Optimal network congestion management using wind farms

With the increased use of wind energy for the power generation several TSO have increasing difficulties for congestion forecasting due to the unpredictable nature of the energy source. An actual method used to deal with days-ahead congestion planning is based on an order of disconnection of the generation of the type “last generation installed, first generation limited”. This paper proposes to enhance the congestion management using a real time supervisor. This supervisor is developed to perform automatic and dynamic re-dispatching using both wind and conventional generators. In order to reduce the production constraints to the minimum, the real time congestion management is based on an indicator of the efficiency of a re-dispatching on the power flowing in the overloaded line. This approach leads to reduced re-dispatching costs and increased network reliability. Actual and proposed methods are compared in the paper using Matlab/Simulink simulations of a realistic test grid. It is shown that the real-time supervisor allows maximization of renewable production during congestions while ensuring network reliability.Congestion management; Wind farm; Power Transfer Distribution Factors (PTDF); Power system control; Active power dispatch; Variable speed wind turbines.

Real time grid congestion management in presence of high penetration of wind energy

With the increased use of wind energy the power generation several Transmission System Operators (TSO) have increasing difficulties for congestion forecasting due to the unpredictable nature of the energy source. This paper proposes to enhance the congestion management using a real time supervisor. This supervisor is developed to perform automatic and dynamic re-dispatching using both wind and conventional generators. In order to reduce the production constraints to the minimum, the real time congestion management is based on an indicator of the efficiency of a re-dispatching on the power flowing in the overloaded line. This approach leads to reduced re-dispatching costs and increased network reliability. The simulation of the supervisor and the test grid is realized using by the EUROSTAG [1]. It is shown that the real-time supervisor allows maximization of renewable production during congestions while ensuring network reliability.Power management ;Power transmission;Energy system management;Wind energy ; Variable speed drive

Chevreuse de Patrick Modiano, ou la quête mémorielle d’un passé insaisissable

Following in the footsteps of vanished existences is one of the motifs of Patrick Modiano’s writings. Chevreuse is a variation on this theme, featuring a character who tries to recover his past threatened by oblivion. It is, however, singular that the modality of this memorial quest is introspective. This article will explore how the narrative navigates the tension between the apparent looseness of the plot, which becomes mimetic of the experience of remembering itself, and the attempt to create, by means of writing, a network allowing the memories to make sense of one another. From this perspective, we will study the two valences of the writing which embrace the convolutions of a lacunar memory on its becoming a hermeneutic instrument; then we will demonstrate that this ars memoriae endows itself with a poetics of dream and imagination to overcome this ambivalence and to proceed to the mental recreation of a disappeared world.C’est un topique des écrits de Patrick Modiano que de partir sur les traces d’existences disparues. Mettant en scène un personnage qui tente de se ressaisir de son propre passé menacé par l’oubli, Chevreuse se comprend comme une variation sur thème. Il est toutefois singulier que la modalité de cette quête mémorielle soit introspective. Aussi s’agit-il d’explorer la manière dont la narration élabore une tension entre l’apparente lâcheté de l’intrigue qui se fait mimétique de l’expérience même de remémoration, et la tentative d’élaborer par l’écriture un réseau permettant aux souvenirs de faire sens les uns par rapport aux autres. Dans cette perspective, nous étudierons les deux valences de l’écriture qui embrasse les circonvolutions d’une mémoire lacunaire autant qu’elle se mue en instrument herméneutique ; puis nous montrerons qu’en dernière instance, cet ars memoriae se dote d’une poétique du rêve et de l’imagination afin de dépasser cette ambivalence et de procéder à la recréation mentale d’un monde disparu

Le rapport des eleves orthophonistes a la difficulte scolaire en mathematiques

En France, une profession paramédicale occupe le terrain de la prise en charge de l’échec scolaire, les orthophonistes. Initialement spécialisés dans le traitement des pathologies liées au langage, ceux-ci ont progressivement étendu leur champ d’intervention aux difficultés d’apprentissage en lecture (dyslexie) et en mathématiques (dyscalculie). Nous nous intéressons ici au rapport à la difficulté scolaire en mathématiques des étudiants en école d’orthophonie tel qu’il s’exprime à travers un corpus de 41 mémoires de fin d’études soutenus entre 2000 et 2018. Nous mettons en évidence que ce rapport se construit au croisement de deux systèmes de normes non articulés : celui de l’institution scolaire qui détermine l’enjeu de la prise en charge orthophonique et celui de la psychologie et des neurosciences qui déterminent l’objet et les méthodes de cette prise en charge

Generally Accepted Reliability Principle with Uncertainty Modelling and Through Probabilistic Risk Assessment : Functional Analysis of System Development Process

This report gives a functional analysis of the current system development process among European TSOs. System development deals with taking decisions that change transmission capacities either within a TSO’s own system or towards other TSOs systems. Inputs to this report have been gathered from workshops in the GARPUR project and a questionnaire to 10 TSOs that are either part of GARPUR consortium or a member of GARPUR reference group. Despite the limited number of respondents to the questionnaire, the responses are quite representative for European practice since the respondents represent different system sizes, characteristics and control zones within Europe

Upgrading of the decision-making process for system development

The planning horizon for a system development planner is long and a system planner must take into account potential changes to generation capacity and demand during that horizon. The uncertainties that affect system development are greater than those that apply, for example, in system operations. Thus, it is important to build up a credible set of operating states that is informed by various uncertainties and adequately represents the range of conditions that might reasonably be expected to arise. The next step in the system development process is to assess these operating states for system operability. If a power system is not operable on some (probable) operating states, then it identifies a potential need for investment in the system. However, given the number and range of uncertainties relevant to system development, pragmatic approaches must also be developed allowing their assessment. In this report, a comprehensive system development approach is presented

Enhanced, risk-based system development process : a case study from the Belgian transmission network

A large share of renewable generation raises some unique challenges and is forcing change in the operation and planning of electricity transmission systems. In this paper, using real transmission network data representing a part of the Belgian network, the need for building a large set of credible future operating conditions to identify and validate system development decisions is demonstrated. The paper argues that the traditional approach of checking system development options on a few selected operating conditions is no longer adequate in a power system with high penetration of variable generation. An application of a clustering algorithm is demonstrated to build a representative set of operating conditions for system development that not only gives better representation of future operation, but also provides a system development planner with greater confidence with respect to investments that are likely to be necessary. The paper describes the way in which operability of the future system is evaluated and possible need for reinforcement is identified. A discussion is presented of the meeting of demand under initially intact network conditions and while facilitating maintenance outages securely

Pilot testing methodologies, models, scenarios and validation approach

This report describes the pilot tests that will be carried out within GARPUR. The pilot tests aim at assessing and validating, as closely as possible to real-life conditions, the new Reliability Management Approach and Criteria (RMACs) developed in work package 2 and the socio-economic impact assessment framework developed in work package 3, while considering the methodologies and approaches for practical implementation in work packages 4, 5 and 6. The proposed RMACs are compared against the current N-1 practices and approaches determined in work package 1. In addition, some pilot tests will make use of the GARPUR Quantification Platform (GQP) that has been developed by work package 7. A total of eight pilot tests are proposed by five different transmission system operators (TSOs) and given different priority levels for implementation. Three pilot tests make use of the GQP. The five other pilot tests will be implemented at TSOs’ premises in near real-life context. The pilot tests cover real-time operations, short-term operation planning and long-term system development. Different indicators are proposed to assess the proposed reliability management approach and criteria and compare them with current practices. The diversity of the pilot tests in terms of time horizons and the number of involved TSOs demonstrate the general nature of the reliability management approach and criteria proposed within GARPUR

Speech therapy for children with learning difficulties in mathematics

L’objet de cette thèse qui s’appuie sur la théorie anthropologique du didactique est l’étude des praxéologies des orthophonistes en France lorsqu’ils prennent en charge des sujets ayant des difficultés d’apprentissage récurrentes en mathématiques. La première partie présente le contexte de la société française qui conduit à une médicalisation de l’échec scolaire (Morel, 2014). Elle discute des définitions de la difficulté scolaire en mathématiques et de la dyscalculie et présente les cadres théorique et méthodologique de la recherche. La deuxième partie aborde l’histoire de la profession et comment s’est construit son assujétissement au monde de la médecine. La mise au jour des fondements théoriques de la profession concernant la prise en charge des difficultés d’apprentissage récurrentes en mathématiques y est réalisée par le croisement des analyses de différentes données : les plans de formation initiale et continue ; des questionnaires et entretiens avec des étudiants, formateurs et professionnels ; un corpus de mémoires d’étudiants en école d’orthophonie. Les deux dernières parties se fondent sur l’observation naturaliste de bilans et de séances de suivi orthophoniques sur la multiplication. L’analyse praxéologique des organisations mathématiques dans les séances observées contrastée par celle de manuels permet d’identifier différences et similitudes entre praxéologies orthophoniques et scolaires. La cartographie des types de tâches sur la base des ostensifs travaillés représente et révèle l’enjeu didactique du suivi orthophonique et le rôle épistémique du matériel. Enfin, l’analyse des organisations didactiques au sein des séances conduit à définir la relation thérapeutique orthophonique comme modèle de la situation. Cette relation entre l’orthophoniste et l’élève-patient dont les termes sont le plus souvent négociés implicitement est asymétrique. Elle repose d’une part, sur une adhésion et une confiance envers le thérapeute et d’autre part sur un contrat didactique instauré dans les séances de suivis fondé sur des milieux entièrement contrôlés qui réduisent l’élève-patient à l’exécution de tâches répétitives où la manipulation est omniprésente.In this doctoral dissertation, based on the anthropological theory of the didactic, we study French speech-language pathologists’ praxeologies when they treat students with recurrent learning difficulties in mathematics. The first part presents the context of French society which leads to the medicalization of school failure (Morel, 2014). We discuss the definitions of academic difficulty in mathematics and dyscalculia, and we present our theoretical and methodological frameworks. The second part deals with the history of this profession and its relationship with the medical world. Various data are combined to identify the theoretical background of the profession concerning the management of recurrent learning difficulties in mathematics: initial and continuing training syllabuses; questionnaires and interviews with students, trainers and professionals; a corpus of students’ dissertations in speech therapy schools. The last two parts are based on the observation of assessments and therapy sessions on multiplication. The praxeological analysis of the mathematical organizations in the observed sessions is compared to that of textbooks and makes it possible to identify the differences and similarities between speech therapy and school praxeologies. The mapping of the types of tasks, based on the ostensives worked during the session, represents and reveals the didactic stake of speech therapy follow-up and the epistemic role of the educational material. Finally, the analysis of the didactic organizations within the sessions leads to the definition of the speech therapy relationship as a model of the situation. The terms of this asymmetric relationship between the speech therapist and the student-patient are most often negotiated implicitly. It is based, on the one hand, on adherence and trust in the therapist and, on the other hand, on a didactic contract established in the therapy sessions. This special didactic contract is based on fully controlled environments which reduce the student-patient’s activity to the execution of repetitive tasks where manipulation is omnipresent