二次再热机组智能协同优化控制研究

The development of high-parameter two-stage reheat unit is of great significance to ensure the power supply and achieve the goal of energy-saving as well as emission reduction in China. However, in the situation of electrical power system with renewable energy, the unit not only need to maintain high efficient operation of itself, but also need to participate in peak-shaving. Compared with the traditional one-stage reheat unit, the structure of two-stage reheat unit is more complicated, the coupling between its subsystems is more compact, making a bigger heat storage capacity and a larger thermal inertia in the boiler, thereby the traditional control strategy is difficult to meet the new control requirements. In order to solve these problems, an intelligent cooperative optimization control strategy for two-stage reheat unit is researched in this project: 1) a full working condition nonlinear model of two-stage reheat unit and a characterization model of the key operating parameters are established based on the characterization of dynamic characteristics of the thermodynamic system; 2) a precise energy balance coordination control strategy is designed based on multiple-input, single-output predictive control algorithm; and 3) a multivariable decoupling control strategy for two-stage reheat steam temperature is designed based on synergistic control of a steam-electric, dual-drive fan. Through theoretical analysis, simulation test and practical application, a practical and effective solution for the control of two-stage reheat units is explored, and a solid theoretical and application foundation for efficient, stable and flexible operation of two-stage reheat unit is established.

发展高参数二次再热超超临界火电机组，对保证我国电力供应、实现节能减排的目标具有重要的意义。然而在新能源电力系统环境下，二次再热机组除了需保持高效运行外，仍需频繁的参与电网调峰，同时需适应我国煤质煤种多变的特点。二次再热超超临界火电机组相比于传统的一次再热机组，增加一套再热器系统后使得系统结构更加复杂、各子系统间的耦合更紧密、锅炉的蓄热能力和热惯性更强，传统的控制策略难以满足新形势下的要求。为了解决上述问题，本项目提出二次再热机组智能协同优化控制策略：1)基于复杂热力系统动态特性表征方法，建立全工况非线性模型及关键运行参数表征模型；2)设计基于多输入单输出预测控制算法的精准能量平衡协调控制策略；3)基于汽电双驱引风机的协同调温，设计两级再热汽温的多变量解耦控制策略。通过理论分析，仿真试验及现场应用，探索切实有效的解决方法，为保障二次再热机组高效、稳定、灵活运行奠定坚实的理论和应用基础。

发展高参数二次再热超超临界火电机组，对保证我国电力供应、实现节能减排的目标具有重要的意义。然而在新能源电力系统环境下，二次再热机组除了需保持高效运行外，仍需频繁的参与电网调峰，同时需适应我国煤质煤种多变的特点。二次再热超超临界火电机组相比于传统的一次再热机组，增加一套再热器系统后使得系统结构更加复杂、各子系统间的耦合更紧密、锅炉的蓄热能力和热惯性更强，传统的控制策略难以满足新形势下的要求。为针对上述问题，本项目以国电宿迁电厂二次再热机组作为研究对象，提出基于精准能效平衡的二次再热机组智能协同优化控制策略，研究内容如下：1)基于复杂热力系统动态特性表征方法，建立全工况非线性模型及关键运行参数表征模型；2)设计基于多输入单输出预测控制算法的精准能量平衡协调控制策略；3)基于汽电双驱引风机的协同调温，设计两级再热汽温的多变量解耦控制策略。通过理论分析，仿真试验及现场应用，实现了机组动态变负荷时（速率1.7%Pe/min），主蒸汽压力的最大偏差小于0.5MPa，稳态变负荷时，主蒸汽压力最大偏差小于0.3MPa，分离器出口温度最大偏差±5℃；机组两级再热汽温在变负荷过程中两级再热汽温最大偏差小于5℃，且两级再热汽温可以很好的跟随设定值的变化，最大蒸汽温度偏差不超过3.3℃。通过本项目的研究，共发表文章5篇SCI期刊论文，申请发明专利3项，其中已授权2项，获得2020年度中国电力科学技术进步奖1项；项目研究成果已在国家能源集团宿迁热电有限公司2×660MW二次再热发电机组成功应用，并已推广至华能秦煤瑞金发电有限责任公司2×1000MW新建二次再热机组中。