绝缘介质表面流注的发展是沿面闪络中的重要的物理过程,研究绝缘介质表面流注的发展特性有助于揭示沿面闪络的机理,对输电线路及电力设备的绝缘设计有着重要的意义。在"三电极"结构中,利用光电倍增管测量不同绝缘介质表面流注传播概率和传播速度随平板间电场强度的变化规律:绝缘介质表面流注传播所需的稳定传播场强大于流注在空气间隙中稳定传播的场强;同时,在高场强下,绝缘介质表面流注拥有"沿面分量"和"空气分量"2个分量,而流注在空气间隙中传播时不存在"沿面分量",只有"空气分量"。此外,不同绝缘介质表面流注稳定传播场强和传播速度存在差异:沿面流注的稳定传播场强与介质的介电常数成正比;流注的传播速度与介质的介电常数的关系不太明显,主要与介质表面电荷附着效应和光致电子发射效应有关。
The streamer propagation along the insulation surface is a significant physical process during the surface flashover.Research on the streamer propagation along the insulation surface is not only helpful for understanding the process of surface flashover,but also has important significance on the design of transmission lines and electrical equipment.The variation of the streamer propagation probability and average propagation velocity with electric field along the different insulation surface was measured through photomultipliers in three-electrode arrangement.The electric field required for streamer stable propagation along the insulation surface is larger than that in the air alone.At the same time,for electric fields higher than that required for the streamer stable propagation,streamer propagates along insulation surface with a ‘surface’ and an ‘air’ component.However,the streamer propagates in the air alone without a ‘surface’ component,only with an ‘air’ component.The streamer propagation electric field and average velocity are different respectively when the streamer propagates along the different insulation surfaces.The electric field required for streamer stable propagation is in proportion to permittivity of dielectric.However,the relationship between streamer propagation velocity and permittivity is not evident,which is affected by attachment of charge to the surface and photoemission of secondary electrons from the surface so much.