Application of infrared thermography technique in transformers maintenance in distribution network

Reliable and accurate information about the condition of electrical equipment, obtained by thermographic surveys determines their wide use in the maintenance of distribution networks. Well maintained electrical equipment, especially transformers, is one of the main factors for ensuring uninterrupted power supply to the end users. The standard methods for faults diagnosis in most cases require the supply voltage to be switched off. This may lead to financial losses and dissatisfied customers. The biggest advantage of the testing of transformers with thermographic camera is monitoring of each item, regardless of its location within the framework of its operation. Infrared thermography can pinpoint defects that have already occurred and help diagnose others in their initial phase, thus preventing expensive repairs, serious energy losses, short circuits and fires. The aim of this paper is to present a brief theoretical introduction of the infrared thermography technique, an overview of the classification of thermal abnormalities, results, and their analysis, from study of several transformer stations on the premises of a Bulgarian utility company.