Research And Application Of Control Strategy For 900MW Supercritical Unit

The control technique of supercritical unit is an important part of supercritical electricity generation. For the strong coupling and weak heat storage of supercritical unit, it is very difficult to acquire satisfactory controlling performance when the general control scheme is adopted. To attain the secure and economical long-term operation, the advanced control scheme should be adopted. But now, little research about it was done in China.Combined with the practice of the WaiGaoQiao 2×900MW supercritical unit control, this paper improves and optimizes the supercritical unit control strategy and function, solves some key control problems, improves the automation level of 900MW supercritical unit significantly, and accumulates valuable experiences for the 1000 megawatt level units in building. The detailed work is as follows:①Analyses and studies the operation characteristics of the 900MW supercritical unit, acquires the characteristic of the controlled object and establish groundwork for designing reasonable control strategy via object characteristic test;②studies and improves feedwater control system, steam temperature control system, burning control system and some other main subsystem of 900MW supercritical unit, and establishes groundwork for the application of coordinated control system;③analyses the characteristics of controlled object of 900MW supercritical unit coordinated control system in detail, brings forward some applied methods to improve the unit load change ability, improves the control strategy of coordinated control system, enhances the unit operation stability and load responding ability effectively and makes sure the 900MW supercritical unit coordinated control system could be put into use chronically and stably;④based on the analyzing and studying of RB,FCB function, carries out the RB,FCB tests in many kinds of conditions and achieves FCB function including 900MW operating condition successfully;⑤based on the characteristics of supercritical once-through unit, analyses and studies the operating mode of 900MW unit participation in AGC operating mode, constitutes feasible control strategy and firstly becomes the 1000 MW level unit participation in AGC dispatching mode;⑥by improving the control strategy continuously solves some critical problems of supercritical once-through unit in primary frequency regulation, and realizes the 900MW unit's participation in primary frequency regulation .