Research on Rejuvenation Technology for Water Tree in XLPE Cables Based on Siloxane

The safe and stable operation of power system will be threatened because of the water tree aging of XLPE cables after years of running. In this paper, a rejuvenation system for XLPE cables is designed and a field aged cable specimen is restored via this system, making use of rejuvenation fluid based on siloxane. Moreover, the cable rejuvenation process is introduced in detail and the rejuvenation mechanism is analyzed in deep. Furthermore,electric field change, dielectric loss factor and insulation resistance of the specimen before and after rejuvenation is simulated as well as tested. Then the growth of water tree in the restored specimen is observed by optical microscope after accelerated water treeing test. The results show that insulation performance of restored cables is improved since the micro voids is filled with resultant created by the reaction of rejuvenation fluid and water. In addition, the growth of water tree is restrained as the resultant is closed to XLPE in dielectric properties, which results in the extending lifetime of cables.