Partial discharge factory test requirements and in-field partial discharge testing of medium voltage cables

This article presents partial discharge testing of medium voltage cables. Utility engineers are faced with decision on whether to replace some of the older cables in their underground distribution systems. Today, measurement of PD at voltages above 1 Vg on extruded cables more than fifteen years old may not indicate that the cables have developed PD due to in-service aging. Removal of these cables based solely on PD measurements may not be warranted. Failure history of the cable, in conjunction with an analysis of the PD site, should be part of the utility engineer´s decision-making process.