Time-dynamic oxidation stability studies of mineral insulating oils

IEC 61125C, a traditional oxygen-rich material test for determination of oxidation stability of insulating oils, was modified to give continuous data over the entire testing time by application of a logging pH-meter. A complementary oxygen-poor testing method, which may be more relevant to certain power transformer designs, was also developed further. The methods give insight into the chemistry and dynamics of oil oxidation, and may serve as a future means to investigate insulating oil behavior and support development of high performance insulating oils.