Comparison of measured PDs in oil-impregnated insulation using different sensor bandwidths

This paper presents the statistical analysis of partial discharge distributions in oil-impregnated pressboard and paper configurations. The experiment reported here was aimed at an investigation of the characteristics of partial discharges in a cavity for both new and aged oil-impregnated pressboard-paper samples. Two different measurement systems, which provide four different measurement bandwidths were used to observe whether they would produce similar characteristics of discharges. The results indicated that, while there was some general similarity in the shape of PD patterns, a detailed statistical analysis of the PD data showed some significant differences in the results. These differences were significant in terms of the frequency response of the PD sensor systems. As a conclusion, the analysis of such PD data must be performed carefully with particular attention being given to the frequency response