Research on Characteristics of Streamer Propagation Along Insulation Surfaces

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.