Experience Performing Infrared Thermography in the Maintenance of a Distribution Utility

Nowadays, distribution utilities face new technical-economical requirements, aiming at improving the profitability of the electricity distribution systems. Such context requires both, a high reliability and availability of the electric networks. In order to do so, it is necessary to minimize outages, reducing at the same time, their duration. This situation leads to redefine the current maintenance strategies, pointing at predictive actions to minimize the unavailability of the equipment and reduce maintenance costs, searching for a more cost-effective scheme of the business. Within this framework, Edenor S.A. has decided to incorporate thermographic inspections as part of the Predictive Maintenance Annual Plan of its HV Transformer Stations, adopting this technique as an important predictive diagnostic tool of its facilities condition. This paper presents a brief theoretical introduction of the Infrared Thermography technique. Next, thermal criterions developed to apply for the abnormalities detected, characteristics of the technical management for the execution of the project and the advances of the plan are described. The experience obtained is exposed, just as the improvements applied in the development of the plan, describing how its application was extended from detecting abnormalities in contact points visually exposed to the thermographer to “out of sight” situations. The obtained results along a seven-year-period are presented and analyzed, also describing how by performing routine scans, both, unscheduled outages were prevented and several routine maintenance tasks could be turned into condition ones, avoiding unnecessary scheduled outages.