Study of partial discharge activity by excess current

Measurements of partial discharges (PD) play an important role in study of dielectric materials. This work applies a measurement system based on dielectric response technique to study an excess current associated with PD activity, which appears during and after PD activity and shows some prominent properties. The value of such a measurement is demonstrated through studies of two types of test objects, twisted pairs and cavity specimens. A simultaneous use of pulse PD detection in the study shows a correlation between changes in PD amplitudes and non-PD excess current levels. It is concluded that the used methodology can serve as an important complement to the traditionally used pulse PD detection.