Effect of Defective RTV Coatings on Insulation Performance of Porcelain Insulators

摘要

In this work, the effects of defective RTV coatings on insulating performance of porcelain insulators and their performance improvement according to the electric field conditions are investigated. For this purpose, first, two samples of porcelain insulators with the defective coatings in the marginal points of the electric field (points where the electric field is remarkable or very small) are investigated in the salt-fog chamber test, in accordance with the conditions of the dry band arcs (DBA). Then, electric field and the factors affecting its distribution are identified by finite element simulation. Also, in order to identify the mechanism of the occurrence of dry band arc, some tests were implemented on two porcelain samples, one with full coating and the other without any coating. The results show that when the RTV coating is damaged in areas where the intensity of the electric field is considerable, the occurrence of the DBAs is more likely than the other points.