环氧复合绝缘材料表面处理方法对高气压下闪络特性的影响

Effect of Surface Treatment Methods of Epoxy Composite Insulation on Flashover Characteristics under High Pressure

分别采用放电等离子体、离子注入、表面直接氟化的方法对环氧复合绝缘样品进行处理。研究不同处理方法对绝缘材料表面状况及高气压c-C_4F_8/N_2混合气体中的负直流高压下闪络特性的影响。实验结果显示等离子体和离子注入方法对绝缘样品表面改性无法提高样品在高气压c-C_4F_8/N_2混合气体中的沿面闪络电压,并且放电会直接破坏表面结构,导致绝缘失效;采用表面直接氟化处理的环氧绝缘样品,闪络电压有所提高。测量表明,表面氟化引起环氧复合绝缘材料表面电位降低,电位衰减加快,表面陷阱能级下降,陷阱密度随氟化时间加长而增加。通过研究认为,目前放电等离子体和离子注入方法处理绝缘材料表面,在技术上还需要完善。表面直接氟化处理环氧材料表面可以提高其在高气压下闪络特性,但是耐受放电次数的减少将制约它的应用。

Epoxy composite insulation samples were treated by discharge plasma,ion implantation,and surface fluorination treatments,respectively.The effects of different treatment methods on the surface condition of the insulating material and the flashover characteristics under negative DC voltage in high pressure c-C4F8/N2 mixed gas were investigated.The experimental results show that discharge plasma and ion implantation methods cannot increase the surface flashover voltage of the sample in the high gas pressure c-C4F8/N2 mixture gas,and the discharge directly destroys the surface structure,resulting in insulation failure;the flashover voltage of the epoxy-insulated sample after fluorination is improved.Measurements show that the surface fluorination causes the surface potential of the epoxy composite insulating material to decrease,the potential decay to increase,and the surface trap level to decrease.Furthermore,the trap density increases with the increase of the fluorination time.It is believed that discharge plasma and ion implantation methods dealing with the surface of insulating materials need to be improved.Direct surface fluorination method can improve the high-pressure flashover characteristics of the insulating material,but the reduction of the withstand discharge numbers will limit its application.