采用温差法的10kV交联聚乙烯电缆水树老化评估  

Insulation Evaluation of Water-tree Aged 10 kV XLPE Cables Using Thermal Step Method

作　　者：杜伯学[1] 马宗乐[1] 高宇[1] 程欣欣[1] 杨林[1] 李宏博[2] 

机构地区：[1]天津大学电气工程与自动化学院电力系统仿真控制教育部重点实验室,天津300072 [2]石家庄供电公司,石家庄050051

出　　处：《高电压技术》2011年第1期143-149,共7页High Voltage Engineering

基　　金：国家自然科学基金(50777048)~~

摘　　要：交联聚乙烯(XLPE)电力电缆在运行过程中受到电场、温度、水分等因素的共同影响而发生老化,引发事故,给电网的安全运行带来隐患。为此,选取水树老化10kV XLPE电缆为研究对象,采用温差法研究了温差电流与试样老化时间的关系。实验结果表明,温差电流幅值随着试样老化时间的增加而增大;温差电流与直流电压的幅值正相关;随着电缆水树老化时间的增加,空间电荷密度峰值的位置向绝缘层外部移动;内热法与外冷却法分别适用于电缆的整体和局部老化检测,但是对于老化程度较轻的电缆,内热法具有更高的灵敏度。研究结果验证了所提出的温差法评估XLPE电缆水树老化程度的有效性,为XLPE电缆的水树老化检测与寿命评估奠定了基础。A new diagnostic method called thermal step method（TSM） was proposed based on the correlation between degradation of XLPE cable and space charge accumulation.Two variants of the TSM were used： the inner heating technique（IHT） and outer cooling technique（OCT）.10 kV XLPE cables were employed as specimens in the experiment,which were aged by accelerated water-tree test（AWTT） in a curved water-filled tube.Then the specimens were tested by the IHT and OCT,so that the correlation between the thermal step current and the ageing degree was studied.The results show that the amplitude of the thermal step current increases with the ageing time;the TS current of the same specimen is dependent on the applied DC voltage;the IHT and OCT are applied to evaluate the mean insulating state and to analyze local defect respectively;the IHT is more sensitive to a slightly aged cable.The validation of the TSM system on the evaluation of the cable condition is verified.The results are useful for the diagnosis and life evaluation of the water-tree aged XLPE cables.

关 键 词：交联聚乙烯 电力电缆 老化 温差法 内热法 外冷法 空间电荷 评估 

分 类 号：TM247[一般工业技术—材料科学与工程]