中文摘要：

基于常规超超临界机组热力系统，提出了对再热后的第一级抽汽设置外置式蒸汽冷却器的设计方案，并对系统进行了热力学分析，计算了系统的热经济性指标。在此基础上，对常规超超临界机组热力系统和增设外置式蒸汽冷却器的系统在不同负荷下进行热力学分析，计算得到系统的热经济性指标。研究结果表明：采用外置式蒸汽冷却器的机组，在设计工况下热经济性比常规热力系统机组的热经济性有所提高；而且在低负荷工况下运行时，外置式蒸汽冷却器机组相比于常规系统的节能效果更加明显，因此更适合于变工况条件下运行。

英文摘要：

Based on the conventional ultra-supercritical power generation unit , this paper proposes a design scheme of installing external steam cooler of the first extraction steam after reheat .Thermodynamic and economic analysis between the conventional ultra-supercritical unit and the new master cycle system under different working conditions is conducted afterwards.The results show that installing external steam cooler has a better thermodynamic performance with great energy -saving effects than the conventional one .Besides,under the low-load working condition ,the energy-saving effects are more obvious.Thus,installing external steam cooler for ultra-supercritical unit is very suitable for the low-load working condition .