Feedforward structure for controlling steam drum water level in steam turbine FCB test and control method for the same

A feedforward structure for controlling steam drum water level in steam turbine fast cut back (FCB) test, comprising:

• a steam drum provided with a steam drum water level measurement sensor therein, a feed water pipe provided with a feed water flow measurement sensor therein, and a steam inlet pipe provided with a steam flow measurement sensor therein;
• wherein a steam drum water level measurement value I in the steam drum water level measurement sensor is compared with a set value of the steam drum water level;
• the steam drum water level measurement sensor generates a main signal, any change of the steam drum water level caused by disturbances changes an output signal of a regulator to change a feed water flow, so as to restore the steam drum water level to the set value;
• the steam flow measurement sensor generates a feedforward signal, which prevents the regulator from performing an erroneous operation due to a false water level, and improve regulation quality when a steam flow is disturbed;
• the feedforward signal representing the steam flow and a signal representing the feed water flow work together to eliminate a static deviation of a feed water control system;
• when the feed water flow changes, a differential pressure of a transmitter changes quickly and reflects the change of the feed water flow in time;
• a feed water flow signal representing the feed water flow is used as a media feedforward signal, based on which the regulator eliminates internal disturbances when the steam drum water level has not changed, such that a regulation process by the regulator is stable and the feed water flow is stabilized.