Hydro-Québec

About: Hydro-Québec is a government organization based out in Montreal, Quebec, Canada. It is known for research contribution in the topics: Electric power system & Dielectric. The organization has 2596 authors who have published 4433 publications receiving 100878 citations.

Ionization and excitation behavior in a microcavity

Abstract: The excitation and ionization behavior of a 5 /spl mu/m cavity, subjected to an electric field of 270 kV/cm, has been examined. Data on the production of electrons, ions, dissociated molecules and excited species is presented and the associated charge transfer characteristics are considered. The implications of the ionization and excitation processes, as concerns their effect upon the degradation rate of solid insulation, are discussed. >

Theoretical and experimental investigations on the process of high-pressure discharge development

Abstract: The voltage breakdown behavior of a plane-parallel gap of 0.48-mm length filled with helium was examined at atmospheric pressure with admixtures of dry air at relative pressures of 0, 10/sup -4/, 3*10/sup -4/, and 10/sup -3/. The initial stages of the breakdown were investigated by means of a quantitative model consisting of the electron, ion, and excited-particle conservation equations and the Poisson equation. The system of equations was solved for an applied voltage of 180 V, at one single partial pressure of the impurities. Two numerical routines were used for the solution: a commercial IMSL subroutine TWODEPEP, and a newly developed method of solution in several fractional steps. The results were compared and found to be in reasonable agreement although the new method indicated a somewhat slower rate of rise, particularly concerning electron density. The new method permits extension of the calculation up to electron densities equal to almost two orders of magnitude above the earlier limit. >

Rough Terrain Reconstruction for Rover Motion Planning

Abstract: A two-step approach is presented to generate a 3D navigable terrain model for robots operating in natural and uneven environment. First an unstructured surface is built from a 360 degrees field of view LIDAR scan. Second the reconstructed surface is analyzed and the navigable space is extracted to keep only the safe area as a compressed irregular triangular mesh. The resulting mesh is a compact terrain representation and allows point-robot assumption for further motion planning tasks. The proposed algorithm has been validated using a large database containing 688 LIDAR scans collected on an outdoor rough terrain. The mesh simplification error was evaluated using the approximation of Hausdorff distance. In average, for a compression level of 93.5%, the error was of the order of 0.5 cm. This terrain modeler was deployed on a rover controlled from the International Space Station (ISS) during the Avatar Explore Space Mission carried out by the Canadian Space Agency in 2009.

A Fast State Estimator for Systems Including Limited Number of PMUs

Abstract: This paper presents a fast state estimator and a corresponding bad data (BD) processing architecture aimed at improving computational efficiency and maintaining high estimation accuracy of existing state estimation (SE) algorithms, simultaneously. The conventional and phasor measurements are separately processed by a three-stage SE method and a linear estimator, respectively. Then, the derived estimates are combined using estimation fusion theory. To eliminate computational bottlenecks of the conventional BD processing scheme, BD identification is moved before the second stage of supervisory control and data acquisition based SE, and bad phasor measurements or bad conventional measurements in the phasor measurement units observable area are identified and processed all at once, which can dramatically reduce the implementation time, especially for large-scale networks with multiple BD. The proposed estimator is compared to existing methods in terms of estimation accuracy and computational effort through simulation studies conducted on standard IEEE test systems. Promising simulation results show that the proposed estimator could be an effective method to obtain system states in a fast and accurate manner.

Improved Optimal Decentralized Load Modulation for Power System Primary Frequency Regulation

Abstract: Nowadays the interest in smart load technologies for primary frequency regulation is spurred due to the increasing penetration of renewable energy resources. In this paper, an improved optimal load control (improved OLC) is introduced by applying a multiobjective optimization-based gain-tuning method to the conventional OLC approach. The objective is to minimize the frequency nadir, time response, steady-state error, total load shed, and aggregated disutility of controllable loads subject to power balance over the network. Simulation results indicate that enabling a multiobjective optimization-based gain-tuning procedure in the OLC approach can provide better power system frequency regulation. Time-domain analysis confirms the superior performance of improved OLC in terms of frequency nadir (Hz), steady-state error (Hz), control effort, and NERC-based performance metrics (MW/0.1 Hz), with detailed load and wind farm models. Furthermore, small-signal analysis demonstrates that the improved OLC enhances the system closed-loop performance and stability margins by increasing the damping ratio of the system's critical modes.