摘要
XLPE电缆由于长期运行在高温下,电学行为退化,给电缆绝缘造成不可逆损伤,增大了电树形成甚至绝缘失效的概率,因此论文进行试验研究,旨在揭示热老化作用下交联聚乙烯电缆绝缘材料电树枝引发特性。论文进行160℃下XLPE材料0~240 h热老化试验,在电树枝引发试验,系统分析不同热老化时间下的电树枝引发率;同时通过差示扫描量热法分析不同热老化时间下样品的结晶度。研究发现,随着电压从15kV升高到25kV,电树枝的引发概率在不断增大,以老化样品A6为例,电压从15kV升高到25kV,电树枝引发率从10%增加到50%。结合不同样品的老化时间分析,即随着热老化时间的增加,在144 h前,XLPE的绝缘增强,之后其绝缘逐渐下降。144h为样品中结晶度Xc的转折点,其中Xc为35.03%。其刚好对应绝缘增强至绝缘逐渐下降的老化时间拐点,因此表明较高的老化温度会使得材料产生重结晶,结构会更加规整,这也是不同老化程度XLPE电缆电树枝平均起始电压出现拐点的主要原因。
Due to long-term operation at high temperatures,the electrical behavior of XLPE cables deteriorates,causing irreversible damage to the cable insulation and increasing the probability of electrical tree formation or even insulation failure.Therefore,this paper conducts experimental research to reveal the electrical tree initiation characteristics of cross-linked polyethylene cable insulation materials under thermal aging.The paper conducted a thermal aging test of XLPE material at 160℃for 0-240 hours,and conducted a systematic analysis of the electrical tree initiation rate under different thermal aging times;At the same time,the crystallinity of the samples under different thermal aging times was analyzed by differential scanning calorimetry.Research has found that as the voltage increases from 15kV to 25kV,the probability of electric tree initiation continues to increase.Taking aged sample A6 as an example,when the voltage increases from 15kV to 25kV,the probability of electric tree initiation increases from 10%to 50%.By analyzing the aging time of different samples,it can be concluded that with the increase of thermal aging time,the insulation of XLPE was enhanced 144 hours ago,and then gradually decreased.144h is the turning point of crystallinity Xc in the sample,where Xc is 35.03%.It corresponds to the inflection point of the aging time from insulation enhancement to gradual decline of insulation,indicating that higher aging temperatures will cause the material to recrystallize and the structure will be more regular.This is also the main reason for the inflection point of the average initial voltage of electrical tree branches in XLPE cables with different aging degrees.
作者
石聪聪
陈莎
陈晨
翟凯迪
李旭
李瑞
张东东
SHI Congcong;CHEN Sha;CHEN Chen;ZHAI Kaidi;LI Xu;LI Rui;ZHANG Dongdong(State Grid Suqian Power Supply Company,Suqian 223800,China;Nanjing Institute of Technology,Nanjing 215000,China)
出处
《中国测试》
CAS
北大核心
2023年第S02期165-170,共6页
China Measurement & Test
基金
国网江苏省电力公司科技项目(J2023101)
中国博士后科学基金资助项目(2023M732412)
关键词
热老化
电树枝
引发率
结晶度
thermal aging
electric tree branches
initiation rate
crystallinity
