Effect of energizing voltage frequency on partial discharge characteristics of defects in power cable joints

Power cable joints are the weakest points in a cable system and thus highly susceptible to failure. Partial discharge (PD) events are an important indicator of potential defects in these joints. PD behavior is influenced by not only the geometric configuration of a defect but also by the voltage type and environmental conditions. In this study, several cable joints with four types of common defects were fabricated and their PD characteristics under continuous sinusoidal AC voltages with increasing frequencies were investigated. The variations in the PD inception voltage and maximum PD magnitude we found to be nearly independent of frequency, and the number of discharges per second decreased as the frequency increased. The number and magnitude of PDs in the cable joint defects decreased at a very-low frequency (0.1 Hz) voltage, while those in the frequency range of 10-300 Hz were similar. The presented findings can provide practical support for selecting an appropriate energizing voltage frequency during field testing. (c) 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).