Effect of voltage stabilizer injection technology on electrical treeing and PD of the XLPE cable

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 aged cable, three kinds of voltage stabilizers, namely, antioxidant 300, aromatic compound, and ultraviolet absorber were added into the siloxane fluid, respectively, and then they were injected into the thermal aged cable samples. After that, the initiation and growth of electrical trees and the partial discharge (PD) during the propagation of trees were measured. The results indicate that compared with the samples without injecting rejuvenation fluid, the electrical tree initiation voltages are improved and the propagation of electrical trees is suppressed after injection. The antioxidant 300 has the best effect on restraining electrical treeing. Moreover, the phase-resolved partial discharge (PRPD) of the samples injected with three types of voltage stabilizers show an asymmetrical ‘wing-like’ distribution in voltage cycles. Among them, the PD amplitude and discharge number of the samples containing antioxidant 300 rejuvenation fluid are the smallest, which shows that the antioxidant 300 obviously inhibits the PDs. Because the antioxidant 300 can effectively block the oxidation and free radical chain reaction, and the relative molecular weight of the antioxidant 300 is the largest, which is relatively difficult to exude from the insulation. As a result, the rejuvenation fluid containing antioxidant 300 improves the insulation performance of the XLPE; the lifespan of the thermal aged cables is extended.