References of "Wehenkel, Louis"
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See detailTemporal machine learning for switching control
Geurts, Pierre ULg; Wehenkel, Louis ULg

in Proceedings of PKDD 2000, 4th European Conference on Principles of Data Mining and Knowledge Discovery (2000)

In this paper, a temporal machine learning method is presented which is able to automatically construct rules allowing to detect as soon as possible an event using past and present measurements made on a ... [more ▼]

In this paper, a temporal machine learning method is presented which is able to automatically construct rules allowing to detect as soon as possible an event using past and present measurements made on a complex system. This method can take as inputs dynamic scenarios directly described by temporal variables and provides easily readable results in the form of detection trees. The application of this method is discussed in the context of switching control. Switching (or discrete event) control of continuous systems consists in changing the structure of a system in such a way as to contreol its behavior. Given a particular discrete control switch, detection trees are applied to the induction of rules which decide based on the available measurements whether or not to operate a switch. Two practical applications are discussed in the context of electrical power systems emergency control. [less ▲]

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See detailInvestigation and reduction of discretization Variance in decision tree induction
Geurts, Pierre ULg; Wehenkel, Louis ULg

in Proceedings of ECML 2000, European Conference on Machine Learning (2000)

This paper focuses on the variance introduced by the discretization techniques used to handle continuous attributes in decision tree induction. Different discretization procedures are first studied ... [more ▼]

This paper focuses on the variance introduced by the discretization techniques used to handle continuous attributes in decision tree induction. Different discretization procedures are first studied empirically, then means to reduce the discretization variance are proposed. The experiments shows that discretization variance is large and that it is possible to reduce it significantly without notable computational costs. The resulting variance reduction mainly improves interpretability and stability of decision trees, and marginally their accuracy. [less ▲]

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See detailProbabilistic design of power-system special stability controls
Wehenkel, Louis ULg; Lebrevelec, Cyril; Trotignon, Marc et al

in Control Engineering Practice (1999), 7(2), 183-194

A probabilistic approach to the design of power-system special stability controls is presented here. Using Monte-Carlo simulations, it takes into account all the potential causes of blackouts, slow and ... [more ▼]

A probabilistic approach to the design of power-system special stability controls is presented here. Using Monte-Carlo simulations, it takes into account all the potential causes of blackouts, slow and fast dynamics, and modeling uncertainties. A large number of scenarios are simulated in parallel by time-domain numerical integration, and the relevant parameters of the resulting system trajectories are stored in a database. Data-mining tools are used to identify the most important system weaknesses and possible improvements. The approach is tested on a large-scale study on the SouthÐEastern part of the extra-high-voltage system of Electricité de France. [less ▲]

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See detailTransient stability-constrained optimal power flow
Bettiol, Arlan; Ruiz-Vega, Daniel; Ernst, Damien ULg et al

in Proceedings of the IEEE Power Tech'99 (1999)

This paper proposes a new approach able to maximize the interface flow limits in power systems and to find a new operating state that is secure with respect to both, dynamic (transient stability) and ... [more ▼]

This paper proposes a new approach able to maximize the interface flow limits in power systems and to find a new operating state that is secure with respect to both, dynamic (transient stability) and static security constraints. It combines the Maximum Allowable Transfer (MAT) method, recently developed for the simultaneous control of a set of contingencies, and an Optimal Power Flow (OPF) method for maximizing the interface power flow. The approach and its performances are illustrated by means of simulations carried out on a real world power system. [less ▲]

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See detailData mining tools and application in power system engineering
Olaru, Cristina; Geurts, Pierre ULg; Wehenkel, Louis ULg

in Proceedings of the 13th Power System Computation Conference, PSCC99 (1999)

The power system field is presently facing an explosive growth of data. The data mining (DM) approach provides tools for making explicit some implicit subtle structure in data. Applying data mining to ... [more ▼]

The power system field is presently facing an explosive growth of data. The data mining (DM) approach provides tools for making explicit some implicit subtle structure in data. Applying data mining to power system engineering is an iterative and interactive process, requiring an acquainted user with the application specifics. The paper describes data mining tools like statistical methos, visualization, machine learning and neural networks, exemplifying by results obtained with a DM software developed for dynamic security assessment studies. Power system engineering applications where data mining would be useful are reviewed in the second part of the paper. [less ▲]

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See detailEmergency control and its strategies
Wehenkel, Louis ULg

in Proceedings of the Power Systems Computation Conference 1999 (1999)

The objective of this paper is to discuss research trends in the context of power system emergency control. First, different possible strategies are discussed for the design of emergency control schemes ... [more ▼]

The objective of this paper is to discuss research trends in the context of power system emergency control. First, different possible strategies are discussed for the design of emergency control schemes. Then some new research directions are presented. The paper does not restrict its scope to a particular type of stability problem. Rather, it aims at providing a global view of emergency control and discusses the potential impact of new approaches. [less ▲]

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See detailTransient stability-constrained generation rescheduling
Ruiz-Vega, Daniel; Bettiol, Arlan; Ernst, Damien ULg et al

in Proceedings of 1998 IREP Symposium - Bulk Power System Dynamics and Control - IV (1998, August)

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See detailReal-time transient stability emergency control of the South-Southeast Brazilian system
Ernst, Damien ULg; Bettiol, Arlan; Zhang, Yiwei et al

in Proceedings of SEPOPE 1998 (1998)

A method is proposed for during transients emergency control which predicts the evolution of a system undergoing a major disturbance and, if loss of synchronism is anticipated decides control actions able ... [more ▼]

A method is proposed for during transients emergency control which predicts the evolution of a system undergoing a major disturbance and, if loss of synchronism is anticipated decides control actions able to contain it. The method emanates from SIME, a hybrid time-domain direct method originally designed for realtime preventive transient stability assessment and control. The devised “emergency SIME” has similar interesting features, namely, robustness, accuracy, speed - and also predictive capabilities. Besides, the emergency approach has some intrinsic advantages over the “preventive” approach, namely, it is free from modelling and/or parameter uncertainties (since it relies on real-time measurements rather than time-domain simulations), and it encounters the real stability problem (operating point and contingency scenario rather than base case solutions and list of plausible contingencies). The method is general with respect to power system configurations, types of generation and of controls. In this paper a generation shedding scheme is worked out and applied to the real-time monitoring of the Itaipu-Foz do Igua¸cu corridor. It is shown that it can advantageously complement the existing automatic emergency control scheme. [less ▲]

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See detailCompensation schemes for transient stability assessment and control
Ernst, Damien ULg; Bettiol, Arlon; Zhang, Yiwei et al

in Proceedings of LESCOPE 98 (1998)

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See detailVisualizing dynamic power system scenarios for data mining
Geurts, Pierre ULg; Wehenkel, Louis ULg

in Proceedings of LESCOPE 98, Large Engineering Syst. Conf. on Power Engineering (1998)

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See detailEarly prediction of electric power system blackouts by temporal machine learning
Geurts, Pierre ULg; Wehenkel, Louis ULg

in Proceedings of ICML-AAAI 98 Workshop on "Predicting the future: AI approaches to time series analysis" (1998)

This paper discusses the application of machine learning to the design of power system blackout prediction criteria, using a large database of random power system scenarios generated by Monte-Carlo ... [more ▼]

This paper discusses the application of machine learning to the design of power system blackout prediction criteria, using a large database of random power system scenarios generated by Monte-Carlo simulation. Each scenario is described by temporal variables and sequences of events describing the dynamics of the system as it might be observed from real-time measurements. The aime is to exploit the data base in order to derive as simple as possible rules which would allow to detect an incipient blackout early enough to prevent or mitigate it. We propose a novel "temporal tree induction" algorithm in order to exploit temporal attributes and reach a compromise between the degree of anticipation and selectivity of detection rules. Tests are carried out on a a data base related to voltage collapse of an existing large scale power system. [less ▲]

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See detailMachine-learning approaches to power-system security assessment
Wehenkel, Louis ULg

in IEEE Expert (1997), 12(5), 60-72

The paper discusses a framework that uses machine learning and other automatic-learning methods to assess power-system security. The framework exploits simulation models in parallel to screen diverse ... [more ▼]

The paper discusses a framework that uses machine learning and other automatic-learning methods to assess power-system security. The framework exploits simulation models in parallel to screen diverse simulation scenarios of a system, yielding a large database. Using data mining techniques, the framework extracts synthetic information about the simulated system's main features from this database [less ▲]

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See detailPower system security assessment: a position paper
Marceau, R.J.; Endrenyi, J.; Allan, R. et al

in Electra (1997), 175

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See detailSIME: A hybrid approach to fast transient stability assessment and contingency selection
Zhang, Ywee; Wehenkel, Louis ULg; Rousseaux, Patricia ULg et al

in International Journal of Electrical Power & Energy Systems (1997), 19(3), 195-208

We propose an integrated scheme for transient stability assessment which in a sequence screens contingencies and scrutinizes only the selected ones. This scheme is based on a hybrid method, called SIME ... [more ▼]

We propose an integrated scheme for transient stability assessment which in a sequence screens contingencies and scrutinizes only the selected ones. This scheme is based on a hybrid method, called SIME for Single Machine Equivalent. SIME relies on a particular direct method coupled with time-domain programs so as to combine the strengths of both, namely: the flexibility with respect to power system modelling of time-domain methods; the speed and richer information of the direct method. This paper lays the foundations of SIME, devises appropriate techniques for transient stability assessment per se and for contingency screening, and finally integrates these two techniques in a fully general function, i.e. able to comply with any power system modelling and stability scenario, and to assess any type of stability limits (critical clearing times or power limits). Throughout, real-world examples illustrate the proposed techniques and highlight their performances. [less ▲]

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See detailAn approach to real-time transient stability assessment and control
Pavella, Mania ULg; Wehenkel, Louis ULg; Bettiol, Arlon et al

in Techniques for stability limit search - Publication IEEE : TP-138-0 (1997)

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See detailAutomatic learning techniques in power systems
Wehenkel, Louis ULg

Book published by Springer (1997)

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See detailContingency severity assessment for voltage security using non-parametric regression techniques
Wehenkel, Louis ULg

in IEEE Transactions on Power Systems (1996), 11(1), 101-111

This paper proposes a novel approach to power system voltage security assessment exploiting nonparametric regression techniques to extract simple, and at the same time reliable, models of the severity of ... [more ▼]

This paper proposes a novel approach to power system voltage security assessment exploiting nonparametric regression techniques to extract simple, and at the same time reliable, models of the severity of a contingency, defined as the difference between pre- and post-contingency load power margins. The regression techniques extract information from large sets of possible operating conditions of a power system screened offline via massive random sampling, whose voltage security with respect to contingencies is pre-analyzed using an efficient voltage stability simulation. In particular, regression trees are used to identify the most salient parameters of the pre-contingency topology and electrical state which influence the severity of a given contingency, and to provide a first guess transparent approximation of the contingency severity in terms of these latter parameters. Multilayer perceptrons are exploited to further refine this information. The approach is demonstrated on a realistic model of a large scale voltage stability limited power system, where it shows to provide valuable physical insight and reliable contingency evaluation. Various potential uses in power system planning and operation are discussed [less ▲]

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See detailFirst- and multi-swing transient stability limits of the Hydro-Québec system using the SIME method
Zhang, Y.; Wehenkel, Louis ULg; Rousseaux, Patricia ULg et al

in Proceedings of the Melecon'96 Conference (1996)

Detailed reference viewed: 25 (1 ULg)
See detailSIME : a comprehensive approach to fast transient stability assessment
Zhang, Y.; Rousseaux, Patricia ULg; Wehenkel, Louis ULg et al

in Proceeding of the IEE Japan'96 Conference (1996)

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See detailOn uncertainty measures used for decision tree induction
Wehenkel, Louis ULg

in Bouchon-Meunier, Bernadette (Ed.) Information Processing and Management of Uncertainty in Knowledge-Based Systems (1996)

This paper provides a further look at uncertainty or information criteria used in the context of deci- sion tree induction, and more generally of learn- ing conditional class probability models. We show ... [more ▼]

This paper provides a further look at uncertainty or information criteria used in the context of deci- sion tree induction, and more generally of learn- ing conditional class probability models. We show the high degree of similarity among two main families of criteria based respectively on the logarithmic SHANNON entropy function and the quadratic GINI index. We start by introduc- ing a general family of entropy functions and then discuss the latter particular cases, and end up with a short review of the Kolmogorov-Smirnov dis- tance,anotherrelatedmeasure. [less ▲]

Detailed reference viewed: 89 (3 ULg)