## 5 Results
Figure 9 depicts the box chart of the BD strength for each degradation condition using the two-parameter Weibull distribution selected in this study. Each symbol in the box chart represents the value of the Weibull cumulative density function and median value. When using a box chart, the 1% breakdown value, which is a crucial factor in designing the power system, can be visually compared with other degradation conditions. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Degradation**} & \multicolumn{2}{c}{**Selected**} & \multicolumn{2}{c}{**Coefficient of**} & \multicolumn{2}{c}{**Log-Normal**} & \multicolumn{2}{c}{**Weibull**} \\ \multicolumn{2}{c}{**Condition**} & \multicolumn{2}{c}{**Selected**} & \multicolumn{2}{c}{**Distribution**} & \multicolumn{2}{c}{**Determination**} & \multicolumn{2}{c}{**\(\mu^{\prime}\)**} & \(\sigma^{\prime}\)** & \(\eta\)** & \(\beta\) & \(\gamma\) \\ \hline \multicolumn{2}{c}{**Temp. [\({}^{\circ}\)C]**} & \multicolumn{1}{c}{**Time [h]**} & & & & & & & \\ \hline \multicolumn{2}{c}{**-**} & 0 & Log-normal & 0.955 & 5.27 & 0.31 & & & \\ \hline \multicolumn{2}{c}{} & 72 & Log-normal & 0.966 & 5.28 & 0.28 & & & \\ \multicolumn{2}{c}{} & 240 & Weibull-2P & 0.872 & & & 287.17 & 3.19 & \\ \multicolumn{2}{c}{} & 480 & Weibull-3P & 0.970 & & & 95.32 & 1.51 & 195.25 \\ \multicolumn{2}{c}{} & 720 & Weibull-2P & 0.897 & & & 324.02 & 2.44 & \\ \multicolumn{2}{c}{} & 960 & Weibull-2P & 0.982 & & & 319.09 & 6.43 & \\ \hline \multicolumn{2}{c}{} & 72 & Weibull-3P & 0.988 & & 90.93 & 1.14 & 141.02 \\ \multicolumn{2}{c}{} & 240 & Weibull-2P & 0.976 & & & 229.60 & 2.70 & \\ \multicolumn{2}{c}{} & 480 & Weibull-2P & 0.968 & & 261.31 & 7.08 & \\ \multicolumn{2}{c}{} & 720 & Weibull-2P & 0.972 & & 277.68 & 5.51 & \\ \multicolumn{2}{c}{} & 960 & Weibull-2P & 0.929 & & 269.30 & 7.72 & \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Distribution and statistical parameters selected based on degradation conditions. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multicolumn{2}{c}{**Degradation Condition**} & \multicolumn{2}{c}{**Weibull-2P**} & \multicolumn{2}{c}{**Weibull-3P**} & \multicolumn{2}{c}{**Weibull-3P**} \\ \hline \multicolumn{2}{c}{**Temp. [\({}^{\circ}\)C]**} & \multicolumn{1}{c}{**Time [h]**} & \multicolumn{1}{c}{**AIC**} & \multicolumn{1}{c}{**BIC**} & \multicolumn{1}{c}{**AIC**} & \multicolumn{1}{c}{**BIC**} & \multicolumn{1}{c}{**Available**} \\ \hline \multicolumn{2}{c}{} & 0 & 226 & 228 & 225 & 228 & O \\ \hline \multicolumn{2}{c}{} & 72 & 221 & 223 & 221 & 224 & X \\ \multicolumn{2}{c}{} & 240 & 227 & 229 & - & - & X \\ \multicolumn{2}{c}{} & 480 & 196 & 198 & 195 & 198 & O \\ \multicolumn{2}{c}{} & 720 & 222 & 224 & - & - & X \\ \multicolumn{2}{c}{} & 960 & 207 & 209 & 209 & 212 & X \\ \hline \multicolumn{2}{c}{} & 72 & 214 & 216 & 201 & 203 & O \\ \multicolumn{2}{c}{} & 240 & 214 & 216 & 216 & 219 & X \\ \multicolumn{2}{c}{} & 480 & 199 & 201 & 200 & 203 & X \\ \multicolumn{2}{c}{} & 720 & 206 & 208 & 208 & 210 & X \\ \multicolumn{2}{c}{} & 960 & 199 & 201 & - & - & X \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Determination of the number of Weibull parameters according to degradation conditions.