Physicochemical and electrical property of a new AC 500kV XLPE submarine cable insulation with different thermal aging condition

With the rapid development of China's new energy industry, there is a great market for submarine cable products. However, the insulation materials of the cable would be seriously aged during the long term operation of the cable. This paper studied the physicochemical characteristics of a new AC 500kV XLPE submarine cable insulation with different thermal aging condition. The accelerated thermal aging test of the AC 500 kV XLPE submarine cable insulation material was conducted at 130C. The properties of the insulation material were analyzed by tensile test, frequency domain dielectric spectroscopy (FDS), X-ray diffraction (XRD) and scanning electron microscope (SEM). Results show that during the 35 days aging process, the tensile strength of the cable insulating material rises first and then decreases. The dielectric constant, dielectric loss and conductivity tend to decrease and then increase with the deepening of the aging degree. The changes in mechanical and electrical properties are inseparable from the changes in the microstructure of the material.