热老化对挤塑绝缘XLPE直流电缆空间电荷特性的影响  

Influence of Thermal Ageing on Space Charge Characteristics of Extruded XLPE HVDC Cable

作　　者：张福增 李淑琦[2] 朱永华[3] 罗兵 吴建东[2] 尹毅[2] 

机构地区：[1]南方电网科学研究院高电压技术研究所,广州510080 [2]上海交通大学电气工程系,上海200240 [3]上海电缆研究所,上海200093

出　　处：《绝缘材料》2015年第8期41-45,共5页Insulating Materials

基　　金：国家高技术研究发展计划(863计划)(2012AA030310);特高压工程技术(昆明、广州)国家工程实验室开放基金(NEL201411)

摘　　要：对国产200 k V挤塑绝缘交联聚乙烯直流电缆进行切片热老化研究,通过空间电荷测试分析热老化对电缆空间电荷特性的影响。试验结果表明:未热老化试样表面靠近电极区域出现大量异极性空间电荷,导致试样内部电场发生严重畸变。这些异极性空间电荷主要源于电缆制造过程中的交联副产物,因制造过程中脱气不充分而残留在电缆绝缘内部。热老化初期,试样表面区域的异极性空间电荷快速消失,这可能是由于热老化过程中的高温加速了交联副产物的释放,降低了异极性空间电荷量,试样内部的电场畸变得到有效抑制。热老化后,试样表面区域的空间电荷由异极性电荷转变为同极性电荷,且同极性空间电荷量大致随热老化时间的增加而缓慢增加,表明XLPE材料经历了较缓慢的老化过程。A 200kV extruded XLPE HVDC cable made in China was performed thermal ageing experiment, and the influence of thermal ageing on the space charge characteristics was analyzed by testing its space charge. The experimental results indicate that a large number of hetero-charges are accumulated near the surface area of the unaged sample, leading to severe field distortion of the sample. The hetero-charges mainly originate from the cross-linking byproducts of cable, which left in the insulation because of insufficient degassing during manufacturing process. In the initial stage of thermal ageing, the hetero-charges disappear suddenly. This is because the high temperature during thermal ageing process accelerates the release of cross-linking byproducts, resulting in the decrease of hetero-charges amount, making the field distortion be suppressed. When the sample is thermally-aged, the hetero-charges changes into homo-charges, and the amount of homo-charges increase slowly with the increase of thermal ageing time, which indicate that the XLPE experiences a rather slow ageing process.

关 键 词：直流电缆 热老化 空间电荷 场强畸变率 

分 类 号：TM247.1[一般工业技术—材料科学与工程] TQ325.12[电气工程—电工理论与新技术]