Dynamics of Surge Corona Growth on Line Conductors

The accurate evaluation of the impinging surges on substations from the connected overhead lines requires quantification of the surge corona beneficial effects in reducing the amplitude and steepness of the impinging surge overvoltage with the travel distance on the overhead line. However, this is a very complex issue due to the stochastic nature of surge corona inception and growth, involving physical processes greatly affected by overhead line geometry, polarity and waveform characteristics of the impinging surge overvoltage, as well as environmental and weather conditions. In this study, surge corona growth on line conductors is experimentally investigated; dynamic growth characteristics are quantified and discussed. A modeling approach for surge corona growth around line conductors is introduced, implementing growth parameters dependent upon the mode of corona inception; as an application, surge corona of a 400-kV single-circuit line under first and subsequent lightning strokes is evaluated.