The additives of cross-linked polyethylene (XLPE) cable insulation gradually lose with the increase of time, which influences the service life of cables. To study the effect of voltage stabilizer injection on the insulation performance of the aging cable, three different kinds of voltage stabilizers, such as antioxidant, aromatic compound, an ultraviolet absorber, were added into the siloxane rejuvenation fluid, respectively, then injected into the thermal-oxidative aged cable samples. The electrical tree initiation and growth and the partial discharge (PD) of the samples were tested after injection. The results indicated that the initiation voltages, length, and width of the electrical tree are all increased, and the antioxidant 300 has the best effect on restraining the electrical treeing. The phase-resolved partial discharge (PRPD) of the three voltage stabilizers injected showed asymmetrical ‘wing-like’ distribution in the voltage cycles. Among them, The PD amplitude and discharge number of antioxidant 300 rejuvenation fluid are the smallest, and the other rejuvenation fluid containing voltage stabilizers have higher results, which indicate that the antioxidant 300 has the most obvious inhibitory effect on PD. This was because the autoxidation and thermal degradation that occurs during thermal-oxidative aging make a large amount of oxygen and free radicals present in the insulation, and the antioxidant can effectively block the oxidation and free radical chain reaction. Meanwhile, the relative molecular weight of the antioxidant 300 is the largest, and it is relatively more difficult to exude from the insulation. The above studies showed that the antioxidant 300 injection was of great significance for extending the lifetime of thermal-oxidative aged cables.

Voltage stabilizer,Rejuvenation technology,PD,Thermal-oxidative aging,Electrical treeing