摘要
为了判断XLPE电缆绝缘中是否出现水树老化现象,基于水树老化后特有的微观结构及在电场下的力学蠕变特性,提出一种基于连续极化去极化电流(polarization and depolarization current,PDC)测试的水树老化XLPE电缆检测方法。首先分析水树区域在电场下受到麦克斯韦应力下的力学形变,使得流过这一区域的电流在连续PDC测试过程中逐渐增大。之后,对这一过程下的水树区域进行电流仿真,验证了这一现象。最后,对不同老化形式(水树、热、辐照老化)的电缆样本进行连续PDC测试,分析在连续PDC测试过程中直流电导率的变化情况。实验结果表明:对于内部出现水树老化的电缆样本,它们均出现了电导率随测试次数增加而明显增加的现象,同时电导率增加的幅度与水树枝平均长度相关,水树枝越长,则电导率增加越明显;而其他老化形式样本(不包含水树)电导率基本保持不变。这一对比分析结果说明:通过对电缆进行连续多次PDC测试并分析其电导率变化情况,能够判断XLPE电缆中是否存在水树老化现象。
To recognize the XLPE cable with water tree, this paper presented a diagnosing method based on the continuous polarization and depolarization current(PDC) tests. The microstructure and mechanical creep property of water trees were utilized in this method. Firstly, the current through the water tree region will gradually increase during the continuous PDC tests due to the deformation caused by the Maxwell stress. Then a simulation of water tree region was performed to verify the increase in current. Finally, the cable samples with different aging forms(water tree aging, thermal aging and irradiated aging) were tested by continuous PDC tests and the change of conductivity was analyzed. The results indicate that the cable samples with water tree aging show a significant increase in conductivity with the increase in number of PDC tests. The average length of water tree was related to the conductivity. The longer the length of the water tree branch inside the sample, the more the conductivity increased. The conductivity of samples without water tree aging hardly changed during the test. This method can determine whether there are water trees in a XLPE cable by continuous PDC tests and analyzing the changes in its conductivity.
作者
林思衍
周凯
尹游
李明志
龚薇
LIN Siyan;ZHOU Kai;YIN You;LI Mingzhi;GONG Wei(College of Electricwsal Engineering,Sichuan University,Chengdu 610065,Sichuan Province,China;Skill Training Center of Sichuan Electric Power Company of State Grid,Chengdu 611133,Sichuan Province,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2020年第20期6764-6772,共9页
Proceedings of the CSEE
基金
国家自然科学基金项目(51477106)。
关键词
XLPE电缆
水树老化
蠕变特性
极化–去极化电流法
XLPE cable
water tree aging
creep property
polarization and depolarization current method
