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.

Low Hydrogen Overpotential Nanocrystalline Ni‐Mo Cathodes for Alkaline Water Electrolysis

Abstract: Nanocrystalline fcc Ni x Mo 1−x (x=0.60, 0.85 atom percent) metallic powders prepared by high energy mechanical alloying were found to possess electrocatalytic activities for the hydrogen evolution reaction in 30 weight percent KOH at 70°C equivalent to that of the best electrocatalysts. The formation process and the structural properties of these nanocrystalline alloys were investigated. The active phase is a metastable solid solution of Mo in fcc Ni whose electrocatalytic activity is associated with the reduction in the size of the crystallites and correlates with the expansion of the Ni lattice

Fabrication and properties of mechanically milled alumina/aluminum nanocomposites

Abstract: The reinforcement agglomeration in nanocomposites is a key issue that needs to be solved in order to fully benefit of the gain in strength and ductility associated with the decrease in reinforcement size from microscale to nanoscale. In this study, mechanical milling has been used successfully to disperse nanometric alumina (n-Al 2 O 3 ) in an aluminum matrix. Al 2 O 3 /Al nanocomposite powders have been produced for various alumina sizes and concentrations. The 10 vol% n-Al 2 O 3 /Al powders display hardness values near five times higher than pure unmilled Al. A decrease in the Al 2 O 3 particle size from 400 to 4 nm has increased the nanocomposite powder hardness by 11%. The microhardness and compression properties of an Al 2 O 3 /Al nanocomposite compact consolidated by hot pressing were measured. Comparison with modeled values and literature results indicates that the higher experimental yield strength obtained with the addition of n-Al 2 O 3 versus micron size Al 2 O 3 is due to in situ matrix strengthening.

Robust Detection and Analysis of Power System Oscillations Using the Teager-Kaiser Energy Operator

Abstract: Critical to real-time oscillations monitoring is early detection when otherwise dormant natural modes become a serious threat to grid stability. The next urgent issue is to determine the frequency and damping of the problematic modes when the signal is embedded in noise and the system contains closely spaced natural modes. The present paper addresses the detection issue using the Teager-Kaiser energy operator (TKEO) which has shown to be a fast predictor of the instability onset time when applied to the output signals of an orthogonal filter bank. In the system stability context, linear filter decomposition (LFD) is preferred rather than empirical mode decomposition (EMD), well known for its tendency to generate artificial modes with no physical meaning. A narrowband LFD with a less than 0.2-Hz bandwidth is achieved in the range 0.05 to 3 Hz through a cosine-modulated filter bank design. The effectiveness of the scheme in accurately detecting and tracking the frequency and damping of oscillatory modes is demonstrated using Monte Carlo simulations of three closely spaced modes and a detailed analysis of an actual event recorded by Hydro-Quebec's WAMS in 2006.