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.

Lithium Photo‐intercalation of CdS‐Sensitized WO3 Anode for Energy Storage and Photoelectrochromic Applications

Abstract: Integration of solar-energy harvesting and storage functions has attracted significant research attention, as it holds promise for ultimate development of light-chargeable devices. In this context, a functional nanocomposite anode that not only permits electrochemical energy storage through Li-ion photo-intercalation, but also exhibits potential for photoelectrochromic applications, was investigated. The nanocomposite is made of the Li-ion intercalation compound WO3 , thinly coated with TiO2 and sensitized by the photoactive semiconductor CdS. During light exposure, the photoelectrons from CdS are transported to the WO3 /electrolyte interface, where Li-ion intercalation takes place. Photoelectron transport is facilitated by the interfacial TiO2 layer. The WO3 was shown to be functional in multiple photocharge-discharge cycles, but the CdS suffers from degradation and photocorrosion. Hence, the selection of compatible semiconductors and protective coating strategies should be pursued to overcome these issues.

Electrical aging of extruded dielectric cables: a physical model

Abstract: A model is proposed to describe the electrical aging of polymeric cable insulation. It is based on simple thermodynamic concepts in the Eyring theory and supposes that the first step in electrical aging is essentially a molecular process. The authors' model of electrical aging under AC fields supposes that the molecular-chain deformation which will generate submicrocavities in the amorphous region of the insulation, is essentially a fatigue process. Above a critical field F/sub c/, there is an exponential relation between time and field, whereas below F/sub c/, the breakdown strength of the insulation varies very little with time; in other words, there is very limited aging. The model confirms that there is a relation between cable endurance and the insulation morphology, and that the size or submicrocavities is ultimately limited by the amorphous-phase thickness.

Decentralized Nodal-Price Self-Dispatch and Unit Commitment

Abstract: This chapter sets forth a scheme for self-scheduling independent market participants in a power pool. The approach, named DNSA for Decentralized Nodal-Price Self-Scheduling Auction, is proposed as an alternative to centralized Pool auctions and operation. DNSA exploits the intrinsic parallelism of the dual unit commitment problem to decentralize the various scheduling and dispatch functions. Each competing participant (GENCO, DISTCO) maximizes its profit for any set of nodal prices by choosing its level of production or consumption. Similarly, the TRANSCO independently maximizes its merchandising surplus within the network security constraints. The price caller, a centralized entity without access to proprietary cost information, updates prices through an effective Newton algorithm until the power balance at each bus is satisfied. DNSA does not assume a perfect market and accounts for the AC load flow model including transmission losses and line congestion, in addition to integer variables, ramping rates, start-up costs, and minimum up and down times. The convergence of DNSA hinges on the notions of profit optimality and the convexifying market rule. We present several study cases to illustrate the characteristics of DNSA. We conclude that to achieve fairness of treatment for all competing participants, they should be allowed to optimize their profit by self-scheduling. Therefore, to the extent possible, the next generation of unit commitment models should include profit optimality.

Role of turbines in the carbon dioxide emissions from two boreal reservoirs, Québec, Canada

Abstract: [1] The potential for degassing of carbon dioxide stemming from the passage of water through turbines of hydroelectric reservoirs was studied in two boreal reservoirs (La Grande 2 and La Grande 3) located in the James Bay region of Quebec, Canada. Samples of dissolved CO2 were taken monthly over a period of 1 year from the main reservoirs, within the hydroelectric facilities from the shaft entering the turbine system and from the exits below the facilities. Diffusive fluxes from the reservoir surfaces were calculated using the thin boundary layer equation. The differences between CO2 concentrations above and below the dams were used to calculate the amount of degassing per unit of water turbined. Diffusive flux calculations indicated that the reservoirs acted as sources of CO2 to the atmosphere throughout the sampling period, with fluxes ranging between 80 and 1800 mg CO2 m−2 d−1 at LG2 and between 400 and 1500 mg CO2 m−2 d−1 at LG3. Degassing calculated from turbining ranged between 5–45 and 5–25 t d−1 at LG2 and LG3, respectively, and represented between <1 and 7% and mean weighted values of <1% of the equivalent fluxes across the air-water interface of the main reservoirs. The quantity of degassing is seasonally defined, with highest rates observed in the winter/spring period, a result of lower water temperature effects on the solubility of CO2, and the buildup of gases over the winter period due to mineralization of organic matter and the influx from watershed sources due to the springtime melt. Depending on the effluxes occurring at the air-water interface of the main reservoir, degassing can represent a maximum equivalent 16%. This study indicates that the main role of turbining lies in the seasonality of release of GHG rather than the absolute amount.

Introduction of a LIDAR-based obstacle detection system on the LineScout power line robot

Abstract: This paper is a sequel of an earlier paper that featured a thorough characterization of the Hokuyo UTM-30LX laser range finder, which showed promise for a specific application: allowing a power line robot to detect obstacles in its path. After a quick summary of the earlier conclusions, this paper pushes the validation farther by assessing for the first time this popular LIDAR's performance when subjected to the particularly challenging, outdoor, power line environmental conditions: large temperature range, changes in lighting, strong magnetic fields, and oscillating or vibrating targets. Use of return signal intensity, predictably affected by the angle of incidence on the target and by target surface finish, is also investigated as a means to detect variations due to an obstacle. Scanning results with LineScout traveling at maximum speed on a full-scale power line span are then analyzed to validate the proposed detection thresholds.