Method for detecting dielectric breakdown of electric apparatus

TLDR: In this paper, the dielectric breakdown voltage from the partial discharge pulses generated intermittently in the insulator of an electric apparatus was detected by detecting the voltage in which the large partial-discharge pulses generating intermittently at intervals of several Hertz - several tens Hertz begin to grow sharply.

Abstract: PURPOSE:To prevent the dielectric breakdown accident during execution of a withstand voltage test by detecting the dielectric breakdown voltage from the partial discharge pulses generated intermittently in the insulator of an electric apparatus. CONSTITUTION:The voltage from a high voltage power source 1 is imposed on a stator coil 2 which is a test specimen Cx, and the voltage is boosted until the insulation of the coil 2 breaks down by a stepwise boosting method of holding the voltage for 1 minute at a 5-kV step. The partial discharge pulses generated in the insulator of the coil 2 at tis time are measured with a partial discharge measuring device 3 and a synchroscope 4. The voltage in which the large partial discharge pulses generating intermittently at intervals of several Hertz - several tens Hertz begin to grow sharply is detected, whereby the dielectric breakdown is detected.