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.

Insulator pollution performance at high altitude: major trends

Abstract: A survey of the data available from the literature was conducted in order to assess major trends in insulator performance with altitude. The literature comprised tests on individual insulator strings under natural and artificial conditions along with actual live-line performance. The data covered pollution performance as well as the air-gap breakdown performance of insulators under reduced pressure conditions for AC and DC applied voltages. The major trends reported here suggest a pressure dependence (p/p/sub 0/)/sup 0.35/ for DC and (p/p/sub 0/)/sup 0.5/ for AC, of V/sub 50/ for standard polluted insulators at altitudes lower than about 4 km (p approximately 0.6 atm). These pressure dependences impose a derating of the relative performance of leakage path length or flashover voltage with altitude, namely 6%/km for AC, 5%/km for positive DC, and 4%/km for negative DC applied voltages. Dielectric breakdown, in contrast, imposes a 10.5%/km degradation of insulating air gaps with altitude. >

Improving process representation in conceptual hydrological model calibration using climate simulations

Abstract: Different sets of calibrated model parameters can yield divergent hydrological simulations which in turn can lead to different operational decisions or scientific conclusions. In order to obtain reliable hydrological results, proper calibration is therefore fundamental. This article proposes a new calibration approach for conceptual hydrological models based on the paradigm that hydrological process representation, along with the reproduction of observed streamflows, need to be taken into account when assessing the performance of a hydrological model. Several studies have shown that complementary data can be used to improve hydrological process representation and make hydrological modeling more robust. In the current study, the process of interest is actual evapotranspiration (AET). In order to obtain a more realistic representation of AET, meteorological variables and the AET mean annual cycle simulated by a regional climate model (RCM) driven by reanalysis are used to impose constraints during the optimization procedure. This calibration strategy is compared to a second strategy which relies on AET derived from reference data and to the classical approach based solely on the reproduction of observed discharges. The different methodologies are applied to calibrate the lumped conceptual model HSAMI, used operationally at Hydro-Quebec, for six Canadian snow-dominated basins with various hydrometeorological and physiographical characteristics.

Highly-stable polymeric electrolyte and use thereof in electrochemical systems

Abstract: The invention relates to a polymeric electrolyte for an electrochemical generator, comprising at least one four-branched polymer, at least one poly(vinylidene fluoride), a co-polymer of poly(vinylidene fluoride-co-hexafluoropropene), a polytetrafluoroethylene, a poly(ethylene-co-propylene-co-5-methylene-2-norbornene) or a copolymer of ethylene propylene diene, a polyol, a polymethylmethacrylate, a polyacrylonitrile, SiO2-Al2O3, or nano TiO2 coated or not with an organic material. Said electrolyte permits the preparation of electrolytic compositions which find application in high-performance electrochemical devices.

Slip power recovery induction generators for large vertical axis wind turbines

Abstract: Simulation results are presented for the performance of a slip power recovery induction generator coupled to a vertical-axis wind turbine. The suitability of this type of generator for wind-driven applications is discussed. A qualitative comparison with two other alternatives is made, highlighting the basic features of the generator configuration studied. Quantitative simulation analysis showed that it is possible to reduce the ripple in the electrical power substantially with stable operation through various changes in wind speed. Regenerative braking is possible, especially in the upper range of speed, which reduces the wear on the mechanical brakes. The design described ensures smooth motor start-up for the induction machine in the motor-mode. >