The field operation of AC GIS in recent years shows that foreign fibers can cause equipment failure

among which polyester fiber

as the main material of insulation rod and clothing fabric

exhibits more complex movement in the DC field. In this paper

the motion and discharge experiment platform of parallel electrode fibers is built to analyze the influence of fiber size and voltage amplitude on the fiber motion with the force and charge model

and the discharge mechanism of fibers in standing

reciprocating

and bridging states is studied. The results show that the critical lift voltage of the polyester fiber is unrelated to its length

but is proportional to the square root of its diameter. In the reciprocating and dispersive stages

the standing time of the fiber is negatively correlated with voltage and fiber length

and the degree of dispersion rises with the increase of voltage and the decrease of fiber length. In the bridging stage

fibers are bridged multiple times

and the fiber length is the main factor affecting the bridging probability. Fibers with length of 4~14 mm can reduce the breakdown voltage by 8%~20%

which is the most serious threat to equipment safety among three types of fiber motion.