Statistical analysis for internal and surface discharges identification in XLPE insulation under AC voltages

One of the most effective methods to assess the quality of solid insulated cable under AC or DC voltage is partial discharge (PD) analysis. Several common methods to analyze PD phenomenon based on PD data sets, such as PD magnitude, phase, and occurrence time, have been investigated and interpreted. In this paper, a new approach using the statistical parameters obtained from the PD magnitude density function and inter-time density function was used. To carry out this identification process, a technique for measuring PD with high sensitivity under AC voltage was developed, with the aid of TF map algorithm to separate noise from PD. The results show that identification of internal and surface discharges can be performed successfully.