Research Of Automatic Control System Of Luohe Power Plant

At present, the power network regulation is still mainly based on large capacity and high parameter thermal power unit, and the power network dispatching has higher requirements for the AGC and primary frequency regulation of thermal power unit.Because of the uncertain and time-varying characteristics of the controlled object of the thermal power plant,in particular, the boiler side has large inertia large delay,the conventional PID is difficult to meet the requirements.In this article,taking the first project of 2x330MW of Huadian Luohe Power Generation Co. Ltd. as the research object, based on the practical situation that AGC and primary frequency regulation can not meet the requirements of power grid,through the establishment of the model of the unit,the change tendency of the main parameters of the unit is predicted,in order to meet the requirements of the load change rate at the same time, reducing the main steam pressure fluctuations.Firstly, this paper analyzes the latest information in the unit modeling,control algorithm optimization,new control algorithm application.By comprehensive analysis and comparison,the scheme is adopted that on the basis of the establishment of the accurate mathematical model of the unit,a forecasting system is established to predict the main parameters such as the main steam pressure etc..The structure and control principle of the unit are analyzed in depth. The coal milling system and the water wall heat absorption are combined as a single link,reducing the oreder,in the premise of ensuring the accuracy of the model.Based on the relationship between material balance and energy balance, 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 set up by using the logic module in the DCS system of the object unit.Through the data model and the unit actual operation data comparison analysis shows that the model has good accuracy and reproducibility.On the basis of the establishment of simplified model,corresponding improvement is made to adjust the relationship between input and output.The input is unit load and fuel instruction, and the output is the main steam pressure, so main steam pressure prediction model is established.According to the forecast model, the change trend of main steam pressure is predicted by the load command and the current fuel quantity.By the prediction on the main steam pressure change trend and combining the current advance pressure value, fuel quantity is changed in advance to reduce the main steam pressure fluctuation.By comparing the data before and after the reform, it is proved that the control strategy has good control effect.The current evaluation criteria of primary frequency regulation of power grid is analyzed and the main problems existing in primary frequency regulation is found out.The main problems of hardware is the network frequency time lag and low speed of the acquisition of low precision and the software aspect is mainly the logic unreasonable question.In view of the existing problems, the improvement scheme and improvement measures are put forward to upgrade the hardware and improve the logic.By comparison before and after the practice, the pass rate of primary frequency regulation significantly increases so as to meet the relevant requirements.