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.

Streamer propagation and breakdown under ac voltage in very large oil gaps

Abstract: This paper presents a study of prebreakdown and breakdown phenomena under ac voltage in mineral oil in very large gaps (/spl les/80 cm). The investigations presented concern the measurement of breakdown voltages together with the recording of streamers in rod-plane and sphere-plane electrode systems, at different gap sizes. A breakdown mode specific to ac voltage is found, in which 'bursts' composed of streamers initiated at each half cycle appear. This mode leads to the lowest breakdown fields recorded under ac. Values of the average stress required for burst or direct breakdown modes are deduced from the experiments. Positive streamers are responsible for breakdown in large gaps: their propagation is easy and does not depend on the gap geometry and on the presence of particles. On the other hand, the propagation of negative streamers is quenched when not very divergent fields are used.

A systematic method for power system restoration planning

Abstract: This paper describes a systematic method for power system restoration planning. System restoration at Hydro-Quebec is performed according to a set of detailed emergency instructions. The basis for these instructions is a restoration plan that is prepared off-line by operation planners. This plan includes a switching scenario with a set of values for the control variables-generator voltages, shunt reactors and load levels-that satisfy the operating constraints. Finding a suitable set of control variables usually requires many load-flow runs in a trial-and-error process. However, the problem can be formulated as a nonlinear optimization problem. The optimization algorithm which solves that problem provides values for the control variables automatically. This algorithm is linked to a user interface which constitutes a powerful tool for system restoration planning. >

Phasor measurement unit based wide-area monitoring and information sharing between micro-grids

Abstract: Micro-grid (MG) monitoring and information sharing between them through a central monitoring unit is required in the present day operational environment. The proposed research focuses on developing wide-area monitoring platform for multiple MGs running in parallel. This is achieved by using C37.118.1 complied phasor measurements units (PMUs) which provides accurate and reliable information monitoring at remote ends of the MGs and are further connected to the Phasor Data Concentrator which acts as the central monitoring unit. This process not only retrieves information at different nodes of the MGs equipped with PMUs, but the information can be exchanged between MGs for further action if required during contingencies. The PMUs are used to monitor phasors (amplitude and phases) and frequency of fundamentals which are further used to compute wide-area functions at different operating nodes of the MGs at grid connected and islanded modes of operation including different operating conditions. The proposed PMU and MG models are developed on MATLAB/SIMULINK platform. Extensive test results indicate that the proposed monitoring process is highly essential to retrieve the operational status of the multiple MGs observed at the central monitoring unit.