Preventive inspection of line insulators through corona emission: A case study

This paper presents the main results regarding the presence of corona on 138 kV lines. Although the study and analysis was mainly focused on the obtention of corona activity through a UV camera, results stemming from an IR camera will also be presented. The substitution of suspected flawed insulators represent to most of the distribution utilities one of the causes of major concern. The results performed in both a HV laboratory and field tests are presented herein. It was not found a similar behaviour and intensity of the corona activity between both cases. However, both type of tests agreed in that the faulty insulator(s) that have its leakage current increased, does not show corona activity.