Study on the influence of thermal aging on the discharge characteristics of the interface between the stress control tube and EPDM of the vehicle high voltage cable terminal
The interface between the stress control tube (SCT) and ethylene propylene rubber (EPDM) is a common part of the cable terminal insulation breakdown fault caused by frequent discharge, and those changes of thermal aging characteristics of SCT is one of the key factors affecting the development of its discharge. For exploring the influences of thermal aging characteristics of SCT on the discharge characteristics of composite layer interface, according to the special insulation structure and actual operation conditions of vehicle high voltage cable terminal, the artificial accelerated thermal agi；ng tests of SCT were designed under three aging environments such as 100 ℃, 125 ℃ and 140 ℃, and the composite layer interface model of aging SCT/EPDM was also made. Those influences of the SCT specimen on the initial discharge voltage and flashover voltage of the interface between the composite layers under different aging conditions was studied. The surface charge transport model of the stress tube was established, and also the carrier conductivity and migration rate of the SCT surface under different aging conditions were revealed. The mechanism of the influence of the change on the discharge characteristics of the composite interface model was also revealed. Through the above research, the development process and evolution law of the composite interface of the actual cable terminal are revealed indirectly.