With the rapid development of high voltage DC (HVDC) transmission in China, the surface charge accumulation under the DC voltage has been a serious threat to the safety and reliable operation of HVDC system. In this paper, an atmospheric pressure plasma jet was introduced to deposit SiOx films on epoxy resin surface to accelerate the dissipation of surface charge on insulating material. The reaction precursor was TEOS. The multi-parameters were analyzed before and after plasma modification, including chemical composition, surface conductivity, surface charge distribution, trap depth and voltage endurance. The results showed that a large number of inorganic groups including Si-O-Si and Si-OH groups were introduced on epoxy resin surface, and the surface conductivity increased by 2 orders of magnitude. With the increase of the modification time, the initial accumulation surface charge decreased and the dissipation rate was accelerated. The energy trap depth became shallower after plasma treatment. Besides, the flashover voltage increased to a maximum value of 9kV at 180s. It is shown that atmospheric pressure plasma jet deposited SiOx film on the polymer surface is an effective method for improving the electrical properties of epoxy resin, and provides an effective modification method for industrial application.%随着高压直流输电迅猛发展,绝缘材料在直流电压下表面电荷积聚现象严重威胁直流输电系统的安全可靠运行.为加快绝缘材料表面电荷的消散,采用大气压等离子体射流,以TEOS为前驱物,在环氧树脂表面沉积SiOx薄膜.对改性前后材料表面化学组成、表面电导率、表面电荷特性、表面陷阱分布以及耐压特性进行多参数测量,研究等离子体射流改性前后环氧树脂表面特性.实验结果表明:等离子体处理在环氧树脂表面引入大量以Si-O-Si及Si-OH基团为主的无机基团,且表面电导率提高2个数量级.随着改性时间的延长,表面电荷的初始积聚量减少,消散速度加快,陷阱能级深度变浅;沿面闪络电压呈现先增后降的趋势,在改性180s时闪络电压提高到最高值9.0kV.研究结果表明:通过大气压等离子体射流在聚合物表面沉积薄膜能够提高环氧树脂绝缘性能,为其工程应用提供了有效的改性方法.
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