中文摘要：

基于常规超超临界机组热力系统（常规系统），提出了取消中压缸抽汽，引入回热式小汽轮机抽汽的主循环（MC）系统的设计方案.以某超超临界1000 MW 机组为例，利用EBSILION软件对常规系统和 MC 系统进行机组变工况下热力学计算分析和比较.结果表明：采用MC系统的机组，在设计工况下，机组发电效率比常规系统提高0．15％，发电煤耗降低0．92 g/（kW·h）；在30％负荷下，机组发电效率比常规系统提高0．24％，发电煤耗降低1．61 g/（kW·h）.因此，采用 MC 系统的超超临界机组具有良好的变负荷特性，且更适合于低负荷工况下的高效经济运行.

英文摘要：

On the basis of thermal system in conventional ultra-supercritical power generation units,a design scheme for a master cycle （MC）system was proposed.In this scheme,the steam extraction from the intermediate pressure （IP）cylinder is replaced by extracting steam from an added regenerative small steam turbine.Taking an ultra-supercritical 1 000 MW unit as the example, the EBSILION software was applied to conduct thermodynamic and economic analysis for the conventional system and MC system under different working conditions.The results show that：the power generation efficiency of the unit applying the MC system is 0.15% and 0.24% higher than that using the conventional system,and the coal consumption rate is 0.92 g/（kW·h）and 1.61 g/（kW·h）lower,under design condition and 30% load condition,respectively.Thus,the ultra-supercritical unit employing MC system is more suitable to work under low-load working conditions.