An innovative high frequency microdischarge detection technique

Today´s modern electrical devices are increasingly subject to, and must withstand, high frequency stressing. Such stressing contributes to accelerated aging of electrical insulation and has resulted in premature failure of components. In order to understand the aging mechanisms (i.e. erosion) and make valid conclusions regarding the service lifetime of components used under high frequency conditions, the electrical insulation must be examined under the same high frequency conditions as that it will be used. Conventional electrical techniques used to detect partial discharges are limited to below 2 kHz applied ac test voltages. In order to stress electrical insulation and examine the microdischarge activity for frequencies up to 100 MHz, a new technique was developed. This technique uses series resonance to achieve high frequency sinusoidal steady state ac test voltage and a bridge type test cell to detect the resulting microdischarge activity. Calibration and simulations support the critically damped single output pulse per discharge events temporal resolution of <0.5 μs. Typical output traces are presented and preliminary test data is presented