Partial Discharge Patterns of Typical Installation Defects in MV Power Cable Terminations

The partial discharge patterns of three typical defects in MV cable terminations were characterised. The defects included a semi-conductor feather, a tram line in the cross-linked polyethylene insulation and a ring cut in the cross-linked polyethylene. Terminations were prepared with these artificial defects and subjected to a standard overvoltage test, during which partial discharge activity was monitored. All the defects passed the voltage test, despite some showing significant discharges. The semi-conductor feather defect exhibited partial discharge behaviour resembling a corona-like discharge. The tram line defect had a discharge pattern consistent with that of a narrow cavity, and the ring cut showed a flat cavity partial discharge pattern. Partial discharge magnitudes of the…