Speaker
Description
This paper describes the results of an experimental investigation carried out to compare the contamination performance and surface degradation of outdoor insulators made from different polymeric materials. The tested insulators included silicone rubber (SR), ethylene propylene diene monomer (EPDM) and high-density polyethylene (HPDE), which were used for reference. To replicate typical harsh marine pollution environments, a modified solid layer contamination deposition method was used in the experimental work. This method represented conditions similar to those installed near shorelines exposed to saline and acid spray during winter and early spring. Tests were carried out in acidic and normal cold fog. The physico-chemical changes and electrical parameters were measured during the test to characterize the performance of each insulator. The analysis showed that the electrical performance of the insulators was significantly affected by the combined application of saline contamination and acidic cold fog. However, during clean cold fog application, the insulator material showed localized surface degradation while there was no evidence of serious dents and cracks. Saline contamination with normal cold fog generated a reduction of flashover voltage equal to 40%. This reduction was more pronounced in acidic fog conditions – 85%. The scanning electron microscopy (SEM) and hydrophobicity results showed that surface degradation is more strongly correlated with acidic cold fog contents than those of normal cold fog. It was found that SR insulators perform better than EPDM and HPDE in harsh environments.
