摘要
为研究高压直流(HVDC)交联聚乙烯(XLPE)电缆在负荷循环试验中的空间电荷积聚特性,按照国际大电网组织CIGRE TB496的试验要求,对电压等级为30 k V的直流电缆开展了型式试验中的30 d负荷循环试验,采用脉冲电声法(PEA)测量了其空间电荷特性,重点研究了温度和加压时间对直流电缆空间电荷特性的影响。研究结果表明:温度对直流电缆的空间电荷特性具有显著的影响,在加热的过程中,随着温度的升高,电缆绝缘中主要表现为异极性空间电荷的注入(异极性空间电荷通常是由杂质在电场作用下被电离而造成的),且正极性电压作用下的异极性空间电荷注入比负极性电压作用下的要强;此外,随着加压时间的增加,电荷会逐渐由高温侧向低温侧迁移;在冷却过程中,电缆绝缘中会产生与电压极性相同的电荷积聚;48 h正极性负荷循环试验与24 h正极性负荷循环试验下的电荷积聚特性类似,不同的是随着加压时间的增加,相比于加热前,冷却24 h后电缆中积聚了少量的正极性空间电荷。
To study the characteristics of space charge accumulation of high voltage direct current（HVDC） cross-linked polyethylene （XLPE） cables in load cycle test, the 30 d load cycle test in type tests is carried out on a 30 kV DC cable according to the test requirements of CIGRE TB496 organization, and the pulse electro-acoustic method （PEA） is used for measuring its space charge. The effects of temperature and voltage application time on the space charge characteristics are mainly focused on in the test. The results verify that the temperature has a significant influence on the space charge cha- racteristics. During the heating process, as the temperature rises, the injection of heteropolarity space charge （usually come from the impurities＇ ionization in electric field） is obvious in the cables＇ insulation layer, which is more intensive under the positive voltage application than that under the negative voltage application. Additionally, with the increase of time of voltage application, the space charge slowly migrates from the high temperature side to the low temperature side. During the cooling process, the space charge of the same polarity with the applying voltage will accumulate in the insula- tion layer of the cable, mainly in the vicinity of the low temperature side. Furthermore, the performance of the space charge accumulation is similar in 48 h load cycle test and 24 h load cycle test. However, with the increase of the time of voltage application, a small amount of positive space charge accumulates in the cable after the cooling process for 24 h compared with that before heating process.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2016年第8期2416-2425,共10页
High Voltage Engineering
基金
国家电网公司科技项目(EPRIGYKJ[2014]3176号)
国家重点研发计划(2016YFB0900704)~~
关键词
直流电缆
空间电荷
脉冲电声法
负荷循环试验
温度
异极性
DC cables
space charge
pulse electro-acoustic method
load cycle test
temperature
heteropolarity
