The role of supply frequency in the evaluation of partial discharge inception voltage in XLPE-embedded cavities

We have investigated recently the role of voltage supply frequency on partial discharge inception voltage (PDIV) measurement for cavities embedded in a polyethylene matrix. From the experimental results, it was ascertained that lower frequencies could lead to lower PDIV values, whereas increasing the supply frequency could quench partial discharge activity. Some explanations were proposed, but a further experimental activity was planned to confirm (or reject) some of the hypotheses. In this paper, the results presented earlier are further validated through an extensive experimental survey. The conclusions derived from the present data are that PDIV does not change appreciably with frequency, whereas, its measured value does. Very low frequency systems seem to provide results that are more accurate than those obtained using higher frequencies.