Research On Modeling And Control Method Of Power Plant Coordinated Control System

In recent years, with the rapid development of China's power industry, dominated thermal power has also developed rapidly. In the eighties of the last century our country mainly researched on 300 MW Subcritical Unit, since 1990 s began to transform to 600 MW Supercritical Unit, and now study on 1000 MW Ultra Supercritical Unit. Currently, 600 MW Supercritical Unit has become the development direction of China's thermal power grid and gradually become the main unit. So we select 600 MW Supercritical Unit as the research object.Compared to Subcritical Unit, Supercritical Unit has more complex features, and its control system requirements will be higher. In order to improve their own efficiency and the ability to follow the grid load instruction, many experts and scholars at home and abroad are working on Supercritical Unit coordinated control system. At the same time, it can be said that a precise mathematical model of Supercritical Unit target is the basis for coordinated control system design and research. Therefore, based on the summarizing previous work, this paper proposed research ideas of modeling and control method of Supercritical Unit coordinated control system.In modeling. Since Supercritical Unit object has the characteristics of large inertia, high-parameter, multivariable and strong coupling, pure mechanism modeling for such a complex thermal system will be difficult to establish its precise mathematical model. In the absence of necessary prior knowledge, experimental modeling approach is difficult to determine the structure of the premise identification system mathematical model, and it is likely to cause large errors. Therefore, this paper proposes a modeling method which is the combination of mechanism modeling and experimental modeling, namely ‘gray-box method'. Firstly, through mechanism analysis of Supercritical Unit objects, we determine the basic structure of the object mathematical model. And then we take the site run historical data of thermal power plant as the initial data of the experimental identification, with the selected data preprocessing low pass filter, coarse value and zero initial value processing. Finally, under the application of MATLAB programming tools, we use particle swarm(PSO) algorithm to optimize the parameters of object model, so that the output of identification model and the actual system can be as close as possible, and then we can get the mathematical model of Supercritical Unit object.In the study of the control method. Many experts and scholars have many advanced control theory research and control methods of the Supercritical Unit coordinated control system. While these advanced control algorithms can achieve good control effect in the simulation study, but they have complex structure, many tuning parameters and not clear physical meaning which is too difficult to master. So it is difficult to promote a wide range in practice. Therefore, from the perspective of practical application to proceed, this article focuses on architecture design of Supercritical Unit coordinated control system, and designs pressure back loop and unit load instruction feedforward loop. It analyzes the multi-objective optimization system to solve the problem of Pareto set. With the MATLAB programming tools, it finally uses PSO algorithm to optimizate parameters of the controller. And the simulation result presents that the research of architecture design of Supercritical Unit coordinated control system has better control effect.