Study of supercritical coal-fired power plant dynamic responses and control for grid code compliance
Study of supercritical coal-fired power plant dynamic responses and control for grid code compliance
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发表时间：
2015-08
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通讯作者：
M. Draganescu
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作者：
M. Draganescu
本论文通过数学建模和仿真研究超临界燃煤电厂的动态响应。与亚临界发电技术相比，超临界技术可实现更高效的能量转换，因此从经济和环境角度来看，超临界技术被认为是英国替代老化火力发电厂的可行选择。然而，由于尚不清楚超临界电厂的动态响应是否能够满足英国电网规范对频率响应和频率控制的要求，因此对该技术的采用存在担忧。为了回答上述问题，博士研究项目的目标如下：研究发电厂在不同控制模式下的动态响应，以评估其在提供英国电网规范规定的频率控制服务方面的合规性；评估和改进电厂模拟器现有控制回路的性能，在这方面，设计了一个基于动态矩阵控制算法的控制器来调节煤流量，并实施了另一个基于广义预测控制算法的控制器来调节过热蒸汽的温度；对发电厂层面的频率控制进行调查，然后对从几个欧洲和非欧洲国家的电网规范中提取的频率控制要求进行分析。对超临界电厂的结构和运行进行了深入研究和介绍。本文提出的所有模拟测试都是通过与中国北京清华大学合作开发的复杂的600兆瓦电厂模拟器进行的。通过仿真试验研究表明，该类型电厂目前的控制方式很难满足英国电网规范的频率控制要求。因此，有必要研究更有效的控制策略来提高其动态响应。在本文中，开发了新的模型预测控制发电厂控制策略，并且通过基于模型预测控制的控制器的实施，极大地提高了控制回路的性能，从而大大提高了发电厂的性能。
The thesis is concerned with the study of the dynamic responses of a supercritical coal-fired power plant via mathematical modelling and simulation. Supercritical technology leads to much more efficient energy conversion compared with subcritical power generation technology so it is considered to be a viable option from the economic and environmental aspects for replacement of aged thermal power plants in the United Kingdom. However there are concerns for the adoption of this technology as it is unclear whether the dynamic responses of supercritical power plants can meet the Great Britain Grid Code requirement in frequency responses and frequency control. To provide answers to the above concerns, the PhD research project is conducted with the following objectives: to study the dynamic responses of the power plant under different control modes in order to assess its compliance in providing the frequency control services specified by the Great Britain Grid Code; to evaluate and improve the performance of the existing control loops of the power plant simulator and in this regard a controller based on the Dynamic Matrix Control algorithm was designed to regulate the coal flow rate and another controller based on the Generalized Predictive Control algorithm was implemented to regulate the temperature of the superheated steam; to conduct an investigation regarding frequency control at the power plant level followed by an analysis of the frequency control requirements extracted from the Grid Codes of several European and non-European countries. The structure and operation of the supercritical power plant was intensively studied and presented. All the simulation tests presented in this thesis were carried out by the mean of a complex 600 megawatts power plant simulator developed in collaboration with Tsinghua University from Beijing, China. The study of the conducted simulation tests indicate that it is difficult for this type of power plant to comply with the frequency control requirements of the Great Britain Grid Code in its current control method. Therefore, it is essential to investigate more effective control strategies aiming at improving its dynamic responses. In the thesis, new Model Predictive Control power plant control strategies are developed and the performance of the control loops and consequently of the power plant are greatly improved through implementation of Model Predictive Control based controllers.