The power transformer is a crucial piece of equipment in the power system. However, it can experience various faults due to voltage fluctuations, insulation degradation, and other factors. The traditional method for diagnosing these faults, such as Dissolved Gas Analysis (DGA), determines primarily the fault type based on the hydrocarbon composition and proportion of dissolved gases in the power transformer oil. However, different fault locations can lead to different outcomes. , the carbon oxide composition and proportion of the gas in the power transformer oil can help determine if the fault is related to the paper. The present invention further utilizes changes in the carbon oxide proportion over time to develop an auxiliary DGA analysis indicator for the power transformer. This uses the regular DGA report as input (no need to add new sensors), and it can help determine potential fault locations in the power transformer without shutting it down. It is also integrated into the power transformer diagnostic management platform to prevent accidents before they occur and reduce unexpected power outages through different monitoring and diagnostic methods.