摘要
在电工材料介电性能测量时,可移动的载流子在电极-试样界面处积累形成空间电荷,产生宏观电极极化。电极极化通常被误认为是材料的本征电极化,或者覆盖材料的本征电极化,导致对材料介电性能的错误认知。因此,完善对电工材料电极极化特性的研究,对进一步理解材料的介电弛豫和正确分析材料的电气特性有重要的意义。该研究通过理论分析和电路模型对电极极化的特性进行分析,并通过有机交联聚乙烯绝缘、无机储能陶瓷和液体电缆油进行实验验证。研究发现,电极极化一般发生在低频1Hz以下,通常伴随着样品的高漏电导率,电极极化的产生将会在电极-试样界面产生附加电容,其特征是导致低频介电常数急剧增大,低频介质损耗随频率偏离成反比变化,同时复电导率虚部在低频区表现为随测量频率的下降呈先减小后增大的趋势。
Movable charged carriers can accumulate at the electrode-sample interface,generate space charge and give rise to the macroscopic electrode polarization during the dielectric property test.Electrode polarization is often mistaken for the intrinsic electric polarization,or masks the intrinsic electric polarization,resulting in a false performance recognition to electrical materials.Consequently,a clear insight into the electrode polarization is of great importance to further understand dielectric relaxation and analyze the electrical property of electrical materials.In this work,the theory analysis and circuit model were proposed to describe the electrode polarization,which can be experimentally validated by several electrical materials such as organic crosslinked polyethylene(XLPE),inorganic energy storage ceramics and liquid cable oil.It was found that electrode polarization generally occurred at low frequency below 1 Hz,resulting from a high leaky conductivity of the sample.Electrode polarization can result in an additional capacitance to the sample,which causes a sharp increase of permittivity at low frequency.Low-frequency dielectric loss deviates from inversely proportional variation with frequency as well as the imaginary part of complex conductivity drops firstly and then increases with the test frequency reducing.
作者
侯帅
周福升
赵学童
李宇鹏
聂永杰
Hou Shuai;Zhou Fusheng;Zhao Xuetong;Li Yupeng;Nie Yongjie(Electric Power Research Institute China Southern Power Grid Guangzhou,510663 China;State Key Laboratory of Power Transmission Equipment and System Security and New Technology Chongqing University,Chongqing 400044 China;Electric Power Research Institute Yunnan Power Gird Co.Ltd,Kunming 650217 China)
出处
《电工技术学报》
EI
CSCD
北大核心
2021年第S02期430-437,共8页
Transactions of China Electrotechnical Society
基金
南方电网公司技术研究中心开放基金(NEL201912)
国家自然科学基金(51877016)
教育部霍英东教育基金(171050)资助项目。
关键词
介电性能
电极极化
电工材料
介电弛豫
Dielectric property
electrode polarization
electrical materials
dielectric relaxation
