## 2 Dissolved Gas Analysis (DGA) Dataset  
Three groupings of constituent gases are generated during the breakdown of transformer oil: H\({}_{2}\), CH\({}_{4}\), C\({}_{2}\)H\({}_{2}\), C\({}_{2}\)H\({}_{4}\), C\({}_{2}\)H\({}_{6}\), and carbon oxides (CO and CO\({}_{2}\)). The type and concentration of gas created because of the breakdown of insulating oil give clues about the potential transformer incipient fault type, as the creation of these fault gases is dependent on temperature [5,6]. Table 1 lists the gases that can originate because of insulation failure and potential transformer early failure [6]. In thermal faults below 300 \({}^{\circ}\)C, ethane points to overheating of the paper or mineral oil, while methane suggests degradation of the insulating materials. At higher temperatures, between 300 \({}^{\circ}\)C and 700 \({}^{\circ}\)C, methane and ethylene indicate more serious faults, such as carbonization of the paper. Above 700 \({}^{\circ}\)C, the predominance of ethylene signals extreme conditions that can cause severe damage to the insulating system. Electrical faults, on the other hand, are characterized by the presence of hydrogen in low-energy discharges and acetylene in high-energy arcs, indicating more intense and destructive electrical events. Regular analysis of dissolved gases is crucial for the early detection of these faults, allowing quick and effective interventions to prevent further damage and guarantee the continued safe operation of power transformers. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Cause of Gas Generation**} & \multirow{2}{*}{**Main Gas Type**} & \multicolumn{2}{c}{**Medium Gas Type**} & \multirow{2}{*}{**Minor Gas Type**} \\  & & & **Type** \\ \hline Partial discharge—Corona & H\({}_{2}\) & - & - \\ \hline Stray gassing—T \textless{} 200 \({}^{\circ}\)C & H\({}_{2}\) & CH\({}_{4}\) & CH\({}_{4}\), C\({}_{2}\)H\({}_{6}\) \\ \hline Thermal fault—T \textless{} 300 \({}^{\circ}\)C & C\({}_{2}\)H\({}_{6}\) & CH\({}_{4}\) & C\({}_{2}\)H\({}_{4}\), C\({}_{2}\)H\({}_{6}\) \\ \hline Overheating of paper 1  or mineral oil & C\({}_{2}\)H\({}_{6}\) & CH\({}_{4}\) & H\({}_{2}\), C\({}_{2}\)H\({}_{4}\) \\ \hline Carbonization of paper 1  & CH\({}_{4}\) & C\({}_{2}\)H\({}_{4}\), C\({}_{2}\)H\({}_{6}\) & H\({}_{2}\), C\({}_{2}\)H\({}_{4}\) \\ \hline Thermal fault—300 \({}^{\circ}\)C \textless{} T \textless{} 700 \({}^{\circ}\)C & CH\({}_{4}\), C\({}_{2}\)H\({}_{4}\) & H\({}_{2}\), C\({}_{2}\)H\({}_{6}\) & H\({}_{2}\), \\ \hline Thermal fault—T \textgreater{} 700 \({}^{\circ}\)C & C\({}_{2}\)H\({}_{4}\) & H\({}_{2}\), CH\({}_{4}\) & - \\ \hline Discharge low energy or sparking & H\({}_{2}\) & C\({}_{2}\)H\({}_{2}\), C\({}_{2}\)H\({}_{4}\) & C\({}_{2}\)H\({}_{2}\), C\({}_{2}\)H\({}_{6}\) \\ \hline Discharge high energy (acting) & H\({}_{2}\), C\({}_{2}\)H\({}_{2}\) & C\({}_{2}\)H\({}_{4}\), C\({}_{2}\)H\({}_{4}\) & CH\({}_{4}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Gas importance by faults in power transformers (adapted of [6]). Reference [20] is the standard for analyzing gases generated and dissolved in transformer-insulating oil. It covers everything from recommended practices for monitoring, analysis, diagnosis, and maintenance to the theory of gas creation and how it relates to faults. A totally dissolved combustible gas study examines the evolution rates of the gases (by kind and total value) and connects them to criteria for maintenance and monitoring during the transformer's operational life. Under typical working conditions, the following are the limit values for gas concentrations specified in the standard [20], expressed in \(\mu\)L/L (or ppm): H\({}_{2}\) = 100, CH\({}_{4}\) = 120, C\({}_{2}\)H\({}_{2}\) = 1, C\({}_{2}\)H\({}_{4}\) = 50, and C\({}_{2}\)H\({}_{6}\) = 65. The dataset is composed of 815 samples used for training and validation phases obtained from reference [19; 20; 21; 22; 23; 24; 25].