In service evaluation of polyethylene and crosslinked polyethylene insulated power cables rated 15 to 35 kV

This paper describes mobile inverted dissipation factor and mobile partial discharge equipment developed to measure long lengths of installed shielded power cables in the voltage range 5-35 kV. The techniques employed during field measurements and the results obtained at ten widely spaced geographical locations using this mobile equipment are presented. The field measurements are compared with laboratory measurements on portions of the cables tested. It is concluded that the mobile dissipation factor bridge equipment is an excellent tool for the detection of electrochemical trees in the cable insulation, extensively corroded concentric neutral wires and excessive conductor and insulation shield resistances. It is additionally concluded that the mobile partial discharge detector is an excellent tool for determining the existence of partial discharges of installed cable systems.