预鉴定试验对直流电缆中空间电荷特性的影响  

Effects of Pre-qualification Tests on Space Charge Characteristics in DC Cables

作　　者：沈耀军 陈振新 钱恺羽 徐蓓蓓 吴建东[2] 尹毅[2] SHEN Yaojun;CHEN Zhenxin;QIAN Kaiyu;XU Beibei;WU Jiandong;YIN Yi(Zhoushan Power Supply Company of State Grid Zhejiang Electric Power Company,Zhoushan 316000,China;Department of Electrical Engineering,Shanghai Jiao Tong University,Shanghai 200240,China)

机构地区：[1]国网浙江省电力公司舟山供电公司,浙江舟山316000 [2]上海交通大学电气工程系,上海200240

出　　处：《绝缘材料》2018年第8期64-68,74,共6页Insulating Materials

基　　金：国家重点研发计划项目(2016YFB0900701);国家电网公司科技项目(52110114017B)

摘　　要：为研究预鉴定试验对直流交联聚乙烯(XLPE)电缆的影响,对国内自主研发的200 k V直流XLPE电缆进行了预鉴定试验,并采用傅里叶红外光谱测试(FTIR)、差示扫描量热法(DSC)、空间电荷测试等方法,分析了预鉴定试验前后电缆XLPE绝缘中层绝缘的状态变化。结果表明:预鉴定试验前后,电缆绝缘材料本征基团对应的特征吸收峰基本不变,熔融温度、结晶温度变化不大,电缆材料未发生明显老化。预鉴定试验前后,电缆绝缘中层切片试样均有明显的异极性空间电荷积累,30℃下预鉴定试验后试样短路过程中的平均体电荷密度明显大于预鉴定试验前的试样。预鉴定试验使电缆绝缘层内的交联副产物沿电缆径向由线芯侧向外侧扩散,使电缆绝缘中部的交联副产物含量增多。电缆绝缘中层切片经实验室脱气处理后,异极性空间电荷的积累量大幅下降,表明现有200 k V直流XLPE电缆经脱气处理后,仍留存大量的交联副产物,需要进一步改进生产过程中的脱气工艺。In order to investigate the effect of pre-qualification tests on DC cross-linked polyethylene（XLPE） cables, pre-qualification tests were carried out on a self-developed 200 k V DC XLPE cable in domestic. The state changes of the middle layer of cable insulation before and after pre-qualification tests were analyzed by FTIR, DSC, and space charge tests. The results show that the characteristic absorption peaks of intrinsic groups of XLPE insulating material before and after pre-qualification test are almost the same, the melting temperature and crystallization temperature change little, and the cable insulating material does not age obviously. There are obvious heteropolar space charges accumulation in the middle layer slice samples of cables insulation before and after pre-qualification test, and the average volume charge density during depolarization in the samples after pre-qualification test at 30 ℃ is significantly greater than that in the samples before pre-qualification test. The pre-qualification test makes the crosslinking by-products in the cable insulation layer diffuse radial from the core to outside, and the contents of crosslinking by-products in the middle section of cable insulation increase. The accumulation of heteropolar space charges of the middle layer slice of cable insulation decreases after degassing treatment in laboratory, indicating that the existing 200 k V DC XLPE cables still retain a large amount of crosslinking by-products after degassing treatment in factory, therefore the degassing process should be further improved.

关 键 词：交联聚乙烯 预鉴定试验 直流电缆 空间电荷 

分 类 号：TM215.1[一般工业技术—材料科学与工程]