A Study on the Generation Characteristics of Decomposition Gases for Insulating Oil of Transformer Bushing

In recent years, the number of failures caused by oil impregenated paper(OIP) bushings applied to long-term power transformers has been increasing, and some of them have progressed to fires, increasing the possibility of facility damage. As OIP bushings are more than 70% of the long-term bushings in operation, there is a high probability of fire in case of failure, so it is necessary to develop diagnostic technology for aging bushings. Although KEPCO is implementing insulation oil gas analysis to prevent the continued occurrence of failures and recurrence of failures due to bushing insulation breakdown. However, since KEPCO currently does not have its own bushing oil gas maintenance standards, it is necessary to establish management standards that reflect the differences in insulation oil types among manufacturers. Therefore, in this study, we evaluated the generation characteristics of major decomposed gases by failure type based on KEPCO's accumulated bushing dissolved gas analysis database for major bushing manufacturers in operation, bushing internal dismantling inspection, and accelerated aging experiments for each manufacturer. Based on this, it is expected to contribute to the establishment of abnormal diagnosis criteria for OIP bushings and improvement of facility inspection efficiency.