Study of Storage Activity of XLPE Pre-Crosslinked Material for High Voltage AC Cables

XLPE has been widely used in the main insulation of cables of various voltage levels. However, the self-decomposition characteristics of the cross-linking agent in the pre-crosslinked polyethylene materials for cable insulation during long-term storage will affect the consistency of cable extrusion and cross-linking processes. Therefore, it is necessary to study the effect of storage time on the activity of the pre-crosslinked material. In this paper, with accelerated aging test, the mechanical and insulation properties of XLPE which are prepared by pre-crosslinked material with different equivalent storage time are measured, and the storage activity of pre-crosslinked polyethylene material for 220 kV high voltage AC cable is evaluated. The results show that the degree of crosslinking of XLPE is significantly reduced after high temperature aging, the thermal extension performance is seriously deteriorated, the mechanical properties are reduced by about 16%, and the insulation properties are improved slightly. Therefore, in order to ensure the stability of the performance of the XLPE insulated high voltage AC cable, it is recommended that the storage time of the pre-crosslinked material be less than 5 years, and it is proposed that the thermal extension performance can be used as a basis for determining the activity of the pre-crosslinked material.