为准确评估乙丙橡胶(EPDM)车载电缆的绝缘老化状态,引用了等温松弛电流(IRC)法和局部放电(PD)法,分别讨论了老化因子、局部放电特征信息与电缆老化状态之间的映射关系,结果表明:随着车载电缆运行里程的增加,老化因子、局部放电量、放电次数和放电电流均呈现规律性增长趋势,多种老化应力协同作用是造成车载电缆绝缘劣化的主要原因,绝缘材料内部陷阱的增多和加深是车载电缆老化的微观表现.协同等温松弛电流法和局部放电法对车载电缆绝缘状态的评估具有有效性和可行性,通过建立微观陷阱分布特性与宏观局部放电特性之间的联系,分析可得:深陷阱捕获电荷的能力较强,电荷极易集聚,局部放电容易发生,因此基于IRC法和局部放电法对车载电缆绝缘状态进行评估具有一定的价值意义,可指导高速动车组电网规划及电缆检修工作.
For accurately assessing the insulation aging condition of ethylene propylene rubber(EPDM)vehicle ca-ble,the isothermal relaxation current(IRC)method and the partial discharge(PD)method are used,and the mapping relationship among the aging factor,the characteristic information of partial discharge and the aging condition of the cable is discussed respectively.The results show that with the increase of the operating mileage of the vehicle cable,the aging factor,the amount of partial discharge,the number of discharges and the discharge current show a regular growth trend.The synergistic effect of multiple aging stresses is the cause of the deterioration of the vehicle cable in-sulation.The increase and deepening of internal traps in insulating materials are the microscopic manifestations of the aging of vehicle cables.Both synergistic isothermal relaxation current(IRC)method and the partial discharge(PD)method have effectiveness and feasibility on the insulation condition of the vehicle cable.It is known by setting up the relation and analysis between micro trap distribution characteristic and macro partial discharge characteristic that the deep traps have a strong ability to capture charges.It is very easy to agglomerate and partial discharge is prone to occur.Therefore,the IRC method and the partial discharge method have a definite significanc,which can guide the grid planning and maintenance of cable of high-speed EMUs.