【作者】 弓岱伟；

【导师】 孙德敏；

【作者基本信息】 中国科学技术大学 ， 控制理论与控制工程， 2008， 博士

【摘要】 工业企业改革和国际化的深入使国内企业面临着前所未有的竞争和挑战,同时节能减排成为“十一五”的重点,这都要求企业采用先进的控制和优化方法,努力在提高生产效率和安全性的同时节能降耗,以提高综合经济效益。火电占国内电力总装机容量超过四分之三,先进控制与优化的应用在火电领域有着非常重要的意义,这是因为先进控制与优化在火电机组的应用率仍然很低,这有多方面的因素:(1)先进算法很多过于复杂,难于计算机应用,且参数复杂调节难度大,不适合一般的工程人员;(2)大量早期投产的大型火电机组,由于设计和陈旧等原因,缺乏必要的控制手段;(3)缺乏自主研发的先进控制与优化软件系统。而本文则重点对其中两个方面进行了研究,即先进控制与优化软件系统的设计和实现,以及先进控制方法用于电站锅炉的主汽温控制。一、主蒸汽回路为电站锅炉最主要的回路之一,主汽温度的稳定直接影响锅炉运行的效率和安全性。主汽温平均温度提高1℃,机组效率直接提高1‰左右,同时汽温控制须非常稳定,超温将直接影响锅炉的安全运行,经常的超温会大大影响管路寿命,甚至会产生暴管事故而被迫停机维修,而过低的汽温会大幅影响锅炉效率。但是很多尤其是早期建设的电站锅炉系统,其主汽温自动控制很不理想,甚至无法投用,这是因为主蒸汽回路具有典型的大惯性、大滞后特点和对象模型随负荷变化较大等特点,同时较老机组存在较多的原始设计缺陷并缺乏执行手段,这就大幅增加了自动控制的应用难度。为此,我们针对此问题存在较为严重的平圩#1和石横#2机组主蒸汽回路,提出了一种基于多模型切换的阶梯式广义预测控制方法,并结合考虑风量、主汽压、上层磨煤量、蒸汽流量等影响因素成功应用于主汽温串级控制,在机组正常工作负荷范围内均能达到很好的控制品质,成功解决了两厂建厂以来一直无法解决的主汽温自动控制问题,具有推广应用价值。二、现有控制系统软件普遍存在的一些问题,如稳定性欠缺,功能单一,可移植、可扩展性弱,无法与大型DCS紧密结合并高速稳定进行数据交换等等。针对这些问题,提出了几种高效的高速数据交换方法用于不同应用场合,并通过对模块调度方式的分析和仿真,设计了高效的模块调度策略,同时基于工程实践经验,针对性的设计了双向数据缓冲池、统一的数据预处理接口、统一的模块模板用于算法的模块化实现、多线程模块动态挂接和调度、统一的配置文件支持和配置数据库支持、标准化格式的日志系统以及心跳信号等,首次自主研发了基于Solaris操作系统的DCS嵌入式先进控制与优化软件系统,系统具有稳定性高、模块化通用性强、数据处理稳定快速、算法便于应用和扩展并易于移植等特点,软件在石横#2机组主汽温控制和燃烧优化项目中的应用,显示了显著的性能和稳定性优势。更多还原

【Abstract】 Industrial enterprise reform and the deepening of the internationalization let the domestic enterprises facing unprecedented competition and challenges. At the same time, energy reduction become the "11th Five-Year Plan". These all requires enterprises to adopt advanced control and optimization method, in an effort to improve production efficiency and reduce the energy consumption so as to improve overall economic efficiency.Thermal power takes more than three-quarters of the total electricity capacity in China. So, the applications of advanced control and optimization in this field have a very important significance. It is because of the application rate of advanced control and optimization in thermal power units remains low, which is multifaceted: (l)Advanced algorithms are generally too complicated and are difficult for computer applications. And the parameters are also too complicated for normal engineers to adjust; (2)There are a large number of early built large scale thermal power units, which lack of the necessary means of control ability because of the outdated design and obsolescence; (3)The lack of advanced control and optimization software system based on independent intellectual property rights. This paper will focus on two aspects: The development and implementation of advanced control and optimization software system. And the application of advanced methods for the control of the super-heat steam temperature of large scale power plants.1. Super-heat steam loop is one of the most important loops of power plant boiler system. The stability of super-heat steam temperature directly affects the boiler efficiency and also the safety. And the unit’s efficiency increases l%o when super-heat steam temperature increases 1°C. At the same time, steam temperature must be very stable, because overheating will directly affect the boiler safety, and frequently overheating will lower pipes’ life, and even produce pipe explosion and forces boiler to be shutdown for maintenance; On the other side, over-low-temperature will significantly drop the boiler’s efficiency. However, many power plant boilers, especially the early built ones, their super-heat steam temperature control were not optimal, or even unable to be automatic controlled. It is because the super-heat loop is of a typically large inertia, and the model varies much with the boiler load. At the same time, many of them lack controllable instruments, which has substantially increased the difficulty of the control. Because Pingwei #1 and Shiheng #2 Unit are of the most problematic boilers, we specifically proposed a Model-switching Stair-like Generalized Predictive Control method, and taking air volume, main steam pressure, feeds of the upper coal, steam flow, and other factors into consideration. And then we designed cascaded controller based on the model-switching method and the controller showed very good control quality. The controller design successfully solved the automatic super-heat steam temperature control problem since the two plants’ foundation, and showed exclusive performance and portability of the new method.2. Existing control software system generally has problems such as lack of stability and functionality, weak of portability and scalability, unable to tightly integrate with large scale DCS system and perform stabile and high-speed data exchange with DCS, etc. To solve these problems, we proposed several efficient data exchange methods for different application occasions, and designed a highly efficient module-scheduling strategy. And we also designed many advanced features such as bi-directional data pool, unified data preprocessing interface, unified module template, multi-threaded dynamic loaded and scheduled modules, unified configuration file and configuration database support, standardized formatted logging system, and heartbeat signals support. Finally, based on the Solaris operating system, we produced DCS-embedded advanced control and optimization software system. The system features high stability, versatile modularity, fast&stable data processing, and is highly expansible and portable. The software’s application in the super-heat steam temperature control and combustion optimization project in Shiheng Power Plant showed significant performance and stability advantages.更多还原