Partial discharges activated by impulses and superimposed voltages in a high voltage cable model

In practice, High-voltage (HV) cables are occasionally exposed to impulse and superimposed transient conditions, which may initiate partial discharges (PD) temporarily. Whether such PDs persist under AC voltage after the transient conditions have vanished, is at focus in the research described in this paper. Since for cross-linked polyethylene (XLPE) cables the accessories are weak links in the HV cable insulation system, we investigated the PD behavior of an artificial joint defect in a HV cable model under impulse and superimposed voltages. By applying a dedicated PD measuring system it was found that, the impulse and superimposed voltages can initiate PD in the artificial defect, which under local electrical field conditions can persist for some time. The different parameters of the applied voltages have different effects on the PD behavior.