Effect of Electrode Spacing on Partial Discharge Characteristics of Silicon Nitride Lining under Different Voltage Conditions

High voltage and high power semiconductor devices are the core devices in the fields of flexible DC power transmission and rail transit, and the internal ceramic liner and silicone gel interface are the insulation weak links of the device packaging structure. In order to meet the increasing performance requirements and the reliability of device insulation under actual conditions, it is necessary to study the partial discharge characteristics of the interface between silicone gel and silicon nitride liner under different voltage conditions. In this paper, the partial discharge starting voltage of silicon nitride liner with four electrode spacing parameters on copper layer was studied for typical operating conditions of power frequency AC voltage, positive polarity DC voltage and positive polarity repeated square wave voltage, and the influence of voltage working conditions and electrode spacing parameters on insulation characteristics of the liner was obtained. The mechanism of partial discharge of silicon nitride lining was analyzed.