RTV Coated Glass Insulators Applied in High Humidity Areas to Reduce the Risk of Transmission Line Outage

This paper presents a successful trial that has been applied by a Brazilian power utility company to mitigate the excessive outage rate due to the air humidity of a 230 kV power transmission line. In this study, it was used insulators with Room Temperature Vulcanized Silicone Rubber. This transmission line has experienced a history of numerous outages during winter when humidity is high. Most of the outages have been identified as caused by sudden flashover and associated single-phase faults randomly located over the line length, which motivated the development of studies to identify their main reasons. A milestone study identified the correlation between the behavior of the relative air humidity and the rate of the line's protection tripping. Based on that and other studies, this work brings the analysis of the performance of four different string configurations using RTV coated insulators as a permanent solution to mitigate the relatively high rate of line outages.