Case Studies on Diagnostic Integration: Challenges and Findings in the Condition Assessment of 500 kV Transformers and Reactors

Power transformers and shunt reactors operating at extra-high-voltage levels, particularly at 500 kV, play a fundamental role in ensuring the reliability, stability, and operational security of modern transmission systems. Due to their strategic importance, high replacement costs, and extended outage recovery times, failures of these assets can result in severe technical, operational, and economic consequences. As a result, their condition assessment and maintenance require diagnostic approaches that are fully aligned with their criticality, complexity, and exposure to extreme electrical and mechanical stresses.