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.

Methods for making lithium vanadium oxide electrode materials

Abstract: A method of making vanadium oxide formulations is presented. In one method of preparing lithium vanadium oxide for use as an electrode material, the method involves: admixing a particulate form of a lithium compound and a particulate form of vanadium compound; jet milling the particulate admixture of the lithium and vanadium compounds; and heating the jet milled particulate admixture at a temperature below the melting temperature of the admixture to form lithium vanadium oxide.

A portable, multiprocess, track-based robot for in situ work on hydropower equipment

Abstract: In the hydropower industry, in situ maintenance work of turbine runners to address issues such as cavitation damage and cracking is mainly performed manually. Alternatively, the entire turbine requires disassembly and is repaired off site at greater cost. This paper presents the development and fundamentals of robotic technology designed to perform work in situ on hydroelectric equipment. A second paper surveys field implementations carried out with the technology over the past 15 years. A new portable manipulator was designed with unique track-based kinematics well suited to accessing turbine blades in a confined space. The robot is driven by position-controlled stepper motors but relies on a hybrid force/position controller to perform processes in contact with the work piece, such as grinding. A major obstacle for robotic repair is excessive programming time. As most work is done on curved surfaces, the robot relies on a model of curvilinear space for trajectory generation. The robot is coupled to an accurate measurement system to scan surface topography in three dimensions. It has been equipped to perform several processes, such as welding and grinding, to facilitate the manufacture and maintenance of hydropower equipment. Despite the robot's inaccuracy and flexibility, surface profiles may be reconstructed with great accuracy through the use of a controlled metal removal rate strategy that relies on an innovative dynamic model of the grinding process. © 2011 Wiley Periodicals, Inc.

Multivariate analysis of flood characteristics in a climate change context of the watershed of the Baskatong reservoir, Province of Québec, Canada

Abstract: The analysis of the impact of climate change (CC) on flood peaks has been the subject of several studies. However, a flood is characterized not only by its peak, but also by other characteristics such as its volume and duration. Little effort has been directed towards the study of the impact of CC on these characteristics. The aim of the present study is to evaluate and compare flood characteristics in a CC context, in the watershed of the Baskatong reservoir (Province of Quebec, Canada). Comparisons are based on observed flow data and simulated flow series obtained from hydrological models using meteorological data from a regional climate model for a reference period (1971–2000) and a future period (2041–2070). To this end, two hydrological models HSAMI and HYDROTEL are considered. Correlations, stationarity, change-points, and the multivariate behaviour of flood series were studied. The results show that, at various levels, all flood characteristics could be affected by CC

Interpretation of resistivity sounding measurements in N-layer soil using electrostatic images

Abstract: Geophysical inversion involves the estimation of soil parameters from a set of observations. Multilayer soils are modeled by N horizontal layers with distinct resistivities and depths. For known soil parameters, the apparent resistivity distribution can be computed efficiently from electrostatic images. Since the model responses are generally nonlinear functions of the model parameters, least-squared minimization techniques prove to be useful for evaluating layer resistivities and depths to agree with measurements. This paper demonstrates how electrostatic images can be combined for increasing efficiency in the computation of apparent resistivities and sensitivity factors such as the first and second gradient of the distance with respect to the model parameters. The factors are then used to solve the more demanding task of resistivity interpretation of measurements from Wenner, Schlumberger, Dipole or alternate electrode configurations. Results are presented for two-layer soil and for actual cases with three layer soil.