When do all the steam traps connected to the steam turbine’s drain expansion tank open?

Since I am not aware of the specific traps installed in your hydrophobic expansion tanks, I can only provide a general overview. In principle, it needs to be properly turned on during both startup and shutdown processes; I’m not sure whether you are referring to the startup or the shutdown process. Generally, the high and low pressure cylinders as well as the control stage drains should be opened appropriately during the warming-up and idling periods (they should be closed promptly after all water has been drained when the cylinders are sealed); their opening degree should be gradually reduced/increased as the temperature of the cylinders rises/falls. Prevent the cylinder temperature from rising slowly due to excessive or insufficient valve opening, which in turn delays the warming-up time and causes poor drainage of water from the cylinders. Other issues such as voltage equalization boxes, steam inlet chambers, and door rod air leakage can be handled flexibly depending on the actual conditions on site.

Is it still necessary to keep it on during winter to prevent freezing and condensation? It seems that some condensed water will accumulate inside the pipelines