直流电压下热老化对表面划伤交联聚乙烯电缆局部放电特性的影响  

Effect of thermal ageing on partial discharge characteristics of surface scratched XLPE cables at DC voltage

作　　者：王新 金泱 杨敏 王启隆 黄小凡 陈向荣 WANG Xin;JIN Yang;YANG Min;WANG Qiong;HUANG Xiaofan;CHEN Xiangrong(Zhejiang Energy R&D Institute Co.,Ltd.,Hangzhou 311121,China;Zhejiang Key Laboratory of Energy Conservation&Pollutant Control Technology for Thermal Power,Hangzhou 311121,China;College of Electrical Engineering,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]浙江浙能技术研究院有限公司,浙江杭州311121 [2]浙江省火力发电高效节能与污染物控制技术研究重点实验室,浙江杭州311121 [3]浙江大学电气工程学院,浙江杭州310027

出　　处：《绝缘材料》2024年第7期76-83,共8页Insulating Materials

基　　金：浙江省自然科学基金重点项目(LZ22E070001);浙江浙能技术研究院有限公司科技项目(JSYJY-SCFW-2022-009)。

摘　　要：为了研究热老化对表面划伤交联聚乙烯(XLPE)电缆直流局部放电发展过程的影响,本文采用实体10 kV电缆制作了表面划伤缺陷模型并进行不同时间的加速热老化处理,利用脉冲电流法研究了直流电压下缺陷电缆的局部放电特性。基于缺陷电缆局部放电量随加压时间的变化,提取出最大放电量、不同放电区间的平均放电量和放电重复率的统计图谱,然后基于电荷运输理论提出了局部放电和电荷输运模型对缺陷电缆局部放电结果进行解释。结果表明:缺陷电缆的局部放电起始电压随着老化时间的增加而增大,其放电量-时间图谱呈现“梳齿”状放电特征;随着热老化时间的增加,缺陷电缆在>100 pC区间的平均放电量和放电重复率逐渐减小,且其“梳齿”状放电特征在老化21天时彻底消失,表现出局部放电的自愈性。热老化过程中XLPE划伤缺陷表面氧化产生了电荷陷阱,由此产生了均匀密集的空间电荷层,使缺陷内部电场下降,从而削弱了缺陷电缆的局部放电。研究结果为XLPE电缆缺陷的直流局部放电研究提供了数据支撑。In order to investigate the impact of thermal ageing on the development of DC partial discharge of surface scratched cross-linked polyethylene(XLPE)cables,a surface scratched defect model weas made using a physical 10 kV cable,and subjected to the accelerated thermal ageing treatments with different times.The partial discharge characteristics of defective cables under DC voltage were studied using the pulse current method.On basis of the variation of partial discharge with voltage applying time,the statistical charts of the maximum discharge capacity,average discharges capcity,and discharge repetition rate in different discharge intervals were extracted.Then based on the charge transport theory,partial discharge and charge transport models were proposed to explain the partial discharge results of defective cable.The results show that the initial partial discharge voltage of the defective cable increases with the increase of thermal ageing time,the discharge quantity-time spectrum shows"comb"discharge characteristics.As the thermal ageing time increases,the average discharge capacity and discharge repetition rate of the defective cable in the interval greater than 100 pC decrease gradually,and the“comb"discharge characteristics disappear completely after 21 days of ageing,demonstrating the self-healing ability of partial discharge.During thermal ageing,the surface oxidation of XLPE scratched defects produces charge traps,resulting in a uniform and dense space charge layer,which reduces the internal electric field of the defects and weakens partial discharge in defective cables.The research results provide data support for the study of DC partial discharge of XLPE cable defects.

关 键 词：交联聚乙烯电缆 表面划伤缺陷 局部放电 直流电压 热老化 

分 类 号：TM215[一般工业技术—材料科学与工程]