Breakdown of Polyethylene Film-Liquid Nitrogen Composite Systems

This paper reports on the breakdown characteristics of lowdensity polyethylene film-liquid nitrogen composite systems. The breakdown characteristics depend on the number of film layers in the sample, the electric field distribution inside the film, and the front time and polarity of the applied impulse voltage. Three effects are discussed. (1) The effect of field distribution: a strong field at the film surface triggers a breakdown streamer; however, the streamer development is supported by the field inside the film. (2) The effect of front time: The breakdown voltage is considered to be governed by the breakdown time lag and the injected charge density which increases with the front time of the applied impulse voltage. (3) The effect of number of layers: The sample with the larger number of layers has a higher resistance to impulse voltage.