Propagation models for motion processes of long ac arcs on overhead lines

Flashovers due to lightning, pollution and other factors frequently generate long ac arcs along the surfaces of insulator strings on overhead transmission lines; they cause great damage to insulators. Based on the motion characteristics of long ac arcs obtained from experiments, this paper presents the propagation models of the motion processes of long ac arcs, these simulations are important to design suitable parallel arc horns to protect insulator strings. The simulation models include the spatial model, the temporal model of a long ac arc, and the motion simulation models of an arc root and an arc column. The spatial model discretizes a long arc to current elements; the temporal model is proposed to consider the motion mode of a current element; and the motion simulation models of an arc root and an arc column describe the motion processes of an arc root and a column, respectively. At last, numerical simulations and corresponding experiments of long ac arcs along the surfaces of insulator strings of overhead transmission lines are compared. Both of them show a similar motion trend.

► The motion characteristics of long ac arcs based on experiments are summarized, especially the relationships between the length of an anode arc root and the arc current, and between a cathode arc root and the arc current are presented.
► The paper presents the propagation models of the motion processes of long ac arcs, including the spatial model discretizing a long arc to current elements, the temporal model considering the motion mode of a current element, the motion simulation models of an arc root and an arc column describing the motion processes of an arc root and an column a spatial model, are proposed.
► The motion processes of long ac arcs along the surfaces of insulator strings of overhead transmission lines are proposed from experiments.
► The numerical simulations of long ac arcs along the surfaces of insulator strings of overhead transmission lines, which have a similar motion trend with the corresponding experiments, are verified.