STEAM SYSTEM, AND ITS CONTROL SYSTEM AND CONTROL METHOD

摘要

Provided is a steam system control method, which is applied to a steam system including a low-pressure side header for accumulating low-pressure steam, a high-pressure side header for accumulating high-pressure steam, a steam turbine connected between the two headers, and a turbine bypass line for feeding the steam of a controlled quantity of the high-pressure side header to the low-pressure side header while bypassing the steam turbine. The low-pressure side header is equipped with a discharge valve for discharging excess steam to the outside. The steam system control method comprises an ordinary time discharge valve control step of PI-controlling the opening of the discharge valve, and an trip time discharge valve control step of controlling the opening of the discharge valve by changing an MV value to the specified trip time opening set value when the turbine trips. By this method, when the turbine trips so that the excessive steam flows into the bypass, the opening of the discharge valve is controlled by the specified MV value so that the excessive steam having flown into the low-pressure side header is promptly discharged to the outside. Even when the turbine trips, the steam system can be safely run.