Automatic Control System Of Steam Drum Water Level In Power Plant

In the modern power plant,it is very important to ensure the safe and stable power output of the boiler.In the boiler automatic control system,the drum water level automatic control system is the top priority.In the process of unit operation,there are many working conditions,which can be divided into low load condition and high load condition,respectively corresponding to the two schemes of recirculation control valve control and feed pump frequency conversion speed control.The unit power parameters are used as the selection conditions to ensure the unit from start to stop In practice,the conventional PID control method is adopted for the drum water level control,and the dynamic characteristics of the drum water level and several common control methods are analyzed in detail.Finally,the combination of conventional PID control and three impulse control mode of drum water level is determined.Considering the occurrence of false drum water level in actual operation,steam flow is added as feed-forward signal of water level signal in the control system,which acts on the feed water in advance。According to the control requirements of the control system,this paper summarizes the required control equipment and corresponding I / o point table,and then carries out the hardware design and selection of DCS control system according to the point table.After the hardware system is built,the system software configuration is created and compiled,and the system program required for the control is built through the CFC logic language block,and finally realized through the control network of DCS The data transmission and control command transmission between the operator station and the field controller can realize the automatic control of boiler drum water level under various working conditions.