计及电缆绝缘不均匀老化的接地电流相位角特性研究  

Study on Phase Angle Characteristics of Grounding Current Considering Uneven Aging of Cable Insulation

作　　者：刘刚 王秀茹[1] 邱冬[1] 王德[1] 鲍诗杰 张东东 LIU Gang;WANG Xiuru;QIU Dong;WANG De;BAO Shijie;ZHANG Dongdong(State Grid Suqian Power Supply Company,Jiangsu Suqian 223800,China;Nanjing Institute of Technology,Nanjing 215000,China)

机构地区：[1]国网宿迁供电公司,江苏宿迁223800 [2]南京工程学院,南京215000

出　　处：《高压电器》2024年第5期156-163,共8页High Voltage Apparatus

基　　金：国网江苏省电力公司科技项目(J2023101);中国博士后科学基金资助项目(2023M732412)。

摘　　要：交联聚乙烯(XLPE)电力电缆广泛应用于配电网和输电网,但它们在持续的电应力下遭受长期的老化退化,电缆老化容易造成绝缘击穿事故。为了提升电缆绝缘老化状态的在线评估技术,基于PSCAD建立了计及电缆绝缘不均匀老化的三芯管型电缆接地电流相位角计算模型,通过快速傅里叶变换FFT变化得到单相不均匀老化、双相不均匀老化、三相均匀老化3类情况的接电线电流相位角特性。结果表明:相比于钢铠接地线电流,屏蔽线电流相角对于老化特性的反应更为灵敏;对于单相老化,介电常数由2增加为5,屏蔽线电流相位角从-51.01°递增为-50.6°;对于双相老化,随老化程度增加,相位角增幅逐渐增大;对于三相均匀老化,相比于正常电缆的屏蔽线电流相角增值为0.24°,同时相比于介电常数同为2.8的单相老化与双相老化的屏蔽线电流相角增值为最大(单相老化为0.15°、双相老化为0.17°);通过屏蔽线电流相位幅值,不仅可以判断电缆绝缘是否老化,还可区分老化相别与老化程度。本研究结果可为通过地线电流相位角评估电缆绝缘老化等级提供重要理论依据。Cross linked polyethylene(XLPE)power cable is widely used in transmission and distribution network and,however,suffers from long-term aging degradation under continuous electrical stress,and cable aging can easily cause insulation breakdown.In order to improve the online assessment technology of cable insulation aging status,a three-core tube-type cable grounding current phase angle calculation model considering uneven aging of cable insulation is set up based on PSCAD.The phase angle characteristics of such three types of the grounding wire current as single-phase uneven aging,two-phase uneven aging and three-phase uniform aging are obtained through FFT variation.The result shows that compared to the current of steel armored grounding wires,the response of phase angle of shielding wire current to the aging characteristics is more sensitive.For the single-phase aging,the dielectric constant increases from 2 to 5,and the phase angle of the shielding wire current increases from-51.01°to-50.6°.For the two-phase aging,the amplitude of phase angle gradually increases with the increase of degree of aging;For the three-phase uniform aging,the phase angle increment of the shielding wire current is 0.24°compared to normal cables and,at the same time,the phase angle increment of the shielding wire current is maximum compared to single-phase aging and two-phase aging with the same dielectric constant of 2.8(0.15°for single-phase aging and 0.17°for two-phase aging).The analysis of the phase amplitude of the shielded wire current can not only judge the aging status of the cable insulation,but also distinguish the aging phase and degree.The research results in this paper can provide important theoretical basis for assessing the insulation aging level of cables through the phase angle of grounding wire current.

关 键 词：三芯电缆 绝缘老化 介电常数 接地电流相位角 

分 类 号：TM247[一般工业技术—材料科学与工程]