气体绝缘输电管道用环氧树脂/氮化硼高导热复合材料表面电荷动态特性

Surface Charge Dynamic Behaviors of Epoxy/BN Composite with High Thermal Conductivity for Gas Insulated Transmission Pipeline

大容量气体绝缘管道输电（GIL）运行过程中产生的温升问题会加速环氧树脂绝缘子老化,温度梯度下绝缘子表面电荷行为也与沿面闪络密切相关。为解决上述问题,制备了环氧树脂/氮化硼（EP/BN）高导热复合材料,研究其在加热至60oC再散热不同时间下针板电晕后的表面电荷动态特性。结果表明：在相同温度下,试样表面电荷消散速度随着BN含量的增加而先减慢后加快,起始表面电荷密度先升高后降低;对于同一种试样,随着散热时间的增加,表面电荷消散速度变慢,起始表面电荷密度升高,且通过陷阱能级分布特性发现,试样的深、浅陷阱能级均变低,深陷阱密度增大,浅陷阱密度减小,且BN掺杂含量越高,该分布特性越明显。

The temperature rises during gas insulated transmission pipeline（GIL） operation will accelerate the aging of epoxy insulators, and the surface charge behavior of insulators under temperature gradient is also closely related to flashover. In order to solve the above problems, EP/BN composites with high thermal conductivity were prepared, of which the surface charge dynamics under needle-plane corona system were investigated with different cooling time after being heated to 60 ℃. The results show that the surface charge dissipation rate of the sample decreases first and then increases with increasing the BN contents at the same temperature, and the initial surface charge density increases first and then decreases. For the same sample, the surface charge dissipation slows down and the initial surface charge density increases with the lapse of the cooling time. Besides, it can be found from the trapping distribution characteristics that the depth of both deep and shallow traps becomes lower, and the deep trap density increases while the shallow trap density decreases. The higher the BN content is, the more obvious the distribution characteristics are.