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.

Evaluation of strain rate sensitivity by constant load nanoindentation

Abstract: Constant load measurements by nanoindentation offer the potential for measuring strain rate sensitivity from individual features and defects on a submicron scale. However, recent reports reveal a conflicting load dependence (both increasing and decreasing strain rate sensitivity with load) which has yet to be fully explained. In this study, constant load measurements on five materials (Zn, Al, Cu, Ti, and SiO2) were conducted over a range of peak loads, and then compared with both constant strain rate results and conventional values in the literature. The load dependence was found to be caused by the increasing contribution of drift errors throughout the test. A proposed framework, involving higher loads, shorter hold and loading times, and a physically sound fitting method, was found to produce unambiguous results free from load dependencies, with improved correlations to conventional values and reduced standard deviations.

A method of predicting the corona performance of conductor bundles based on cage test results

Abstract: In the paper is presented a smmary of cage measurements of the radio interference, the audible noise, and the corona losses for a large number of conductors and conductor bundles. The analysis of the test results obtained also leads to the establisment of a theoretical method of predicting the corona performance of conductor bundles, based on experimental data obtained with single conductors and taking into account the actual distribution of the field strength at the surface of individual sub-conductors in the bundle. Some cases of practical interest are discussed with reference to the effect of conductor aging and the asymmetry of the bundle configuration. Application of the theoretical method to the prediction of the corona performance of long three-phase lines, taking the actual field distributions at the center and outer phase conductors into account, is also discussed.

A Combined Directional and Faulted Phase Selector Element Based on Incremental Quantities

Abstract: In this paper, differential incremental or superimposed voltage and current quantities are used in order to determine directionality of a fault in a network. It is shown that this can be accomplished by performing three scalar products between three voltage and current phasor pairs. The relative levels of these same three scalar products can be furthermore used to identify the faulted phases. While, in ultra-high-speed directional comparison relays, superimposed voltage and current had to be treated in the time domain in order to get speed. In this paper, all computations are done in the frequency domain.

On walrasian equilibrium for pool-based electricity markets

Abstract: We present a single time period decentralized electricity market clearing model that includes reactive power and demand responsiveness in addition to the more common framework of generation-side competition for the real power commodity. The approach allows self-interested agents, namely producers and consumers, independently to maximize their individual surpluses subject to prices. This is consistent with the very notion of a competitive market as defined in equilibrium theory. An auctioneer computes equilibrium prices that achieve power balance at every network node as required by Kirchhoff 's laws. The overall scheme is justified by duality theory for which there is a rich theoretical support, and convergence is achieved using a Newton price-updating algorithm.