Gas-solid interface charge accumulation pattern of repetitive impulse voltages based on runaway electron beams-charge combined measurement

Repetitive impulse voltages widely exist in electronic circuits, pulse power supplies, and transmission equipment, which will reduce the insulation performance of equipment and lead to equipment failure. Affected by impulse voltages, runaway electron beams and charge accumulation at the gas-solid interface may be important factors for equipment failure. It is of great significance for the research of gas-solid interface charge accumulation. In this study, a combined measurement platform of runaway electron beams and interface charge was built. The runaway electron beams and the interface charge of epoxy samples generated by repetitive impulse voltages were measured. The number and energy of runaway electrons as well as the interface charge accumulation were obtained. It was found that the energy spectrum of runaway electron beams presented a single-peak pattern. The interface charge was close to the bell-shaped distribution, however there was a depression in the center. During the first 10 impulse voltages, the interface charge increased significantly, and then the interface charge began to decrease gradually and stabilized after 10,000 impulse voltages. Considering the incident and scattering processes of the runaway electrons during the accumulation, the charge accumulation pattern of the gas-solid interface under repetitive impulse voltages was proposed. It was considered that the development of interface charge was formed by the superposition of runaway electrons incident and secondary electron emission so that the interface charge increased first and then decreased and finally tended to be stable.