Análise e validação dos sistemas de monitoramento de transformadores de extra alta tensão - um estudo de caso

Abstract

Monitoring extra‑high‑voltage transformers is essential to ensuring the reliability of the electrical system and preventing failures with significant operational impact. This study presents a comparative analysis between two transformers subjected to real anomaly conditions, evaluating the effectiveness of intrinsic sensors, mechanical protections, and the Schweitzer SEL‑2414 multifunction relay in preventing severe damage. The methodology included a literature review, document analysis, relay record examination, field inspections, and direct comparison between one transformer that evolved into a fire and another that was preserved through the immediate action of protection devices. The results show that, in the case where the equipment suffered total loss, the fault remained sustained for several minutes due to delayed operation of the devices and insufficient correlation logic among monitored variables. In contrast, the preserved transformer was disconnected within fractions of a second, preventing thermal rise, gas formation, and structural damage. It was found that the effectiveness of monitoring depends directly on proper parameter configuration, integration among sensors, and the response speed of the protection system. It is concluded that well‑configured supervision architectures increase equipment availability, reduce operational risks, and contribute to more accurate preventive and predictive maintenance practices.