Experimental study on cable rejuvenation via simulated cable operation

To extend the cable service life, the feasibility of cable rejuvenation on two retired cables through heat treatment was investigated in this study. First, two retired 110 kV AC cables without overheated record were annealed at four temperatures of 90, 95, 100, and 105 °C by simulating the cable operation. Second, the insulation layer of the annealed cables was peeled, and the peels near the inner conductor were selected as test samples. Then, differential scanning calorimetry was performed, and the DC conduction current and dielectric breakdown strength E
_B
were measured. The results showed that the heat treatment of simulating cable operation could be a feasible method to rejuvenate retired cables and 95 °C was determined to be the optimum annealing temperature for the two cables.