References of "Van Cutsem, Thierry"
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See detailInvestigating State Reconstruction from Scarce Synchronized Phasor Measurements
Glavic, Mevludin; Van Cutsem, Thierry ULg

in Proceedings of the IEEE Trondheim Power Tech 2011 conference (2011, June)

Synchronized phasor measurements can potentially track the system dynamics between two classical state estimations. However, in the PMU configurations available nowadays and in the near future, those ... [more ▼]

Synchronized phasor measurements can potentially track the system dynamics between two classical state estimations. However, in the PMU configurations available nowadays and in the near future, those measurements are too scarce for the whole system state to be estimated. Therefore, we investigate the possibility to reconstruct coherent, time-synchronized system states from the available PMU data. State reconstruction is formulated as an optimization problem. The objective is to minimize, in the space of bus powers, the distance between the reconstructed state and the last state estimate provided by a standard state estimator. PMU data are imposed as equality constraints. Furthermore, the placement of PMUs near generators is advocated for higher accuracy of state reconstruction. The performance and potential benefits of the approach are illustrated by processing snapshots obtained from detailed time simulation of a test system subject to a disturbance and corrective actions. [less ▲]

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See detailA load shedding scheme against both short- and long-term voltage instabilities in the presence of induction motors
Otomega, Bogdan; Van Cutsem, Thierry ULg

in Proceedings of the IEEE Trondheim Power Tech 2011 conference (2011, June)

In the presence of induction motors in loads, long-term voltage instability may result in sharp voltage decreases, once the generators supporting transmission voltages have their field currents limited ... [more ▼]

In the presence of induction motors in loads, long-term voltage instability may result in sharp voltage decreases, once the generators supporting transmission voltages have their field currents limited. Furthermore, after a fault, induction motors may fail re-accelerating and their stalling leads to short-term voltage instability. This paper investigates the ability of the load shedding scheme, previously proposed by the authors, to deal with both short and long-term voltage instabilities. The scheme is distributed with minimal amount of information exchange. It is also shown that the selectivity of this protection scheme can be increased by prioritizing in time the various controllers. Detailed time simulations of a test system are reported. [less ▲]

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See detailOn angle references in long-term time-domain simulations
Fabozzi, Davide ULg; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2011), 26(1), 483-484

Abstract—In power system dynamic models the complex network equations and the various phasors are projected onto reference axes. After a short critical review of commonly chosen reference axes, this ... [more ▼]

Abstract—In power system dynamic models the complex network equations and the various phasors are projected onto reference axes. After a short critical review of commonly chosen reference axes, this letter proposes to use the center-of-inertia at the previous integration time step. This approach is shown to combine the advantages of the center-of-inertia with a sparser Jacobian structure and an easier handling of network splits. [less ▲]

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See detailA Taxonomy of Multi-Area State Estimation Methods
Gomez-Exposito, Antonio; de la Villa Jaen, Antonio; Gomez-Quiles, Catalina et al

in Electric Power Systems Research (2011), 81(4), 1060-1069

This paper presents a critical review of the state of the art in Multi-Area State Estimation (MASE) methods, which are currently gaining renewed interest due to their capability of properly tracking multi ... [more ▼]

This paper presents a critical review of the state of the art in Multi-Area State Estimation (MASE) methods, which are currently gaining renewed interest due to their capability of properly tracking multi-TSO transactions and accommodating highly redundant information systems. Based on several classification criteria, a taxonomy of MASE methods is first proposed. Two main categories, namely two-step or hierarchical versus decentralized, are identified. Then, for each class of methods, the resulting model structure and area interactions are discussed and a brief presentation is made of a selected subset of references. [less ▲]

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See detailWind integration and AGC frequency dynamics simulations using Quasi Steady-State approximation
Lebeau, Simon; Qako, Niko; Van Cutsem, Thierry ULg

in Proc. of 9th international workshop on large-scale integration of wind power in powers systems (2010, October)

Frequency dynamics studies are important at Hydro-Québec (HQ). Wind integration raises questions about HQ ability to maintain frequency regulation in normal operation and during contingencies. Quasi ... [more ▼]

Frequency dynamics studies are important at Hydro-Québec (HQ). Wind integration raises questions about HQ ability to maintain frequency regulation in normal operation and during contingencies. Quasi Steady-State (QSS) approximation is the best alternative to simulate long-term voltage and frequency dynamics without compromising the exactness of simulation results. Collaboration between HQ and University of Liège allowed the development of numerous models. Frequency dynamics is represented by machines inertia, speed governors and a complete AGC controlling 13 hydro power plants including transmission delays. For voltage dynamics, static var compensators, synchronous condensers and tap changer transformers are also represented. Wind farms are modeled as generation patterns (Pwind = f(t)) including a Wind Farm Management System (WFMS). This paper addresses wind farm integration and AGC frequency regulation. Based on HQ field measurements and observations, the most pessimistic cases were simulated. Two scenarios are detailed: the 3500 MW of wind farms currently planned for 2015 and a hypothetical 10 000 MW of wind integration. The results show that actual AGC settings are accurate for the planned wind farms, but might need some changes for a 10 000 MW scenario. [less ▲]

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See detailLocalization and latency concepts applied to time simulation of large power systems
Fabozzi, Davide ULg; Van Cutsem, Thierry ULg

in Proceedings of the 2010 IREP Symposium (2010, August)

This paper reports on investigations to speed up time domain simulations of large electric power systems. First, a decomposed scheme is considered which exploits the bordered block diagonal structure of ... [more ▼]

This paper reports on investigations to speed up time domain simulations of large electric power systems. First, a decomposed scheme is considered which exploits the bordered block diagonal structure of the original Jacobian involved in the Newton iterations, and keeps the resulting “local” Jacobians constant over multiple iterations. Next, a localization technique is considered, allowing to perform less iterations on the system components with lower activity. Finally, a third scheme consists of visiting only a subset of components, identified as active, and skipping the other ones, identified as latent. The first two techniques solve the whole set of equations with the required accuracy, while the third one involves an adjustable degree of approximation. The methods are illustrated on a small system, while preliminary checks of computational savings from a large test system are reported. Additional results deal with the application of the localization and latency techniques to simplified simulation of the detailed model. [less ▲]

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See detailAn integrated autonomous protection system against voltage instability based on Load Tap Changers
Vournas, Costas; Lambrou, C.; Glavic, M. et al

in Proceedings of the 2010 IREP Symposium- Bulk Power System Dynamics and Control – VIII (2010, August)

In this paper we propose a local, completely autonomous protection system against voltage instability that can be readily integrated in the controller of each bulk power delivery LTC transformer. The ... [more ▼]

In this paper we propose a local, completely autonomous protection system against voltage instability that can be readily integrated in the controller of each bulk power delivery LTC transformer. The protection system will identify an imminent voltage instability and will subsequently apply the necessary corrective measures to restore stable operation by properly adjusting the distribution voltage setpoint of the LTC. Application of this system on a 52-bus test system showed excellent performance for two unstable cases. For reasons of comparison, the indirect load curtailment proposed in a severe instability case is compared with direct load shedding schemes based on the local detection of instability, as well as on a global detection of instability assuming wide area measurements. [less ▲]

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See detailEnergy and Transmission Allocation in the presence of Overlapping Electricity Markets
Marinakis, Adamantios ULg; Bakirtzis, Anastasios; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2010), 25(3), 1402-1414

The possibility for market participants to simultaneously place their bids in different markets across an interconnection is investigated in this paper. Transaction schedulers settle multilateral ... [more ▼]

The possibility for market participants to simultaneously place their bids in different markets across an interconnection is investigated in this paper. Transaction schedulers settle multilateral transactions among participants, while a central entity coordinates the overall operation through interactions with the transaction schedulers. Two issues are dealt with in this context. First, the market participants are allowed to place their bids simultaneously in more than one transactions scheduler’s market, and, second, the available transmission capacity is fairly shared among the transaction schedulers. Economically interesting transactions are favored, while confidentiality of market data and independence of transaction schedulers’ clearing mechanisms are preserved. The corresponding iterative algorithm is illustrated in detail on a 15-bus as well as the IEEE-RTS system. [less ▲]

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See detailAdaptive Wide-Area Closed-Loop Undervoltage Load Shedding Using Synchronized Measurements
Glavic, Mevludin; Van Cutsem, Thierry ULg

in Proceedings of IEEE PES 2010 General Meeting (2010, July)

This paper proposes an emergency load shedding scheme aimed at stopping a developing voltage instability before system disruption. The proposed scheme has a wide-area view of the system, adapts itself to ... [more ▼]

This paper proposes an emergency load shedding scheme aimed at stopping a developing voltage instability before system disruption. The proposed scheme has a wide-area view of the system, adapts itself to the emergency situation to be handled, and works in closed-loop. It relies on the detection of voltage instability from synchronized measurements recently proposed by the authors. It inherits the assumptions of this detection method (availability of a rich phasor measurement set and communication infrastructure). The method is adaptive in so far as the voltage thresholds used by this undervoltage load shedding scheme are determined from the measurements of the system evolution itself, and the curtailed power is adjusted to the severity of the situation. The features of the proposed scheme are illustrated on a small but realistic system. [less ▲]

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See detailEnergy and transmission allocation in overlapping electricity markets : incorporating N-1 security and accounting for losses
Marinakis, Adamantios ULg; Van Cutsem, Thierry ULg

in Proceedings of the 7th international conference on the European Electricity Market (2010, June)

The possibility for market participants to place their bids in markets where they are not geographically located is investigated in this paper. An iterative procedure enabling the simultaneous clearing of ... [more ▼]

The possibility for market participants to place their bids in markets where they are not geographically located is investigated in this paper. An iterative procedure enabling the simultaneous clearing of those overlapping markets by transaction schedulers while managing the resulting pre and post-contingency congestion is proposed. Transmission losses are calculated during the iterations and are accounted for by allocating them to the various transaction schedulers. The procedure is illustrated and commented on a test system. [less ▲]

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See detailMinimal Reduction of Unscheduled Flows for Security Restoration: Application to Phase Shifter Control
Marinakis, Adamantios ULg; Glavic, Mevludin; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2010), 25(1), 506-515

More and more transmission system operators, noticeably in Europe, equip their systems with phase shifting transformers to counteract transit flows that take place in a large meshed interconnection. This ... [more ▼]

More and more transmission system operators, noticeably in Europe, equip their systems with phase shifting transformers to counteract transit flows that take place in a large meshed interconnection. This paper proposes algorithms for the coordinated control of several phase shifters by one operator with the objective of reducing the unscheduled flow through its system. Minimum reduction of unscheduled flow and minimum deviation with respect to present operating point are sought in order to minimize the trouble caused, while ensuring secure operation. Attention is paid to combining pre and post-contingency controls. The resulting algorithms, simple and compatible with real-time applications, are illustrated on a realistic test system. [less ▲]

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See detailSecuring Transient Stability using Time-Domain Simulations within an Optimal Power Flow
Zarate-Minano, Rafael; Van Cutsem, Thierry ULg; Milano, Federico et al

in IEEE Transactions on Power Systems (2010), 25(1), 243-253

This paper provides a methodology to restore transient stability. It relies on a well-behaved optimal power flow model with embedded transient stability constraints. The proposed methodology can be used ... [more ▼]

This paper provides a methodology to restore transient stability. It relies on a well-behaved optimal power flow model with embedded transient stability constraints. The proposed methodology can be used for both dispatching and redispatching. In addition to power flow constraints and limits, the resulting optimal power flow model includes discrete time equations describing the time evolution of all machines in the system. Transient stability constraints are formulated by reducing the initial multi-machine model to a one-machine infinite-bus equivalent. This equivalent allows imposing angle bounds that ensure transient stability. The proposed optimal power flow model is tested and analyzed using an illustrative 9-bus system, the well-known New England 39-bus, 10-machine system and a real-world 1228-bus system with 292 synchronous machines. [less ▲]

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See detailDecentralized tap changer blocking and load shedding against voltage instability: prospective tests on the RTE system
Capitanescu, Florin ULg; Otomega, Bogdan; Lefebvre, Hervé et al

in International Journal of Electrical Power & Energy Systems (2009), 31(9), 570-576

This paper reports on prospective tests of a system protection scheme against long-term voltage instability relying on a set of distributed controllers, each monitoring a transmission voltage, blocking ... [more ▼]

This paper reports on prospective tests of a system protection scheme against long-term voltage instability relying on a set of distributed controllers, each monitoring a transmission voltage, blocking tap changers and shedding loads in a zone. The emergency actions adjust in magnitude and location to the disturbance. Each controller acts in closed-loop, which guarantees robustness. The method is illustrated on a real-life model of the Western region of the RTE system. The choice of the controller settings is discussed in some detail and examples of performance are given, combining the above remedial action with capacitor switching and secondary voltage control. [less ▲]

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See detailWide-area Detection of Voltage Instability from Synchronized Phasor Measurements. Part II: Simulation results
Glavic, Mevludin; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2009), 24(3), 1417-1425

This two-part paper deals with the early detection of an impending voltage instability from the system states provided by synchronized phasor measurements. Recognizing that voltage instability detection ... [more ▼]

This two-part paper deals with the early detection of an impending voltage instability from the system states provided by synchronized phasor measurements. Recognizing that voltage instability detection requires assessing a multidimensional system, the method fits a set of algebraic equations to the sampled states, and performs an efficient sensitivity in order to identify when a combination of load powers has passed through a maximum. This second part of the paper presents simulation results obtained from detailed time-domain simulation of the Nordic32 test system, without and with measurement noise, respectively. Several practical improvements are described such as anticipation of overexcitation limiter activation, and use of a moving average filter. Robustness to load behaviour, non updated topology and unobservability is also shown. Finally a comparison with Thevenin impedance matching criterion is provided. [less ▲]

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See detailWide-area Detection of Voltage Instability from Synchronized Phasor Measurements. Part I: Principle
Glavic, Mevludin; Van Cutsem, Thierry ULg

in IEEE Transactions on Power Systems (2009), 24(3), 1408-1416

This two-part paper deals with the early detection of an impending voltage instability from the system states provided by synchronized phasor measurements. Recognizing that voltage instability detection ... [more ▼]

This two-part paper deals with the early detection of an impending voltage instability from the system states provided by synchronized phasor measurements. Recognizing that voltage instability detection requires assessing a multi-dimensional system, the method fits a set of algebraic equations to the sampled states, and performs an efficient sensitivity computation in order to identify when a combination of load powers has passed through a maximum. The important effects of overexcitation limiters are accounted for. The approach does not require any load model. This first part of the paper is devoted to theoretical foundations of sensitivity calculation along the system trajectory, derivation of the algebraic model, and illustration on a simple 5-bus system involving the long-term dynamics of a load tap changer and a field current limiter. [less ▲]

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See detailSecurity Assessment by Multiple Transmission System Operators Exchanging Sensitivity and Tie-Line Power Flow Information
Fabozzi, Davide ULg; Glavic, Mevludin; Wehenkel, Louis ULg et al

in Proceedings of the 2009 IEEE PES Power Tech conference (2009, July)

This paper considers a procedure for multi-area static security assessment of large interconnected power systems operated by a team of Transmission System Operators (TSOs). In this procedure, each TSO ... [more ▼]

This paper considers a procedure for multi-area static security assessment of large interconnected power systems operated by a team of Transmission System Operators (TSOs). In this procedure, each TSO provides the other TSOs with his own equivalent model as well as the detailed effects of contingencies in his control area on all tie-line flows. The paper deals with the implementation of sensitivity-based equivalents suitable for static security assessment. Accuracy with respect to the unreduced model and computational efficiency are considered in evaluating the proposed approach. The relevance of the procedure in the context of recent UCTE operational security policy recommendations is also stressed. The procedure has been implemented in an AC power flow program and tested on a three-area variant of the IEEE 118-bus test system. [less ▲]

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See detailA Framework for the Simultaneous Clearing of Multiple Markets within a Common Transmission System
Marinakis, Adamantios ULg; Rosehart, William; Van Cutsem, Thierry ULg

in Proceedings of the 2009 IEEE PES Power Tech conference (2009, July)

The possibility for market participants to place their bids in all the markets of an interconnection irrespective of where they are physically connected is investigated in this paper. A mechanism is ... [more ▼]

The possibility for market participants to place their bids in all the markets of an interconnection irrespective of where they are physically connected is investigated in this paper. A mechanism is proposed for managing the resulting congestion. It consists in iteratively sharing the transmission line capacities between the different market operators based each time on their present schedules. The algorithm is applied on a small test system. The results are assessed in terms of their property of being Nash equilibria and of their distance of the set of Pareto optimal operating points. [less ▲]

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See detailSimplified time-domain simulation of detailed long-term dynamic models
Fabozzi, Davide ULg; Van Cutsem, Thierry ULg

in Proceedings of the 2009 IEEE PES General Meeting (2009, July)

Time-domain simulation of power system long-term dynamics involves the solution of large sparse systems of nonlinear stiff differential-algebraic equations. Simulation tools have traditionally focused on ... [more ▼]

Time-domain simulation of power system long-term dynamics involves the solution of large sparse systems of nonlinear stiff differential-algebraic equations. Simulation tools have traditionally focused on the accuracy of the solution and, in spite of many algorithmic improvements, time simulations still require a significant computational effort. In some applications, however, it is sufficient to have an approximate system response of the detailed model. The paper revisits the merits of the Backward Euler method and proposes a strategy to control its step size, with the objective of filtering out fast stable oscillations and focusing on the aperiodic behaviour of the system. The proposed method is compared to detailed simulation as well as to the quasi-steadystate approximation. Illustrative examples are given on a small but representative system, subject to long-term voltage instability. [less ▲]

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See detailLocal vs. wide-area undervoltage load shedding in the presence of induction motor loads
Otomega, Bogdan; Van Cutsem, Thierry ULg

in Proceedings of the IEEE PES PowerTech 2009 conference (2009, July)

In the presence of induction motor loads, long-term voltage instability may end up in a sharp voltage decrease, which makes the tuning of undervoltage load shedding more delicate. This paper first ... [more ▼]

In the presence of induction motor loads, long-term voltage instability may end up in a sharp voltage decrease, which makes the tuning of undervoltage load shedding more delicate. This paper first investigates the ability of a purely distributed load shedding scheme, previously proposed by the authors, to cope with these situations. Owing to difficulties to reconcile dependability and security, an alternative wide-area protection is considered. The latter consists of generators sending overexcitation signals to the load shedding controllers in order to allow the latter to act faster. Detailed time simulations of a test system are reported. [less ▲]

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See detailCoupling optimization and dynamic simulation for preventive-corrective control of voltage instability
Capitanescu, Florin ULg; Van Cutsem, Thierry ULg; Wehenkel, Louis ULg

in IEEE Transactions on Power Systems (2009), 24(2), 796-805

This paper proposes an approach coupling security constrained optimal power flow with time-domain simulation to determine an optimal combination of preventive and corrective controls ensuring a voltage ... [more ▼]

This paper proposes an approach coupling security constrained optimal power flow with time-domain simulation to determine an optimal combination of preventive and corrective controls ensuring a voltage stable transition of the system towards a feasible long-term equilibrium, if any of a set of postulated contingencies occurs. A security-constrained optimal power flow is used to adjust the respective contribution of preventive and corrective actions. Furthermore, information is extracted from (quasi steady-state) time-domain simulations to iteratively adjust the set of coupling constraints used by a corrective security constrained optimal power flow until its solution is found dynamically secure and viable. Numerical results are provided on a realistic 55-bus test system. [less ▲]

Detailed reference viewed: 107 (19 ULg)