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.

Graphitization and particle size analysis of pyrolyzed cobalt phthalocyanine/carbon catalysts for oxygen reduction in fuel cells

Abstract: Cobalt phthalocyanine (CoPc) adsorbed on a carbon black support (Vulcan XC-72) and pyrolyzed at various temperatures is a potential catalyst for the reduction of oxygen in solid polymer electrolyte fuel cells. This paper reports the results of the microstructural characterization of β-Co particles that are formed after pyrolysis at temperatures of 700, 900, and 1050 °C. Transmission electron microscopy (TEM) indicated that (i) for a pyrolysis temperature of 700 °C, the size distribution of the Co particles is bell-shaped with an average value of 4 nm and mean deviation of 1 nm; (ii) for a pyrolysis temperature of 900 °C, the Co particle size distribution skews toward larger particle sizes. The most probable particle size is about 6 nm, and the average particle size is 13 nm. By comparison with the TEM results, the particle size estimated from a spectroscopic method like x-ray absorption is underestimated, while from x-ray diffraction is overestimated. The TEM images show that Co particles act as heterogeneous nucleation sites for the graphitization of amorphous carbon. It is shown that (i), at least for pyrolysis temperature of 900 °C and above, most of the β-Co particles are surrounded by a shell of graphitic carbon layers that appears to protect the particles from corrosion in acidic media; (ii) for pyrolysis temperature of 1050 °C, graphite strings also appear throughout the amorphous carbon support in areas where Co particles are not detected. This behavior was not observed after pyrolysis of as-received carbon support at 1050 °C. These results allow for a better understanding of the behavior of the pyrolyzed catalysts immersed in an acidic solution or in a solid polymer fuel cell.

Investigations on some electrochemical aspects of lithium-ion ionic liquid/gel polymer battery systems

Abstract: Electrochemical and interfacial characteristics of Li-ion battery system based on LiFePO4 cathode and graphite anode with ionic liquid (IL) electrolytes have been investigated, both with and without addition of a small amount of polymer to the electrolyte. The IL electrolyte consisted of bis(fluorosulfonyl)imide (FSI) as anion and 1-ethyl-3-methyleimidazolium (EMI) or N-methyl-N-propylpyrrolidinium (Py13) as cation, and operated at ambient temperature. We reported previously that the SEI formation with IL was stabilized in the graphite anode at 80% coulombic efficiency (CE) in the first cycle, when FSI anion is used. In this work, we extend the study to the LiFePO4 cathode material. Gel polymer with IL is one part of this study. The stepwise impedance spectroscopy was used to characterize the Li/IL-Gel polymer/LiFePO4 at different states of charge. This technique revealed that the interface resistance was stabilized when the cathode is at 70% DoD (Depth of Discharge). The diffusion resistance is higher at the two extremes of discharge when monophase LiFePO4 state (0%DoD and 100%DoD) obtains. When polymer is added to the IL, interface resistance is improved with 1 wt.% but results with IL alone are not improved for the case of 5 wt.% polymer added. Good cycling life stability was obtained with Li/IL-FSI/LiFePO4 cells, with or without polymer. The first evaluation of the Li-ion cell, LiFePO4/IL-FSI-(5 wt.%) gel polymer/graphite, has shown low first CE at 68.4% but it recovers in the third cycle, to 96.5%. Some capacity fade was noticed after 30 cycles. The rate capability of the Li-ion cell shows a stable capacity until 2 C discharge rate.

Evaluation of the costs and benefits of Microgrids with consideration of services beyond energy supply

Abstract: This paper examines a number of alternate business cases for Microgrids based on a variety of benefits that Microgrids have been reported to provide. The authors draw on proven methodologies for quantifying benefits and demonstrate how provision of services relating to social/environmental and technical benefits can support an economic business case for Microgrid development. The benefits are viewed in terms of a framework that relates stakeholders and benefits, and the methodology is tested in a case study based on an extant Canadian Microgrid. The potential impact of each benefit is calculated, and a break-even analysis is conducted to determine the value each benefit should provide to make the Microgrid feasible for stakeholders. These derived values are then compared to some typical market or contract values.

Field‐oriented developments for LineScout Technology and its deployment on large water crossing transmission lines

Abstract: Condition assessments for power transmission line infrastructure and conductors are essential to maintain a reliable and efficient system LineScout is a high-performance robot designed to undertake detailed, comprehensive inspections of transmission lines, which contributes to maintaining the integrity of equipment and the safety of inspection crews This paper outlines Hydro-Quebec's LineScout Technology, describing briefly the main systems and key design issues and discussing the technology's impact and benefits on power transmission line inspection and maintenance practices The paper then focuses on field results gathered over the past 2 years with LineScout Technology Very important lessons were learned from more than 20 field deployments of the robot on live transmission lines An appreciable amount of significant feedback came from these field visits and was decisive in improving the technology Specifically, transportation and installation methods and onboard energy management strategy are presented Also discussed, for the first time, is a simplified wheel contact radius estimate, useful for improving the wheel odometer readings Finally, one field deployment on a large water crossing transmission line is presented in detail The paper discusses the importance of the work done and of newly implemented features in terms of the quality and efficiency of inspections, the reliability of systems, and the safe operation of the technology © 2011 Wiley Periodicals, Inc