The Effect of Alumina Nanoparticles on Increasing the Lifespan of Aged XLPE MV Cable Insulations

This study presents a method for rejuvenation, life elongation and Restoration of XLPE cables insulation by a silicone rejuvenation fluid containing alumina nanoparticles. The rejuvenation fluid included a type of silane coupling agent and alumina (aluminum oxide) nanoparticles. The silane coupling agents react with the water in the cable insulation and water tree regions, remove the water molecules and dry the cable insulation. In this way, they fill the water tree voids and bond the alumina nanoparticles with polymer matrix of the cable and improve the dielectric properties of the cable. After injecting the rejuvenation fluid into the aged XLPE cables, tanδ test was repeated on rejuvenated samples every week for one month and its variations were compared with new and aged samples. Microstructural analysis of the aged and rejuvenated samples was carried out and compared by SEM microscope. FTIR analysis evaluates and compares the chemical bonds in the rejuvenated and aged cable insulations. EDX spectroscopy determined the type and amount of absorbed elements on the rejuvenated sample surface. The impact of rejuvenation fluid on aged XLPE cables was determined according to the 4 mentioned tests.