The reason for the turbine shutdown is unknown
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The temperature of the 3.5MPa steam dropped instantly from 400 degrees Celsius to 180 degrees Celsius. The compressor shuts down during the cooling process. At points where there are no measured values for interlock memory (bearing temperature, vibration, displacement, and oil pressure are all normal) that are excessively high. The instrument indicates that the shutdown signal comes from the general alarm; the aircraft’s status is abnormal. What’s going on?
There should be a interlock in the chain system to address low superheated steam temperature; steam at 3.5 MPa at 180 degrees definitely contains a significant amount of water, which can have fatal effects on the turbine. Such an interlock is usually in place. Our 3.2MPa steam shuts down at temperatures below 350 degrees.
Start with the easier ones. First, check whether all the instruments are functioning properly; it is necessary to verify all relevant instruments. If the instruments are fine, it indicates that the temperature drop is real. I think there are two possible reasons for this temperature drop. 1. Insufficient steam source. 2. Check whether all the temperature reducers in the steam pipeline ahead of the compressor are operating properly, by focusing on the opening values of the cooling water control valves before the temperature reducers and the temperature readings after them. I can’t think of any others for now; I’ll leave you a message once I come up with some.
First, check whether the steam pressure also decreases. If the pressure change is small, such a large temperature change is likely caused by water in the steam; the shutdown should be triggered by the low-temperature interlock for the fresh steam at the unit inlet.
Our company has also experienced such situations, with the rotor being severely impacted by water hammer. It’s a significant hit to production; we just finished doing the dynamic balancing today and came back.