE PES Innovative Smart Grid Technologies Conference Europe, ISGT-Europe 2017 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2017Conference paper (Refereed)
    Abstract [en]

    This paper describes the modeling and parameter identification of a frequency dependent transmission line model from time-domain data. To achieve this, a single-phase transmission line model was implemented in OpenModelica where the frequency dependent behavior of the line was realized by a series of rational functions using the Modelica language. Next, the developed line model was exported as a Functional Mock-up Unit (FMU). The RaPId toolbox was then used for automated parameter optimization of the model within the FMU that was interfaced to RaPId via the FMI Toolbox for MATLAB. Given a reasonable starting guess of the set of parameters, the toolbox improved the model's response significantly, resulting in a good approximation even though low-order representations were used for the identification process. It was found that even though the process was straightforward, it can be enhanced by exploiting the physical/numerical properties of this specific problem.

  • 68.
    Jonsdottir, Gudrun Margret
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Almas, Muhammad Shoaib
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Baudette, Maxime
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Palsson, Magni
    Landsnet, Reykjavik.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Statnett SF, Norway.
    RT-SIL Performance Analysis of Synchrophasor-and-Active Load-Based Power System Damping Controllers2015In: 2015 IEEE Power & Energy Society General Meeting, IEEE conference proceedings, 2015Conference paper (Refereed)
    Abstract [en]

    The Icelandic power network has transmission constraintsthat often lead to inter-area oscillations. Although conventionalstabilization methods have been applied successfully inthe past, there is potential to exploit large industrial loads toenhance system stability during stringent operation conditions.This paper analyzes the performance of two damping controllers.The controllers can use both synchrophasor signals and localmeasurements as their inputs. Damping is achieved by loadmodulation generated by a phasor-based oscillation signal. Real-Time Software-in-the-Loop testing is performed using Opal-RT’s eMEGAsim Real-Time Simulator to derive hardware andcomputational requirements of a hardware prototype that willbe implemented in the future.

  • 69.
    Khan, Naveed Ahmad
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems. HVDC ABB AB, Dept Syst Studies, Ludvika, Sweden.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Stattnet SF, Oslo, Norway.
    Li, Wei
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Haider, Arif
    KTH, School of Electrical Engineering (EES), Electric Power Systems. HVDC ABB AB, Dept Syst Studies, Ludvika, Sweden.
    Hybrid Nearest Level and open loop control of Modular Multilevel Converters with N+1 and 2N+1 levels2014In: Power Electronics and Applications (EPE'14-ECCE Europe), 2014 16th European Conference on, IEEE conference proceedings, 2014Conference paper (Refereed)
    Abstract [en]

    In this paper a Nearest Level Control with open loop approach for modular multilevel converter (MMC) is proposed. By using open loop approach it is possible to suppress circulating currents without using feedback controllers. Moreover, with this method, both N+1 and 2N+1 levels (N=number of sub-modules) can be obtained at the output voltage. In addition, the voltage quality is improved and the total harmonic distortion is reduced at higher and lower modulation indices by increasing the number of levels up to 2N+1. Simulation results of 3-phase MMC are presented for both 2N+1 and N+1 levels together with the description of proposed Nearest Level Control scheme.

  • 70. Kilter, Jako
    et al.
    Almas, Muhammad Shoaib
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Palu, Ivo
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Statnett.
    Experiences with dynamic PMU compliance testing using standard relay testing equipment2015In: Innovative Smart Grid Technologies Conference (ISGT), 2015 IEEE Power & Energy Society, IEEE conference proceedings, 2015, p. 1-5Conference paper (Refereed)
    Abstract [en]

    This paper presents the results of dynamic compliancetesting of phasor measurement units (PMUs) from threedifferent vendors in a laboratory environment. Testing is performedby providing three phase voltage and current injectionsto the VT and CT inputs of the PMUs through Freja-300stand-alone protection relay test set. Testing is performedaccording to the standard “IEEE C37.242-2013 - IEEE Guidefor Synchronization, Calibration, Testing, and Installation ofPhasor Measurement Units (PMUs) for Power System Protectionand Control”. The paper discusses the test setup, testingprocess, calculation of performance evaluation parametersand overall test results of this project.

  • 71.
    Kuehn, Walter
    et al.
    FH FFM Frankfurt University of Applied Sciences.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Fischer, W.
    PSI AG.
    HVDC System Stability – Analysis, Monitoring and Control in Wide Area Power Systems2014In: CIGRÉ Belgium Conference 2014: INNOVATION FOR SECURE AND EFFICIENT TRANSMISSION GRIDS, CIGRE (International Council on Large Electric Systems), 2014Conference paper (Refereed)
    Abstract [en]

    To a great extent future electric power systems will use HVDC technologies, based on either current sourced or voltage sourced converters (CSC, resp. VSC). Both technologies have their merits and range of applications being connected to technical capabilities, costs and operational properties and performance. Voltage stability is an important issue in classical CSC-based HVDC systems, while voltage stability and angle stability (both transmission angle and rotor angle) are of concern in VSC-HVDC systems. The systems are vulnerable against static instability when the AC connection point at either transmission end becomes weak in a very slow and unobserved manner. These systems may also be subject to transient instability at sudden major changes of grid structure and power flow. The present work intends to provide pertinent information for the development of diagnostic tools for stability assessment and of stabilizing controls relating to HVDC systems.

    The proposed approach is to implement online stability assessment (OSA) based on

    1. Synchrophasors obtained from WAMS for measurement based assessment,

    2. Off-line predictive static and dynamic stability computations from D-2 to near real-time considering uncertainties and the inclusion of detailed HVDC dynamics

    3. Online static and dynamic stability computations utilizing continuous power flow (CPF) and fast dynamic simulations using detailed HVDC models

    This article proposes developments in necessary concepts and methodologies to support different tasks in point 3 above, focusing on angle and voltage stability where VSC-HVDCs are considered. Such methods can enhance operator tools such as those currently being developed in different European projects ([1], [2]). This paper deals primarily with the computation of the voltage sensitivity factor (VSF) of VSC-HVDC systems and the impact of converter controls and controls limitation on VSF curves and stability margins. Sensitivity curves holding for normal undisturbed operation and for credible (n-1)-contingencies are calculated and from these curves thresholds are determined. The study shows the effect of VSC current limitation on the stability margin. The limitation can be imposed either on the reactive current or on the real current. In both cases the limitation reduces the stability margin.

    Transient simulations on the PSCAD/EMTDC simulator are performed with static voltage sources feeding the HVDC converter converters. Comparison of the power dependent voltage and angle curves obtained from these simulations with the static curves obtained from load-flow computations show differences due to control lags. This, however, does not impair the validity of the static curves for normal power ramps and their applicability for undisturbed operation.

    By replacing the static voltage sources with rotating synchronous generators it can be shown that suddenly occurring negative steady state margins must not necessarily lead to instability. Immediate DC power reduction can prevent instability. Required are a sufficiently fast response and an adaptive reduction value. It needs to be further investigated whether and how pre-calculated VSF curves from contingency computations can be used for this task.

  • 72.
    Lavenius, Jan
    et al.
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric power and energy systems. Statnett SF, Norway.
    Taranto, Glauco N.
    Performance Assessment of PMU-Based Estimation Methods of Thevenin Equivalents for Real-Time Voltage Stability Monitoring2015In: 2015 IEEE 15TH INTERNATIONAL CONFERENCE ON ENVIRONMENT AND ELECTRICAL ENGINEERING (IEEE EEEIC 2015), IEEE , 2015, p. 1977-1982Conference paper (Refereed)
    Abstract [en]

    This paper investigates the performance of different methods for calculating the Thevenin equivalent parameters based using only data obtained from real-time synchrophasor measurements. Estimating the parameters from data affected by noisy measurements, transients, and continuously varying power system parameters may yield Thevenin equivalents that do not reflect the actual voltage stability of the system. The paper proposes using a total least squares method to take into account errors in the model from time-varying Thevenin parameters and noise. The paper reviews two different methods for Thevenin equivalent estimation proposed in the literature. The suitability of the three methods described in the paper is tested in case studies, where the performance of the methods are tested with both noise-free and noisy data. The papers also investigates effect of changes in the power consumptions at other buses on the Thevenin parameters seen from the monitored load bus.

  • 73. Laverty, D. M.
    et al.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Al Khatib, Iyad
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Applegreen, Viktor K.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Best, R. J.
    Morrow, D. J.
    The OpenPMU Project: Challenges and perspectives2013In: 2013 IEEE Power and Energy Society General Meeting (PES), IEEE , 2013Conference paper (Refereed)
    Abstract [en]

    The OpenPMU project is a platform for the development of Synchrophasor measurement technology, Phasor Measurement Units (PMU), in an open source manner. The project has now been operating for a number of years and has seen increased adoption at Universities and interest from electrical utilities. The OpenPMU device has recently been tested against the IEEE C37.118 standard and shown to operate within the specification. This paper discusses the OpenPMU project from the perspective of the past two years of experience and evaluates successes and opportunities for improvements in both the OpenPMU device and the philosophy of the design.

  • 74. Laverty, David M.
    et al.
    Best, Robert J.
    Brogan, Paul
    Al Khatib, Iyad
    KTH.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Morrow, D. John
    The OpenPMU Platform for Open-Source Phasor Measurements2013In: IEEE Transactions on Instrumentation and Measurement, ISSN 0018-9456, E-ISSN 1557-9662, Vol. 62, no 4, p. 701-709Article in journal (Refereed)
    Abstract [en]

    OpenPMU is an open platform for the development of phasor measurement unit (PMU) technology. A need has been identified for an open-source alternative to commercial PMU devices tailored to the needs of the university researcher and for enabling the development of new synchrophasor instruments from this foundation. OpenPMU achieves this through open-source hardware design specifications and software source code, allowing duplicates of the OpenPMU to be fabricated under open-source licenses. This paper presents the OpenPMU device based on the Labview development environment. The device is performance tested according to the IEEE C37.118.1 standard. Compatibility with the IEEE C37.118.2 messaging format is achieved through middleware which is readily adaptable to other PMU projects or applications. Improvements have been made to the original design to increase its flexibility. A new modularized architecture for the OpenPMU is presented using an open messaging format which the authors propose is adopted as a platform for PMU research.

  • 75. Laverty, David M.
    et al.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Best, Robert J.
    Morrow, D. John
    Nordström, Lars
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Chenine, Moustafa
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    OpenPMU technology platform for Synchrophasor research applications2012In: Power and Energy Society General Meeting, 2012 IEEE, IEEE conference proceedings, 2012, p. 6345398-Conference paper (Refereed)
    Abstract [en]

    OpenPMU, the Open Source Phasor Measurement Unit, is a platform for the development of Synchrophasor measurement technology in an open source manner. The OpenPMU design modularizes the key components of a Phasor Measurement Unit (PMU) into three subsystems; measurement, phase estimation and telecoms. The advantage to the researcher is that the interfaces between each subsystem are open and human readable, allowing for rapid integration of new work into an existing framework. This allows for new work to be prototyped rapidly and tested in an online environment.

    This paper introduces the OpenPMU technology platform. The subsystem modules and the methods of exchanging data are described. Present work on the platform is discussed and an open invitation to join the development process is extended to all.

  • 76.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    A Synopsis on Synchrophasor Standards and Guides: Measurements, Data Transfer, Concentration, Testing and Implementation RequirementsArticle, review/survey (Refereed)
    Abstract [en]

    In 2009 the US Department of Energy announced the award of $3.4 Billion under the Smart Grid Investment Grant Program. As a result, many operators in North America were awarded grants to deploy a great number PMUs across their service area, with its related communications and IT infrastructure. Outside North America the deployment of new PMUs and related infrastructure also continues to increase.The availability of this new infrastructure will enable the development and implementation of new applications that utilize time-synchronized dynamic measurements. The recently developed synchrophasor standards PC37.118.1 and PC37.118.2, and guides PC37.242, and PC37.244, are relevant for the development of synchrophasor applications by providing a framework to support interoperability and reliability.This section provides a synopsis of the recently developed standards on synchrophasor measurement requirements and data transfer, as well as guides for requirements on phasor data concentration, and synchronization, calibration, testing, and installation of PMUs.

  • 77.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    "All-in-one" test system modelling and simulation for multiple instability scenarios2011Report (Other academic)
  • 78.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Detailed modelling, implementation and simulation of an "all-in-one" stability test system including power system protective devices2012In: Simulation (San Diego, Calif.), ISSN 1569-190X, E-ISSN 1878-1462, Vol. 23, p. 36-59Article in journal (Refereed)
    Abstract [en]

    This paper presents modelling and simulation results for multiple instability scenarios of the "all-in-one" test system. The test system is an alteration of the Bonneville Power Administration test system constructed to capture transient (angle), frequency and voltage instability phenomena, resulting in system collapse, within one system. The paper describes general overview of the test system and its associated individual devices modelling. These modelling are both customized and adapted from the built-in model developed by PowerFactory simulation software. The paper also provides a description of different instabilities that can be reproduced by this self-contained system. One of the case study is demonstrated in detail with the necessary initialization settings for reproducing instability scenario.

  • 79.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Power System Protective Relaying: basic concepts, industrial-grade devices, and communication mechanisms2011Report (Other academic)
  • 80.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Power System Protective Relaying: basic concepts, industrial-grade devices, and communication mechanisms2012In: Standard Handbook for Electrical Engineers / [ed] W. Beaty, McGraw-Hill, 2012, 16Chapter in book (Other academic)
    Abstract [en]

    This chapter provides a survey of protective relaying technology and its associated communications technology used in today’s power transmission systems. A review and comparison between different vendors of protective relays is provided to highlight the industrial state-of-the art implementation of protective functions currently available. The bulk of this chapter is concerned mainly with power system relaying communication. The various protocols and network topologies used for protective relaying purposes are explained. Associated communication standards are outlined. The aim of this part is to provide an introduction and sufficient background on the communication technologies used by protection systems.

  • 81.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    State-of-the-art in the industrial implementation of protective relay functions, communication mechanism and synchronized phasor capabilities for electric power systems protection2012In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 16, no 7, p. 4385-4395Article, review/survey (Refereed)
    Abstract [en]

    Protective systems in electricity delivery networks have a major role to play in the increasing of renewable energy systems, and a broad understanding of their current a future application can aid into better taking them into account for achieving future energy networks that adapt for the incorporation of renewable energy generation sources. This paper provides a survey in the state of the art of protective relaying technology and its associated communications technology used in todays power transmission systems. The paper also provides the fundamental knowledge concerned with power system relaying communications. The unifying theme of this paper is to highlight that the future potential of these devices lies in realizing the possibility of going beyond their traditional application as stand-alone equipments with the single role of acting the last line of defense so that they can be handled with the increment of renewable energy power delivery systems in near future.

  • 82.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Utilizing synchrophasor-based protection systems with VSC-HVDC controls to mitigate voltage instability2012In: 2012 IEEE International Conference on Power System Technology (POWERCON), New York: IEEE , 2012Conference paper (Refereed)
    Abstract [en]

    This article rationalizes the need of coordination between protective systems and VSC-HVDC controls to steer power systems away from voltage instability conditions. The concept of coordination involves the use of feasible communication mechanisms which can be exploited by protection systems to send out a 'protective information set' to an algorithm which will determine preventive, corrective, and protective actions particularly by taking advantage of the availability of VSC-HVDC. This 'protective information set' considers synchrophasor vector processing capabilities which allows for the exploitation of phasor measurements while satisfying protective relaying data transmission and processing requirements. Coordination refers to the ability of the protective systems and VSC-HVDCs to cooperate and to synchronize their actions so that voltage instability can be avoided.

  • 83.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Almas, Muhammad Shoaib
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Voltage Stability Monitoring using Sensitivities Computed from Synchronized Phasor Measurement Data2012In: Power and Energy Society General Meeting, 2012 IEEE, IEEE , 2012, p. 6344838-Conference paper (Refereed)
    Abstract [en]

    Wide-area early warning systems are dependent on synchrophasor data-based applications for providing timely information to operators so that preventive actions can be taken. This article proposes the use of voltage sensitivities computed from syncrhophasor data for voltage stability monitoring, and a visualization approach that can be implemented in wide-area early warning systems. In order to provide reliable information, synchrophasor data must be pre-processed to extract only the useful features embedded in measurements and correct for errors. Hence, this article also addresses the issue of data filtering and correction, and proposes a filtering methodology for robust voltage sensitivity computation. The methodology is developed considering both positive-sequence simulations for methodology development purposes, and real phasor measurement data from a real-time (RT) hardware-in-the-loop (HIL) laboratory for testing the robustness of the developed approach for use in the control room. The results from both approaches are contrasted against each other, the limitations of the positive-sequence simulation ap- proach for developing PMU-data applications are highlighted and the challenges of working with the RT HIL lab are recognized. 

  • 84.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Ghandhari, Mehrdad
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Coordination of protection and VSC-HVDC systems for mitigating cascading failures2010In: 2010 International Conference on Power System Technology: Technological Innovations Making Power Grid Smarter, POWERCON2010, VDE Verlag GmbH, 2010, p. 5666604-Conference paper (Refereed)
    Abstract [en]

    This paper proposes a methodology to coordinate protection relays with a VSC-HVDC link for mitigating the occurrence of cascading failures in stressed power systems. The methodology uses a signal created from an evaluation of the relay's status and simplifications of certain system parameters. This signal is sent to a Central Control Unit (CCU) which determines corrective action in order to reduce the risk of cascading failures.

  • 85.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Gjerde, J. O.
    Lovlund, S.
    PMU-based voltage instability detection through linear regression2013In: 2013 IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC), IEEE Computer Society, 2013, p. 6837108-Conference paper (Refereed)
    Abstract [en]

    This paper proposes a linear regression method using synchrophasor measurement for voltage stability monitoring. The method preprocesses synchrophasor measurements in order to eliminate inconsistencies and errors that embedded in them. This data is then used in the computation of sensitivities suitable for voltage stability monitoring. Some important electrical components such as Over Excitation limiter and OnLoad Tap Changer which create discrete changes affecting in voltage instability have been included to assess the method's performance. Moreover, both process and measurement noises, obtained from real-time hardware-in-the-loop simulation and real PMU measurements from the Norwegian network, respectively, have been applied to validate robustness of the proposed methodology.

  • 86.
    Leelaruji, Rujiroj
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Uhlen, Kjetil
    Gjerde, Jan Ove
    Computing Sensitivities from Synchrophasor Data for Voltage Stability Monitoring and Visualization2015In: International Transactions on Electrical Energy Systems, E-ISSN 2050-7038, Vol. 6, p. 933-947Article in journal (Refereed)
    Abstract [en]

    Wide-area early warning systems are dependent on synchrophasor data-based applications for providing timely information to operators so that preventive actions can be taken. This article proposes the use of voltage sensitivities computed from synchrophasor data for voltage stability monitoring, and a visualization approach that can be implemented in widearea early warning systems. In order to provide reliable information, this article addresses the issue of data filtering and correction, and proposes a filtering methodology for robust voltage sensitivity computation. The methodology is developed considering both positive-sequence simulations for methodology development purposes, and real phasor measurement data from a real-time (RT) hardware-in-the-loop (HIL) laboratory for testing the robustness of the developed approach under more realistic conditions. The limitations of the positive-sequence simulation approach for developing PMU-data applications are highlighted, and the challenges of working with the RT HIL lab are recognized. The proposed sensitivity computation approach have also been applied to a real PMU-data obtained from the Nordic transmission system where results are sustained.

  • 87.
    Li, Wei
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    A PMU-based state estimator considering classic HVDC links under different control modes2015In: Sustainable Energy, Grids and Networks, ISSN 2352-4677, Vol. 2, p. 69-82Article in journal (Refereed)
    Abstract [en]

    This paper aims to develop a PMU-based state estimation algorithm that considers the presence of classic HVDC links operating under different control modes. Thus, hybrid AC/DC grid state estimation becomes feasible. In this algorithm we assume that DC link measurements can be sampled and reported at the same rate as PMU measurements, so that both AC and DC states can be estimated simultaneously in real-time. The estimation algorithm uses synchrophasors in polar coordinates, which allows angle bias detection and correction. In addition, some practical issues for the proposed state estimator are discussed, including observability and measurement redundancy, measurement noise and weightings, and angle bias correction. Finally, study cases using different power system models are carried out to show the state estimator’s performances during both steady conditions and dynamic changes. Relatively small residuals during steady conditions validate accuracy; results during dynamic changes verify the estimator’s reliability.

  • 88.
    Li, Wei
    et al.
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric power and energy systems. Statnett SF, Norway.
    A PMU-based state estimator for networks containing FACTS devices2015In: 2015 IEEE Eindhoven PowerTech, PowerTech 2015, IEEE conference proceedings, 2015Conference paper (Refereed)
    Abstract [en]

    This paper presents a PMU-based state estimation algorithm that considers the presence of flexible AC transmission system (FACTS). The models of FACTS devices, including thyristor- and converter-based devices, are developed and then combined with an AC network model. Considering the characteristics of PMU measurements, the network model for state estimation is separated from the measurements. By applying the nonlinear weighted least squares (WLS) algorithm, a PMU-based state estimator can estimate the states of an AC system and its embedded FACTS devices simultaneously. To validate the algorithm, simulation studies for a 9-bus system are performed.

  • 89.
    Li, Wei
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Statnett SF, Research and Development, Oslo, Norway.
    A PMU-Based State Estimator For Networks Containing VSC-HVDC links2015In: 2015 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, IEEE , 2015Conference paper (Refereed)
    Abstract [en]

    This paper presents a PMU-based state estimation algorithm that considers the presence of voltage source converter-based high voltage direct current (VSC-HVDC) links. The network model of a VSC-HVDC link with its control modes is developed and then combined with an AC model to accomplish a hybrid AC/DC network model. The measurement model in this algorithm considers the properties of PMU measurements, thus separating the network model with measurements. Additionally, DC link measurements are assumed to be sampled synchronously, time-stamped and reported at the same rate as PMU measurements. Then, by applying the nonlinear weighted least squares (WLS) algorithm, a PMU-based state estimator can solve for both AC and DC states simultaneously. To validate the algorithm, a simulation study for a 6-bus hybrid AC/DC test system is shown in this paper.

  • 90.
    Li, Wei
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Inclusion of Classic HVDC links in a PMU-based state estimator2014In: PES General Meeting | Conference & Exposition, 2014 IEEE, IEEE conference proceedings, 2014, p. 1-5Conference paper (Refereed)
    Abstract [en]

    This article presents a PMU-based state estimator algorithm that considers the presence of classic HVDC links. A hybrid AC/DC network model is developed to combine the AC network and DC links. The algorithm assumes that DC link measurements can be sampled synchronously, are time-stamped and reported at the same rate as PMU measurements. Then, by applying the weighted least squares algorithm, a linear state estimator can solve for both AC and DC states simultaneously. To validate the algorithm, a state estimation model is built for a 9-bus and the KTH-Nordic 32 systems, for both AC-only and hybrid AC/DC networks. In addition, the influence of losing DC measurements and effects of measurement noise on the state estimator are briefly discussed.

  • 91.
    Li, Wei
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Chompoobutrgool, Yuwa
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Development and implementation of hydro turbine and governor models in a free and open source software package2012In: Simulation (San Diego, Calif.), ISSN 1569-190X, E-ISSN 1878-1462, Vol. 24, p. 84-102Article in journal (Refereed)
    Abstract [en]

    This article studies accurate and detailed hydro turbine and governor models, and implements these models in Power System Analysis Toolbox (PSAT)-a free and open source software. The implementation of these models in PSAT is approached using a general methodology, which is described in detail. To evaluate the performances of the developed hydro turbine and governor models, simulation studies are carried out on test systems of different scales, from a single-machine infinite-bus (SMIB) system to a larger system which includes 20 generators. Further more, transient stability analysis and small signal stability analysis are carried out to assess the performance of the implemented models.

  • 92.
    Li, Wei
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Farrokhabadi, Mostafa
    Modeling of Custom Hydro Turbine and Governor Models for Real-Time Simulation2012In: 2012 IEEE COMPENG 2012: Workshop on Complexity in Engineering, IEEE conference proceedings, 2012, p. 83-88Conference paper (Refereed)
    Abstract [en]

    This article develops three different hydro turbineand governor (HTG) models to fulfill adequate modeling requirements for the representation of hydro power generation inthe Nordic grid. To validate the performance of the developed models, both off-line and real-time simulation studies on a single machine infinite-bus (SMIB) system are carried out. Apart from SMIB system, real-time simulations are also executed for alarger scale power system—the IEEE Reliability Test System1996 (IEEE RTS 96) in this article to determine the models’dynamic performance in larger and more complex networks. Inaddition, how to properly transfer an off-line models developedin SimPowerSystems (SPS) for real-time simulation in RT-LAB is addressed; including valuable experiences obtained from these simulation exercises.

  • 93.
    Mahmood, Farhan
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems. KTH The Royal Institute of Technology.
    Hooshyar, Hossein
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems. KTH The Royal Institute of Technology.
    Lavenius, Jan
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Lund, Per
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems. KTH The Royal Institute of Technology.
    Real-time reduced steady state model synthesis of active distribution networks using PMU measurements2016In: IEEE Transactions on Power Delivery, ISSN 0885-8977, E-ISSN 1937-4208, Vol. 32, no 1, p. 546-555Article in journal (Refereed)
    Abstract [en]

    Due to the increase of generation sources in distribution networks, it is becoming more and more complex to develop and maintain models of these networks. Network operators need to determine reduced models of distribution networks to be used in grid management functions. This paper presents a novel method that synthesizes steady state models of unbalanced active distribution networks by the use of dynamic measurements (time series) from PMUs. As PMU measurements may contain errors and bad data, the paper presents the application of a Kalman Filter technique for real-time data processing. In addition, PMU data captures the power system’s response at different time-scales, which are generated by different types of power system events; the presented Kalman Filter has been improved to extract the steady state component of the PMU measurements to be fed to the steady state model synthesis application. Performance of the proposed methods has been assessed by real-time hardware-in-the-loop simulations on a sample distribution network.

  • 94.
    Mahmood, Farhan
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Hooshyar, Hossein
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Statnett SF, Norway.
    A method for extracting steady state components from syncrophasor data using Kalman filters2015In: 2015 IEEE 15th International Conference on Environment and Electrical Engineering, EEEIC 2015 - Conference Proceedings, IEEE , 2015, p. 1498-1503Conference paper (Refereed)
    Abstract [en]

    Data from Phasor Measurement Units (PMUs) may be exploited to provide steady state information to the applications which require it. Raw PMU data is polluted with noise and cannot be directly fed to applications without adequate processing. This paper presents a method to extract steady state components from Syncrophasor data using Kalman Filters (KF). This method is capable of reducing the noise, to compensate for missing data and filtering of outliers in signals. The Residue in each KF iteration is computed. The measurement noise covariance matrix R is calculated by computing the variance of residue using rolling windows. The performance of presented method is evaluated by using PMU data generated from a Hardware-In-the-Loop (HIL) experimental setup.

  • 95.
    Mahmood, Farhan
    et al.
    KTH, School of Electrical Engineering (EES), Electric power and energy systems. KTH The Royal Institute of Technology.
    Hooshyar, Hossein
    KTH, School of Electrical Engineering (EES), Electric power and energy systems. KTH The Royal Institute of Technology.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric power and energy systems. KTH The Royal Institute of Technology.
    Extracting Steady State Components from Synchrophasor Data Using Kalman Filters2016In: Energies, ISSN 1996-1073, E-ISSN 1996-1073, Vol. 9Article in journal (Refereed)
    Abstract [en]

    Data from phasor measurement units (PMUs) may be exploited to provide steady state information to the applications which require it. As PMU measurements may contain errors and missing data, the paper presents the application of a Kalman Filter technique for real-time data processing. PMU data captures the power system’s response at different time-scales, which are generated by different types of power system events; the presented Kalman Filter methods have been applied to extract the steady state components of PMU measurements that can be fed to steady state applications. Two KF-based methods have been proposed, i.e., a windowing-based KF method and “the modified KF”. Both methods are capable of reducing noise, compensating for missing data and filtering outliers from input PMU signals. A comparison of proposed methods has been carried out using the PMU data generated from a hardware-in-the-loop (HIL) experimental setup. In addition, a performance analysis of the proposed methods is performed using an evaluation metric.

  • 96.
    Mahmood, Farhan
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Hooshyar, Hossein
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Sensitivity Analysis of a PMU-Fed Steady State Model Synthesis Method for Active Distribution Networks2017In: 2017 IEEE POWER & ENERGY SOCIETY GENERAL MEETING, IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    The purpose of this paper is to carry outsensitivityanalysisofa method that performssteady state model synthesis(SSMS)of active distribution networksusing SyncrophasorMeasurements.An extended version of the Total Vector Error (TVE) is used as a metric to evaluate how sensitive the output of the SSMS method is to the changesinthe inputsto the method.Location of PMUs in the system,system operating point,and occurrence of different disturbancesareconsideredas the input tothe SSMS method. The sensitivity analysis is performed through several case studieseach containing changesin one of the inputs.

  • 97.
    Mahmood, Farhan
    et al.
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric power and energy systems. Statnett SF, Norway.
    Hooshyar, Hossein
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Detailed modeling of a photovoltaic system for distribution networks2014Conference paper (Refereed)
  • 98.
    Mahmood, Farhan
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Hooshyar, Hossein
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Modeling of a detailed photovoltaic generation system for EMT-type simulation2014In: ENERGYCON 2014 - IEEE International Energy Conference, IEEE Computer Society, 2014, p. 916-921Conference paper (Refereed)
    Abstract [en]

    This article presents a detailed three-phase grid connected PV model which includes important control systems required for EMT-type simulation. A one diode model for the PV array is used to simulate environmental constraints such as solar irradiation. A detailed control system including dc voltage control, inner current control, MPPT and PWM control are implemented in order to simulate the model during steady state and dynamic conditions. The PV model is merged with a simple distribution network to investigate the PV's interaction with the AC grid. Several simulation scenarios are presented in order to validate the performance of the model.

  • 99. Mahseredjian, Jean
    et al.