Characteristics of Secondary AC Arc Column Motion Near Power Transmission-Line Insulator String

Power system secondary ac arcs are plasma discharges in free space with dimensions in meters. The motion of secondary arcs was investigated experimentally using high-speed video on a 1-m scale with a 3-MVA source. The measurements that were evaluated imposed forces, including wind, effects of the arc root, as well as early-stage horizontal and late-stage vertical movement. Partial short circuits of the arc column were observed. The arc column elongated with the de-ionization effect being increased. The column approached a maximum length before the arc extinction. An arc chain model was applied to establish the governing velocity equation. Based on the proposed model, simulations agreed well with the physical experiments.