改进型DEB协调控制在大迟延控制对象上的应用

针对神华陕西国华锦界能源有限责任公司(锦界电厂)3号亚临界600MW机组燃料量对主蒸汽压力变化响应的纯迟延长、惯性大的特点,将原机组协调控制系统的单纯直接指令平衡(DIB)控制系统前馈-反馈调节结构优化为改进型直接能量平衡(DEB)控制系统+动态预超调燃料前馈控制结构。应用结果表明,改进后的协调控制系统克服了机组的大迟延环节对主蒸汽压力调节的影响。当机组负荷指令变化时,控制系统快速改变汽轮机调节阀开度,从而消除或减小了锅炉主控对负荷变化响应的迟延;通过合理配置较大比例的动态预超调燃料前馈量,及时提高锅炉蓄热量,减小了主蒸汽压力的动态偏差。DEB控制系统在主蒸汽压力变化前通过锅炉热量信号动态预调节燃料量,使主蒸汽压力快速跟踪其设定值,对长迟延、大惯性系统具有较好的适应性。

APPLICATION OF IMPROVED DEB COORDINATED CONTROL ON LARGE DELAY CONTROL OBJECT

For the No.3 subcritical 600MW unit of Shenhua Guohua Jinjie Energy Co.,Ltd.of Shaanxi Province,the response of fuel amount on the steam pressure changes has long pure delay and large inertia.According to this characteristic,an improved direct energy balance(DEB) control system which increased the dynamic pre-over modulation fuel feed-forward control system was proposed to replace the existing simple direct instruction balance(DIB) control system.Field application showed that,the improved coordination control system overcame the impact of long delay link on the main steam pressure regulation.When the unit load command changed,the control system quickly regulated the valve opening of steam turbine,thus,response delay of boiler master control to load changes was eliminated or reduced;through rationally configuring larger proportions of the dynamic pre-overshoot fuel feedforward volume,the heat storage was timely improved,so the dynamic deviation of main steam pressure was reduced.Before the main steam pressure changes,EDB control system dynamically pre-regulates fuel quantity according to the boiler heat signal,so the main steam pressure can quickly track its set value.Therefore,the improved DEB control system has good adaptive ability on the long delay,large inertia system.