Abstract
This paper describes deterioration phenomena and mechanisms on silicone rubber housing on the polymer insulators by corona discharge. The corona discharge was observed on the trunk portion of one of the three insulators tested in a fog chamber. Nitric acid and ozone generated by the corona discharge were recognized on that trunk portion, which was discolored whitish. The discolored area was expanded with test period. Surface conditions and mechanical properties of six kinds of the silicone rubber containing Alumina trihydrate (ATH) and Calcium carbonate (CaCO3) as fillers, were investigated after immersion in 1N nitric acid for 96 hours.
As a result, larger weight loss of test pieces containing some types of filer, such as CaCO3, was recognized. Cracks were observed on the surface of two specimens containing CaCO3 filler, and not observed on that not containing CaCO3 filler. This shows the cracks on the surface due to the corona discharges are depending on the kind of the filler. The careful survey on the deterioration of the housing rubber due to the corona discharge should be done when we select the housing materials for the polymer insulators.
