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Institution

Hydro-Québec

GovernmentMontreal, Quebec, Canada
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.


Papers
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Journal ArticleDOI
K. Srinivasan1
TL;DR: In this article, the authors proposed a method for direct calculation of flicker level from digital measurements of voltage waveforms using a fast Fourier transform (FFT) as the first step in the computation.
Abstract: The author deals with cyclic variations in the envelope of voltage waveforms. European power utilities have done substantial work already in their characterization, based on the effects on visual perception. They have also established a norm for the calculation of an instantaneous flicker level, a short-term severity coefficient, and a long-term severity coefficient. The measurement techniques that they propose are basically designed for analog instrumentation. Digital implementations of the analog design are neither cost effective nor optimal in performance. The author proposes a method for direct calculation of flicker level from digital measurements of voltage waveforms. The direct digital implementation uses a fast Fourier transform (FFT) as the first step in the computation. A pruned FFT, customized for the flicker level computation, is also proposed. >

106 citations

Journal ArticleDOI
TL;DR: In this article, the effect of recycled aggregate on total void ratio, strength and permeability of porous concrete was examined and the optimum mix proportions were employed to prepare porous concretes using normal and recycled aggregates.

106 citations

Journal ArticleDOI
TL;DR: In this paper, the nature and causes of corrosive sulfur induced failures in oil-filled transformers and shunt reactors are examined in the presence of paper tapes insulating the conductors.
Abstract: The nature and causes of corrosive sulfur induced failures are examined in oil-filled transformers and shunt reactors. Copper sulfide, which is formed when the corrosive sulfur in a mineral oil reacts with the copper conductors, is likely to diffuse into the paper tapes insulating the conductors. Since copper sulfide is partially conducting, the dielectric losses of the contaminated oil-impregnated-paper tapes are markedly increased; paper tapes in close proximity to the copper conductors are found to attain tan delta values > 1.0 even at room temperature. It is highly likely that thermal instabilities develop at those sites at operating temperatures, leading to increased loss currents and, ultimately, short circuits between the turns. This sequence of events is substantiated by evidence from the field, which indicates large areas of thermally degraded insulations and charred breakdown regions along the coils, the extent of which becomes more pronounced at higher operating temperatures (toward the top of the windings).

105 citations

Journal ArticleDOI
F.A.M. Rizk1
TL;DR: In this article, a general criterion for leader inception of phase-to-ground air insulation under positive critical switching impulses was introduced, which established the correspondence between continuous leader initiation in the vicinity of the highly stressed electrode and conditions prevailing later at the instant of the final jump.
Abstract: The author introduces a general criterion for leader inception of phase-to-ground air insulation under positive critical switching impulses. This criterion established the correspondence between continuous leader initiation in the vicinity of the highly stressed electrode and conditions prevailing later at the instant of the final jump. The criterion is applied to several complex electrode configurations, including rod-rod, conductor-rod, and conductor-structure gaps, where both analytic and digital techniques are used to compute the leader inception voltage, 50% breakdown voltage, and gap factor. The theory has been systematically tested against available experimental results with quite satisfactory agreement. >

105 citations

Journal ArticleDOI
TL;DR: In this article, a general model covering both the main-path magnetic saturation and frequency effects in the dynamic equations is proposed to predict the steady-state and transient performance of synchronous machines.
Abstract: It is generally felt that no major accuracy breakthrough in predicting the steady-state and transient performance of synchronous machines could be achieved without taking proper account of the iron saturation effects as well as eddy-current losses. Although the two issues were often treated separately in the past, this paper attempts to unite them by developing a general model covering both the main-path magnetic saturation and frequency effects in the dynamic equations. Mathematical analysis in the d-q space pinpoints cross-saturation coupling which, a priori, does not seem to be symmetrical for salient-pole machines. Yet the model is theoretically sound, since it fulfils at least the physical constraints using energy balance principles. Some test points from a 555-MVA turbine-generator are used for an initial assessment the model's capability to predict the field current and internal angle for various loading conditions.

104 citations


Authors

Showing all 2603 results

NameH-indexPapersCitations
John B. Goodenough1511064113741
Mark Sutton128100978703
Pierre Legendre9836682995
Jackie Y. Ying8958735694
Karim Zaghib6953316785
Geza Joos6751415880
M. V. Reddy6625415772
Kamal Al-Haddad6182821017
Jean-Pol Dodelet5916418473
Taha B. M. J. Ouarda5834912230
Michael R. Wertheimer5432011003
Richard Martin5433911465
Michel Armand5415244873
Marc Lucotte501698088
Abdelbast Guerfi492156739
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Performance
Metrics
No. of papers from the Institution in previous years
YearPapers
20231
202256
2021115
2020173
2019162
2018156