低压电缆绝缘老化对材料力学性能作用机制  

Mechanism of the Aging of the Low Voltage Cable Insulation on the Mechanical Properties of the Material

作　　者：吴向峰 李康乐 张宏亮[1] 周凯[2] 王国栋 张志鲟 化亮 WU Xiangfeng;LI Kangle;ZHANG Hongliang;ZHOU Kai;WANG Guodong;ZHANG Zhixun;HUA Liang(Lanzhou University of Technology,Lanzhou,Gansu 730050,China;Sichuan University,Chengdu,Sichuan 610065,China;State Grid Gansu Transmission and Transformation Engineering Limited Corporation,Lanzhou,Gansu 730070,China)

机构地区：[1]兰州理工大学,甘肃兰州730050 [2]四川大学,四川成都610065 [3]国网甘肃送变电工程有限公司,甘肃兰州730070

出　　处：《塑料》2023年第6期116-121,135,共7页Plastics

基　　金：国家自然科学基金(51607082);甘肃省高校创新基金(2020A-023)。

摘　　要：为了研究变电站低压电缆PVC绝缘老化对其力学性能的影响,对变电站用低压电缆样本进行加速老化,并且,研究了PVC绝缘老化特征及力学性能特征。制备A、B、C、D 4组低压短电缆样本,其中,A组为对照样本,不进行老化。在B、C、D 3组样本上制作V形缺陷,将B、C、D 3组样本浸泡在CuSO4溶液中,在样本上施加1 kV的交流电压进行加速老化实验,3组样本老化时间分别为7、14、21 d。老化结束后,采用扫描电镜(SEM)观察PVC微观形貌;用红外光谱仪(IR)检测PVC化学结构;用卤素水分仪测定PVC含水量;用力学拉伸仪测试PVC绝缘力学性能参数。测试结果表明,加速老化中同时存在电力学老化及电化学老化,导致PVC的绝缘力学性能下降。未老化PVC样本弹性模量为135.9 MPa,老化7 d后,样本弹性模量下降至122.1 MPa;老化14 d后,弹性模量下降至115.3 MPa;老化21 d后,样本弹性模量下降至102.4 MPa。样本弹性模量下降速率呈先减小后增大的趋势变化,其他力学参数的变化规律类似。因此,不同老化阶段PVC绝缘力学性能变化主要是由电力学及电老化特点决定的。To investigate the influence of the aging of low voltage cable PVC insulation in transformer station on its mechanical properties,some low voltage cable samples in station were subjected to accelerated aging,and the aging characteristics as well as mechanical properties of the PVC insulation were investigated.Four groups of samples of A,B,C and D were produced in which group A samples were comparative samples and were not aged.V shaped defects were produced in the three groups of samples B,C and D and they were immersed in CuSO4 solution and a alternate voltage of 1 kV was exerted on the samples in accelerated aging,the aging time of the three groups of samples were 7,14 and 21 d.After the aging,the microscopic morphologies of the PVC were observed by a scanning electron microscopy,the chemical structure of the PVC were detected by an infrared spectrometer(IR),the water content of the samples was measured by a halogen moisture meter,and the mechanical property parameters of the PVC insulation were measured by a mechanical tensile machine.The test results showed that there were electro-mechanical and electro-chemical aging in the accelerated aging and they could result in the decrement of the mechanical properties of the PVC insulation.The elastic modulus of the unaged PVC samples was 135.9 MPa,and it decreased to 122.1 MPa after 7 d,115.3 MPa after 14 d,and 102.4 MPa after 21 d.The decreasing rates of the samples first decreased and then increased,and the changing characteristics of the other mechanical parameters were similar.It was analyzed that the changes of the mechanical properties of the PVC insulation were mainly decided by the characteristics of electro-mechanical aging and electro-chamical aging.

关 键 词：变电站 低压电缆 PVC绝缘 微观结构 化学结构 老化特征 力学性能 

分 类 号：TQ325.3[化学工程—合成树脂塑料工业]