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.

Electrode Design for Testing in Uniform Field Gaps

Abstract: The efficiency of producing uniform fields in the test gap was evaluated for practical electrode configurations corresponding to the plane, the Rogowski and the Bruce profiles. The field intensity was calculated using the known charge simulation method and the calculated distributions of the field intensity at the surface of different electrode configurations were compared. The results obtained show a pronounced end effect at plane-profile electrodes. With the Rogowski profile, the effective uniform-field region is dependent on the gap spacing. The Bruce profile was found to be a good compromise, with a negligible end effect and a nearly constant uniform field region. Practical considerations are also presented together with the limitations of various profile configurations in the design of uniform field electrodes.

Dielectric barrier discharges in helium at atmospheric pressure: experiments and model in the needle-plane geometry

Abstract: We present an experimental and numerical modelling study of dielectric barrier discharges in pure, flowing helium at atmospheric pressure, in a 3.0 mm length needle-plane gap. Ultra-high speed imaging and synchronous, real-time dual detection (optical–electrical) diagnostics have been carried out. The high-voltage electrode was a hyperboloidal steel needle with a sharp point of 40 μm radius, while the grounded electrode was covered with 1.6 mm of Al2O3. The surface of the latter was either bare (case 1) or coated with ~20 nm of semiconducting graphite (case 2) or metallic aluminium (case 3), all at floating potential. Axial [z(t)] and radial [r(t)] time-evolutions (≤2 μs) of discharge propagation across the gap were found to depend very strongly upon surface charging or conduction (cases 1–3). A two-dimensional model of the needle-plane discharge, based on coupled solution of the continuity equations for electrons, ions and excited neutral particles and of Poisson's equation, was found to agree very well with the observed [r,z](t) behaviour.

Power quality indices and objectives

Abstract: System operators are encouraged to report information relating to power system performance towards external parties, such as users and regulators. Some power quality indices have already been defined in standards, others are still missing. The joint working group CIGRE C4.07/CIRED (formerly CIGRE WG 36.07) has collected available measurement data and existing indices for MV, HV and EHV systems and recommends a set of internationally relevant power quality indices and objectives that can be seen as the outer envelope of performance for each power quality parameter. This paper will present the results of the work accomplished by the working group CIGRE C4.07/CIRED. The paper sends also a message to equipment manufacturers to provide monitoring equipment able to measure the recommended indices and to implement the flagging concept, as introduced in IEC 61000–4–30. It is expected that once published, these recommendations will also help facilitate the future presentation of power quality data to third parties, typically regulators and customers.