摘要
超导能源管道终端由于其特殊的运行环境,终端用绝缘材料在承受高电场的同时,也承受着近百摄氏度的低温温度梯度。为此基于超导电缆终端常用绝缘材料——环氧玻璃纤维材料,研究了低温温度梯度下绝缘材料表面电荷积聚特性及其对沿面闪络特性的影响机制。首先测量了环氧玻璃纤维材料在不同温度以及不同温度梯度下的沿面闪络特性;随后利用仿真软件建立了绝缘材料气-固界面的电荷迁移模型,分析了不同温度以及不同温度梯度对材料表面电荷积聚特性和表面电场分布特性的影响;最后结合试验结果与仿真结果,提出了低温温度梯度对绝缘材料沿面闪络的影响机制。试验结果表明:当温差ΔT=100K时,绝缘材料表面的局部放电起始电压与闪络强度分别为无温度梯度时的74.0%和75.9%。而仿真结果显示,低温温度梯度下绝缘材料表面电荷积聚现象明显,表面最高电场强度可达到不存在温度梯度时的10倍左右。因此,温度梯度下材料表面电荷积聚以及电场的畸变被认为是造成绝缘材料沿面绝缘强度下降的重要原因。该研究有助于理解低温温度梯度下材料表面电荷积聚特性及其对电场分布和闪络电压的影响机制,对低温下绝缘材料的绝缘特性研究以及绝缘优化设计具有重要意义。
Due to the extreme operating conditions of superconducting cable terminal,the insulation material is subjected to high electric fields with a maximum temperature gradient of nearly 100 K.The operating conditions of terminal insulation material GFRP(Glass Fiber Reinforced Plastic)are taken into account,and the surface charge accumulation characteristics under temperature gradient and its influence on the surface flashover voltage are studied.Firstly,the surface flashover voltage of GFRP under different temperature gradients is measured.Secondly,the simulation model of charge transfer model in gas-solid interface is established,and the charge accumulation characteristics under the different temperature conditions is calculated as well as the distortion of electric field.Results show that temperature gradient will significantly reduce the surface flashover voltage.When the temperature gradient is 100 K,the partial discharge initial voltage and flashover voltage are only 74.0%and 75.9%of that without temperature gradient,respectively.Furthermore,the surface electric field can increase nearly 10 times owing to the surface charge accumulation,as suggested by stimulation results.Therefore,the surface charge accumulation under the temperature gradient is responsible for the decrease of surface flashover strength.This research is helpful to understand the characteristic of charge accumulation and its effect on flashover voltage under temperature gradient,and is of great significance to insulation optimization design of low temperature dielectric insulation.
作者
宋波
任明
陈跃
胡一卓
柳玉洁
董明
SONG Bo;REN Ming;CHEN Yue;HU Yizhuo;LIU Yujie;DONG Ming(State Key Laboratory of Electrical Insulation and Power Equipment,Xi'an Jiaotong University,Xi'an 710049,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2023年第2期554-564,共11页
High Voltage Engineering
基金
国家电网公司科技项目(5500-202218131A-1-1-ZN)。
关键词
超导电缆终端
温度梯度
表面电荷积聚
沿面闪络
低温绝缘
superconducting cable terminal
temperature gradient
surface charge accumulation
surface flashover
low temperature insulation
