漯河电厂自动控制系统研究

发布时间：2018-05-31 09:13

本文选题：火电机组 + 简化模型　；参考：《华北电力大学(北京)》2016年硕士论文

【摘要】：目前电网调节仍然以大容量、高参数火电机组为主,电网调度对火电机组AGC和一次调频有较高的要求。而由于火电机组的被控对象具有不确定性、时变性的特点,特别是锅炉侧具有大惯性大迟延,传统的常规PIID很难满足要求。本文以华电漯河发电有限公司一期2x330MW热电联产机组为实践对象,针对AGC和一次调频相关指标不能满足电网调度考核要求的现实状况。通过建立机组的数学模型从而预测出机组主要参数的变化趋势,在保证变负荷率满足要求的同时,减少主汽压的波动。本文首先分析了目前在机组建模、控制算法优化以及新型控制算法应用等方面的最新动态。综合分析比较,采用建立机组较为准确的数学模型,并在此基础上建立预测系统,来预测主汽压等主要参数变化趋势的方案。对机组结构及控制原理进行深入分析。将制粉系统和水冷壁吸热合并为一个环节,在确保模型准确的前提下降低了阶次。根据物质平衡关系和能量平衡关系,在合理简化的基础上,通过机理分析与实验建模的方法建立起机组的数学模型。根据机组的运行数据及动态扰动试验,确定相关动、静态参数,并在对象机组DCS系统中运用逻辑模块搭建起机组的简化模型。通过模型数据与机组实际运行数据的对比分析,验证了该模型具有较好的准确性与复现性。在已建立的机组简化模型基础上,对其进行相应的改进,调整输入输出关系,即输入量为机组负荷和燃料指令,输出量为主汽压力,建立了主汽压预测模型。根据预测模型,由负荷指令和当前燃料量预测出主汽压力变化趋势。过对主汽压变化趋势的预测并结合当前压力值,超前改变燃料量,减少主汽压波动。通过改造前后数据对比分析,证明该控制策略具有良好的控制效果。对目前电网对机组一次调频的评价标准进行分析,找出目前一次调频存在的主要问题,硬件方面主要有网频时间滞后、转速采集精度低等问题,软件方面主要是逻辑不合理的问题。针对存在的问题,提出出改进方案和改进对策,进行了硬件的升级和逻辑系统的改进。通过实践前后对比,一次调频合格率大幅调高,满足了相关要求。
[Abstract]:At present, the regulation of power grid is still in the form of large capacity and high parameter thermal power units. The power grid dispatching has higher requirements for AGC and primary frequency modulation of thermal power units. Due to the uncertainty and time-varying characteristics of the controlled object of thermal power unit, especially the large inertia and large delay on the boiler side, the traditional conventional PIID is difficult to meet the requirements. In this paper, the 2x330MW cogeneration unit of Huadian Luohe Power Generation Co., Ltd. is taken as the practical object, aiming at the fact that the AGC and primary frequency modulation related indexes can not meet the requirements of power grid dispatching assessment. By establishing the mathematical model of the unit, the variation trend of the main parameters of the unit is predicted, and the fluctuation of the main steam pressure is reduced while the variable load rate meets the requirements. This paper first analyzes the latest developments in unit modeling, control algorithm optimization and application of new control algorithms. Through comprehensive analysis and comparison, the scheme of predicting the change trend of main steam pressure and other main parameters is proposed by establishing a more accurate mathematical model of the unit and establishing a prediction system on this basis. The structure and control principle of the unit are deeply analyzed. The pulverizing system and water wall heat absorption are combined into one link, and the order is reduced on the premise of ensuring the accuracy of the model. According to the relation of material balance and energy balance, on the basis of reasonable simplification, the mathematical model of the unit is established by the method of mechanism analysis and experimental modeling. According to the operation data of the unit and the dynamic disturbance test, the related dynamic and static parameters are determined, and the simplified model of the unit is built by using the logic module in the object unit DCS system. The accuracy and reproducibility of the model are verified by comparing the model data with the actual operation data of the unit. On the basis of the simplified model of the unit established, the corresponding improvement is made to adjust the relationship between input and output, that is, the input quantity is the unit load and the fuel instruction, the output quantity is the main steam pressure, and the main steam pressure prediction model is established. According to the prediction model, the change trend of main steam pressure is predicted by load instruction and current fuel quantity. The change trend of the main steam pressure is forecasted and combined with the current pressure value to change the fuel quantity ahead of time and to reduce the fluctuation of the main steam pressure. The comparison and analysis of the data before and after the transformation show that the control strategy has a good control effect. This paper analyzes the evaluation standard of primary frequency modulation in power grid, and finds out the main problems existing in primary frequency modulation. The main problems in hardware are the lag of grid frequency time, the low precision of speed acquisition, and so on. Software is mainly a logical problem. Aiming at the existing problems, the improvement scheme and countermeasures are put forward, and the hardware upgrade and logic system improvement are carried out. Through the comparison before and after practice, the qualified rate of primary frequency modulation is greatly increased to meet the relevant requirements.
【学位授予单位】：华北电力大学(北京)
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TM621;TP273

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