珙县电厂2×600MW超临界机组CCS的分析与改进

Analysis and optimization of coordinated control system for 2 × 600 MW supercritical unit

针对珙县电厂600 MW超临界直流机组蓄热能力小、采用W型火焰炉等特点,在对机组运行特性及原协调控制系统(CCS)进行分析的基础上,对其进行了改进和优化,如:引入直接能力平衡信号,在稳态和变负荷情况下锅炉主控采用不同的前馈;充分利用机组蓄热;引入具有预测功能的预加煤控制技术等。现场实际应用表明,改进后的CCS不仅使机组运行更加稳定,而且有效地提高了机组的负荷响应能力,动态过程中负荷最大偏差为±3.0 MW,主汽压力最大偏差为±0.5 MPa。

The 600 MW supercritical once-through unit of Gongxian power plant has limited thermal storage capacity and applies W-shape flame furnace. Its coordinated control system is analyzed and optimized according to its features：direct energy balance signal is introduced and different feedforward signals are applied for the boiler master control under steady state and varying load conditions;the boiler thermal capacity is fully utilized;the pre-feed coal control with forecast function is introduced. Practical application shows that,the optimized coordinated control system is more stable and the response of unit to load variation is effectively improved. The maximum load deviation is ＋3.0 MW and the maximum main steam pressure deviation is ＋0.5 MPa.