抄録
The extinction of the partial discharge (PD) pulse has been frequently observed in an epoxy specimen with a closed void during voltage endurance tests using a CIGRE Method- II electrode. The individual discharge pulse becomes so small that the discharges cannot be detected by conventional pulse detection methods. Such discharges are known as "swarming pulsive microdischarges" (SPMD). In this paper, the SPMD characteristics are investigated by varying the pressure and gap spacing used in the range of 10 to 760 torr and in the range of 0.025 to 0.25mm, respectively. As a result, the SPMD are found to occur at small gap spacing with high pressure or at large gap spacing with low pressure. Since the behaivior of gas discharge depends on gas density, the relation between p•d and SPMD seems to be meaningful, where p and d are the pressure and gap spacing, respectively. The SPMD occurs in the range of under 6 torr•mm. This region corresponds to the region of minimum sparking voltage of Paschen's law.
