Control method and control device of steam system

Abstract

A steam system control method applied to a steam system including: a low-pressure header storing low-pressure steam; a high-pressure header storing high-pressure header; a steam turbine connected between them; and a turbine bypass line introducing controlled amount of steam from the high-pressure header to the low-pressure header by bypassing the steam turbine. The low-pressure header has a blow-off valve for discharging excessive steam to the outside. The steam system control method includes: a normal time blow-off valve control step of PI controlling the opening of the blow-off valve; and a trip time blow-off control step of controlling the opening of the blow-off valve by changing the MV value to a predetermined trip time opening set value when the turbine is tripped. According to this method, the opening of the blow-off valve is controlled based on the predetermined MV value when the turbine trips and excessive steam flows into the bypass, so that excessive steam flows into the low-pressure header is quickly discharged to the outside. Stable operation can be achieved even when a turbine trips.