Optimal PMU-based monitoring architecture design for power systems

International audienceThis paper is dedicated to a new methodology for designing an optimal monitoring architecture by using a limited number of PMUs (Phasor Measurement Units) and PDCs (Phase Data Concentrators). The optimal design problem consists in defining the optimal location of both PMUs and PDCs by maximizing the expected value of the trace of the observability gramian of the power system over a large number of set point scenarios, while minimizing some communication infrastructure costs. Furthermore, a nonlinear dynamical state-observer, based on the Extended Kalman Filter, is proposed. This state-observer allows to take transient phenomena into account for wide-area power systems described by algebraic-differential equations, without needing nonlinear inversion techniques. The overall approach is illustrated with the IEEE 10 generator 39 bus New England power system

A Variational Calculus Approach to Wildfire Monitoring Using a Low-Discrepancy Sequence-Based Deployment of Sensors

International audienceThis paper deals with the estimation of the wildfire ignition location by using a variational approach, which, to the best of my knowledge, has never been proposed before. Wildfires are here modeled by using two balance equations for energy and fuel, where the fuel loss due to combustion is defined by the fuel reaction rate. The physical coefficients of the model, together with the initial fuel distribution, are here supposed to be known. The use of a small number of low cost temperature sensors constituting a sensor network distributed on the field according to a low-discrepancy sequence is investigated which provides some promising results for this estimation problem considered to be very difficult in the litterature

Infectious Risk Factors Related to Operating Rooms

Risk factors related to operating rooms include patient-associated risks, the operating room environment, ventilation systems, cleansing and sterilization, and operating room personnel. Although constantly debated, surgical wound infection surveillance with appropriate feedback to surgeons is one of the few effective measures that helps reduce surgical infection rates, and we strongly recommend its use. We also recommend the further study of other potential components of effective infection control programs for surgical patient

Universal quantum transport and impurity band super metallicity in self-similar graphene carpets

Fractals, a fascinating mathematical concept made popular in the eighties, remained for decades a beautiful scientific curiosity mainly. With the tremendous advances in nanofabrication techniques, such as nanolithography, it has become possible to design self-similar materials with fine structures down to nanometer scale. Here, we investigate the effects of self similarity on quantum electronic transport in graphene Sierpinski carpets. We find that a gap opens up in the electron spectrum in the middle of which lies a flat band of zeros energy modes. Although these states have a zero velocity, a supermetallic phase is found at the neutrality point. For Fermi energy located in the valence/conduction band and in the presence of a small inelastic scattering the system stays metallic and the transport is found strongly anisotropic.Comment: 6 figure

An advanced On-line Wind Resource Prediction system for the optimal management of wind park

International audienceThe paper presents an advanced wind forecasting system that uses on-line SCADA measurements, as well as numerical weather predictions as input to predict the power production of wind parks 48 hours ahead. The prediction tool integrates models based on adaptive fuzzy-neural networks configured either for short-term or long-term forecasting. In each case, the model architecture is selected through non-linear optimization techniques. The forecasting system is integrated within the MORE-CARE EMS software developed in the frame of a European research project. Within this on-line platform, the forecasting module provides forecasts and confidence intervals for the wind farms in a power system, which can be directly used by economic dispatch and unit commitment functions. The platform can run also as a stand-alone application destined only for wind forecasting. Detailed results are presented on the performance of the developed models on a real wind farm using HIRLAM numerical weather predictions as input

Simulation parallèle de la relaxation post-sismique dans la région de Sumatra

National audienceOn s'intéresse ici au calcul des déformations post-sismiques, dues principalement au phénomène de relaxation dans l'asthénosphère visqueuse. Ces simulations font intervenir un comportement viscoélastique et des éléments de zone cohésive pour modéliser le glissement sur la faille. La prise en compte de la géométrie particulière de cette zone, ainsi que la nécessité de couvrir une zone géographique allant de la Chine à l'Australie conduit à des calculs par éléments finis de très grande taille, que l'on aborde par décomposition de domaines sur calculateur parallèle

State and parameter estimation in 1-D hyperbolic PDEs based on an adjoint method

International audienceAn optimal estimation method for state and distributed parameters in1-D hyperbolic system based on adjoint method is proposed in thispaper. A general form of the partial differential equations governingthe dynamics of system is first introduced. In this equation, theinitial condition or state variable as well as some empiricalparameters are supposed to be unknown and need to be estimated. TheLagrangian multiplier method is used to connect the dynamics of thesystem and the cost function defined as the least square error betweenthe simulation values and the measurements. The adjoint state method isapplied to the objective functional in order to get the adjoint systemand the gradients with respect to parameters and initial state. Theobjective functional is minimized by Broyden–Fletcher–Goldfarb–Shanno(BFGS) method. Due to the non-linearity of both direct and adjointsystem, the nonlinear explicit Lax–Wendroff scheme is used to solvethem numerically. The presented optimal estimation approach isvalidated by two illustrative examples, the first one about state andparameter estimation in a traffic flow, and the second one in anoverland flow system

A Decentralized Optimal LQ State Observer Based On An Augmented Lagrangian Approach

à paraître dans AUTOMATICA en 2014International audienceThis paper is devoted to the design of a decentralized optimal batch LQ state observer for state estimation of large-scale interconnected systems, well suited for implementation on a sensor network. The here-proposed approach relies on both the use of an augmented Lagrangian formulation and a price-decomposition-coordination algorithm. The state estimation of an open-channel hydraulic system illustrates the effectiveness of this approach and is used to provide a comparison with alternative methods