Steam system, control system thereof and control method thereof

A control system for a steam system comprising:

• a discharge valve controller configured to control an opening of a discharge valve for discharging low-pressure steam to outside of a low-pressure header such that a pressure of the low-pressure steam stored in the low-pressure header decreases when a pressure of the low-pressure steam is larger than a discharge valve pressure set value;
• a bypass valve controller configured to perform a normal control in which an opening of a bypass valve for controlling steam flow in a bypass for introducing steam from a high-pressure header storing a high-pressure steam to the low-pressure header by bypassing a turbine driven by the high-pressure steam supplied from the high-pressure header;
• 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.

A control method for a steam system comprising:

• controlling an opening of a discharge valve for discharging low-pressure steam to outside of a low-pressure header such that a pressure of the low-pressure steam stored in the low-pressure header decreases when a pressure of the low-pressure steam is larger than a discharge valve pressure set value;
• performing a normal control in which an opening of a bypass valve for controlling steam flow in a bypass for introducing steam from a high-pressure header storing a high-pressure steam to the low-pressure header by bypassing a turbine driven by the high-pressure steam supplied from the high-pressure header;
• and
• performing 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 performing a normal control comprises:
• performing 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.