摘要
直流接地电树枝对高压直流电缆绝缘安全构成了严重威胁。为了研究直流预压对交联聚乙烯(XLPE)中直流接地电树枝引发特性的影响,在10 s、5 min和1 h不同预压时间下,对XLPE试样进行了直流接地电树枝引发试验。同时对该材料在不同场强下的空间电荷积累特性进行了测量,并根据空间电荷注入理论及测试结果对直流接地电树枝的引发特性进行了分析说明。研究结果表明:直流预压时间对直流电树枝的引发率影响较小,接地电树枝平均长度随预压时间的增加略有增加,并有饱和的趋势;同时,直流接地电树枝具有明显的极性效应,负极性接地电树枝的50%引发电压(-19.3 kV)明显低于正极性时的引发电压(25.7 kV),且负极性下的平均电树枝长度也明显高于正极性时的电树枝长度。研究结果有助于进一步了解直流电树枝的引发机理,并为今后同类试验参数的选取提供参考。
Grounded DC tree is a serious threat for the safety of HVDC cable insulation. In order to investigate the effect of DC pre-stress on initiation characteristics of grounded DC tree in cross-linked polyethylene （XLPE）, we experimental- ly investigated the grounded DC tree with different pre-stress time （10 s, 5 min and 1 h）. Besides, we measured the space charge accumulation characteristics of the material used in the electrical tree tests , and analyzed the grounded DC tree properties by the space charge injection theory and the space charge test results. The grounded DC tree test results show that pre-stress time has little influence on the initial rate of the grounded DC tree. However, the length of the grounded DC tree increases to a certain extent with the pre-stress time and has a trend of saturation. Besides, there is an obvious polarity effect for the grounded DC tree. The 50% tree inception voltage of negative polarity （-19.3 kV） is significantly lower than that of positive polarity （25.7 kV）, and the average tree lengths of negative polarity are larger than those of positive polarity. The results help to further understand the initiation mechanism of DC electrical tree and provide a reference for the parameter selection of later similar experiments.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2017年第2期666-672,共7页
High Voltage Engineering
基金
国家重点研发计划(2016YFB0900705)
中央高校基本科研业务费专项资金(2016SX92)~~
