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.

Study of the activation process of Mg-based hydrogen storage materials modified by graphite and other carbonaceous compounds

Abstract: A nanocomposite (Mg–V)nano made of 90 wt% Mg and 10 wt% V was prepared by high-energy ball-milling during 40 h. The activation characteristics of (Mg–V)nano are rather poor, the hydrogen content [H] reaching 4 wt% after more than 100 h (t4wt%) following the initial exposure of the material to H2. Adding 9 wt% graphite to (Mg–V)nano and resuming the milling operation for 30 min leads to the formation of (Mg–V)nano /G, which exhibits a t4wt% value of only 10 min. The addition of more than 9 wt% graphite to (Mg–V)nano does not lead to any significant reduction of the t4wt% value. However, extending the milling period with graphite over 30 min leads to a steady increase in t4wt% and, thus, to a deterioration of the activation characteristics. Comparison of the behavior of graphite with other C-based compounds revealed that perylene (C20H12) and pentacene (C22H14), which are made of linked benzene rings, and thus have a 2D structure similar to that of the graphene sheet, are as effective as graphite in improving the activation characteristics of (Mg–V)nano. A structural investigation of (Mg–V)nano /G as a function of the milling time through both C 1s core-level x-ray photoelectron spectroscopy and C K edge x-ray absorption near-edge spectroscopy has shown that the integrity of graphite is progressively lost as the milling period is extended over 30 min. On the basis of these results, it is hypothesized that the adsorption of graphene layer on freshly created Mg surfaces and the formation of highly reactive C species during milling prevents the re-formation of the surface oxide layer responsible for the poor activation characteristics of untreated (Mg–V)nano

Comparative analysis of IEEE 112-B and IEC 34-2 efficiency testing standards using stray load losses in low voltage three-phase, cage induction motors

Abstract: Since 1998, 817 motor efficiency test data sets, in the 1-500 hp (0.75-375 kW) range have been collected from several sources in different countries around the world, for 50 and 60 Hz. The test data include the motor efficiency using the IEC 34-2 and IEEE 112-B test standards, and the quantification of the stray load losses (SLLs), using the IEEE 112-B method. In 125 cases, the test data include the efficiency computed with both methods. The aim of this paper was the quantification of the discrepancy between the two mentioned standards, and to establish an approximate method to allow the comparison between motors tested with the two standards. Based on the significant number of collected motor data sets, it was concluded that, when compared to the IEEE 112-B standard, the IEC 34-2 standard is less accurate, and gives typically higher efficiency values, mainly because of the SLLs estimation procedure. The IEEE 112-B SLLs computed values are typically higher than the IEC SLLs predefined values, on average of 1.0 and 0.8 percentage points for 50-Hz and 60-Hz motors, respectively. Also, the average SLLs values vary slightly with the motor power. Using efficiency measurements made with both standards on the same motors, it was possible to confirm that the SLLs are the main reason for the observed discrepancy in the efficiency values. The results of the analysis carried out in this paper offer the possibility of comparing the efficiency of motors tested under the IEC 34-2 standard with motors tested with IEEE 112-B, leading to a choice of the most cost-effective option. This paper also provides a key contribution to the ongoing revision of the IEC 34-2 standard.

On the application of VTOL UAVs to the inspection of power utility assets

Abstract: This paper presents a review of the state of the art and a discussion on vertical take-off and landing (VTOL) unmanned aerial vehicles (UAVs) applied to the inspection of power utility assets and other similar civil applications. The first part of the paper presents the authors' view on specific benefits and operation constraints associated with the use of UAVs in power industry applications. The second part cites more than 70 recent publications related to this field of application. Among them, some present complete technologies while others deal with specific subsystems relevant to the application of such mobile platforms to power line inspection. The authors close with a discussion of key factors for successful application of VTOL UAVs to power industry infrastructure inspection.