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.

High Capacity and High Efficiency Maple Tree-Biomass-Derived Hard Carbon as an Anode Material for Sodium-Ion Batteries

Abstract: Sodium-ion batteries (SIBs) are in the spotlight because of their potential use in large-scale energy storage devices due to the abundance and low cost of sodium-based materials. There are many SIB cathode materials under investigation but only a few candidate materials such as carbon, oxides and alloys were proposed as anodes. Among these anode materials, hard carbon shows promising performances with low operating potential and relatively high specific capacity. Unfortunately, its low initial coulombic efficiency and high cost limit its commercial applications. In this study, low-cost maple tree-biomass-derived hard carbon is tested as the anode for sodium-ion batteries. The capacity of hard carbon prepared at 1400 °C (HC-1400) reaches 337 mAh/g at 0.1 C. The initial coulombic efficiency is up to 88.03% in Sodium trifluoromethanesulfonimide (NaTFSI)/Ethylene carbonate (EC): Diethyl carbonate (DEC) electrolyte. The capacity was maintained at 92.3% after 100 cycles at 0.5 C rates. The in situ X-ray diffraction (XRD) analysis showed that no peak shift occurred during charge/discharge, supporting a finding of no sodium ion intercalates in the nano-graphite layer. Its low cost, high capacity and high coulombic efficiency indicate that hard carbon is a promising anode material for sodium-ion batteries.

Cumulative effects assessments at Hydro-Québec: what have we learned?

Abstract: Twelve cumulative effects assessments (CEAs) have been conducted at Hydro-Quebec since 1999. This article explains how they have evolved in a seven-step approach. It also describes the problems encountered and solutions found for each of these steps. Hydro-Quebec's CEAs focus on historical and regional perspectives, including a detailed past baseline description. However, there is no specific methodology proposed for significance determination, and possibly no need for it. CEAs provide a broader view that is found useful to assess impacts sometimes not properly tackled at the project level, but the question of how the promoter should conduct follow-up and mitigation efforts in the context of cumulative effects is still open. CEA must be a separate section of an impact assessment with its own methodology, spatial and temporal scales. Only certain environmental components should be examined. A well-documented past baseline condition is essential. Future effects can rarely be predicted over a ten-year period...

Studies on modeling corona attenuation of dynamic overvoltages

Abstract: An experimental and theoretical study is presented on the corona characteristics of conductor bundles under dynamic overvoltages. Measurements have been made in the outdoor test cages of Institut de Recherche d'Hydro-Quebec on two bundles, under conditions of fair weather and heavy rain, for steady 60 Hz voltages as well as dynamic overvoltages. Based on the data on corona currents and losses obtained, a nonlinear resistance model of corona is proposed for attenuation studies. The Suliciu model for corona, originally developed for unipolar impulses, has been adapted for dynamic overvoltages. Both these corona models are used to study the influence of corona on the dynamic overvoltages developed during line energization and load shedding of a single-phase line. Among other findings, it is shown that the corona phenomenon stabilizes after the first half-cycle of the dynamic overvoltage. The corona losses of conductor bundles under fair weather conditions increase rapidly with the conductor surface voltage gradient; they approach losses under heavy rain at higher gradients. >

Selection of input/output signals for wide area control loops

Abstract: This paper studies the various aspects of input/output selection for wide-area damping controllers, targeted at the power system inter-area oscillation modes. The objectives is to choose a control loop which has large impact to a few selected modes, while does not affect the other system modes, hence the interactions problem can be greatly reduced. For this purpose, a new modal interaction index is proposed. Non linear simulations are also carried out to validate the modal analysis results.