PROJECT TITLE:

Characteristics of streamer propagation along the insulation surface: influence of dielectric material

ABSTRACT:

Research on dynamics of streamer propagation along different dielectric materials under the same electric field is presented. In the three-electrode arrangement, the variation of the streamer propagation likelihood, velocity and light-weight intensity with electric field in the air and along the different dielectric materials was measured through three photomultipliers. The images of the streamer propagation within the air and along the various dielectric materials were taken with an ultraviolet camera. The check results have shown that the electric field required for streamer propagation in air alone is but along the insulation surface. Furthermore, for electrical fields above streamer `stability' propagation fields, the streamer propagates along insulation surface with a `quick' and a `slow' component. However, the streamer propagates in air alone while not a `quick' component, solely with a `slow' part. The velocity of the streamer propagating in air alone is significantly less than the speed of the `fast' component, and is higher than the rate of the `slow' element. The streamer `stability' propagation field and velocity rely upon the character of the dielectric material. Specifically, higher electric fields are required for streamers to propagate along a dielectric material with larger permittivity. The speed of streamer propagation along the dielectric material is also affected by attachment of charge to the surface and photoemission of secondary electrons from the surface thus much. Consequently, beneath the same electrical field, the connection between streamer propagation velocity and permittivity of dielectric material is not very evident, roughly inverse proportion.