The 500 kV Xingó-Angelim II Line passes through an area of heavy natural pollution. The project was designed irrespective to the local ambient conditions selecting insulators with low hydrophobicity and low endurance to pollution. A combination of pollution and high humidity resulted in high levels of outages over the years. The São Pedro Mountain Range was selected as a case study, inter-alia, since most outages were concentrated there. The solution to use RTV coating proved successful for a period of time but it did not solve the problem. It was eventually decided to replace the toughened glass strings with a composite polymeric type suitable for the local conditions.
The configuration and interpretation of the corona camera images was crucial to determine the criticality of the strings to be replaced. It also lead the maintenance crews to inspect the new strings properly.
Finally, the new concept of inspection must be implemented in order to face some issues that the use of polymeric insulators brings and TAESA is equipping and training its teams to this new challenge.