基于水树微观结构特征的水树老化电缆PDC支路参数特征  

PDC Branch Parameter Characteristics of Water Tree Aged Cables Based on the Microstructural Characteristics of Water Trees

作　　者：马骁 李康乐[1] 周凯[1] 李原 黄科荣 MA Xiao;LI Kangle;ZHOU Kai;LI Yuan;HUANG Kerong(College of Electrical Engineering,Sichuan University,Chengdu 610065,China)

机构地区：[1]四川大学电气工程学院,成都610065

出　　处：《高电压技术》2022年第2期716-723,共8页High Voltage Engineering

基　　金：国家自然科学基金(51877142)。

摘　　要：为了研究水树老化电缆极化-去极化电流(polarization and depolarization current,PDC)支路参数变化特征及原因,分析了水树微观结构特征,并揭示了水树微观结构对电缆PDC支路参数的影响。对短电缆和长电缆样本进行加速水树老化,利用PDC检测样本极化–去极化电流,并计算老化样本Debye模型三支路参数。利用光学显微镜观测短电缆样本中的水树形态,利用扫描电镜(scanning electron microscopy,SEM)观测水树区域微观形貌。PDC三支路参数辨识结果表明,水树老化样本第3支路时间常数显著高于未老化样本。另外,第3支路电容增加量高于电阻减小量。微观观测结果表明水树区域存在大量孤立微孔,分析认为,水树生长将造成材料分子链断裂及形成大量微孔–XLPE界面,导致材料偶极极化时间及界面极化时间增长,样本第3支路时间常数显著增大。另外,水树区域存在大量孤立微孔,其限制了离子在水树区域的运动,从而导致样本第3支路电容增大量高于电阻减小量。To investigate the changing characteristics of the polarization and depolarization currents(PDC)branch parameters of water tree aged cables,we analyzed the microstructural characteristics of the water trees,and revealed the influence of the microstructures of water trees on the PDC branch parameters.Short and long cable samples were subjected to an accelerated water tree aging.The polarization and depolarization currents of the samples were tested by the PDC method,and the Debye model branch parameters of the aged samples are calculated.The water trees in the short cable samples were observed by a microscope,and the microstructures in water tree regions were observed by a scanning electron microscope(SEM).The identification results of the PDC three branch parameters show that the time constant of the third branch of water tree aged samples is significantly higher than that of the unaged samples.In addition,the increment of the capacitance is higher than the decrement of the resistance.The microscopic observation results show that there are numbers of isolated microvoids in the water tree regions.It is analyzed that water tree propagation can result in the fracture of the XLPE molecular chain segments and the formation of large numbers of interfaces between microvoid and XLPE,thus both the dipole polarization time and the interfacial polarization time increase,and the polarization time constant of the third branch increases.In addition,there can be large numbers of isolated microvoids in the water tree regions,which inhibit the movement of the ions in the water tree regions,thus resulting in the higher increment of the capacitance than the decrement of the resistance of the third branch.

关 键 词：XLPE电缆 局部缺陷 水树 检测 支路辨识 微观结构 

分 类 号：TM247[一般工业技术—材料科学与工程]