Influence of 16k-30kHz Sinusoidal Voltage on the Partial Discharge and Breakdown Characteristics of Parallel Wires at Low Pressure

Due to the requirements of certain special communication frequency bands (Very Low Frequency, VLF) for high-altitude platforms, the internal insulation design of power source faces challenges posed by low air pressure and voltage frequencies in the range of 3–30 kHz. Presently, limited research exists on the partial discharge and breakdown characteristics within the VLF band, particularly concerning the impact on discharge characteristics under low pressure conditions. In this study, we established an experimental platform where a 16k-30kHz VLF sinusoidal voltage was applied to a parallel conductor gap. We measured the Partial Discharge Inception Voltage (PDIV) and breakdown voltage within the pressure range of 19.4kPa to 57.8kPa. The results indicated a notable decrease in PDIV with voltage frequency for a 10 cm air gap. For a 2 cm gap distance, the breakdown voltage under 50Hz voltage was marginally lower than that under VLF frequency at low pressure, although they exhibited similarity at atmospheric pressure. As the gap distance increased to 3cm, the breakdown voltages under the two voltage types became comparable under low pressure conditions. Upon reaching atmospheric pressure, the breakdown voltage under VLF frequency was markedly lower than that under power frequency conditions.