Mechanical Behavior of Aged EPDM Insulation of High-Voltage Cable Joints in Thermal-Oxidative Environment

Abstract

In this thesis, the thermal aging behaviour at 130°C, 145°C and 160°C for 220kV cable joint EPDM insulation was investigated. The tensile strength and elongation of EPDM insulation both before and after the thermal-oxidative aging were measured, and the microstructure of materials was observed by SEM. The microstructure observation showed that pores formed and expanded into pieces inside the EPDM insulation with thermal aging course, the cracks would appear at the end of aging process. Both tensile strength and elongation of EPDM insulation decreased with aging process lasting, and decreased more gradually with increasing aging temperature. The tensile strength was more sensitive than elongation for aging process. The results can provide theoretical support for the fabrication, operating and maintenance for EPDM cable joint.