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Pelissou S.,Hydro Quebecs Research Institute | Lessard G.,Hydro - Quebec
IEEE Transactions on Power Delivery | Year: 2011

This paper, the first of three parts, deals with the penetration depth and concentration of silicone fluid in cable insulation and its duration when injected in real-size, service-aged 28-kV extruded cables and subjected to various simulated service conditions in the laboratory. There were four aging conditions, namely, a cycling conductor temperature of 55 °C or 90 °C, in air or water, and with or without pressurized soak silicone, and always under service voltage. Samples were taken as a function of time and analyzed for silicone and water content in the insulation, and at the end for water treeing. The results indicate that the silicone content in the insulation changes circumferentially and can reach values between 1 and 4% after 96 thermal cycles, before stabilizing more or less up to 255 cycles. Furthermore, it was found that while water reacts with silicone, it contributes to the silicone retention in the insulation. Also, the study revealed that the number and size of water trees were not affected by the laboratory aging treatment and show no increase due to the presence of silicone. © 2011 IEEE.


David E.,École de Technologie Supérieure of Montreal | Frechette M.,Hydro Quebecs Research Institute
IEEE Electrical Insulation Magazine | Year: 2013

The dielectric properties of a number of polymeric nanocomposites (PNC) have been investigated and reported, and there are very good reviews available, for example, see [1]-[3]. CIGRE Working group D1.24 has also performed several collaborative investigations on mostly epoxy- and polyethylene-based nanocomposites, which are reported in CIGRE publications [4], [5] as well as in archived papers [6], [7]. Dielectric nanocomposites investigated in the literature include various polyolefins such as polyethylene (PE; and PE blends) and polypropylene, ethylene vinyl acetate, polyamine, epoxy, and elastomers such as silicone rubber, containing various nanofillers such as metallic oxides, silica, alumina, titanium oxide, zinc oxide, and layered silicates (clays). Due to the very high specific surface area of nano-sized fillers, a few percent addition can significantly affect the dielectric properties of a polymeric material. The most common and practical processing methods suitable for thermoplastic nanocomposites are melt compounding, using a mixer, extruder, or both, and mixing in the liquid phase prior to polymerization for thermosetting resins, a process commonly called the in situ polymerization process [8]. Figure 1 gives examples of typical microstructures of polyolefin-based nanocomposites processed by melt compounding. The striking similarity of the microstrucmicro structure shown in Figures 1(b) and 1(c) should be noted as both were obtained in two different labs from the melt compounding of fumed silica and a thermoplastic resin using a twin screw extruder. Similar microstructures are also reported for isotactic polypropylene/SiO2 nanocomposites melt blended by extrusion [9]. © 2006 IEEE.


Couderc H.,Hydro Quebecs Research Institute | Frechette M.,Hydro Quebecs Research Institute | David E.,École de Technologie Supérieure of Montreal
33rd Electrical Insulation Conference, EIC 2015 | Year: 2015

Polymer nanocomposites have been shown to exhibit enhanced properties compared to those of the matrix. However the main problem in their fabrication is to obtain an efficient dispersion of nanoparticles in the matrix. In this work, polypropylene powder and nanosilica colloidal suspensions were mixed using planetary milling at 1 wt%. Two sizes of nanosilica particle were used (10-20 nm and 140-150 nm). Different rotation speeds and milling durations were tested for the fabrication process. Thermo Gravimetric Analyses were conducted to ensure that there was no contamination during fabrication. The resulting samples were studied by Dielectric Breakdown, Dielectric Spectroscopy and Thermo Gravimetric Analysis. © 2015 IEEE.


Montambault S.,Hydro Quebecs Research Institute | Pouliot N.,Hydro Quebecs Research Institute
Proceedings of the 3rd International Conference on Applied Robotics for the Power Industry, CARPI 2014 | Year: 2015

This paper summarizes the work related to power line robotics over the past 15 years at Hydro-Québec's research institute (IREQ). Robotic platforms are presented as well as the inspection and maintenance systems equipping them. The paper also presents a new organizational unit recently established at IREQ and called the 'Power Line Robotics Program' (PLRP). This novel structure's objective is to leverage the benefits of external collaboration and international interest in power line robotics, in order to provide Hydro-Québec with professional inspection services, manufacturing capacity and strategic funding for new developments. More recent activities related to non-destructive probes are also discussed. Examples of PLRP tasks and responsibilities are given, stating why this structure is relevant within a power utility and how it accelerates the use and benefit of robotics in the power industry. © 2014 IEEE.


Miralles F.,Hydro Quebecs Research Institute | Boivin G.,Hydro Quebecs Research Institute
Proceedings of the 3rd International Conference on Applied Robotics for the Power Industry, CARPI 2014 | Year: 2015

In the past years, a laser scanning system to measure hydraulic gate frames with high precision was developed by Hydro-Québec. Inspired by this first design, a new compact and lower cost platform was developed. The WireScan technology is actually applicable to measure the geometry of any structure that is vertical and underwater. The applicability of this technology was further extended with improvements to the localization algorithm of the laser scanner. Its robustness to marine snow was increased by taking advantage of the newly available computing power of general purpose graphical processing units. Four case study related to hydro plant (water intake gate and spillway stoplogs), and navigation locks (balancing gates and channel width) are presented. © 2014 IEEE.


Vu V.H.,École de Technologie Supérieure of Montreal | Thomas M.,École de Technologie Supérieure of Montreal | Lakis A.A.,Ecole Polytechnique | Marcouiller L.,Hydro Quebecs Research Institute
Mechanical Systems and Signal Processing | Year: 2011

This paper presents improvements of a multivariable autoregressive (AR) model for applications in operational modal analysis considering simultaneously the temporal response data of multi-channel measurements. The parameters are estimated by using the least squares method via the implementation of the QR factorization. A new noise rate-based factor called the Noise rate Order Factor (NOF) is introduced for use in the effective selection of model order and noise rate estimation. For the selection of structural modes, an orderwise criterion called the Order Modal Assurance Criterion (OMAC) is used, based on the correlation of mode shapes computed from two successive orders. Specifically, the algorithm is updated with respect to model order from a small value to produce a cost-effective computation. Furthermore, the confidence intervals of each natural frequency, damping ratio and mode shapes are also computed and evaluated with respect to model order and noise rate. This method is thus very effective for identifying the modal parameters in case of ambient vibrations dealing with modern output-only modal analysis. Simulations and discussions on a steel plate structure are presented, and the experimental results show good agreement with the finite element analysis. © 2010 Elsevier Ltd.All rights reserved.


Moreau A.,Hydro Quebecs Research Institute | Laurencelle F.,Hydro Quebecs Research Institute
Energy Procedia | Year: 2012

From 2009 to 2011, the Ministère des Ressources naturelles et de la Faune (MRNF), which is the ministry responsible for natural resources and wildlife in Quebec, supported a pilot project aiming to develop the solar domestic water heater (SDWH) market in Québec. Seventy participants took part in this program, of which 23 agreed to be part of a campaign for monitoring the energy performance of their solar system. The Laboratoire des technologies de l'énergie (LTE) of the Hydro-Québec Research Institute was commissioned by the MRNF to conduct the monitoring. The main results of the study are published in this paper. © 2012 The Authors.


Jaoua A.,University of Montréal | L'Ecuyer P.,University of Montréal | Delorme L.,Hydro Quebecs Research Institute
Simulation | Year: 2013

The effect on multiskill call-center performance of pooling dependent call types is investigated. For this purpose, a copula-based modeling approach is used to provide multivariate models that take into account the call types' asymmetric dependence structures found in empirical data. Then, the realistic input models of the call-type-dependent arrival processes are used in a simulation study to explore the sensitivity of the pooling decision to this dependence. We find that the widely used assumption of independence, as well as the misspecification of the dependence structure, can lead to substantial misestimation of call-center performance. This demonstrates the importance of modeling call-type dependence in stochastic simulation studies of call centers. We also show, through case studies, that pooling two asymmetric left-tail-dependent call types is more likely to lead to low agents occupancy; whereas the presence of right-tail dependence structure increases the risk of service-level shortfall. This work provides new managerial insights to improve decision making in determining which call types to merge in the same pool in multiskill call centers. © 2013 The Society for Modeling and Simulation International.


Vu V.H.,École de Technologie Supérieure of Montreal | Thomas M.,École de Technologie Supérieure of Montreal | Lafleur F.,Hydro Quebecs Research Institute | Marcouiller L.,Hydro Quebecs Research Institute
Journal of Sound and Vibration | Year: 2013

A method is developed for the automatic identification of the spectrum and modal parameters of an operational modal analysis using multi sensors. A multivariate autoregressive model is presented, and its parameters are estimated by least squares via the implementation of QR factorization. A noise-independent minimum model order, from which all available physical modes may be identiied, is developed. This so-called optimal model order is selected from the convergence of a global order-wise signal-to-noise ratio index. At this model order or higher, the modes are classiied based on a decreasing damped modal signal-to-noise (DMSN) criterion. This decreasing order classiication allows for easy identiication of all the physical modes. A signiicant change in the DMSN index enables the determination of the number of physical modes in a speciic frequency range, and thus, an automatic procedure for identifying the modal parameters can be developed to discriminate harmonic and natural frequencies from spurious ones. Furthermore, a multispectral matrix can be constructed from selected frequencies by introducing a powered ampliication factor, which provides a smooth, balanced, noise-free spectrum with all main peaks. The proposed method has been performed on simulated multi-degree-of- freedom systems, on a laboratory test bench, and on an industrial operating high power hydro-electric generator offering the potential for automatic operational modal analysis and structural health monitoring. © 2012 Elsevier Ltd. All rights reserved.


Moreau A.,Hydro Quebecs Research Institute
Energy Procedia | Year: 2011

Because they store hot water, water heaters are easily-shifted loads that can be controlled to reduce peak demands. However, load shifting may have some detrimental consequences on the domestic hot water supply temperature if the heating element is deactivated for a long period of time. Furthermore, a new peak may be caused if a significant number of heaters are reactivated at the same time. This study presents a control strategy for water heaters that minimizes the pick-up demand when the heating elements are reactivated at the end of a load shifting period and that ensures, in all cases, the client's hot water supply. The study is based on a simulation model of a water heater that was experimentally validated and takes into account the diversity of the population's hot water withdrawal profile. More specifically, the data of 8,167 real water withdrawal profiles of several clients were input into the simulation model in order to evaluate the performance of water heaters under different operating conditions. © 2011 Published by Elsevier Ltd.

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