Patent ID: 8656718

Claim:
A steam system comprising: a high-pressure header configured to store high-pressure steam; a turbine configured to be driven by the high-pressure steam supplied from the high-pressure header; a low-pressure header configured to store steam discharged from the turbine as low-pressure steam; a discharge valve configured to discharge the low-pressure steam to outside of the low-pressure header; a discharge valve controller configured to control an opening of the discharge valve such that a pressure of the low-pressure steam decreases when a pressure of the low-pressure steam is larger than a discharge valve pressure set value; a bypass configured to introduce steam from the high-pressure header to the low-pressure header by bypassing the turbine; a bypass valve configured to control steam flow in the bypass; a bypass valve controller configured to perform a normal control in which an opening of the bypass valve is controlled based on a plant value of a pressure of the low-pressure steam when the turbine is driven; and a trip time control section configured to perform a trip time control in which steam is supplied from the high-pressure header to the low-pressure header by bypassing the turbine in response to a trip signal indicating that the turbine trips, wherein the bypass valve controller performs an after-trip control in which an opening of the bypass valve is controlled to be larger than in the normal control after the trip time control and when the turbine is tripped.