The effects of polypropylene on the impulse breakdown mechanism ofthe laminated oil-impregnated PPLP

摘要

The impulse breakdown mechanism of PPLP (polypropylene laminatedpaper) is investigated in detail, taking into consideration the effectof PP (polypropylene) film. It is found that, although both positive andnegative streamers affect the impulse breakdown mechanism, each effectis very different. That is, the positive charges are trapped on thesurface of PP film easily, while the negative charges tend to spreadinto the insulating material. Consequently, it is suggested that themost essential factor of the impulse breakdown mechanism is the positivecharges. Comparison of a sheet of PPLP and a specimen made of Kraftpapers and PP film suggests the importance of the effect of oil thinfilms between Kraft paper and PP film