Abstract:

Surface discharge is a common type of discharge occurring in gas-insulated switchgear equipment, of which the microscopic process remains unclear. Additionly, there is a lack of theoretical correlation between the microscopic process of partial discharge due to defects and the macroscopic detection signals. First, the surface discharge process in SF₆ is simulated based on a fluid-chemical simulation model, revealing the variation patterns of charged particle concentration and surface streamer velocity. Then, taking the current pulse generated in the microscopic discharges as excitation sources, the discharge signals resulting from the surface discharges are simulated based on the finite integral method, establishing a correspondance between the microscopic partial discharge process and the detectable discharge signals. Compared with the conventional Gaussian excitation source, the time-domain waveforms of electromagnetic signals obtained from the microscopic discharge simulation more chosely matches to realistic conditions. These findings effectively supplement existing researches on the microscopic mechanisms of partial discharge signals, laying a foundation for the insulation state evaluation based on the discharge signal analysis.

Key words: surface discharge, microscopic process, fluid-chemical model, finite integral method, discharge signal, multiscale simulation