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.

Quasi steady-state models for long-term voltage and frequency dynamics simulation

Abstract: The quasi steady-state (QSS) approximation of long-term dynamics relies on time-scale decomposition and consists of replacing faster phenomena by their equilibrium conditions, in order to reduce the complexity of the whole model and increase the computation efficiency of time simulations. This paper describes the extension of a QSS model extensively used in long-term voltage stability studies, to readily incorporate the frequency dynamics that takes place over the same time scale. This extended QSS model relies on a common-frequency assumption. Its advantages, limitations and possible improvements are discussed through simulation results on the hydro-Quebec system, where it has been compared to full time scale simulations. Disturbances with an impact on either frequency or voltages are considered and the coupling between these two aspects of long-term dynamics is briefly discussed.

A Novel In Situ Efficiency Estimation Algorithm for Three-Phase Induction Motors Operating With Distorted Unbalanced Voltages

Abstract: This paper presents a novel algorithm for in situ efficiency estimation for induction motors operating with unbalanced distorted voltages. The proposed technique utilizes the genetic algorithm, IEEE form F2-method F1 calculations, large motor test database, and a novel stray-load loss formula. The technique is evaluated by testing three small- and medium-sized induction motors with different combinations of voltage unbalance and total harmonic distortion. The results showed acceptable accuracy. The repeatability and usability of the technique with balanced sinusoidal voltages are also validated. The technique may be used as a potential industrial tool that can help derate induction motors in the presence of voltage unbalance and harmonics.

De-icing EHV overhead transmission lines using electromagnetic forces generated by moderate short-circuit currents

Abstract: This paper presents the test results of a new method for de-icing EHV overhead transmission lines following severe ice storms aimed at de-icing conductors with the lowest I/sub SC/ amplitude and duration. The method involves circulating short-circuit current (I/sub SC/) at the rated voltage of the transmission lines and the subsequent action of electromagnetic forces that allow conductors to knock against each other and the ice to fall off. Tests were performed on a sample of overhead transmission lines of twin (315 kV) and quad (735 kV) bundles installed in the switchyard at IREQ's high-power laboratory. Impacts on power system stability and power quality are also discussed and relevant conclusions are drawn for application of the new method on Hydro-Quebec's power transmission system.

High voltage measuring circuit coupled to the capacitive grounding tap bushing of an HV device

Abstract: A high voltage measuring circuit for broadband measurement of transient signals occurring in high voltage apparatus The measuring circuit is housed in a shielded housing having an input sensing circuit for connection to a capacitive grounded tap of the high voltage apparatus The sensing circuit is connected to an output circuit through an electrical shielded connection The measuring circuit generates output signals which are replicas of the transient signals appearing on the bushing of the high voltage apparatus The broadband of the measuring circuit extends over a frequency range of from about 1 Hz to 1 MHz and has a signal level higher than background noise

Integrating ecological and genetic structure to define management units for caribou in Eastern Canada

Abstract: Genetic diversity is a key parameter to delineate management units, but many organisms also display ecological characteristics that may reflect potential local adaptations. Here, we used ecological and genetic information to delineate management units for a complex system involving several ecotypes of caribou (Rangifer tarandus) from Quebec and Labrador, eastern Canada. We genotyped 560 caribou at 16 microsatellite loci and used three Bayesian clustering methods to spatially delineate and characterize genetic structure across the landscape. The different approaches employed did not converge on the same solution, and differed in the number of inferred genetic clusters that best fit the dataset but also in the spatial distribution of genetic variation. We reconciled variability among the methods using a synthetic approach that considers the sum of the partitions obtained by each of them and retrieved six genetically distinct groups that differ in their spatial extent across the range of caribou in the study area. These genetic groups are not consistent with the presently defined ecological designations for this species. Combining both genetic and ecological criteria, we distinguished eight independent management units. Overall, the management units we propose should be the focus of conservation and management actions aimed to maximize genetic and ecological diversity and ensure the persistence of caribou populations inhabiting increasingly disturbed landscapes.