局放Partial discharge XX partial discharges in air part II selection of line conductors.pdfVIP

F E A T U R E A R I l C L E Partial DischargeXX: Partial Discharges inAir Part II:Selection of Line EFFECTSOF CORONAFROM OVERHEADLINES by N. GXAOTRINH Three corona-related phenomena have a significant impact on the design of H V overhead lines. They are corona losses, Institut de recherche Hydro-Qukbec electromagnetic interference, and audible noise. The physical mechanisms that generate these phenomena and the methods for evaluation thereof are discussed below. Coronafrom overhead transmission lines causes radio Corona-InducedPower Dissipation The primary source of corona-induced energy loss is the interference, television motion of corona-generated ions of either polarity that are subject to the electric field around the line conductors. For ac interferen ce, a udible noise, and lines, the motion of such an ionic space charge is limited to the power loss. Overhead lines are immediate vicinity of the line conductors, corresponding to the field-induced ion displacement during one half cycle, typically designed to limit such a few tens of centimete