Short-Circuit Impacts on Power Transformers Case Study

This paper investigates the impacts of short-circuit events on power transformers, focusing on a case study involving an incident that damaged the TR-01 power transformer at ABC Substation, owned by an electric utility company in São Paulo, Brazil. Given the growing demand for safety and reliability in electrical systems, analyzing short-circuit effects has become crucial. The study highlights the electromagnetic and thermal forces acting on windings and insulation, resulting in cumulative deformations and insulating paper degradation. The most common mechanical failure in transformers is often caused by external short circuits, making it vital to monitor electrical and mechanical conditions, especially after significant events. During a short circuit, transient forces can cause considerable mechanical damage, compromising equipment efficiency and safety. Although protection technologies have advanced, older transformers face additional challenges such as winding contraction and insulation degradation. This case study documents the event occurrence, including images of equipment damage from the short circuit and accumulated energy. Furthermore, the paper emphasizes the need to investigate and develop actions to minimize such failures in the future, enhancing transformer resilience against extreme events and ensuring power grid operational continuity.

Short circuit; Insulation degradation; Mechanical failure; Power transformer.

Carlos Eduardo Bento Honório He is a master’s student at the Faculty of Electrical and Computer Engineering – State University of Campinas – São Paulo/Brazil. He is currently a professor at the Centro Paula Souza – São Paulo/Brazil. His research interests are in the areas of transformer, insulating oil and asset monitoring

Gilmar Barreto has received a PhD from the Faculty of Electrical and Computer Engineering – State University of Campinas (UNICAMP) – São Paulo/Brazil. He is currently a Professor at the State University of Campinas. His research interests are in the areas of electrochemistry, engineering education and entrepreneurship in engineering.

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