On-site Condition Assessment of XLPE MV Cable Joints by Using an Insulation Tester

In this paper, on-site time domain dielectric response measurements have been performed once a month on medium voltage XLPE cable links with heat shrink joints using a conventional 5 kV DC insulation tester. The main purpose of this work has been to examine the reproducibility of the measured currents. It is shown that both the polarization and depolarization currents remain approximately unchanged, and that they can provide robust criteria for cable condition assessment. It is advantageous to use the insulation tester before applying any other more advanced diagnostic techniques.