基于电化学交流阻抗谱的硅橡胶阻水性能研究  

Study on the Water Barrier Property of Silicone Rubber Based on the Electrochemical Impedance Spectroscopy

作　　者：汪政 彭向阳[1] 黄振 杨粤 何春清 方鹏飞[2] WANG Zheng;PENG Xiangyang;HUANG Zhen;YANG Yue;HE Chunqing;FANG Pengfei(Guangdong Key Laboratory of Electric Power Equipment Reliability,Electric Power Research Institute of Guangdong Power Grid Co.,Ltd.,Guangzhou,Guangdong 510080,China;College of Physics and Technology,Wuhan University,Wuhan,Hubei 430072,China)

机构地区：[1]广东省电力装备可靠性企业重点实验室(广东电网有限责任公司电力科学研究院),广东广州510080 [2]武汉大学物理科学与技术学院,湖北武汉430072

出　　处：《广东电力》2021年第11期75-86,共12页Guangdong Electric Power

基　　金：中国博士后科学基金项目(2020M682609);中国南方电网有限责任公司科技项目(GDKJXM20200403)。

摘　　要：水分入侵硅橡胶是引起复合绝缘子发热及断裂故障的主要原因,目前用于评估硅橡胶阻隔水汽的能力的基于称重试验的吸水性、透水性测试方法,存在精确度低、耗费人工的问题。对此,提出一种基于电化学交流阻抗谱的硅橡胶阻水性能评估方法。该方法利用电化学工作站三电极体系实现自动测试,节省人工且灵敏度高。研究表明,水溶液扩散系数与阻抗谱时间常数数量是评估硅橡胶阻水性的2个重要特征参量。扩散系数采用电容法计算得到,用于定量评估硅橡胶对水溶液的阻隔特性。阻抗谱时间常数数量可在图谱中直接得到,用于判断硅橡胶是否失效透水。通过探讨不同Al(OH)_(3)含量硅橡胶的阻水性,发现:未老化硅橡胶的阻水性较好;经电晕老化后,硅橡胶阻水性随Al(OH)_(3)含量呈现出先增强后减弱的趋势。硅橡胶中的Al(OH)_(3)存在逾渗临界含量,超过该含量的硅橡胶经电晕老化后更容易丧失阻水性。Invasion of water into the silicone rubber is the main reason leading to abnormal heating and fracture of a composite insulator.At present,some methods of water absorption and water permeability tests based on the weighing test used for evaluating the property of the silicone rubber obstructing water or moisture have problems of low precision and artificial consumption.Therefore,this paper proposes an evaluation method to study the water barrier property of the silicone rubber based on electrochemical impedance spectroscopy.This method uses electrochemical workstation and its three-electrode system to implement automated test,which can save labor and is of high sensitivity.The research shows that the water diffusion coefficient and the number of time constant are two important characteristic parameters for evaluating water barrier property of the silicone rubber.The diffusion coefficient is calculated by the capacitance method,which is used to quantitatively evaluate barrier property of the silicone rubber to water solution.The number of time constants of impedance spectrum can be directly obtained from the spectrum,which can be used to judge whether the silicone rubber is invalid or not.By studying water barrier properties of silicone rubbers with different mass fractions of Al(OH)_(3),it is found that water barrier performance of each virgin silicone rubber is very good,while the water barrier performance of corona aged ones firstly increases and then decreases with the increasing content of Al(OH)_(3).The mass fraction of Al(OH)_(3)in the silicone rubber has a critical percolation content,and the silicone rubber with more than this percolation content is more likely to lose water barrier property after corona aging.

关 键 词：电晕放电 阻水性 硅橡胶 电化学阻抗谱 扩散系数 

分 类 号：TM215.3[一般工业技术—材料科学与工程]