The effect of space charge on phenomenology of partial discharges in insulation cavities

The effect of space charge accumulated in insulation cavities on partial discharge activity is dealt with in the paper. Partial discharges were measured on non-polarized and DC-polarized XLPE specimens. In order to characterize space charge distribution, pulsed-electroacoustic (PEA) space charge measurements were also performed on polarized and PD-aged specimens. The results show that space charge can affect, although in some complex way, partial discharge phenomenology. Moreover, space charge measurements on stressed specimens can help in the inference of degradation mechanisms (e.g., trap formation at the cavity surface) associated to partial discharge activity.