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  • 301.
    Hamon, Camille
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Review Paper on Wind Power Impact on Operation of Reserves2011In: 2011 8th International Conference on the European Energy Market, EEM 11, 2011, p. 895-903Conference paper (Refereed)
    Abstract [en]

    This paper reviews studies concerning new challengesfor European transmission system operators (TSOs) when operating primary, secondary and tertiary reserves in a systemwith large amounts of wind power. The review adopts three perspectives. First, the impact on existing markets is discussed and it is shown that need for additional reserve requirements does not necessarily mean need for new reserve capacity. Secondly, possible designs of improved load-frequency control schemes are presented.The proposed solutions exhibit a trend towards market-based procurement mechanisms and automation of reserve operations. Finally, participation of wind power in load-frequency control is examined. Technical designs are presented for participation inprimary control.

  • 302. Hannele, Holttinen
    et al.
    Meibom, Peter
    Orths, Antje
    Lange, Bernhard
    O’Malley, Mark
    Tande, John Olav
    Estanqueiro, Ana
    Gomez, Emilio
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Strbac, Goran
    Smith, J. Charles
    van Hulle, Frans
    Impacts of large amounts of wind power on design and operation of power systems, results of IEA collaboration2009In: 8th International Workshop on LargeScale Integration of Wind Power into Power Systems as well as on Transmission Networks of Offshore Wind Farms, 2009Conference paper (Refereed)
    Abstract [en]

    IEA WIND R&D Task 25 on “Design and Operation of Power Systems with Large Amounts of Wind Power” collects and shares information on wind power impacts on power systems, with analyses and guidelines on methodologies. There are dozens of studies made and ongoing related to wind integration, however, the results are not easy to compare. In the stateoftheart report (October, 2007), and the final report of the 3 years period (July, 2009) the most relevant wind power grid integration studies have been analysed especially regarding methodologies and input data. Several issues that impact on the amount of wind power that can be integrated have been identified. Large balancing areas and aggregation benefits of large areas help in reducing the variability and forecast errors of wind power as well as help in pooling more cost effective balancing resources. System operation and functioning electricity markets at less than dayahead time scales help reduce forecast errors of wind power. Transmission is the key to aggregation benefits, electricity markets and larger balancing areas. Best practices in wind integration studies are described. There is also benefit when adding wind power to power systems: it reduces the total operating costs and emissions as wind replaces fossil fuels and this should be highlighted more in future studies.

  • 303.
    Harnefors, Lennart
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems. ABB Corporate Research, Västerås, Sweden .
    Yepes, Alejandro G.
    Vidal, Ana
    Doval-Gandoy, Jesus
    Passivity-Based Controller Design of Grid-Connected VSCs for Prevention of Electrical Resonance Instability2015In: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, Vol. 62, no 2, p. 702-710Article in journal (Refereed)
    Abstract [en]

    The time delay in the current control loop of a grid-connected voltage-source converter (VSC) may cause destabilization of electrical resonances in the grid or in the VSC's input filter. Instability is prevented if the input admittance of the VSC can be made passive. This paper presents an analytical controller design method for obtaining passivity. The method is equally applicable to single-and three-phase systems, i.e., in the latter case, for both stationary-and synchronous-frame control. Simulations and experiments verify the theoretical results.

  • 304.
    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.

  • 305.
    Hasan, Rokibul
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Development, calibration and simulation of generic VSC-HVDC high level controls for DC grid Simulation2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Energy security concerns and the environmental impact of conventional power generation

    sources has led to an increase in renewable energy penetration worldwide. Power transmission

    from remote generation sites to consumers over long distance is most efficient using high

    voltage direct transmission lines. Therefore, long distance power transmission and the

    integration of power generated by renewable energy resources are considered as key aspects

    in the development of sustainable energy systems capable of secure and stable electric power

    supply.

    Voltage source converter based high voltage direct current (VSC-HVDC) long distance power

    transmission lines are needed to incorporate renewable energy sources to the grid. The

    significance of the research work in this field is obvious, however, advances in the area are

    detracted because of the lack of available VSC-HVDC system models. The purpose of this

    thesis is to provide generic models of VSC-HVDC controls and meshed networks. This thesis

    studies VSC-HVDC control systems and improves high level controls for the VSC. A point to

    point and four terminal VSC-HVDC systems are modeled in MATLAB/Simulink. Both

    offline and real-time simulation models are developed. The controllers are tuned and then

    tested in the developed test systems with several test cases through offline simulations in

    MATLAB/Simulink. All the models are modified and transferred to Opal-

    RT’s real time

    targets and simulations are carried out for several test cases. Improved controller simulation

    results along with results from the conventional controllers are contrasted.

  • 306.
    Hassanpoor, Arman
    et al.
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Norrga, Staffan
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Nee, Hans-Peter
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Ängquist, Lennart
    KTH, School of Electrical Engineering (EES), Electrical Energy Conversion.
    Evaluation of different carrier-based PWM methods for modular multilevel converters for HVDC application2012In: IECON 2012 - 38th Annual Conference on IEEE Industrial Electronics Society, IEEE , 2012, p. 388-393Conference paper (Refereed)
    Abstract [en]

    The outstanding features of modular multilevel converters (M2C) make it attractive for high voltage direct current (HVDC) systems. In order to achieve high efficiency in HVDC converter stations, the switching frequency and the capacitor voltage ripple of the converter should be minimized. A suitable modulation algorithm should achieve an optimal tradeoff between these two requirements. This paper evaluates different carrier-based PWM algorithms and discusses the most challenging technical aspects of an efficient M2C. It is observed that decoupling the waveform synthesis from the selection of which cell to switch at each instant has beneficial impact on operation performance. The evaluation is done by time-domain simulation considering a grid connected, three-phase M2C converter and an advanced control system. Results of this study can be used for implementing more economical HVDC converters.

  • 307.
    Hedlund, Hands
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Dimensionering av reservkraftsaggregat för kopplings- och transformatorstationer2009Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Questions raised on the basis of this work are, witch loads are there at the stations, how big are the loads, are there nonlinear loads, are there motor loads with high starting currents, how do the rectifiers interact with batteries? The diesel unit starts about 10 minutes after a regional or national interference in a transformer station. The station’s DC power system is then fed during that time from batteries. The question of how rectifiers interact with the batteries is of importance because rectifiers are large instantaneous loads after some discharge of the battery.

    The loads that occur at the stations is heat in the control building, server room cooling, lighting inside and out, cooling the reactor, electrical engines, PTO, heating for high voltage circuit breakers etc. These loads will not be active simultaneously and each will not consume a maximum power all the time. This means that you must find the tools to handle these loads. The present report presents developed load factor of the various components involved.

    A diesel generator model has been developed consisting of a diesel engine coupled to a synchronous generator in operation through two control systems to regulate voltage and rotor speed. Based on measurements at stations with diesel power, steering systems have been modified for the unit to conform to reality as much as possible. Based on the model, simulations have been done to see what the start-up currents from the motor loads have for effect of voltage and frequency with different sizes of diesel generators.

    Calculations have been made to examine the size of short circuit currents in different levels of the station's electrical system. This is to analyse if the fuses can be broken if necessary.

    Duration curves of station loads are presented from various measurements to get a better picture of how the total load actually behaves.

    From there, appropriate diesel unit size is developed and also EENS and LOLP are calculated.

    Duration curves are also simulated based on the load factors that have been worked out and the actual duration curves made. The idea is that the simulated duration curve should conform to reality for engineers to be able to examine the probability of power shortages in emergency use in a planned station.

    The results of the report are guidelines and instructions for an easy way to make good diesel units dimensioning of a reserve and emergency operation.

    It turned out that the rectifiers have to be started in sequence to avoid to large fast charge cycles. Also a safety factor is multiplied to the rectifier continuous operation to avoid harmonics in the system at emergency operations.

    Start currents from reactors cooling system must be analyzed separately and the generator requirements for those is determined from calculations found in the guide. It also turned out to a certain station can get by with a diesel unit at 100kVA instead of the current 400kVA.

  • 308.
    Hejri, Mohammad
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Giua, A.
    Hybrid modeling and control of switching DC-DC converters via MLD systems2011In: IEEE Int. Conf. Autom. Sci. Eng., 2011, p. 714-719Conference paper (Refereed)
    Abstract [en]

    Modeling and control of DC-DC converters is a non trivial problem in power electronics. Such converters exhibit both autonomous and non-autonomous switching phenomena which are commonly modeled by general classes of hybrid systems. This paper addresses the modeling and control of a DC-DC buck converter via Mixed Logical Dynamical (MLD) systems and hybrid predictive control based on Mixed Integer Quadratic Programming. The main contribution of the paper is the novel concept of Forward MLD as opposed to the classical modeling approach that we call Backward MLD. The advantage of the proposed method is to introduce a prediction of the continuous behavior at a the switching instant. This results in a more accurate model and allowing to reduce by one step the prediction horizon necessary to compute the optimal control. The proposed technique reduces the complexity of the resulting MIQP program. The transient and steady state performances of the closed-loop control system over a wide range of operating points show satisfactory operation of the proposed modeling and control scheme.

  • 309. Hejri, Mohammad
    et al.
    Mokhtari, Hossein
    Azizian, Mohammad Reza
    Ghandhari, Mehrdad
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    On the Parameter Extraction of a Five-Parameter Double-Diode Model of Photovoltaic Cells and Modules2014In: IEEE Journal of Photovoltaics, ISSN 2156-3381, Vol. 4, no 3, p. 915-923Article in journal (Refereed)
    Abstract [en]

    The main contribution of this paper is to present a new set of approximate analytical solutions for the parameters of a photovoltaic (PV) five-parameter double-diode model that can be used as initial values for the numerical solutions based on the Newton-Raphson method. The proposed formulations are developed based on only the limited information given by the PV manufacturers, i.e., the open-circuit voltage (V-oc), the short circuit current (I-sc), and the current and voltage at the maximum power point (I-m and V-m). Compared with the existing techniques that require the entire experimental I-V curve or additional information such as the slope of the I-V curves of the open circuit and the short circuit points, the proposed technique is quite independent of these additional data, and, it is therefore, a low cost and fast parameter extraction method. The accuracy of the theoretical I-V curves is evaluated through the comparison of the simulation results and experimental data. The results of the application of the proposed technique to different PV modules show the accuracy and validity of the proposed analytical-numerical method.

  • 310.
    Hellstrand, Erik
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Wide Area System Protection2007Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 311.
    Henry, Alexandre
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Modeling and dynamic analysis of offshore wind farms in France: Impact on power system stability2011Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
  • 312.
    Henry, Jerome
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    TOWARDS USING AN ACTIVE / REACTIVE SIMULATION TOOL FOR GRID DEVELOPMENT STUDIES2008Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    As part of the KTH civil engineer degree, this final degree project was done at RTE, the company responsible for operating, maintaining and developing the French electricity grid, within the group responsible for the 400 kV grid and interconnection studies.

    After studying how adding production influences flows in a neighboring area, in order to get familiar with simulation tools, the next step was to work on RTE’s grid model, aiming at updating it with reactive data. Moreover, another task has been to analyze, understand and solve problems with the group’s active-reactive simulation tool.

    During these months, methodologies were developed to construct more accurate reactive data assumptions for 2015. Then, some methods proved being solid enough to quickly obtain valid and useful data, some others have not. Finally, a solution was also developed, allowing the group’s engineer to overcome errors in how power balance is treated within the active-reactive simulation tool. The method should be implemented in an upcoming release of the tool.

    Of course, considerable knowledge on how a grid works and is operated was acquired by working at RTE, and furthermore it also helped to understand a company’s daily organization and all what it implies.

  • 313.
    Hernandez-Solis, Augusto
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Carlsson, Fredrik
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Diagnosis of Submersible Centrifugal Pumps: A Motor Current and Power Signature Approaches2010In: EPE Journal: European Power Electronics and Drives Journal, ISSN 0939-8368, Vol. 20, no 1, p. 58-64Article in journal (Refereed)
    Abstract [en]

    Early detection of undesired conditions during the operation of a centrifugal pump has become very important in order to avoid consequential damages, thus outage time and repair costs can be reduced. Faults in centrifugal pumps can be caused through the changes inflow conditions such as cavitation, that lead to impeller degradation and ultimately to the deterioration and breakdown of pump material. In this project the diagnosis of a submersible centrifugal pump is performed, proving that it is possible to detect not only when cavitation is present but also when it starts using the current and power signature analyses of its motor drive as diagnostic tools. Experimental currents and voltages are measured for different operating points of the pump in order to study the correlation between the cavitation phenomena and the power of the motor.

  • 314.
    Hesamzadeh, Mohammad
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    The economic analysis of transmission investment policies2011In: 2011 8th International Conference on the European Energy Market, EEM 11, Zagreb, 2011, p. 501-506Conference paper (Refereed)
    Abstract [en]

    This paper defines and discusses three types of benefits for economic analysis of transmission investment policies. These benefits are termed (1) The Efficiency Benefit, (2) The Static Competition Benefit, and (3) The Dynamic Competition Benefit. To provide more insights to these benefits, an example system is studied. The results show that a transmission network service provider can and should use the transmission investment policies to improve the competition (static and dynamic) in the supply electricity industry. Further research is necessary to model the static and dynamic competition benefit in the process of transmission expansion planning.

  • 315.
    Hesamzadeh, Mohammad
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Amelin, Mikael
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    A generation expansion planning model of a strategic electricity generating firm2011In: Power and Energy Society General Meeting, 2011 IEEE, IEEE , 2011, p. 1-7Conference paper (Refereed)
    Abstract [en]

    This paper derives a mathematical structure for investment decisions of a profit-maximising and strategic producer in liberalised electricity markets. The paper assumes a Cournot producer in an energy market with nodal pricing regime. The Cournot producer is assumed to have revenue from selling energy to the pool. The investment problem of the strategic producer is modelled through a leader-follower game in applied mathematics. The leader is the strategic producer seeking the optimal mix of its investment technologies and the follower is a stochastic estimator. The stochastic estimator forecasts the reactions of other producers in the market in response to the investment decisions of the producer in question. The stochastic estimator takes the investment decisions of the producer and it calculates the stochastic prices. The mathematical structure is a stochastic linear bilevel programming problem. This problem is reformulated as a stochastic MILP problem which can be solved using the commercially available software packages. Finally, the developed mathematical structure is applied to a six-node example system to highlight the strengths of the whole approach.

  • 316.
    Hesamzadeh, Mohammad
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Amelin, Mikael
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Assessment of the market power cost in liberalised electricity markets using SMPI, PMPI, and NMPI indicators2011In: Energy Market (EEM), 2011 8th International Conference on the European, 2011, p. 844-848Conference paper (Refereed)
    Abstract [en]

    Market power analysis is one of the major issues facing regulators of wholesale electricity markets. The exercise of market power both distorts wholesale price signals and reduces the efficiency of the operation of and investment in the wholesale electricity market. This paper deals with a systematic way for quantifying and visualising market power. The paper first proposes three indicators termed the System Market Power Indicator, SMPI, the Producer Market Power Indicator, PMPI, and the Nodal Market Power Indicator, NMPI. The game theory in applied mathematics and the concept of social welfare in microeconomics are used in formulating of these indicators. The SMPI finds the total cost of exercising market power by generating companies. The contribution of a specific generating company in system market power is calculated using the PMPI. The NMPI finds the contribution of each power system node in the total market power cost. Then after, a colour contour map is used to visualise the exercise of market power and its associated cost. The proposed market power indicators are applied to the modified Garver’s example system to show the promising performance of these indicators.

  • 317.
    Hesamzadeh, Mohammad
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Amelin, Mikael
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Modelling market power cost in the assessment of transmission investment policies2011In: PowerTech, 2011 IEEE Trondheim, 2011, p. 1-6Conference paper (Refereed)
    Abstract [en]

    This paper develops a mathematical tool for modelling market power cost in transmission expansion planning decisions. The mathematical modelling is based on the game theory in applied mathematics and the concept of social welfare in microeconomics. We assume the generating companies as Cournot players and the Transmission System Operators as a regulated social transmission planner. To tackle the multiple Nash equilibria problem, the concept of worst-Nash equilibrium is defined and mathematically formulated. The developed mathematical structure is a mixed-integer linear programming problem. This closed form mathematical structure can be solved efficiently using the available computational packages.

  • 318.
    Hesamzadeh, Mohammad
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Biggar, D. R.
    Hosseinzadeh, N.
    Wolfs, P. J.
    Transmission augmentation with mathematical modeling of market power and strategic generation expansion - Part I2011In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, ISSN 0885-8950, Vol. 26, no 4, p. 2040-2048Article in journal (Refereed)
    Abstract [en]

    This paper proposes a new mathematical structure for evaluating the economic efficiency of transmission investment in a liberalized electricity market. The problem faced by a transmission planner is modeled using the concept of social welfare from economics. The behavior of generators is modeled as the Nash equilibrium of a strategic game. The Nash solution concept is reformulated as an optimization problem and a new concept - the Stackelberg-Worst Nash equilibrium - is introduced to resolve the problem of multiple equilibria. The proposed structure can take into account the effects of a transmission augmentation on both market power and strategic generation investment. Accordingly, the optimal solution to the transmission planner's problem may allow additional transmission capacity both to reduce market power and to defer investment in the generation sector. A methodology is proposed to decompose the benefits of a transmission augmentation policy into the efficiency benefit, competition benefit, and the deferral benefit. The outcomes of the proposed approach to transmission augmentation are compared with the outcomes of two other approaches to transmission augmentation using a simple three-bus network example.

  • 319.
    Hesamzadeh, Mohammad
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Biggar, D. R.
    Hosseinzadeh, N.
    Wolfs, P. J.
    Transmission augmentation with mathematical modeling of market power and strategic generation expansion - Part II2011In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, ISSN 0885-8950, Vol. 26, no 4, p. 2049-2057Article in journal (Refereed)
    Abstract [en]

    This paper describes a numerical approach to solving the mathematical structure proposed in the first part of this paper. The numerical approach employs a standard genetic algorithm (GA) embedded with an island parallel genetic algorithm (IPGA). The GA handles the decision variables of the transmission network service provider, (TNSP) while the IPGA module finds the equilibrium of the electricity market. The IPGA module uses the concept of parallel islands with limited communication. The islands evolve in parallel and communicate with each other at a specific rate and frequency. The communication pattern helps the IPGA module to spread the best-found genes across all isolated islands. The isolated evolution removes the fitness pressure of the already-found optima from the chromosomes in other islands. A stability operator has been developed which detects stabilized islands and through a strong mutation process re-employs them in exploring the search space. To improve the efficiency of the proposed numerical solution, two high performance computing (HPC) techniques are used - shared-memory architecture and distributed-memory architecture. The application of the proposed approach to the assessment of transmission augmentation is illustrated using an IEEE 14-bus example system.

  • 320.
    Hesamzadeh, Mohammad
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Hosseinzadeh, N.
    Wolfs, P. J.
    A bi-level formulation of transmission planning problem in liberalised electricity markets2011In: Australian Journal of Electrical and Electronics Engineering, ISSN 1448-837X, Vol. 8, no 2, p. 119-128Article in journal (Refereed)
    Abstract [en]

    This paper sets out an alternative formulation for transmission planning in liberalised electricity markets. The formulation follows the concept of the leader-follower game in applied mathematics. In this neio formulation, the transmission network service provider acts as the leader of the game and the electricity market operator acts as the follower of the game. Using this new formulation, the transmission network service provider can measure the impact of additional transmission capacity on nodal (or regional) market prices. This allows the transmission network service provider to implicitly model the competitive effect of additional transmission capacity in its investment decisions. A metric termed L-Shape Area is developed to measure the deviation of market prices from the competitive ones. The alternative formulation is a bi-level optimisation problem. To solve this problem, the inner optimisation problem is replaced by its equivalent Karush-KuhnTucker optimality conditions. The result is a non-linear programming problem that is solved using a gradient search method. IEEE 14-bus example system is used for numerical studies.

  • 321.
    Hesamzadeh, Mohammad
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Hosseinzadeh, N.
    Wolfs, P. J.
    Transmission augmentation with the competition benefit modelling of additional transmission capacity2011In: Australian Journal of Electrical and Electronics Engineering, ISSN 1448-837X, Vol. 8, no 2, p. 105-118Article in journal (Refereed)
    Abstract [en]

    Additional transmission capacity can improve the performance of the electricity market from two perspectives: firstly, efficiency benefit in terms of improving the social welfare of the electricity industry; and, secondly, competition benefit that leads to increasing competition among generating companies. This paper introduces an algorithm to model both the efficiency and competition benefits of additional transmission capacity in the process of transmission augmentation. The economic mathematical model is developed based on game theory in applied mathematics and the concept of social welfare in microeconomics. Transmission network service providers, generating companies and market management companies are placed in different stages of the developed model. The multiple Nash equilibria problem is tackled through the introduced concept of worst-Nash equilibrium. A numerical algorithm is designed to solve the developed model. The Garver's and IEEE 14-bus example systems are carefully modified to suit the purpose of this study; the former is used for conceptual evaluation of the algorithm, and the latter for testing the developed numerical solution. The results show that the proposed approach can improve the efficiency of the electricity market and reduce the market power in the generation sector using the transmission augmentation policies.

  • 322.
    Hesamzadeh, Mohammad R.
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Biggar, D. R.
    Computation of extremal-nash equilibria in a wholesale power market using a single-stage MILP2012In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 27, no 3, p. 1706-1707Article in journal (Refereed)
    Abstract [en]

    This letter proposes a new approach to the computation of extremal-Nash equilibria in a wholesale power market with transmission constraints. The approach uses linearization techniques to formulate the extremal-Nash equilibrium problem as a single-stage mixed-integer linear programming problem which can be solved with standard software. Through the introduced concept of extremal-Nash equilibria, the derived structure can efficiently locate all Nash equilibria of the game. We show that this approach offers significant performance improvements over existing approaches to computing Nash equilibria.

  • 323.
    Hesamzadeh, Mohammad R.
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Biggar, Darryl R.
    Hosseinzadeh, N.
    The Application of High Performance Computing Technologies in Studying the Strategic Behaviours of Electricity Market Players2011In: Advances in Energy Research, New York: Nova Science Publishers, Inc., 2011, p. 507-523Chapter in book (Refereed)
  • 324.
    Hesamzadeh, Mohammad R.
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Biggar, Darryl R.
    Hosseinzadeh, N.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Transmission Investment in Liberalized Electricity Markets in the Context of Market Power2011In: Advances in Energy Research, New York: Nova Science Publishers, Inc., 2011, p. 185-228Chapter in book (Refereed)
  • 325.
    Hesamzadeh, Mohammad R.
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Biggar, Darryl R.
    Hosseinzadeh, Nasser
    The TC-PSI indicator for forecasting the potential for market power in wholesale electricity markets2011In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 39, no 10, p. 5988-5998Article in journal (Refereed)
    Abstract [en]

    Wholesale electricity market regulators have long sought a simple, reliable, transparent indicator of the likely impact of wholesale market developments on the exercise of market power. Conventional indicators, such as the Pivotal Supplier Indicator (PSI) and the Residual Supply Index (RSI) cannot be extended to apply to meshed transmission networks, especially when generating companies hold a portfolio of generating units at different locations on the network. This paper proposes a generalisation of these standard measures termed the "Transmission-Constrained Pivotal Supplier Indicator (IC-PSI)". The TC-PSI of a generating company is defined as the maximum must-run generation for any subset of generating plant while allowing for strategic operation of other plant in the portfolio. We illustrate the use of the TC-PSI using a five-node model of the Australian NEM.

  • 326.
    Hesamzadeh, Mohammad R.
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Rahman, A K M Zami-Ur
    KTH, School of Information and Communication Technology (ICT), Electronic Systems.
    Amelin, Mikael
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    The Probabilistic TC-PSI for Studying Market Power2011Conference paper (Refereed)
    Abstract [en]

    It is widely recognized that wholesale electricity markets tend to be prone to the exercise of market power. The exercise of market power has antisocial impacts in the liberalised electricity markets. It results in inefficient short-term dispatch outcomes, and affects the efficiency of longer-term generation investment decisions. And thus, it results in power price rises and substantial wealth transfers between electricity customers and generators. Electricity market regulators around the world tend to be interested in mechanisms for predicting marker power ex ante and detecting and controlling the exercise of market power ex post. The common indices of ex ante market power indicators however, mostly disregard transmission constraints, variation of wind farms' capacities, and dynamics of electric power systems. This paper carries out a probabilistic study of market power using an index termed Probabilistic Transmission-Constrained Pivotal Supplier Indicator (Probabilistic TC-PSI). Two probabilistic approaches (a) Monte Carlo Method (MCM), and (b) Two-Point Estimation Method (T-PEM) are employed in the probabilistic study and then compared.

  • 327.
    Hesamzadeh, Mohammad Reza
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Biggar, Darryl Ross
    Merger Analysis in Wholesale Power Markets Using the Equilibria-Band Methodology2013In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 28, no 2, p. 819-827Article in journal (Refereed)
    Abstract [en]

    Around the world, electricity market regulators and competition authorities are struggling to find ways to reliably assess the likely market impact of mergers of generators. Conventional indicators of market power fail to capture key aspects of the exercise of market power in wholesale electricity markets. On the other hand, full-scale computation of Nash equilibria has historically been time consuming, non-transparent, and typically results in multiple Nash equilibria. In this paper we propose two methodological advances: an efficient approach to computing extremal-Nash equilibria in a wholesale power market with market power and the application of this approach in the assessment of wholesale market mergers. The extremal-Nash equilibria are those equilibria which have the highest or the lowest social cost to the society. The resulting formulation is a Mixed Integer Linear Program which efficiently finds the full set of extremal-Nash equilibria. The continuum of these extremal-Nash equilibria over a range of demand conditions describes the upper and lower envelopes of the Equilibria Band. To illustrate the advantages of the proposed approach, two case studies are explored, involving the New South Wales region of the Australian National Electricity Market, on the one hand, and the IEEE 14-Bus Test System, on the other.

  • 328.
    Hesamzadeh, Mohammad Reza
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Galland, Olga
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Biggar, D. R.
    Short-run economic dispatch with mathematical modelling of the adjustment cost2014In: International Journal of Electrical Power & Energy Systems, ISSN 0142-0615, E-ISSN 1879-3517, Vol. 58, p. 9-18Article in journal (Refereed)
    Abstract [en]

    In a typical liberalised wholesale power market, an optimisation process ensures the economically efficient utilisation of the controllable resources every few minutes. But electricity networks are subject to constant shocks to the available generation, load, or transmission assets. The response to these shocks is through a variety of ad hoc mechanisms which do not involve an optimisation process and therefore cannot achieve economically efficient utilisation of the available assets. But the higher the cost of responding to contingencies ex post the greater the need there is to distort the ex ante operation of the power system. In cases where the power system cannot respond at all to a particular contingency ex post, the power system must often be operated ex ante as though the contingency has already happened. This significantly reduces the efficiency with which the available assets can be utilised ex ante. In this paper the concept of short-run economic dispatch is introduced and mathematically modelled. The concept of short-run economic dispatch is formulated through three stages: (1) the initial steady-state equilibrium, (2) transition to a new steady-state equilibrium, and (3) final steady-state equilibrium. These three stages model the state of power system before, during, and after contingency occurred. The derived mathematical model is a linear programming problem. The approach is illustrated using the IEEE 24-node example system.

  • 329.
    Hesamzadeh, Mohammad Reza
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Yazdani, Mohammad
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Transmission Capacity Expansion in Imperfectly Competitive Power Markets2014In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 29, no 1, p. 62-71Article in journal (Refereed)
    Abstract [en]

    This paper proposes a mathematical model for transmission planning in an environment where there is imperfect competition in electricity supply industry. The model is developed based on the concept of the leader-followers game in applied mathematics. The leader of the game is the transmission planner and the followers are the strategic electricity producing firms. The reaction of the strategic electricity producing firms to the transmission planning decision is modeled using the introduced concept of the worst-Cournot-Nash equilibrium. The worst-Cournot-Nash equilibrium can handle the multiple Nash equilibria problem. The whole mathematical formulation is a bilevel mixed-integer linear programming problem. This formulation is achieved using the Karush-Kuhn-Tucker optimality conditions and a binary mapping approach. The application of the proposed approach to the three-node example system and the modified six-node Garver's example system are studied. The transmission planning with perfect competition is formulated and used as the benchmark. The numerical results show that the proposed approach in this paper can efficiently allocate the additional transmission capacity to the transmission grid such that it reduces the market power cost in the electricity supply industry. However, further studies should be carried out to scale up the proposed approach to the larger case studies.

  • 330.
    Hodge, Bri-Mathias
    et al.
    National Renewable Energy Laboratory, USA.
    Lew, Debra
    National Renewable Energy Laboratory, USA.
    Milligan, Michael
    National Renewable Energy Laboratory, USA.
    Holttinen, Hannele
    VTT, Finland.
    Sillanpää, Samuli
    VTT, Finland.
    Gómez-Lázaro, Emilio
    University of Castilla-La Mancha.
    Scharff, Richard
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Larsén, Xiaoli Guo
    Technical University of Denmark.
    Giebel, Gregor
    Technical University of Denmark.
    Flynn, Damian
    University College Dublin, Ireland.
    Dobschinski, Jan
    Fraunhofer Institute for Wind Energy and Energy System Technology, Germany.
    Wind Power Forecasting Error Distributions: An International Comparison2012Conference paper (Refereed)
    Abstract [en]

    Wind power forecasting is essential for greater penetration of wind power into electricity systems. Because no wind forecasting system is perfect, a thorough understanding of the errors that may occur is a critical factor for system operation functions, such as the setting of operating reserve levels. This paper provides an international comparison of the distribution of wind power forecasting errors from operational systems, based on real forecast data. The paper concludes with an assessment of similarities and differences between the errors observed in different locations.

  • 331. Holttinen, H.
    et al.
    Meibom, P.
    Ensslin, C.
    Hofmann, L.
    McCann, J.
    Pierik, J.
    Tande, J. O.
    Hagstrøm, E.
    Estanqueiro, A.
    Amaris, H.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Strbac, G.
    Parsons, B.
    Design and operation of power systems with large amounts of wind power production, IEA collaboration2006In: European Wind Energy Conference and Exhibition 2006, 2006, p. 156-165Conference paper (Refereed)
    Abstract [en]

    New R&D collaboration on "Design and Operation of Power Systems with Large Amounts of Wind Power Production" has been formed in IEA Wind. The R&D task will collect and share information on the experience gained and the studies made on power system impacts of wind power, and review methodologies, tools and data used. This paper outlines the power system impacts of wind power, the national studies published and on-going and describes the goals of the international collaboration. There are dozens of studies made and ongoing related to cost of wind integration, however, the results are not easy to compare. An in-depth review of the studies is needed to draw conclusions on the range of integration costs for wind power. State-of-the art review process will seek for reasons behind the wide range of results for costs of wind integration - definitions for wind penetration, reserves and costs; different power system and load characteristics and operational rules; underlying assumptions on variability of wind etc.

  • 332. Holttinen, H.
    et al.
    Meibom, P.
    Ensslin, C.
    Hormann, L.
    Tuohy, A.
    Tande, J. O.
    Estanqueiro, A.
    Gomez, F.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Shakoor, A.
    Smith, J. C.
    Parsons, B.
    Hulle, F.
    State-of-the-art of design and operation of power systems with large amounts of wind power, summary of IEA wind collaboration2007In: European Wind Energy Conference and Exhibition 2007, EWEC 2007, 2007, p. 489-499Conference paper (Refereed)
    Abstract [en]

    An international forum for exchange of knowledge of power system impacts of wind power has been formed under the IEA Implementing Agreement on Wind Energy. The task "Design and Operation of Power Systems with Large Amounts of Wind Power" is analysing existing case studies from different power systems.There are a multitude of studies made and ongoing related to cost of wind integration. However, the results are not easy to compare. This paper summarises the results from 15 case studies.

  • 333. Holttinen, H.
    et al.
    Meibom, P.
    Orths, A.
    Hulle, F. V.
    Lange, B.
    O'Malley, M.
    Pierik, J.
    Ummels, B.
    Tande, J. O.
    Estanqueiro, A.
    Matos, M.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Strbac, G.
    Shakoor, A.
    Ricardo, J.
    Smith, J. C.
    Milligan, M.
    Ela, E.
    Design and operation of power systems with large amounts of wind power2009Book (Refereed)
    Abstract [en]

    There are already several power systems coping with large amounts of wind power. Hi h penetration of wind power has impacts that have to be manage through proper plant interconnection, integration, transmission planning, and system and market operations. This report is a summary of case studies addressing concerns about the impact of wind power.s variability and uncertainty on power system reliability and costs. The case studies summarized in this report are not easy to compare due to different methodology and data used, as well as different assumptions on the interconnection capacity available. Integration costs of wind power need to be compared to something, like the production costs or market value of wind power, or integration cost of other production forms. There is also benefit when adding wind power to power systems: it reduces the total operating costs and emissions as wind fossil fuels. Severalissues that impact on the amount of wind power that can be integrated have been identified. Large balancing areas and aggregation benefits of large areas help in reducing the variability and forecast errors of wind power as well as help in pooling more cost effective balancing resources. System operation and working electricity markets at less than day-ahead time scales help reduce forecast errors of wind power. Transmission is the key to aggregation benefits, electricity markets and larger balancing areas. From the investigated studies it follows that at wind penetrations of up to 20 % of gross demand (energy), system operating cost increases arising from wind variability and uncertainty amounted to about 1.4 ./MWh. This is 10 % or less of the wholesale value of the wind energy.

  • 334. Holttinen, H.
    et al.
    Meibom, P.
    Orths, A.
    Rohrig, K.
    O'Malley, M.
    Ummels, B.
    Tande, J. O.
    Estanqueiro, A.
    Gomez, E.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Smith, J. C.
    Impacts of large amounts of wind power on design and operation of power systems, results of IEA collaboration2009In: European Wind Energy Conference and Exhibition 2009, EWEC 2009, 2009, p. 1171-1185Conference paper (Refereed)
  • 335. Holttinen, H.
    et al.
    O'Malley, M.
    Dillon, J.
    Flynn, D.
    Keane, A.
    Abildgaard, H.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Steps for a complete wind integration study2013In: Proceedings of the Annual Hawaii International Conference on System Sciences, 2013, p. 2261-2270Conference paper (Refereed)
    Abstract [en]

    There have been many wind integration studies in recent years, and these efforts are expected to continue. Because power systems and data availability vary significantly, the results and methodologies used in these studies vary. This paper presents findings from international collaboration under IEAWIND Task 25 working towards Recommended Practices for Wind Integration studies. An overview of a complete wind integration study is presented as a flow chart. The setup of a study and main assumptions are important because they have a crucial impact on the results. The main steps in the simulations are presented with methodologies, which include the increase in reserve requirements, estimating impacts on other generation and balancing, capacity value of wind power and increase in transmission due to wind power.

  • 336. Holttinen, Hannele
    et al.
    Meibom, Peter
    Orths, Antje
    Lange, Bernhard
    O'Malley, Mark
    Tande, John Olav
    Estanqueiro, Ana
    Gomez, Emilio
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Strbac, Goran
    Smith, J. Charles
    van Hulle, Frans
    Impacts of large amounts of wind power on design and operation of power systems, results of IEA collaboration2011In: Wind Energy, ISSN 1095-4244, E-ISSN 1099-1824, Vol. 14, no 2, p. 179-192Article in journal (Refereed)
    Abstract [en]

    There are dozens of studies made and ongoing related to wind integration. However, the results are not easy to compare. IEA WIND R&D Task 25 on 'Design and Operation of Power Systems with Large Amounts of Wind Power' collects and shares information on wind generation impacts on power systems, with analyses and guidelines on methodologies. In the state-of-the-art report (October, 2007), and the final report of the 3 years period (July, 2009) the most relevant wind power grid integration studies have been analysed especially regarding methodologies and input data. Several issues that impact on the amount of wind power that can be integrated have been identified. Large balancing areas and aggregation benefits of wide areas help in reducing the variability and forecast errors of wind power as well as help in pooling more cost effective balancing resources. System operation and functioning electricity markets at less than day-ahead time scales help reduce forecast errors of wind power. Transmission is the key to aggregation benefits, electricity markets and larger balancing areas. Best practices in wind integration studies are described. There is also benefit when adding wind power to power systems: it reduces the total operating costs and emissions as wind replaces fossil fuels and this should be highlighted more in future studies.

  • 337. Holttinen, Hannele
    et al.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Ela, Erik
    et al.,
    Design and operation of power systems with large amounts of wind power: Final report, IEA WIND Task 25, Phase one 2006-20082009Report (Other academic)
  • 338.
    Holttinen, Hannele
    et al.
    VTT Technical Research Centre of Finland, Espoo, Finland .
    Tuohy, A.
    Milligan, M.
    Lannoye, E.
    Silva, V.
    Müller, S.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    The flexibility workout: Managing variable resources and assessing the need for power system modification2013In: IEEE Power & Energy Magazine, ISSN 1540-7977, Vol. 11, no 6, p. 53-62Article in journal (Refereed)
    Abstract [en]

    Power systems have been designed and operated so that the demand for electricity can be met at all times and under a variety of conditions. Depending on the season, the climate, and the weather, demand can fluctuate significantly over a single day, week, or month. For example, in France the extensive use of electricity to generate heating creates a relationship between increase in electricity demand and decrease in temperature that amounts to close to 2,400 MW/°C. In addition to meeting the variability requirements, there is always some inherent uncertainty about future demand and the future availability of generators. The power system must thus be able to manage both variability and uncertainty.

  • 339.
    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.

  • 340.
    Hooshyar, Hossein
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Baran, M. E.
    Fault analysis on distribution feeders employing solid state transformers2014In: 2014 IEEE PES General Meeting | Conference & Exposition: , IEEE Computer Society, 2014, p. 6938868-Conference paper (Refereed)
    Abstract [en]

    This paper focuses on fault analysis of a distribution feeder which employs Solid State Transformers (SSTs) rather than magnetic transformers in order to facilitate large scale integration of Distributed Energy Resources (DERs) into the system. To estimate the fault current profile on such a feeder, the paper proposes a new method which extends the capability of conventional short-circuit analysis method. Performance of the proposed method has been assessed by simulations on a sample distribution feeder.

  • 341.
    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.

  • 342.
    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)
  • 343.
    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.

  • 344.
    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.

  • 345.
    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.

  • 346.
    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.

  • 347. Hosseinzadeh, N.
    et al.
    Hesamzadeh, Mohammad
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Korki, M.
    Role of laboratory in the education of modern power systems2011In: IEEE Power and Energy Society General Meeting, Detroit, MI, 2011Conference paper (Refereed)
    Abstract [en]

    Power system laboratories should be developed and fully exploited to educate capable power engineers, who would be able to easily integrate with the industry workforce. There are various tools and methods of using these tools, which can be utilized in power system laboratories. Particularly, hands-on hardware-based equipment or simulation-based software packages can be used. Also, the utilization of laboratories depends on the teaching-learning methodology. These methods may be classified as conventional lecture-based, project-based learning (PBL), and hybrid conventional-PBL mode of delivery of a unit of study. This paper discusses the role of a power system laboratory in each of these delivery modes and also discusses the assessment methods of the laboratory practice in each mode.

  • 348. Hosseinzadeh, Nasser
    et al.
    Hesamzadeh, Mohammad Reza
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Application of Project-Based Learning (PBL) to the Teaching of Electrical Power Systems Engineering2012In: IEEE Transactions on Education, ISSN 0018-9359, E-ISSN 1557-9638, Vol. 55, no 4, p. 495-501Article in journal (Refereed)
    Abstract [en]

    Project-based learning (PBL), a learning environment in which projects drive learning, has been successfully used in various courses in the educational programs of different disciplines. However, concerns have been raised as to the breadth of the content covered and, in particular, whether PBL can be applied to specialized subjects without compromising the coverage of the required technical content. This paper discusses the advantages and drawbacks of using the PBL methodology in teaching specialized subjects in electrical power engineering, based on the authors' reflections and student feedback. The design and delivery of a PBL-based course in power system modeling and analysis is used as an example. It is asserted that proper usage of PBL makes it possible to deliver both technical content and generic professional skills in a specialized course.

  • 349.
    Hrag, Margossian
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    VALIDATION OF THE PSS/E MODEL FOR THE GOTLAND NETWORKR2010Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The aim of the project is to revise the load flow and dynamic PSS/E models of the Gotland network and validate them against a set of measurements collected during a major disturbance, a three phase short circuit in the 70 kV system.

    The main task in revising the model is to convert the induction machine models of the wind turbines into user and manufacturer wind turbine models. The validation of the model is divided into two phases. The first is to use the measurements as well as some assumptions on the wind power generation and load distribution from the time of the fault to validate the dynamic behaviour of the system. The second is to use new measurements during a normal operation day. The latter would not be very helpful to illustrate the dynamic behaviour of the system, because of the lack of a major fault that would drastically affect the system, but it would nevertheless be useful to validate the load flow with greater accuracy.

  • 350.
    Huang, Shan
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    On Accuracy of Conic Optimal Power Flow2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Nowadays, with the increasing need for security and economic operation of power systems, the optimal power flow (OPF) has been an essential and predominant tool for economic and operation planning of power systems. A developed conic formulation for OPF has been proposed [1]. This model is bases on the line based flow equations and can be transformed into the form of second order cone programming (SOCP). The SOCP formulation of OPF problem can be solved using interior point methods (IPMs) [2]. In this thesis, a study on the performance of this developed conic formulation for OPF is carried out. Firstly, the accuracy of SOCP formulation is studied. A more accurate model is developed. The model is obtained by modifying the phase angle constrains of SOCP formulation. The modified model can be solved using sequential conic programming method. A comparison of results from these two models is made on different test systems. Secondly, the SOCP formulation is applied to both small and large test systems. The results of SOCP formulation is compared with the results from PSS/EOPF. The performance of SOCP formulation has shown the accurate and effectiveness for solving OPF problems.

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