## 4 Simulation Conditions  
### Single Wind and Snow Condition  
In the study of wind and snow conditions, wind and snow loads are considered as the primary factors, while excluding the effects of thermal stress caused by temperature variations and ash accumulation loads. Additionally, human factors and other uncontrollable variables affecting the structure, such as potential damage during transportation and installation processes, are disregarded. Initially, static simulations were conducted to assess various thickness configurations, with the aim of selecting an optimal wall thickness scheme. Using a baseline thickness of 2.5 mm and setting a standard step size of 0.5 mm for thickness adjustment, the thickness was incrementally increased to 3 mm to evaluate the specific impact of thickness augmentation on structural performance. Similarly, the thickness was decreased step by step to 2.0 mm, 1.5 mm, 1.0 mm, and 0.5 mm for a comparative analysis. This incremental adjustment method facilitates a detailed observation of the effect of thickness variation on structural stress and strain, providing a scientific basis for determining the optimal thickness. The simulation results are presented in Table 7. A comparative analysis revealed that the stress levels for thicknesses of 1.0 mm, 0.5 mm, and 0.25 mm exceeded the material's yield strength, indicating insufficient structural safety, thus excluding them from subsequent combined load simulations. Additionally, the 2.0 mm- and 1.5 mm-thickness schemes, although approaching the material's yield strength, remained within the safety range, making them ideal candidates for further simulation studies. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Response** & **X** & **Y** & **Z** & **XZ** & **ZY** \\ \hline Von Mises Stress (MPa) & 0.74187 & 0.0058215 & 0.034293 & 0.74187 & 0.034783 \\ Total Deformation (mm) & 0.20956 & 0.0013857 & 0.0081451 & 0.20958 & 0.0082622 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Simulation results for different seismic wave directions. Figure 14: ZY-direction stress and deformation of box-type substation under earthquake conditions. Figure 13: XZ-direction stress and deformation of box-type substation under earthquake conditions. Next, after selecting three thickness schemes, considering the extreme wind and snow conditions that inland and coastal regions may encounter, the structural design of the box-type substation in this study needs to withstand wind speeds of level 10 and snow loads of 40-50 cm. The loading conditions are illustrated in Figure 15, where wind load refers to the force exerted on the box-type substation by the wind, and snow load refers to the weight of snow borne by the box-type substation. The formula for wind pressure calculation is P = 0.613 V\({}^{2}\), where P is the wind pressure and V is the wind speed. The maximum snow load calculation formula is w = ph, where w is the snow load, \(\rho\) is the density of snow, and h is the depth of snow, assuming a maximum snow depth of 50 mm. After calculation, the maximum wind pressure is 494.42 KPa, and the maximum snow load is 0.98 KN/m\({}^{2}\). The basic wind pressure is 0.7225. Based on the data mentioned above, the wind and snow loads applied to the windward and leeward walls, as well as the roof of the box-type substation, are derived and presented in Table 8. The stress and deformation results of the box-type substation under the combined action of wind and snow loads are obtained through simulation, as depicted in Figure 16.