Enhancing Inhibition of Electrical Treeing in XLPE Cables Based on the Targeted Movement of Rejuvenation Fluid Induced by Electric Field

In this study, the inhibition effect of electrical treeing is investigated in a cross-linked polyethylene (XLPE) cable under the targeted movement of rejuvenation fluid induced by an electric field. First, the fluid concentration around the defects is characterized by Fourier transform infrared (FTIR) spectroscopy under different voltages, application durations, and application temperatures. These results show that with increasing applied voltage, application duration, and temperature, the fluid concentration around the defects increases nonlinearly. Next, the electrical treeing features of samples with and without electric field induction show that the tree initiation voltage increases and the tree accumulated damage decreases for the samples with electric field induction. By analyzing the changes in the molecular chain structure of the XLPE under different influencing factors, it is found that with applied voltage and duration increase and application temperature decreases, the methyl groups increase and the methylene groups decrease, and the diffusion channel of fluid is expanded. Finally, it is proposed that the dielectrophoretic (DEP) force changes in molecular chain structure and molecular thermal motion determine the behaviors of the targeted movement of fluid in insulation. The fluid concentration around the defects increases after the targeted movement of fluid, and the electrical treeing inhibition effect is enhanced.