660 MW超临界燃煤机组变负荷过程动态特性的仿真研究

燃煤机组变负荷速率的提升是电网AGC（automatic generation control）调节过程灵活性的重要评价指标。建立了660 MW超临界一次再热燃煤机组的动态仿真模型，并嵌入了详细热工控制模型，获得了75%~100%THA范围内不同变负荷速率下的机组主要热力参数的动态变化规律。利用工质最大温度偏差和平均标准煤耗率差值为评价指标，对燃煤机组AGC变负荷过程的安全性和经济性开展了分析。研究结果表明：随着变负荷速率的提高，输出功率、主汽温度和再热蒸汽温度波动越来越剧烈，水冷壁出口、屏式过热器出口、水平低温再热器入口和垂直低温再热器出口的工质最大温度偏差逐渐增大，最大值分别为24.7、29.1、26.1和41.3 ℃。随着升负荷速率的提高，平均标准煤耗率差值逐渐减小，变化范围为2.35~2.53 g/（kW·h），随着降负荷速率的提高，平均标准煤耗率差值的绝对值逐渐减小，变化范围为-2.64~-2.50 g/（kW·h）。

Simulation Study on the Dynamic Characteristics of a 660 MW Supercritical Coal-Fired Power Unit During AGC Processes

Improvement of loading change rate in coal-fired power units is one of the key evaluation index of flexibilities in the power system during automatic generation control (AGC) regulating processes. In this study, the dynamic simulation models of a 660 MW supercritical reheat coal-fired power unit were developed with the detailed control systems embedded. Then, the dynamic characteristics of main thermal parameters at different loading change rate ranging from 75% to 100% THA were obtained. Taking the maximal fluid temperature deviation and average standard coal consumption rate deviation as the evaluation indexes, the security and economy of the coal-fired power units during AGC load change processes were analyzed. The results reveal that with the increase of loading change rate, the output power, main steam temperature and reheat steam temperature fluctuate more drastically. Besides, the maximal fluid temperature deviations increase gradually at water wall outlet, platen superheater outlet, horizontal low-temperature reheater inlet, and vertical low-temperature reheater outlet, which are 24.7, 29.1, 26.1, 41.3℃, respectively. The average standard coal consumption rate deviation decreases when the loading up rate increases, ranging from 2.35 to 2.53 g/(kW·h). On the other hand, the absolute value of average standard coal consumption rate deviation decreases when loading down rate goes up, ranging from -2.64 to -2.50 g/(kW·h).