基于低频高压频域介电谱的XLPE电缆电树枝老化状态评估  

Evaluation of Electrical Tree Aging State of XLPE Cables Based on Low Frequency and High Voltage Frequency Domain Spectroscopy

作　　者：刘骥[1] 闫爽 王守明 张明泽[1] 李爽 Liu Ji;Yan Shuang;Wang Shouming;Zhang Mingze;Li Shuang(Key Laboratory of Engineering Dielectrics and Its Application Ministry of Education Harbin University of Science and Technology,Harbin,150080,China)

机构地区：[1]哈尔滨理工大学工程电介质及其应用教育部重点实验室,哈尔滨150080

出　　处：《电工技术学报》2023年第9期2510-2518,共9页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金资助项目(51977051)。

摘　　要：应用传统的频域介电谱(FDS)法对10 kV及以上电压等级的交联聚乙烯(XLPE)电缆绝缘进行测试时,存在抗干扰能力差、微电流采集困难等问题。因此该文提出一种基于I/V转换微电流采集装置的FDS测试方法,用于电缆绝缘状态评估。搭建了一套低频-高压FDS测试系统,用于对不同老化程度的电缆试样进行频域介电谱测试,发现对于同一老化程度的电缆而言,随着激励电压的升高,在低频段内表征出的非线性特征越加明显。基于老化电缆的频域介电谱所表征出的非线性现象,该文提出非线性特征参数的概念,以定量的形式对老化电缆所表现出的非线性进行分析。结果表明,随电树枝长度的增加,非线性特征参数以指数形式增大。通过指数函数关系式可以以非破坏性手段对电树枝长度进行预测,实现对电缆绝缘状态的有效评估。In the process of manufacturing,transportation and laying,cross linked polyethylene(XLPE)cables often lead to some minor defects in the insulation layer,which may develop into electrical treeing fault.Therefore,it is necessary to carry out research on electrical treeing aging assessment and diagnosis methods in cable insulation.Dielectric response method is the most widely used non-invasive diagnostic method in recent years.When the traditional frequency domain spectroscopy(FDS)method is used to test the insulation of XLPE cables with 10 kV and above voltage levels,there are problems such as poor anti-interference ability and difficulty in measuring micro current.Therefore,based on the traditional FDS test method,I/V conversion principle and non-phase shifting transimpedance amplifier circuit,a set of low frequency high voltage FDS test system is designed in this paper.Compared with the traditional test method,the test system increases the test voltage to 7.5 kV,and adds a zero phase-shift digital filter based on FRR(forward filter,reverse filter and reverse output)algorithm,which has higher signal-to-noise ratio,better sampling accuracy and stronger anti-interference capability.In this paper,cable samples with different electrical tree aging degrees were cultivated in the laboratory,and FDS tests were carried out using the test system.For cables with the same aging degree,with the increase of test excitation voltage,the nonlinear characteristics of cables in the frequency range of 10 mHz~1 Hz become more obvious.The nonlinear characteristic parameters are quantized,and the exponential relationship between the nonlinear characteristic parameters and the electrical tree length is established.The results show that the nonlinear characteristic parameters increase exponentially with the increase of electrical tree length.The exponential function can be used to predict the length of electrical tree in a non-destructive way,so as to effectively evaluate the insulation conditions of cables.In this paper,COMSOL finite el

关 键 词：XLPE电缆 电树枝老化 频域介电谱 绝缘状态评估 

分 类 号：TM85[电气工程—高电压与绝缘技术]