Study on the Morphological Characteristics of Multiple-Reignition Secondary Arcs on EHV/UHV Transmission Lines

Transient faults on extra-high-voltage/ultrahigh-voltage (EHV/UHV) transmission lines are mostly single-phase-to-ground faults, and the corresponding extinction characteristics of secondary arc affect the success rate of single-phase auto-reclosing (SPAR) and the transient stability of power system. In this article, based on the equivalent experiments performed in the laboratory, the binary image of the secondary arc is extracted by the method of grayscale expansion after the logarithmic transformation of the arc images, and the morphological characteristics of the secondary arcs are described by calculating and analyzing the skeleton and the sinuosity of the arc, the barycenter and Feret’s maximum and minimum diameters and their maximum and minimum angles. The sinuosity and the curvature distribution of the secondary arc, the barycenter velocity, momentum, acceleration, and resultant force of the secondary arc are visually plotted and quantitatively calculated. Their corresponding variation rules are also summarized. The results of this study will provide a more complete experimental basis and a better understanding of the morphological characteristics of secondary arc.