# Multi-Domain Modeling and Analysis of Marine Steam Power System Based on Digital Twin
## 5 Fault Simulation Analysis of Marine Steam Power System Based on Digital Model
It can be seen from Figures 29 and 30 that, with the increase of air leakage into the condenser, the proportion of the air volume inside the condenser increases. According to [PERSON]'s partial pressure law, the pressure in the condenser will also increase, reducing the thermal cycle efficiency of the turbine. In addition, the air film formed will reduce the heat transfer coefficient, and the heat transfer end difference of the condenser will also increase. (3) Increase of steam turbine exhaust  
During the steady-state operation of the steam turbine unit, the cooling conditions of condenser also remain unchanged. When the exhaust steam in the steam turbine increases, the steam quantity inside the condenser will change. In order to study the rule of the influence of steam turbine exhaust on the condenser, assuming that other input and output variables of the system remain unchanged. The change in the main operating state parameters of the condenser due to the increase of steam turbine exhaust is analyzed according to the established digital model. The main performance parameters of the condenser are shown in Table 7. \begin{table}
\begin{tabular}{c c c} \hline
**Increase Proportion of Steam** & **Condenser Pressure** & **Temperature Rise Increment** \\
**Turbine Exhaust (\%)** & **Increment (bar)** & **of Cooling Water (\({}^{\circ}\)C)** \\ \hline
5 & 0.015 & 0.46 \\
10 & 0.029 & 0.77 \\
15 & 0.048 & 1.25 \\
20 & 0.062 & 1.84 \\
25 & 0.098 & 2.31 \\ \hline \end{tabular}
\end{table} 
Table 7: Influence of increased steam turbine exhaust on main state parameters of condenser. Figure 30: Variation curve of cooling water temperature rise. Figure 29: Variation curve of condenser pressure. According to the state parameters of the condenser, the relationship curves between the pressure increment of the condenser, the temperature increment of the circulating cooling water and the increased proportion of the steam turbine exhaust are drawn as shown in Figures 31 and 32. It can be seen from Figures 31 and 32 that, if the cooling conditions of the condenser remain unchanged, when the steam exhaust volume of the turbine gradually increases, the proportion of steam in the condenser increases, the pressure of the condenser rises, the vacuum degree drops, the cooling water temperature rises, and the heat transfer end difference of the condenser also increases, which is consistent with the mechanism model analysis. In a word, through the fault simulation research on the condensate feed water system based on the high-precision digital model, it can be seen from the fault simulation results that the digital model can accurately simulate the change law for each fault parameter, accurately describe the actual fault state, realize the quantitative analysis of the fault using the digital model, and build the fault database of the digital twin model according to the parameter change laws for these faults. When the actual digital twin model is running, it can be compared in time through the real-time mapping of online data to extract typical faults, which can speed up online diagnosis and fault prediction and provide guidance for the safe and stable operation of the marine steam power system.