交联聚乙烯直流电缆料高温空间电荷行为特性  

Space Charge Behavior of DC Cable’s XLPE Material at High Temperatures

作　　者：程子霞[1] 鲁泽楷 张灵[2] 周远翔[2] 张云霄[2] 陈铮铮 CHENG Zixia;LU Zekai;ZHANG Ling;ZHOU Yuanxiang;ZHANG Yunxiao;CHEN Zhengzheng(School of Electrical Engineering,Zhengzhou University,Zhengzhou 450001,China;State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments,Tsinghua University,Beijing 100084,China;China Electric Power Research Institute,Wuhan 430074,China)

机构地区：[1]郑州大学电气工程学院,郑州450001 [2]清华大学电力系统及发电设备安全控制和仿真国家重点实验室,北京100084 [3]中国电力科学研究院有限公司,武汉430074

出　　处：《高电压技术》2018年第8期2664-2671,共8页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2014CB239501);国家自然科学基金(51707100;51377089);中国博士后科学基金(2016M591176;2017T100079);河南省国际科技合作计划(162102410072)~~

摘　　要：为研究进口交联聚乙烯（XLPE）直流电缆料高温空间电荷行为,开展了XLPE试样脱气前后的直流电导、介电和高温下空间电荷稳态暂态过程试验。结果表明：未脱气XLPE的电导电流和介质损耗均大于脱气XLPE;在-30 MV/m下脱气前后XLPE内部均为负极性电荷积聚,且在30℃和70℃下电场畸变率不超过25%;70℃、-100 MV/m下极化初始2 s的快速测量发现,脱气XLPE出现正空间电荷包的快速迁移,而-150 MV/m下则出现了负空间电荷包的注入与迁移,正、负空间电荷包的运动过程均遵循负微分迁移率。分析认为：脱气处理降低了XLPE交联副产物的含量,减少了离子电离,从而减小了低频区的电导率;在-30 k V/mm时,试样内部积聚的少量负电荷主要由交联副产物及杂质电离所产生,随着场强的提高,开始出现由电极注入的正电荷且杂质离子产生的速率要高于正电荷的注入速率;70℃、-150 MV/m下极化初始阶段,正电荷快速迁移至阴极附近,致使阴极附近电场严重畸变（畸变率最大达61.5%）,导致阴极大量注入负电荷并在试样内部形成负空间电荷包。In order to study the space charge behavior of imported DC cable＇s XLPE material at high temperatures, we prepared undegassed and degassed XLPE samples for the tests, including DC conduction, dielectric and space charge during steady and transient processes at high temperatures. The results show that both the conduction current and dielectric loss of undegassed XLPE are larger than those of degassed XLPE. Negative charge accumulation is observed in the bulk of degassed and undegassed XLPE under-30 MV/m, and the distortion ratio of internal electric fields is below 25% at 30 ℃ and 70 ℃. A positive space charge packet appears and subsequently moves quickly within the first 2 s polarization under-100 MV/m at 70 ℃. However, the injection and migration of a negative space charge packet can only be observed when the applied field raises to-150 MV/m. Here, both polarities of space charge packets follow negative differential mobility. The analyses reveal that degassing treatment can effectively reduce the amount of crosslinking byproducts in XLPE, resulting in the decrease of ionization and conductivity in low frequency regions. A small amount of negative charge accumulating in the bulk is produced mainly by the ionization of crosslinking byproducts and impurities, but the positive charge is injected from the anode with the increase of electric field, and the rate of impurity ionization is higher than the positive charge injection rate. During the initial stage of polarization processes under-150 MV/m at 70 ℃, the fast transit of positive charge leads to the severe distortion of the local field near the cathode（up to 61.5%）, resulting in a large amount of negative charge injection and the formation of a negative space charge packet in the bulk.

关 键 词：直流电缆 交联聚乙烯 空间电荷 高温 暂态过程 

分 类 号：TM247[一般工业技术—材料科学与工程]