Feedwater automatic-control system for steam generators

A new differential pressure method for measuring the water level in steam generator of PWR is introduced, and the stability and setting parameters of a three-element feedwater control system are analysed in detail. The functions and features of a DDC series-cascaded feedwater control system are also briefly introduced. With the new differential pressure method, the measuring accuracy is as high as 2%. With the flow-preponderated mode, the three-element feedwater controller is able to compensate the 'swell-and-shrink' effects of the water level when load changes, and so the expected transient response for the level can be achieved. By adopting the DDC series-cascaded control, the monitoring function and operation reliability of the control system are enhanced