Characteristic Pulse Pattern Features of Different Types of Partial Discharge Sources in Power Cables

The measurement of partial discharges (PD) is an important approach used in identifying the presence of defects in high voltage insulation. This paper investigates various parameters characteristic to different types of PD, which can be used for the purposes of achieving more effective PD source discrimination. Measurements were performed on three distinct PD sources using a high-frequency current transformer to detect pulses. Parameters to characterize the PD activity were calculated, including statistical, pulse width, pulse interval and sequential pulse voltage differences. The degree of positive and negative half-cycle asymmetry was also determined. The results obtained indicate that the most significant differences in the parameter values, which can be used to distinguish between different source types, are associated with pulse count, pulse peak values, PD occurrence phase, pulse widths, sequential pulse intervals, voltage differences and correlation between pulse waveforms.