During which procedure is the turbine isolated from the operational system?

The procedure during which the turbine is isolated from the operational system is off-line washing. This activity is designed to clean the turbine when it is not in operation, ensuring that any accumulated debris or contaminants can be effectively removed without any risk to the operational integrity of the system.

Isolating the turbine during off-line washing allows for a thorough cleaning process, minimizing any potential damage or interference that could occur if the turbine were still connected and operational. This procedure is typically executed by shutting down the turbine, ensuring that no steam or fluid flows through it, which makes it safe for maintenance personnel to perform the washing process.

This practice highlights the importance of keeping the turbine clean for optimal performance and efficiency, reducing the likelihood of issues related to turbine blade fouling or deposits that can affect performance. Thus, off-line washing is crucial for maintaining the turbine's operational efficiency while ensuring safety during maintenance activities.