油纸及XLPE绝缘高压直流电缆的电场分布特性研究  

Study on electric field distribution characteristics of oil-paper and cross-linked polythylene insulated HVDC cables

作　　者：但京民 李文清 崔戎舰 刘英[2] 李健 吴高波 DAN Jingmin;LI Wenqing;CUI Rongjian;LIU Ying;LI Jian;WU Gaobo(Central Southern China Electric Power Design Institute Co.,Ltd.of China Power Engineering Consulting Group,Wuhan 430071,China;School of Electrical Engineering,Xi′an Jiaotong University,Xi′an 710049,China)

机构地区：[1]中国电力工程顾问集团中南电力设计院有限公司,湖北武汉430071 [2]西安交通大学电气工程学院,陕西西安710049

出　　处：《绝缘材料》2024年第7期84-93,共10页Insulating Materials

基　　金：中国能源建设集团规划设计有限公司科技项目(GSKJ2-D03-2021)。

摘　　要：直流电缆主要采用油纸及交联聚乙烯(XLPE)作为绝缘,两类材料的电导率特性不同,对电缆中电场分布的影响不同。本文基于500 kV典型直流电缆结构建立有限元模型,对油纸及XLPE绝缘电缆开展热-电耦合仿真分析,研究了两种绝缘在不同温度及温差下的场强分布特性,分析了绝缘电导率温度系数及电场系数对场强分布的影响,对比了相同温度及场强范围内油纸及XLPE绝缘的电导率变化特性。结果表明:在电场强度为10~25 kV/mm和温度为20~90℃的范围内,油纸绝缘中的电场分布受绝缘温差的影响,在确定温差下几乎不随绝缘温度而变化;而XLPE绝缘中的电场分布同时受绝缘温度和温差的影响。此外,油纸绝缘的电导率整体比XLPE绝缘高,随温度和场强的变化幅度大,这可能是油纸电缆绝缘中电场反转发生在更低温差下的原因。对于高压直流电缆中应用的绝缘材料,应控制电导率温度系数即减小温度敏感性。DC cable mainly uses oil-paper and crosslinked polyethylene(XLPE)as insulation,and the conductivity characteristics of the two materials are different,which has a significant effect on the electric field distributions in cable.In this paper,a finite element model was established based on the 500 kV typical DC cable structure,and the thermal-electrical coupled simulation analyses were performed on the oil-paper and XLPE insulated cables.The electric field distribution characteristics in the two insulation under different temperatures and temperature drops were studied,and the influences of the conductivity temperature and electric field coefficient on the field strength distribution were analyzed.The conductivity variations of oil-paper and XLPE insulations among the same temperature and field ranges were compared.The results show that the electric field distribution in oil-paper insulation is affected by the insulation temperature difference in the electric field strength range of 10-25 kV/mm and temperature range of 20-90℃,and hardly changes with the insulation temperature under definite temperature difference,while the electric field distribution in XLPE insulation is affected by both insulation temperature and temperature difference.In addition,the overall conductivity of oil-paper insulation is higher than that of XLPE insulation,and its change amplitude with temperature and field strength is larger,which may be the reason why the electric field inversion in oil-paper cable insulation occurs at a lower temperature difference.For the insulating materials used in HVDC cables,the conductivity temperature coefficient should to be controlled small so as to reduce the temperature sensitivity.

关 键 词：高压直流电缆 油纸绝缘 交联聚乙烯绝缘 电场分布 绝缘电导率 

分 类 号：TM215[一般工业技术—材料科学与工程] TM85[电气工程—电工理论与新技术]