References of "Van Cutsem, Thierry"
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See detailCombined detailed and quasi steady-state time simulations for large-disturbance analysis
Van Cutsem, Thierry ULg; Grenier, Marie-Eve; Lefebvre, Daniel

(2005, August)

This paper deals with the simulation of long-term power system responses to large disturbances in the presence of discrete events. A method combining detailed and quasi steady-state time simulations is ... [more ▼]

This paper deals with the simulation of long-term power system responses to large disturbances in the presence of discrete events. A method combining detailed and quasi steady-state time simulations is presented, the former being used for accuracy and the latter for ef ciency reasons. Detailed time simulation is used to analyze the short-term period following a large disturbance and identify the discrete controls triggered. Next, quasi steady-state simulation is used to simulate the same time interval with the discrete controls imposed as external events, before letting the system evolve as usual in the long term. This simple method has been successfully tested on the Hydro-Québec system. [less ▲]

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See detailQuasi steady-state models for long-term voltage and frequency dynamics simulation
Grenier, Marie-Eve; Lefebvre, Daniel; Van Cutsem, Thierry ULg

(2005, June)

The Quasi Steady-State (QSS) approximation of long-term dynamics relies on time-scale decomposition and consists of replacing faster phenomena by their equilibrium conditions, in order to reduce the ... [more ▼]

The Quasi Steady-State (QSS) approximation of long-term dynamics relies on time-scale decomposition and consists of replacing faster phenomena by their equilibrium conditions, in order to reduce the complexity of the whole model and increase the computation efficiency of time simulations. This paper describes the extension of a QSS model extensively used in long-term voltage stability studies, to readily incorporate the frequency dynamics that takes place over the same time scale. This extended QSS model relies on a common-frequency assumption. Its advantages, limitations and possible improvements are discussed through simulation results on the Hydro-Québec system, where it has been compared to full time scale simulations. Disturbances with an impact on either frequency or voltages are considered and the coupling between these two aspects of long-term dynamics is briefly discussed. [less ▲]

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See detailFast contingency filtering based on linear voltage drop estimates
Otomega, Bogdan; Van Cutsem, Thierry ULg

(2005, June)

This paper deals with the filtering of harmless contingencies in voltage stability and security analyses. In many systems, a post-contingency load flow allows to identify the contingencies with severe ... [more ▼]

This paper deals with the filtering of harmless contingencies in voltage stability and security analyses. In many systems, a post-contingency load flow allows to identify the contingencies with severe impact on voltage stability, as causing either divergence or large voltage drops. However, for filtering purposes, accurate voltage drops need not be computed; linear estimates obtained from sensitivity formulas are appropriate. For a given contingency, the method used in this paper solves a sparse linear system to update the phase angles, assuming constant voltage magnitudes. Then, assuming constant active power flows in the branches, a second sparse system is solved to update the voltage magnitudes. This yields better accuracy than one full load flow iteration while retaining the sparse structure of a decoupled formulation. For contingency analysis, the incidents are filtered by comparing the voltage drops to a threshold. For secure power margin computations, the same procedure is used after stressing the system in the specified direction. The method has been tested on a real system where it has been found to combine simplicity of implementation, quality of filtering and computational efficiency. [less ▲]

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See detailUnified sensitivity analysis of unstable or low voltages caused by load increases or contingencies
Capitanescu, Florin ULg; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2005), 20(1), 321-329

This paper deals with the analysis of situations where load increases and/or contingencies cause transmission voltages to become unstable or unacceptably low. Simple sensitivities are proposed to ... [more ▼]

This paper deals with the analysis of situations where load increases and/or contingencies cause transmission voltages to become unstable or unacceptably low. Simple sensitivities are proposed to determine the relative efficiency of candidate remedial actions, which are parameter changes likely to strengthen the system. To this purpose, the sensitivities of the bus voltage magnitude experiencing the largest drop are considered. In the neighborhood of a loadability limit or a critical point, it is shown that these sensitivities and those based on eigenvalue and eigenvector computation are essentially the same. However, the proposed analysis can also deal with low but stable situations. The accuracy of the proposed sensitivities is demonstrated on the models of two real systems, in which the parameters of concern are bus power injections. [less ▲]

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See detailApplication of real-time voltage security assessment to the Hellenic Interconnected System
Van Cutsem, Thierry ULg; Kabouris, John; Christoforidis, George et al

in IEE Proceedings-Generation Transmission and Distribution (2005), 152(1), 123-131

The online voltage security assessment methods implemented at the national control centre of the Hellenic Interconnected System, within the framework of the OMASES project funded by the European Union are ... [more ▼]

The online voltage security assessment methods implemented at the national control centre of the Hellenic Interconnected System, within the framework of the OMASES project funded by the European Union are described. The heart of all computations is a fast time-domain method. Security is analysed with respect to power transfers in critical corridors or power consumption in load areas. Results take on the form of either precontingency secure operation limits, or postcontingency loadability limits, together with various diagnosis tips. Contingency filtering is performed to meet the real-time requirement. Typical results obtained during the test phase of the project are reported. [less ▲]

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See detailA new training simulator for improved voltage control of the Hydro-Québec system
Van Cutsem, Thierry ULg; Hassé, Gaëtan; Moors, Cédric et al

(2004, October)

This paper reports on the development of a training simulator focusing on voltage control and stability. It has been derived from a quasi steady-state simulation software already used and validated in ... [more ▼]

This paper reports on the development of a training simulator focusing on voltage control and stability. It has been derived from a quasi steady-state simulation software already used and validated in planning and operational planning studies. The computational engine has been provided with a user interface built on the client-server architecture, allowing the simulator to run on a network of PCs in a very flexible way. New displays can be set up easily and quickly. This tool is presently used by Hydro-Québec to improve the operator’s ability to control transmission voltages. Other features, uses and benefits are reported. [less ▲]

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See detailUndervoltage load shedding scheme for the Hydro-Québec system
Lefebvre, Daniel; Bernard, Serge; Van Cutsem, Thierry ULg

(2004, June)

In recent years, Hydro-Québec has undertaken a major program to upgrade the reliability of its transmission system. Much effort has been focused on increasing the system's ability to withstand extreme ... [more ▼]

In recent years, Hydro-Québec has undertaken a major program to upgrade the reliability of its transmission system. Much effort has been focused on increasing the system's ability to withstand extreme contingencies, usually caused by multiple incidents or the successive tripping of transmission lines. This paper deals with the conception and the control logic of an undervoltage load shedding scheme aimed at protecting the Hydro-Québec system against long-term voltage instability. Various results showing the impact of the operation of these automatisms on the system stability are provided in this paper. [less ▲]

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See detailDefinition and Classification of Power System Stability
Kundur, Prabha; Paserba, John; Ajjarapu, Venkat et al

in IEEE Transactions on Power Systems (2004), 19(2), 1387-1401

The problem of defining and classifying power system stability has been addressed by several previous CIGRE and IEEE Task Force reports. These earlier efforts, however, do not completely reflect current ... [more ▼]

The problem of defining and classifying power system stability has been addressed by several previous CIGRE and IEEE Task Force reports. These earlier efforts, however, do not completely reflect current industry needs, experiences and understanding. In particular, the definitions are not precise and the classifications do not encompass all practical instability scenarios. This report developed by a Task Force, set up jointly by the CIGRE Study Committee 38 and the IEEE Power System Dynamic Performance Committee, addresses the issue of stability definition and classification in power systems from a fundamental viewpoint and closely examines the practical ramifications. The report aims to define power system stability more precisely, provide a systematic basis for its classification, and discuss linkages to related issues such as power system reliability and security. [less ▲]

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See detailAn educational simulation tool for power system control and stability
Vournas, Costas; Potamianakis, Emmanuel G.; Moors, Cédric et al

in IEEE Transactions on Power Systems (2004), 19(1), 48-55

This paper presents a Simulink-based educational tool developed for the purpose of illustrating power system control and stability notions as well as introducing students to realistic, though tractable in ... [more ▼]

This paper presents a Simulink-based educational tool developed for the purpose of illustrating power system control and stability notions as well as introducing students to realistic, though tractable in size, design problems. Relevant courses are taught to last-year undergraduate as well as graduate students at the University of, Liege, Belgium, and the National Technical University of Athens, Greece.. After a brief description of the corresponding curricula, the paper describes the simulation tool and gives examples of problems and assignments given to the students. [less ▲]

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See detailDesign of an undervoltage load shedding scheme for the Hydro-Québec system
Lefebvre, Daniel; Moors, Cédric; Van Cutsem, Thierry ULg

(2003, July)

This paper deals with the control logic of an undervoltage, closed-loop load shedding scheme aimed at protecting the Hydro-Quebec system against long-term voltage instability. This scheme relies on a set ... [more ▼]

This paper deals with the control logic of an undervoltage, closed-loop load shedding scheme aimed at protecting the Hydro-Quebec system against long-term voltage instability. This scheme relies on a set of "if-then" rules whose parameters are determined through combinatorial optimisation, relying on the system dynamic response over a set of scenarios. Preliminary results of the above optimisation technique are given, besides a brief description of the foreseen implementation. [less ▲]

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See detailReverse-logic control of load tap changers in emergency voltage conditions
Otomega, Bogdan; Sermanson, Vincent; Van Cutsem, Thierry ULg

(2003, June 26)

This papers deals with the emergency control of Load Tap Changers (LTCs) to face low transmission voltages or voltage instability situations. The proposed simple control logic consists in reverting the ... [more ▼]

This papers deals with the emergency control of Load Tap Changers (LTCs) to face low transmission voltages or voltage instability situations. The proposed simple control logic consists in reverting the tap movements once the voltage at a monitored transmission bus falls below some threshold. A deadband on this voltage allows the system to settle down in between the normal and reverse logic modes. In order to control a large number of LTCs, the latter are divided into clusters, each with its own monitored voltage. The paper also considers the control of two levels of LTCs in cascade, where proper coordination is required between the two levels. The proposed scheme has been tested on a detailed EHV-HV-MV planning model of the Western region of the French transmission system operated by RTE. Long-term time responses to major disturbances are shown to illustrate the performance of the proposed scheme. [less ▲]

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See detailOMASES: A DYNAMIC SECURITY ASSESSMENT TOOL FOR THE NEW MARKET ENVIRONMENT
Bihain, André; Cirio, Diego; Fiorina, Mario et al

(2003, June 26)

The paper presents the efforts and results of a large consortium of European Industries, Research Centers and Universities involved in an EU research project named OMASES in the field of Power System ... [more ▼]

The paper presents the efforts and results of a large consortium of European Industries, Research Centers and Universities involved in an EU research project named OMASES in the field of Power System Dynamic Security Assessment (DSA). The overall structure of an on-line DSA tool including TSA – Transient Stability Assessment, VSA – Voltage Stability Assessment, TS – Training Simulator and MS – Market Simulator is reported. Some basic assumptions and methodological aspects of the tool are presented considering its possible use within actual or future Energy Management Systems under the new electric market environment. Scenarios set up for the validation phase and results are reported with reference to the Italian test facility. [less ▲]

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See detailOn-Line Voltage Security Assessment of the Hellenic Interconnected System
Vournas, Costas; Manos, George; Kabouris, John et al

(2003, June 26)

This paper describes the on-line Voltage Security Assessment environment developed within the framework of the EU-sponsored OMASES project, as well as its application to the Greek Interconnected Power ... [more ▼]

This paper describes the on-line Voltage Security Assessment environment developed within the framework of the EU-sponsored OMASES project, as well as its application to the Greek Interconnected Power System. The heart of all computations is a fast time-domain method. Security is analyzed with respect to power transfers in critical corridors or power consumption in load areas. Results take on the form of either precontingency secure operation limits, or post-contingency loadability limits, together with various diagnosis tips. Typical results obtained during the test phase of the project are reported. [less ▲]

Detailed reference viewed: 45 (1 ULg)
See detailL'instabilité de tension
Van Cutsem, Thierry ULg

in Crappe, Michel (Ed.) Stabilité et sauvegarde des réseaux électriques (2003)

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See detailComputation of simultaneous available transfer capability under thermal and voltage security constraints
Capitanescu, Florin ULg; Van Cutsem, Thierry ULg

(2002, September)

This paper proposes a method to compute the Available Transfer Capability (ATC) of a power system under both thermal and voltage security constraints. The objective is to determine, in some optimal manner ... [more ▼]

This paper proposes a method to compute the Available Transfer Capability (ATC) of a power system under both thermal and voltage security constraints. The objective is to determine, in some optimal manner, the ATC of several simultaneous transactions, such that any postulated contingency does not cause voltage instability nor thermal overloads. Thermal constraints are derived for every branch likely to be overloaded in post-contingency states. Voltage security constraints are derived from voltage unstable post-contingency scenario, obtained by Quasi Steady- State simulation, a fast time-domain method. The paper also addresses the discrimination problem, i.e. the fact that the computed ATC might favor some trades to the detriment of others. Variants will be discussed to deal with such situations. The method is illustrated on an 80-bus test system. [less ▲]

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See detailEvaluating bound on voltage and thermal security margins under power transfer uncertainty.
Van Cutsem, Thierry ULg

(2002, June)

This paper deals with the evaluation of bounds on voltage and thermal security margins with respect to contingencies. A margin is the maximal pre-contingency power transfer between either a generation and ... [more ▼]

This paper deals with the evaluation of bounds on voltage and thermal security margins with respect to contingencies. A margin is the maximal pre-contingency power transfer between either a generation and a load area or two generation areas, such that specirfied contingencies do not overload lines or make the system voltage unstable. The minimum and maximum margins are computed for given intervals of variations of bus injections. Each bound is the solution of a constrained L1-norm minimization (or maximization) problem, for which specific algorithms are given. Thermal overloads are handled through linearization, while for voltage stability, fast time simulation and instability mode analysis are used. Nonlinear situations of branch overload are also considered. The method is illustrated on an 80-bus test system. [less ▲]

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See detailEvaluating bounds on voltage and thermal security margins under power transfer uncertainty
Capitanescu, Florin ULg; Van Cutsem, Thierry ULg

(2002, June)

This paper deals with the evaluation of bounds on voltage and thermal security margins with respect to contingencies. A margin is the maximual pre-contingency power transfer between either a generation ... [more ▼]

This paper deals with the evaluation of bounds on voltage and thermal security margins with respect to contingencies. A margin is the maximual pre-contingency power transfer between either a generation and a load area or two generation areas, such that the specified contingencies do not overload lines or make the system voltage unstable. The minimum and maximum margins are computed for given intervals of variations of bus injections. Each bound is the solution of a constrained L1-norm minimization (or maximization) problem, for which specific algorithms are given. Thermal overloads are handled through linearization, while for voltage stability, fast time simulation and instability mode analysis are used. Nonlinear situations of branch overloads are also considered. The method is illustrated on an 80-bus test system. [less ▲]

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See detailPreventive control of voltage security margins: A multicontingency sensitivity-based approach
Capitanescu, Florin ULg; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2002), 17(2), 358-364

This paper addresses the problem of changing the operating point of a power system in order to keep voltage security margins with respect to contingencies above some minimal value. Margins take on the ... [more ▼]

This paper addresses the problem of changing the operating point of a power system in order to keep voltage security margins with respect to contingencies above some minimal value. Margins take on the form of maximum pre-contingency power transfers either between a generation and a load area or between two generation areas. They are determined by means of a fast time-domain method. We will first discuss the use of a general optimal power flow, in which linear voltage security constraints are added. The simultaneous control of several (possibly conflicting) contingencies is considered. Then, we will focus on the minimal control change objective. Among the possible controls, emphasis is put on generation rescheduling and load curtailment. Examples are presented on an 80-bus test system as well as on a real system. [less ▲]

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See detailDesign of Load Shedding Schemes against Voltage Instability using Combinatorial Optimization
Van Cutsem, Thierry ULg; Moors, Cedric; Lefebvre, Daniel

(2002, January 31)

This paper proposes a methodology for the design of automatic load shedding against voltage instability. In a first step, we describe a method allowing to find the minimal shedding required in a given ... [more ▼]

This paper proposes a methodology for the design of automatic load shedding against voltage instability. In a first step, we describe a method allowing to find the minimal shedding required in a given unstable scenario. In a second step, we describe the structure of various controllers and identify the parameters to be optimized. Next, we present an optimization approach to find the controller parameters which optimize an overall performance objective. Results are presented on the Hydro-Québec system, in which load shedding is presently planned. [less ▲]

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See detailA Time-Scale Decomposition-Based Simulation Tool for Voltage Stability Analysis
Loud, Lester; Rousseaux, Patricia ULg; Lefebvre, Daniel et al

in Proceedings of the IEEE Porto Power Tech Conference (2001, September)

This paper proposes a time domain simulation tool combining Full Time Scale (FTS) simulation in the short-term period following a contingency and Quasi Steady-State (QSS) approximation for the long-term ... [more ▼]

This paper proposes a time domain simulation tool combining Full Time Scale (FTS) simulation in the short-term period following a contingency and Quasi Steady-State (QSS) approximation for the long-term phase. A criterion is devised to automatically switch from FTS to QSS simulation as soon as sufficient damping of short-term dynamics is reached. Various comparisons with FTS simulations have been performed on the Hydro-Qn6bec system. The proposed method is shown to combine accuracy of FTS with computational efficiency of QSS. Sensitivity of simulations to load model and the need for updating the whole model with frequency variations are also discussed. [less ▲]

Detailed reference viewed: 65 (1 ULg)